I think that a truck Norris for the 8.1 would need 12 more degrees intake and the same spread that the 5.3 has between intake and exhaust with an appropriate balance of overlap and LSA. The heads don’t seem to be in need of porting, just more cam and springs to spread the curve out by flattening the torque curve and allow the torque and back pressure to rise more gradually and let it rev to 6200-6400 with a rising boost curve. A T6 with a 1.32A/R should be in the 8.1 s wheelhouse a 5 inch pipe out, and on the 5.3 maybe would prefer a T4 inlet on a 1.25 A/R and the Truck Norris for it and a 4 inch exhaust after pipe . To equalize the velocity and the boost curve rise and back pressure curve desired for each. The reversed manifolds and 2.5 crossover for the 5.3 with the two regulators for each , but the 8.1 using the long tubes with the 3 inch crossover to the T6 volute. This would equalize the velocity and each to my guessing would be on equal footing to make their best power apples to apples. The 8.1 and 5.3 at the same boost would allow each to produce their best performance. The 8.1 would make more power if the NA power is optimized to the same degree as the 5.3.
@@fenatic7484 Vizard has a 496 BBC making 717 bhp and 711 lb-ft. It has a 105* LSA, 236/240, 0.690" lift and it "idles like a Cadillac". The 8100 will be down on power and torque, but it'll be much better than the ZZ502 cam.
my 8.1 allison truck runs so great towing heavy stuff just stock, they really did such a good job designing it just the way it was. A lot of people in the past had tried to use them for something they're not. So cool to have the LS head technology on a big block
My application is very weight sensitive, so I would go with the aluminum 5.3 over the cast iron 8.1. That's 415 pounds for the aluminum 5.3 compared to 557 for the 8.1 truck replacement engine, or 602 for the 8.1 complete engine. Source : 2022 Chevrolet Performance catalog pg. 14.
Assuming a 2000 RPM drop on the shifts, the 5.3 makes more average power. Also, torque breaks transmissions. That said, drop a cam in the BB, and it's no contest
Sheeeeit that 8L has the wall in its plenum still there. Remove that wall from the 8L plenum and smooth the mold lines and casting trash and the 8L can actually breathe. It’s easily an extra 20whp. With a cam an FI the real limitation would be
Keep it going Richard. So many of your videos are nostalgic because I remember the Hot Rod mags they were in. You brought all that knowledge over with this series and you made me and probably many others buy parts and hit junk yards.
In a lightweight car the 5.3 would be close to edging out the 8.1 ina dragrace but I think the 8.1 would still take the smaller motor. On the street, the 8.1 would be alot more fun to drive
Makes sense. Look at the power numbers. The 8.1 is only making 78% the horsepower of the 5.3 literally for liter. They nerfed it for emissions. Then they got rid of it entirely after this generation!
The question of if putting them in the same car reminds me of a Hot Rod Mag article from 20-25 years ago where they build “nearly identical” BBC and SBC (both 408”, same compression, nearly exact same cam specs, same carb, similar heads/intake/headers. With them as slide to the same as possible, the BBC made a bit more power and even more torque. When tested in the same car, the BBC that made about 25 more hp (they were just shy of 500hp if I recall correctly) ended up running 0.2-0.3 sec quicker in the quarter; much of that time being at the launch. Despite weighing more, the extra torque got the car out of the hole considerably better. Keep in mind, the car was a 1970 Nova (if I correctly recall) that had decent tires, suspension bolt ons (Cal tracs I believe), and a converter (forget if TH350 or 400). Given a similar test between the 8.1 and the TN5.3, it’d really depend on the car setup as to which would be quicker; though I’m apt to believe the 8.1 would have the advantage in most cases. The 2 cases where I see the 5.3 having a chance is: 1- The car is so traction limited that the 8.1 can’t utilize its huge torque advantage 2- The car is highly optimized for both combos, and converter/gearing allows the TN5.3 to overcome the torque disadvantage by staying closer to its peak HP number during shifts. The #1 example is where I could see the TN5.3 actually winning. The #2 example I see more as the TN5.3 evening the deficit, but not likely overcoming it. Ultimately, the more traction the car has, the more the 8.1 can utilize its huge torque advantage. I could see them going through the traps at nearly the same speed, but the 8.1 would short track (60ft, 330) quicker when traction isn’t an issue, giving the 8.1 a lower overall ET. Edit: That said, the 8.1 would make for a good sleeper with how mild it’d sound. The TN5.3 would sound cooler since it’d have a little bit of lope.
Truck gets the 8.1 and car gets the 5.3… but only because of fitment and weight ☝️. That 8.1 is a beast. Looking forward to seeing some carb testing with it.
Need to see what the 8.1 does with a Raylar cam, I know the heads run out of breathing room at about 4500 but I'm interested in that torque. Those are diesel numbers!
My brothers stock 8..1 avalanche is stout . we use it too haul two vehicles at a time. . one on the random trailer and have a receiver welded on the rear . and we connect a car dolly for the second car to rind on
The extra 150+ ft lbs is great but I honestly think it loses to the 5.3 simply from the extra 150-200 lbs of additional weight…. The 8.1 would be an amazing tow package. That’s diesel torque on very low boost. Impressive 🤘🤘🤘 Richard, you’re the man. Keep the content coming brother
Try it with a proper cam . They left the stock cam and valve train in the 8.1 . That cam alone upped the horse power to 425 on the 5.3 which is only 310 stock .
@@philthelawnman right . I work in the maritime industry. They use a lot of those 8.1 in marine applications. Mostly air (fan) boats . Let me tell you . They sound nasty when equipped properly 😎
Whichever motor has a driveline that is closer to optimized will win, if they're both optimized then they'll be about even but the greater average power of the 8.1 probably wins.
@@HioSSilver1999 if that was true diesel dragsters would be the top dogs. HP is how much work you can do tq tells you how hard you can twist without slowing the engine down. Now having power over a broader curve helps especially with older tech but in a world that 10speeds is normal you can get away with a more peaky curve
@@mddunlap03 I'm not denying there is some extreme ends of this..... But at the same time a small peaky engine in these trucks isn't gonna work well in the same configuration.....of which that is the question here. These a10s help every engine they're behind. If you multiply more tq by more gear you get more tq than you do multiplying less tq by more gear. There's also tq management in the programming of these a10s. Of which more tq still gers managed more than less tq. But you also run into heavier components with more tq which will reduce acceleration. I mean a 4l80 is gonna kill a 5.3 acceleration wise. But a 8.1 will laugh at that long first gear. Just so many different combos.....but in the end if both are right tq will win.
When horsepower is similar, more torque wins the race, provided traction isn't an issue... That amount more torque generates far better acceleration at higher speeds.
It would be really interesting to see both of these combos in the same car with the same transmission do a quarter mile drag race. Great video Richard of course both engines would need different gearing. I would guess a 3.55 gear for the 8.1 and maybe a 4.10 gear for the 5.3.
Perfect timing that I found this particular test, my business has me on the road alot and with a loaded trailer and being from Wyoming I'm pulling over a mountain pass or 2 daily. 2017 GMC 1500 crew 4×4 L83 a tune & exhaust/headers 2001Chev2500HDext4×4 Alison 8.1 285,000. A comparison I've done is max out the weight on the 5.3 run 500 miles, switch to the 8.1 pulling the same load on the say trip . Fuel mileage/comfort 5.3 hands down. 8.1 low end torque & of course it hands down can handlmore weight. A 6% grade appointmently 1 mile to the top running both at 3000 rpm they top the grade with in a mph or 2 of each other, the extra gears in the trans of 5.3 are probably the main equalizer, even with the miles on the 8.1 the torque from stop to say 3500 rpm is still impressive.5.3 will get a truck Norris/ turbo and a refresh or create with power adder's For the 8.1 and the torque #'s could change my mind on diesel
To answer the questions asked in the video, the larger engine would be inclined to accelerate faster from a stop, due to the massive disparity in low RPM torque. With the right gearing, sure, the 5.3 could then give that big block a good run. Once the 5.3 gets spun up into its power band, it should really start pulling just as the big block has hit the limit of it's useful RPM range. It is always always always all about gearing
With an automatic with a torque converter with good shift extension, there might not be that much difference between the two. The big block would get out of the hole better if not traction limited, but the converter could help the 5.3 stay in the power after shifts.
Love the 8.1 content. Think an aftermarket cam in the 8.1 would have been more fair comparison with the 5.3 TN cam. Please do that next! Then normalize for displacement hp/ci or liter. Your 1/4 mi question, seems like average horsepower divided by weight would be the best indicator of e.t.
I think it would be quite a fun thing to test with cost not being a concern. The weight difference is obviously massive between a tall deck iron block and head big block to a 5.3L aluminum block and head. If you used something like a 2002 Silverado 1500 2wd as your test vehicle I would probably pick the 5.3L to win, but I feel done right it would be very close. I would do a 4L85E behind the 8.1L with a 3.73 gear and a 30" tall tire (9 or 10.5 wide) and run a 2800 stall if budget allowed and if not run a stock torque converter for a 6.0L. With the powerband of the 8.1L the converter would be setup much tighter hydraulically which would be a slight benefit in that respect. Unfortunately the converter would be heavier for a bit of loss there, but I would run it locked from around 53mph or so to well past the 1320 mark to keep every bit of power possible going to the tires (with the exception of unlocking during the shift). With the L33 I would run a 4L60E with around a 3600 stall if budget allowed or an I6 Trailblazer converter if money was a concern. From around 83mph and through the traps I would run the converter locked. For the L33 I would run a 26" tall tire with a 4.10 gear. Hopefully the weight difference between the engine and transmission as well as the parasitic drag difference with the 60E over the 80E would be enough to put the smaller engine out front.
1969 chevelle. 454. Th350. 3.08 gear. 2100 stall. 287hp at the wheels 12.92. Same car 2 weeks before had a 355 with 345hp to the wheels. Ran 13.8s. 454 pulled the whole time.
I've been patiently waiting for someone to take a 383 ls and a 408 ls and compare on a dyno. Using only short blocks. Swapping cam heads and intake over from one to the other. To see the actual differences in the power they both make with the same combination. Always love you videos keep them going 💪
Seems to me with the torque multiplication of lower gearing it would be possible for the 5.3 to match the 1/4 mile time of the 6.1. Also the lighter weight and resulting weight distribution could work in favor of the 5.3.
These 496 line the wreckers. Pretty impressive in the Vortec Max truck. No replacement fir the rotating mass. Wish it would of had the LS main caps, I would build one for bracket. Pretty neat it uses LS style reluctor wheel and coils, good to know. Keep it coming Rich!
Which car would be quicker? Most likely the 8.1. Which car would be faster? Most likely the 5.3. Quicker implies time. Faster implies speed. The low end torque of the 8.1 (as long as you can maintain traction) is going to get the car moving much quicker. The RPM speed the 5.3 is producing the power is going to allow the car run faster.
Awesome video as always. Thanks Richard . In a truck that works for a living or for fun I'd want the 8.1. In a muscle car I'd want the 5.3. I just like revving out a sports car more than I do in the truck. I don't do the same spirited type of driving in a heavy truck basically.
Torque at the crank maybe vastly different but torque to the ground will be similar once you account for gearing, the 5.3 will need at least a full ratio lower say 3.50 for the 8.1l and 4.50 for the 5.3l that will be 1939 lbs-ft to the tire for 8.1l and 1868 kbs-ft for the 5.3l. On the track hard to tell if one has a huge advantage but the street the 8.1l would be my choice.
totally crazy comparo man! were actually debating here at the shop on which engine to put in our ramp truck since we have both. obviously the 8.1 is the right choice, just crazy youre runnin exactly what we talk about! ALL the time!!!! love the show, love the content! keep it up man!
My 2500 avalanche weighing 7500 lbs with a bone stock 8.1 and 4L80 runs a 15.4 @ 80mph. However I have roll raced a bone stock 03 z71 and pulled on the top end. Hell of an engine, especially in a 3000lb car
Same here. Running a mild tune on stock exhaust and intake and have been able to pull on every 1500 I’ve raced from Chevy, dodge and ford. Haven’t lost yet. 🔥
Flash back to 2005-2006 where supercharged E55 AMG's were pitted against V10 M5's. Both made around the same peak HP on the dyno, but the M5 would rev out to 8500. Where the E55 were done at 6500. The 1/4 mile results were decisive the E55 would win every time probably because of its massive torque advantage. 8.1 wins if it doesn't snap something with that torque.
Very interesting results on backpressure . My car is setup to run 2 different turbos , one is the Garrett g42-1450 w a 75mm turbine . I worried it would be too small and build a lot of backpressure, even though Garrett's boost advisor recommended it for my setup . I've seen a lot of 5.3s turning 7500 rpms with high efficiency 75mm turbine exit type turbos and I dont hear many complains . On my 6.2 , I shift around 6500 . Just using simple ( and probably inaccurate ) math, a 6.2 will move similar air at 6500 that a 5.3 does at 7500 rpms. Based on your results , although I know the back pressure is probably starting to get up there, I'm probably in the same boat as a lot of 5.3 guys turning more rpm . I picked that turbo for quick response and only run it up to around 15-16 lbs. My " big " turbo is a FI billet s485 . Its 88mm turbine exit will surely have less backpressure, but is less responsive on the street . Jury is still out on which one will have a permanent home on the ol 6.2 . Both make more than I can use right now and neither come in like I want from a dig . Working on that problem now. Once I get the intake, camshaft, timing worked out , I will dig into which turbo works best for me. I'm getting too old for this , lol.
Having worked at a Track for a while and watching so many private test sessions, I'll say in the same car the 5.3 is gonna get off the line easier. Then HP takes over, and as they are almost the same power, and seeing the 5.3 doesn't have to shift as soon, it's gonna back half that big block. Now 1/8 mile the big block will have it, an hey I guess some guys expect good things to go by quick. Explains a lot in that statement.
Torque is what gets vehicles off the line quicker not horsepower. So the big block with hundreds more ft.lbs of Torque will certainly jump out ahead provided traction isn't an issue.
@@donniecahill5243 yessir I agree. However, that big block hanging out front weighs a lot more than an aluminum 5.3, erego if it's in the same chassis all that torque is good for nothing but spinning. I've watched plenty of guys some on a famous tv show go smaller motor and run way faster just because of the ability to get off the line easier
@@chadbeaver9199 we're comparing apples to apples, not apples to oranges. The weight difference is about 130lbs not like we're comparing a 4 banner. Weight difference won't be very notable
@@donniecahill5243 685 dry with no intake or flexplate on the 454, 520 filled with intake and flexplate for the 5.3. That's 200+ lbs difference. Now figure in a larger radiator for the BBC over the SBC and there's another 20 lbs. So again, if this is the same chassis, the BBC has a lot of bias towards the front over the SBC.
Traction might be harder to come by with all that low end torque in the big block. Plus with the same gear you may run out of rpm in 8.1 setup. The 8.1 will need a rear gear change (higher gear lower numerically).
Both motors will be just as fast in the 1/4 mile, only the 8.1 will start quicker but then stall while the 5.3 will start slower but catch up, the power curves say so. (Sorry I use the translator 😅)
Power numbers don't matter if you can't get the power to the ground. With that much torque down low it will be hard to keep the tire planted with the 8.1. If traction wasn't an issue, I believe the 8.1 would win 9 times out of 10. With proper gearing in both configurations, it would be a closer race for sure.
If we ignore weight and other things I say it's going to be exacly the same depending on the torque curve. Because gearing is literally making these 2 engines the same. 631ft-lb at 4400 makes 530hp and 434ft-lb at 6400rpm makes 530hp. If we apply gearing then it's going to multiply the torque and divide rpm at the same wheel speed. Let's say the wheels spin at 800rpm, the 4400rpm gets a 5.5 gear ratio so it will have 3480ft-lb at the wheels and the 6400rpm gets a 8 gear ratio gets 3480ft-lb at the wheels and they will have the same exact hp.
Great comparison, lots of good info. If I was pulling a loaded quad horse trailer the 8.1 would get the nod. For a weekend warrior down the 1320 the 5.3 would be my choice especially with a little gear.
8.1 if it hooked up would et better however yes the 5.3 can match it with gears but you will probably have to rpm the 5.3 500 past peak that's drag racing 😊
The weight to power ratio would make the greatest difference in either quarter-mile scenario. Guessing that the 8.1 is probably 150 pounds heavier than the aluminum 5.3, I'd give it the advantage in the quarter, but even more in the 1/8th mile regardless of gears.
Probably closer to 400lb. I weighed my ls6. Aluminum ls stuff weighs between 304lb to about 380lb depending on what you want to include....vid is on my channel. A iron bbc will go 700+ lb in similar configurations.
By changing cams you will increase power and torque starting on low end but the peak power and torque will be at the same rpm . The 8.1 will need the power and torque curve flatter to achieve better performance on top end . As soon as the motor hit peak it starts dropping . But you are talking about a motor built specifically for a truck . The 5.3 was built for torque and power throughout a long flat curve .
The big block will pick up speed faster. As long as it dosent tire shake. But general rule of thumb. Big block will smack just about any small block at highway speed. Only thing you can do is raise the revv limit to the moon. Even stock as long as you add a light cam and build the heads for higher rpm use then you can battle it out. The added rpm will give you some added speed overall to a point.
great video! as far as your question, there isn't a right answer because there are too many other variables in the drivetrain, suspension, and trans / torque converter choice IMO
Same hp at same weight means same fasts. Only variable is the launch which would realistically be favoured by the big block in the real world. Here's some food for thought though, in the top end, where it will live while racing, the big block has a roughly 1400rpm window at 400hp and above. The 5.3 also has a 1400rpm window at 400hp and above and its looks slightly flatter. The small motor may actually make MORE average power in that window. All things being equal (including race weight), I'm saying the small motor wins IF the hypothetical driveline lets it get to and maintain the required rpm. If it's a "real world" driveline, the big block will jump away early then they will accelerate at the same rate and the gap will stay the same the whole way down the track (same weight, same hp).
Depends on vehicle your building the 8.1 is the choice for a heavy car or truck in a RV would be a no brainer but something light like a nova Camaro or smaller the 5.3 would be great it's comes down to personal preference it would be really interesting to see we're the 6.0 would fit in
Well I think that Steve B said it best, you are giving up so much at the gear change so the 8.1 will 9/10 times beat the smaller displacement 5.3. Again no replacement for displacement. That’s for the video!
Congrats on 200k... I would guess that the 8.1 would get out front maybe to the 1/8th but then the 5.3 will gain ground and go around it... Bench racing at it's finest 🤣
Very interesting (to me) as I currently have both of those exact motors. I'm likely going to sell the Sierra with the L33, but strongly considering dropping a turbo in my 8.1L Suburban 2500.
Running the numbers in a 3500lb car I get 130mph. 4.10 gear for 5.3, 3.00 (custom?) gear for 8.1. At 3000 rpms the 8.1 gets 17% more tq to the tire. Equal at 4k. 5k rpms the 5.3 is putting out 30% more. Gearing has a phenomenal impact. Personally on the street, give me the 8.1 with a 2200 stall.
As long as there is enough traction the 8.1 even with a taller (numerically lower) gear would win, but a shorter gear for the 5.3 stands a good chance on a lower traction surface. The 8.1 would need a serious tire. Lol.
Gearing and trans the same my moneys on the 8.1. You will shift earlier but you will almost always be in a better power band due to the TQ. If you can optimize gearing and trans in the 5.3 only I would go with the 5.3 as you can optimize the gearing in order to get into the high HP power band faster and stay there when shifting at a higher rpm. just my opinion
I would imagine that everything being the same with the car (weight, perfect traction, etc). The big block would definitely prevail in the 1/8th mile, but hard to say what the outcome would be in the 1/4 mile. Does the small block have enough time and rpm to creep forward after that? 🤔
The difference would be in the driveline. Gearing, stall speed and stall ratio would decide things. Given the torque curve of the 8.1, if it can get out and stay out it'll win. The only thing is the weight.
all about gearing and shift points keep the small block in its power band by the end of the 1/4 it would be right there as well as less weight with the SBC
The 8.1 is just a monster and will likely outlast a 5.3 under the same boost conditions. Plus, turbo lag isn’t even an issue when you have a 496 stroker under your right foot!
7:55 in and the STOCK 8.1 is matching the BOOSTED 5.3 up to 3500 rpm and hangs until almost 4000rpm. Boosted, the 8.1 at 3000 rpm is making 470hp, while the 5.3 is making 290. LOL Driving around normally and pulling I know which vehicle I'd rather be in! Gotta love displacement! That 8.1 must feel like diesel torque with healthy gas hp. Nice.
The big blocks got to weigh an extra 200lbs compared to the aluminum LS. I would be interested to see a project car shootout. Pitch that to freiburger!
Excellent video Richard! I would think, assuming traction wasn't a major issue, the 8.1 would out run the 5.3 regardless of gearing. Although the 5.3 Geared for the extra RPM would make it an exciting race. There's just no replacement for displacement. However, what have you found a correlation between boost pressure and exhaust back pressure in any respect? Such as power output, drive ability or turbo performance for example...
let's look at this from a different direction: what about a tow truck application? a truck norris cammed 8.1 with a zf5spd running 7lbs of boost would pull as well as duramax. using a 3.73 gear. a 5.3 combo would need 5.13-5.5 6 gear and more boost to have the same pulling power. I tow a 40' 15000lb travel trailer so i think like that. imagine a Kodiak with an 8.1 setup with an allison 6spd auto. slight mpg problem vs. diesel, but if you only use it 4 or 5 times a year....
One more piece of data that would be interesting to see is how much fuel each engine was using along the curves and at peak power and torque. To see which engine is making the numbers more efficiently. Bigger displacement at a lower rpm vs smaller displacement at high rpm.
Have a torque converter that locks up at 3500 and my money is on the 5.3. Joking aside it would be interesting to team up with the guys from power nation and use their test chassis.
So if you put a 42% reduction gear on the 5.3, that will shift the power peak to the same rpm as the 8.1 (6,400/4,500 = 1.42). Put the 5.3 and its reduction gear in a "black box" and put that on the dyno. The "black box" makes (630 x 1.42) = 894 ft lb at 3345 rp m (4750/1.42). The 8.1 makes 850 ft lb @ 3650 rpm so the "black box has higher torque and a wider power band - it will blow the 8.1 away. Richard - perhaps you should replot the power curve for the turbo 5.3. (Just shrink the rpm axis by 1/1.42 = 0.7). Then overlay on the 8.1 curve.
I would say no, the 5.3L would hit rev limiter before it could match the 8.1L. The boosted 5.3L suffers from a 36% torque deficit versus the boosted 8.1L, but it's redline is only 16% higher. Based on that it would not be able to overcome the deficit.
That redline of the 8.1 can be massaged a little. I don't remember the name of the shop doing it. But they've apparently got a build kit to make that 8.1L reliably turn 7500
Why over rev it when it's falling hard off the powerband anyways? That's backwards thinking. Big blocks weren't built to make topend power, yes u can sink lot of money in one to do just that, but for all practical purposes for the average Joe a ls or even a small block is way to go. Also they r running a Holley management system, they can set rev limiter. But again, no point in it when it's falling on its face anyway..
Makes me think I want to turbo my 8.1 in my Holiday Rambler RV. Looks like all I would have to do is run 80 lb injectors and an S475 turbo and WALA....800 lb/ft of torque...I bet I would get better gas mileage as well. I don't think my allison 1000 would like it though - its only rated for 625 lb/ft
Wow Richard! So much enthusiasm here for the 8.1, let’s see what you can do with it. Knock out the manifold wall, gap those rings and make this motor sing. Let’s see what it’s got! This was the video I’ve been waiting for.
Congratulations on 200K subscribers ! And one of your best videos ever , even if it is giving me a headache......let's seee......the chicken ? the egg ?
The one that’s faster depends on the transmission and gearing, if you optimize it for both, the 5.3 will be 300 pounds lighter, but you would need a power glide and 4.56 gears, the 8.1 could do it with a 6l90e and 3.08 gears, I’m voting for the 8.1L, even though I own both of those motors, I like the torque of the 8.1L
I enjoy learning what you do. Something I haven't seen, (maybe I overlooked it) using gen 6 heads on mark 5 and then on mark iv using stock everything else. That includes cams. I know you have to change to a carb intake, just use the same intake on both engines I'm looking for stock hp/tq as I don't have the money (disability) to modify these engines. I have both a mark iv and gen 5 engines that are in excellent shape. (Wreck takeouts)
@@richardholdener1727 I understand that you have to use the correct gaskets. I don't have the funds to test these head swaps. What I am asking is if you have done those tests? I have a one time opportunity to put the gen 6 heads on either a mark iv or a gen 5. I am disabled (heart failure) and don't know jow long I have left in this world. I would like to be able to enjoy my truck before I check out. If you know where I can find this test, please let me know.
LS with complimentary gearing ove the big block. Weight is a thing.... cutting weight gains more in a 1/4mile than HP.... its just harder to do after a certain point.
Of course the 8.1 if it gets traction would eat the 5.3 with the same gearing, and if you change gearing for the 5.3 it should run close to or equivalent to the 8.1! all you have to do is multiply the torque at every RPM level "times" the overall gear ratio till you find a ratio increase that makes average torque equivalent!!! and changing the ratio by that amount should deliver equivalent acceleration!
I generally agree but I would like to also have Dino pulls have a time to achieve max rpm. The faster an engine can wrap up to high rpm. Exotics for example with flat plane cranks can rev to rpm so much faster than American V8s. Race car vs drag car rpm range and use. There is not much info in this area on the web because so many variables are involved.
Make a test on a stock bore stock 706 head 4.8/5.3 with a 3.9 or 4.0 inch stroke which would make it a ~5.7. see how the torque curve changes with all the stock components on the engine, after that add a stage 1 torque cam on it
I think the 8.1 needs a "truck norris" camshaft. Because that would be an excellent truck engine.
I think that a truck Norris for the 8.1 would need 12 more degrees intake and the same spread that the 5.3 has between intake and exhaust with an appropriate balance of overlap and LSA. The heads don’t seem to be in need of porting, just more cam and springs to spread the curve out by flattening the torque curve and allow the torque and back pressure to rise more gradually and let it rev to 6200-6400 with a rising boost curve. A T6 with a 1.32A/R should be in the 8.1 s wheelhouse a 5 inch pipe out, and on the 5.3 maybe would prefer a T4 inlet on a 1.25 A/R and the Truck Norris for it and a 4 inch exhaust after pipe . To equalize the velocity and the boost curve rise and back pressure curve desired for each. The reversed manifolds and 2.5 crossover for the 5.3 with the two regulators for each , but the 8.1 using the long tubes with the 3 inch crossover to the T6 volute. This would equalize the velocity and each to my guessing would be on equal footing to make their best power apples to apples. The 8.1 and 5.3 at the same boost would allow each to produce their best performance. The 8.1 would make more power if the NA power is optimized to the same degree as the 5.3.
Not enough intake duration for the exhaust duration on the big block. Port and valve sizes are a very different balance between 5.3 and 8.1.
@@fenatic7484 Vizard has a 496 BBC making 717 bhp and 711 lb-ft. It has a 105* LSA, 236/240, 0.690" lift and it "idles like a Cadillac". The 8100 will be down on power and torque, but it'll be much better than the ZZ502 cam.
I love the 8.1 content!! Keep it coming, and good work!!
New cam and valve springs for the 8.1 = awesome
my 8.1 allison truck runs so great towing heavy stuff just stock, they really did such a good job designing it just the way it was. A lot of people in the past had tried to use them for something they're not. So cool to have the LS head technology on a big block
My application is very weight sensitive, so I would go with the aluminum 5.3 over the cast iron 8.1. That's 415 pounds for the aluminum 5.3 compared to 557 for the 8.1 truck replacement engine, or 602 for the 8.1 complete engine. Source : 2022 Chevrolet Performance catalog pg. 14.
Nice, save those 200lbs😂
If you are weight orentated, you wouldnt want the torque that the 8.1 makes either, spinnin' aint winnin'
Assuming a 2000 RPM drop on the shifts, the 5.3 makes more average power. Also, torque breaks transmissions. That said, drop a cam in the BB, and it's no contest
Sheeeeit that 8L has the wall in its plenum still there. Remove that wall from the 8L plenum and smooth the mold lines and casting trash and the 8L can actually breathe. It’s easily an extra 20whp. With a cam an FI the real limitation would be
The 5.3 comes with a weak 4l60e trans but the 8.1 comes with a much more beefy trans for example 4l80 or Allison
You crazy 🤦🏾♂️
Keep it going Richard. So many of your videos are nostalgic because I remember the Hot Rod mags they were in. You brought all that knowledge over with this series and you made me and probably many others buy parts and hit junk yards.
Been wanting to put an 8.1 in my 79 squarebody. Contemplated a 12v, but after seeing this, I may just turbo an 8.1.
In a lightweight car the 5.3 would be close to edging out the 8.1 ina dragrace but I think the 8.1 would still take the smaller motor. On the street, the 8.1 would be alot more fun to drive
My 8.1 rcsb 1/2 ton is probably the funnest thing I have personally dailyed
That's all I care about, the street. I spend most of my time on it and not a strip.
Unless it's the strip in Vegas.
If you have the 8.1 a little cam it would be night and day especially with the 8.1 showing it’s probably well into boost before 2000 rpm
that 5.3 will blow up way before the big block.
@@mattpacktree92 well that could be wrong. The 8.1 suffers from weak pistons. So 🤷♂️
So the 8.1 needs a cam
True that!
Makes sense. Look at the power numbers. The 8.1 is only making 78% the horsepower of the 5.3 literally for liter. They nerfed it for emissions. Then they got rid of it entirely after this generation!
Richard is a madman… the hero we needed
The question of if putting them in the same car reminds me of a Hot Rod Mag article from 20-25 years ago where they build “nearly identical” BBC and SBC (both 408”, same compression, nearly exact same cam specs, same carb, similar heads/intake/headers. With them as slide to the same as possible, the BBC made a bit more power and even more torque. When tested in the same car, the BBC that made about 25 more hp (they were just shy of 500hp if I recall correctly) ended up running 0.2-0.3 sec quicker in the quarter; much of that time being at the launch. Despite weighing more, the extra torque got the car out of the hole considerably better.
Keep in mind, the car was a 1970 Nova (if I correctly recall) that had decent tires, suspension bolt ons (Cal tracs I believe), and a converter (forget if TH350 or 400).
Given a similar test between the 8.1 and the TN5.3, it’d really depend on the car setup as to which would be quicker; though I’m apt to believe the 8.1 would have the advantage in most cases.
The 2 cases where I see the 5.3 having a chance is:
1- The car is so traction limited that the 8.1 can’t utilize its huge torque advantage
2- The car is highly optimized for both combos, and converter/gearing allows the TN5.3 to overcome the torque disadvantage by staying closer to its peak HP number during shifts.
The #1 example is where I could see the TN5.3 actually winning. The #2 example I see more as the TN5.3 evening the deficit, but not likely overcoming it.
Ultimately, the more traction the car has, the more the 8.1 can utilize its huge torque advantage. I could see them going through the traps at nearly the same speed, but the 8.1 would short track (60ft, 330) quicker when traction isn’t an issue, giving the 8.1 a lower overall ET.
Edit: That said, the 8.1 would make for a good sleeper with how mild it’d sound. The TN5.3 would sound cooler since it’d have a little bit of lope.
Truck gets the 8.1 and car gets the 5.3… but only because of fitment and weight ☝️. That 8.1 is a beast. Looking forward to seeing some carb testing with it.
Need to see what the 8.1 does with a Raylar cam, I know the heads run out of breathing room at about 4500 but I'm interested in that torque. Those are diesel numbers!
The 8.1l was put into the suburban to be a competitive option against the diesel offering by gm at the time
Bo 202 cam is better
I'm getting insane amounts of knowledge from this channel. Awesome video!
Yea this dude is awesome…. The difference between talking and doing.
Absolute Truth. I miss being 30! At 61 I am really hoping to get to show some folks young and old that you can teach an old dog new tricks! The FE!
My brothers stock 8..1 avalanche is stout . we use it too haul two vehicles at a time. . one on the random trailer and have a receiver welded on the rear . and we connect a car dolly for the second car to rind on
The extra 150+ ft lbs is great but I honestly think it loses to the 5.3 simply from the extra 150-200 lbs of additional weight…. The 8.1 would be an amazing tow package. That’s diesel torque on very low boost. Impressive 🤘🤘🤘 Richard, you’re the man. Keep the content coming brother
Try it with a proper cam . They left the stock cam and valve train in the 8.1 . That cam alone upped the horse power to 425 on the 5.3 which is only 310 stock .
Even with the stock cam the torx wins as it get heavy things moving.
@@philthelawnman right . I work in the maritime industry. They use a lot of those 8.1 in marine applications. Mostly air (fan) boats . Let me tell you . They sound nasty when equipped properly 😎
Whichever motor has a driveline that is closer to optimized will win, if they're both optimized then they'll be about even but the greater average power of the 8.1 probably wins.
As with most scenarios. Chassis and suspension win more races than horsepower.
Tq wins
@@HioSSilver1999 if that was true diesel dragsters would be the top dogs. HP is how much work you can do tq tells you how hard you can twist without slowing the engine down. Now having power over a broader curve helps especially with older tech but in a world that 10speeds is normal you can get away with a more peaky curve
@@mddunlap03 I'm not denying there is some extreme ends of this..... But at the same time a small peaky engine in these trucks isn't gonna work well in the same configuration.....of which that is the question here.
These a10s help every engine they're behind. If you multiply more tq by more gear you get more tq than you do multiplying less tq by more gear.
There's also tq management in the programming of these a10s. Of which more tq still gers managed more than less tq.
But you also run into heavier components with more tq which will reduce acceleration. I mean a 4l80 is gonna kill a 5.3 acceleration wise. But a 8.1 will laugh at that long first gear. Just so many different combos.....but in the end if both are right tq will win.
@@DWBmotorsports🤣🤣🤣🤣🤣
Really looking forward to seeing what this 8.1 can do with a bit more upgrades!!
When horsepower is similar, more torque wins the race, provided traction isn't an issue... That amount more torque generates far better acceleration at higher speeds.
It would be really interesting to see both of these combos in the same car with the same transmission do a quarter mile drag race. Great video Richard of course both engines would need different gearing. I would guess a 3.55 gear for the 8.1 and maybe a 4.10 gear for the 5.3.
check out LTC he has an 8.1 turbo truck and it runs 10's in the 1/4
I would like to see the 8.1 with a cam swap. Also would prefer it over the 5.3
Perfect timing that I found this particular test, my business has me on the road alot and with a loaded trailer and being from Wyoming I'm pulling over a mountain pass or 2 daily. 2017 GMC 1500 crew 4×4 L83
a tune & exhaust/headers
2001Chev2500HDext4×4 Alison 8.1
285,000. A comparison I've done is max out the weight on the 5.3 run 500 miles, switch to the 8.1 pulling the same load on the say trip .
Fuel mileage/comfort 5.3 hands down. 8.1 low end torque & of course it hands down can handlmore weight. A 6% grade appointmently
1 mile to the top running both at
3000 rpm they top the grade with in a mph or 2 of each other, the extra gears in the trans of 5.3 are probably the main equalizer, even with the miles on the 8.1 the torque from stop to say 3500 rpm is still impressive.5.3 will get a truck Norris/ turbo and a refresh or create with power adder's
For the 8.1 and the torque #'s could change my mind on diesel
To answer the questions asked in the video, the larger engine would be inclined to accelerate faster from a stop, due to the massive disparity in low RPM torque. With the right gearing, sure, the 5.3 could then give that big block a good run. Once the 5.3 gets spun up into its power band, it should really start pulling just as the big block has hit the limit of it's useful RPM range. It is always always always all about gearing
With an automatic with a torque converter with good shift extension, there might not be that much difference between the two. The big block would get out of the hole better if not traction limited, but the converter could help the 5.3 stay in the power after shifts.
I had a 8.1 in my 04 avalanche 2500. I loved it
Wow Richard this is one of those we have to drop them in and do some on the Track 👣 testing. Love to see that. Thanks buddy always awesome 👌
Love the 8.1 content. Think an aftermarket cam in the 8.1 would have been more fair comparison with the 5.3 TN cam. Please do that next! Then normalize for displacement hp/ci or liter. Your 1/4 mi question, seems like average horsepower divided by weight would be the best indicator of e.t.
you missed the point of the comparison-it was because they had identical peak hp
@@richardholdener1727 no you missed the point . we want engine comparison not number comp
LMAO it is unfortunate how you read things make it out to be a totally different meaning than what was intended.
I think it would be quite a fun thing to test with cost not being a concern. The weight difference is obviously massive between a tall deck iron block and head big block to a 5.3L aluminum block and head. If you used something like a 2002 Silverado 1500 2wd as your test vehicle I would probably pick the 5.3L to win, but I feel done right it would be very close. I would do a 4L85E behind the 8.1L with a 3.73 gear and a 30" tall tire (9 or 10.5 wide) and run a 2800 stall if budget allowed and if not run a stock torque converter for a 6.0L. With the powerband of the 8.1L the converter would be setup much tighter hydraulically which would be a slight benefit in that respect. Unfortunately the converter would be heavier for a bit of loss there, but I would run it locked from around 53mph or so to well past the 1320 mark to keep every bit of power possible going to the tires (with the exception of unlocking during the shift). With the L33 I would run a 4L60E with around a 3600 stall if budget allowed or an I6 Trailblazer converter if money was a concern. From around 83mph and through the traps I would run the converter locked. For the L33 I would run a 26" tall tire with a 4.10 gear. Hopefully the weight difference between the engine and transmission as well as the parasitic drag difference with the 60E over the 80E would be enough to put the smaller engine out front.
1969 chevelle. 454. Th350. 3.08 gear. 2100 stall. 287hp at the wheels 12.92. Same car 2 weeks before had a 355 with 345hp to the wheels. Ran 13.8s. 454 pulled the whole time.
I've been patiently waiting for someone to take a 383 ls and a 408 ls and compare on a dyno. Using only short blocks. Swapping cam heads and intake over from one to the other. To see the actual differences in the power they both make with the same combination. Always love you videos keep them going 💪
please see the 4.8l vs 5.3l vs 6.0l video to show what happens
More cubes = more power
Almost bought a 8.1 single cab dually 4x4 regret not getting it to this day… the truck stock was crazy torque for a gas burner in a truck that light..
Oh how I wish you would bolt the Cadillac 500 up and do the same boost test and see what the Dyno reveals!!!!!
I did that
@@richardholdener1727 it blew up!????
The 8.1 can use a taller gear and run out the 5.3's life
Seems to me with the torque multiplication of lower gearing it would be possible for the 5.3 to match the 1/4 mile time of the 6.1. Also the lighter weight and resulting weight distribution could work in favor of the 5.3.
I couldnt imagine the tire that would be needed for that 8.1 tq lol. It would be one hell of a burnout truck
Semi super single
A wide and soft drag radial at the minimum.
I have a N/A in a RCSB 1/2 ton. It is a fun truck.
Just the stock tires the truck came with lower tire pressure. Same numbers as a Duramax and you can do 4wd on at tires just aired down.
28” tall sumper swamper boggers
These 496 line the wreckers. Pretty impressive in the Vortec Max truck. No replacement fir the rotating mass. Wish it would of had the LS main caps, I would build one for bracket. Pretty neat it uses LS style reluctor wheel and coils, good to know. Keep it coming Rich!
Which car would be quicker? Most likely the 8.1. Which car would be faster? Most likely the 5.3. Quicker implies time. Faster implies speed. The low end torque of the 8.1 (as long as you can maintain traction) is going to get the car moving much quicker. The RPM speed the 5.3 is producing the power is going to allow the car run faster.
Lawrence LT Tolmin does a really good series about the 8.1. And i wish they would come out with more performance packages for the 8100
Awesome video as always. Thanks Richard .
In a truck that works for a living or for fun I'd want the 8.1. In a muscle car I'd want the 5.3. I just like revving out a sports car more than I do in the truck. I don't do the same spirited type of driving in a heavy truck basically.
I want a 8.1 in my 69 buick
Torque at the crank maybe vastly different but torque to the ground will be similar once you account for gearing, the 5.3 will need at least a full ratio lower say 3.50 for the 8.1l and 4.50 for the 5.3l that will be 1939 lbs-ft to the tire for 8.1l and 1868 kbs-ft for the 5.3l.
On the track hard to tell if one has a huge advantage but the street the 8.1l would be my choice.
You are basically a data nerd that loves Chevys. That is why we love your channel so much 🤓
I don't love ONLY Chevys
totally crazy comparo man! were actually debating here at the shop on which engine to put in our ramp truck since we have both. obviously the 8.1 is the right choice, just crazy youre runnin exactly what we talk about! ALL the time!!!! love the show, love the content! keep it up man!
85 chevy truck. Built 406. 505hp at Crank Ran 12.6s. Same truck 468. 383whp ran 11.8s
Awesome awesome awesome Richard excellent comparison!
My 2500 avalanche weighing 7500 lbs with a bone stock 8.1 and 4L80 runs a 15.4 @ 80mph. However I have roll raced a bone stock 03 z71 and pulled on the top end. Hell of an engine, especially in a 3000lb car
Same here. Running a mild tune on stock exhaust and intake and have been able to pull on every 1500 I’ve raced from Chevy, dodge and ford. Haven’t lost yet. 🔥
Flash back to 2005-2006 where supercharged E55 AMG's were pitted against V10 M5's. Both made around the same peak HP on the dyno, but the M5 would rev out to 8500. Where the E55 were done at 6500. The 1/4 mile results were decisive the E55 would win every time probably because of its massive torque advantage. 8.1 wins if it doesn't snap something with that torque.
cool analogy
@@richardholdener1727 I added the part where the E55 would be killing the v10 M5 by like 150-200+ wheel torque
Very interesting results on backpressure . My car is setup to run 2 different turbos , one is the Garrett g42-1450 w a 75mm turbine . I worried it would be too small and build a lot of backpressure, even though Garrett's boost advisor recommended it for my setup . I've seen a lot of 5.3s turning 7500 rpms with high efficiency 75mm turbine exit type turbos and I dont hear many complains . On my 6.2 , I shift around 6500 . Just using simple ( and probably inaccurate ) math, a 6.2 will move similar air at 6500 that a 5.3 does at 7500 rpms.
Based on your results , although I know the back pressure is probably starting to get up there, I'm probably in the same boat as a lot of 5.3 guys turning more rpm .
I picked that turbo for quick response and only run it up to around 15-16 lbs.
My " big " turbo is a FI billet s485 . Its 88mm turbine exit will surely have less backpressure, but is less responsive on the street .
Jury is still out on which one will have a permanent home on the ol 6.2 . Both make more than I can use right now and neither come in like I want from a dig . Working on that problem now. Once I get the intake, camshaft, timing worked out , I will dig into which turbo works best for me.
I'm getting too old for this , lol.
Having worked at a Track for a while and watching so many private test sessions, I'll say in the same car the 5.3 is gonna get off the line easier. Then HP takes over, and as they are almost the same power, and seeing the 5.3 doesn't have to shift as soon, it's gonna back half that big block. Now 1/8 mile the big block will have it, an hey I guess some guys expect good things to go by quick. Explains a lot in that statement.
Torque is what gets vehicles off the line quicker not horsepower. So the big block with hundreds more ft.lbs of Torque will certainly jump out ahead provided traction isn't an issue.
@@donniecahill5243 yessir I agree. However, that big block hanging out front weighs a lot more than an aluminum 5.3, erego if it's in the same chassis all that torque is good for nothing but spinning. I've watched plenty of guys some on a famous tv show go smaller motor and run way faster just because of the ability to get off the line easier
@@chadbeaver9199 we're comparing apples to apples, not apples to oranges. The weight difference is about 130lbs not like we're comparing a 4 banner. Weight difference won't be very notable
@@donniecahill5243 685 dry with no intake or flexplate on the 454, 520 filled with intake and flexplate for the 5.3. That's 200+ lbs difference. Now figure in a larger radiator for the BBC over the SBC and there's another 20 lbs. So again, if this is the same chassis, the BBC has a lot of bias towards the front over the SBC.
@ ok they still weigh the same and make roughly the same power per liter.
Waiting to see the diff the cams make on tbe 8.1, with the boost and back pressure vs the stock 8.1
With a cam it'd be more torque n more hp at higher rpm..
@@P71ScrewHead yep
@@derrelcarter9401 would be kool to see tho, I forgot to add that on my original comment.. 🥸
@@P71ScrewHead If that hoss gets up to 6200, look out!
@@fenatic7484 both modded the same, the big block wins every time, been a "bigger (engine) is better" person since before I could wipe my ass..lol
Traction might be harder to come by with all that low end torque in the big block. Plus with the same gear you may run out of rpm in 8.1 setup. The 8.1 will need a rear gear change (higher gear lower numerically).
Both motors will be just as fast in the 1/4 mile, only the 8.1 will start quicker but then stall while the 5.3 will start slower but catch up, the power curves say so. (Sorry I use the translator 😅)
Power numbers don't matter if you can't get the power to the ground. With that much torque down low it will be hard to keep the tire planted with the 8.1. If traction wasn't an issue, I believe the 8.1 would win 9 times out of 10. With proper gearing in both configurations, it would be a closer race for sure.
Yeah but the big block weighs 2381 lbs while the LS only weighs 320lbs
If we ignore weight and other things I say it's going to be exacly the same depending on the torque curve. Because gearing is literally making these 2 engines the same. 631ft-lb at 4400 makes 530hp and 434ft-lb at 6400rpm makes 530hp. If we apply gearing then it's going to multiply the torque and divide rpm at the same wheel speed. Let's say the wheels spin at 800rpm, the 4400rpm gets a 5.5 gear ratio so it will have 3480ft-lb at the wheels and the 6400rpm gets a 8 gear ratio gets 3480ft-lb at the wheels and they will have the same exact hp.
Great comparison, lots of good info. If I was pulling a loaded quad horse trailer the 8.1 would get the nod. For a weekend warrior down the 1320 the 5.3 would be my choice especially with a little gear.
8.1 if it hooked up would et better however yes the 5.3 can match it with gears but you will probably have to rpm the 5.3 500 past peak that's drag racing 😊
Would be interesting to see the outcome, big block nose weight could be a hindrance, yet a spectacular smoke show.
The weight to power ratio would make the greatest difference in either quarter-mile scenario. Guessing that the 8.1 is probably 150 pounds heavier than the aluminum 5.3, I'd give it the advantage in the quarter, but even more in the 1/8th mile regardless of gears.
might be closer to 200 pounds
8.1 in the truck it came out of it's the same drivetrain as an lb7 Duramax. At those numbers it's going to be very fast in a 3/4 ton truck
Probably closer to 400lb. I weighed my ls6. Aluminum ls stuff weighs between 304lb to about 380lb depending on what you want to include....vid is on my channel. A iron bbc will go 700+ lb in similar configurations.
By changing cams you will increase power and torque starting on low end but the peak power and torque will be at the same rpm . The 8.1 will need the power and torque curve flatter to achieve better performance on top end . As soon as the motor hit peak it starts dropping . But you are talking about a motor built specifically for a truck . The 5.3 was built for torque and power throughout a long flat curve .
a cam won't add low end and keep peak torque and HP the same rpm.
The big block will pick up speed faster. As long as it dosent tire shake. But general rule of thumb. Big block will smack just about any small block at highway speed. Only thing you can do is raise the revv limit to the moon. Even stock as long as you add a light cam and build the heads for higher rpm use then you can battle it out. The added rpm will give you some added speed overall to a point.
great video! as far as your question, there isn't a right answer because there are too many other variables in the drivetrain, suspension, and trans / torque converter choice IMO
Congratulations on 200k subs (should be 500k!)…just a matter of time before you are discovered by all utube car folks
thnx-fingers crossed
Same hp at same weight means same fasts. Only variable is the launch which would realistically be favoured by the big block in the real world. Here's some food for thought though, in the top end, where it will live while racing, the big block has a roughly 1400rpm window at 400hp and above. The 5.3 also has a 1400rpm window at 400hp and above and its looks slightly flatter. The small motor may actually make MORE average power in that window. All things being equal (including race weight), I'm saying the small motor wins IF the hypothetical driveline lets it get to and maintain the required rpm. If it's a "real world" driveline, the big block will jump away early then they will accelerate at the same rate and the gap will stay the same the whole way down the track (same weight, same hp).
Depends on vehicle your building the 8.1 is the choice for a heavy car or truck in a RV would be a no brainer but something light like a nova Camaro or smaller the 5.3 would be great it's comes down to personal preference it would be really interesting to see we're the 6.0 would fit in
look at cash days winners pretty much dominated by big blocks.
@@FRECHKN true
Well I think that Steve B said it best, you are giving up so much at the gear change so the 8.1 will 9/10 times beat the smaller displacement 5.3. Again no replacement for displacement. That’s for the video!
Congrats on 200k... I would guess that the 8.1 would get out front maybe to the 1/8th but then the 5.3 will gain ground and go around it... Bench racing at it's finest 🤣
That 8.1 would be the perfect canidate for a "farmtruck" style build
Very interesting (to me) as I currently have both of those exact motors. I'm likely going to sell the Sierra with the L33, but strongly considering dropping a turbo in my 8.1L Suburban 2500.
Running the numbers in a 3500lb car I get 130mph.
4.10 gear for 5.3, 3.00 (custom?) gear for 8.1.
At 3000 rpms the 8.1 gets 17% more tq to the tire.
Equal at 4k.
5k rpms the 5.3 is putting out 30% more. Gearing has a phenomenal impact.
Personally on the street, give me the 8.1 with a 2200 stall.
As long as there is enough traction the 8.1 even with a taller (numerically lower) gear would win, but a shorter gear for the 5.3 stands a good chance on a lower traction surface. The 8.1 would need a serious tire. Lol.
It came with the same Allison and drivetrain as lb7. 4wd it would be very fast
@@jacobstrutner8232 weight would be the only challenge
Gearing and trans the same my moneys on the 8.1. You will shift earlier but you will almost always be in a better power band due to the TQ. If you can optimize gearing and trans in the 5.3 only I would go with the 5.3 as you can optimize the gearing in order to get into the high HP power band faster and stay there when shifting at a higher rpm. just my opinion
Big bang 8.1? They say the SBE 8.1 can't take much boost. Only one way to find out
I would imagine that everything being the same with the car (weight, perfect traction, etc). The big block would definitely prevail in the 1/8th mile, but hard to say what the outcome would be in the 1/4 mile. Does the small block have enough time and rpm to creep forward after that? 🤔
The difference would be in the driveline. Gearing, stall speed and stall ratio would decide things. Given the torque curve of the 8.1, if it can get out and stay out it'll win. The only thing is the weight.
@@hoost3056 weight would be the same between the two in the OPs hypothetical.
If this man would mod that plenum to remove that partition you would be absolutely appalled at what is left on the table.
It would be a traction game diff gear transmission control In full quarter mile 5.38 mile big block again if traction was dead on
I like the big block but having an all aluminum engine and gearing would make a huge difference
A lot of people would love to see the 6.0 truck Norris combo.
translation-you want to see it-it does the same thing!
all about gearing and shift points keep the small block in its power band by the end of the 1/4 it would be right there as well as less weight with the SBC
The 8.1 is just a monster and will likely outlast a 5.3 under the same boost conditions. Plus, turbo lag isn’t even an issue when you have a 496 stroker under your right foot!
7:55 in and the STOCK 8.1 is matching the BOOSTED 5.3 up to 3500 rpm and hangs until almost 4000rpm. Boosted, the 8.1 at 3000 rpm is making 470hp, while the 5.3 is making 290. LOL Driving around normally and pulling I know which vehicle I'd rather be in! Gotta love displacement! That 8.1 must feel like diesel torque with healthy gas hp. Nice.
The big blocks got to weigh an extra 200lbs compared to the aluminum LS. I would be interested to see a project car shootout. Pitch that to freiburger!
Excellent video Richard! I would think, assuming traction wasn't a major issue, the 8.1 would out run the 5.3 regardless of gearing. Although the 5.3 Geared for the extra RPM would make it an exciting race. There's just no replacement for displacement.
However, what have you found a correlation between boost pressure and exhaust back pressure in any respect? Such as power output, drive ability or turbo performance for example...
Literally watched a video with boost and said 'no replacement for displacement.' It didn't get more obvious.
let's look at this from a different direction:
what about a tow truck application?
a truck norris cammed 8.1 with a zf5spd running 7lbs of boost would pull as well as duramax. using a 3.73 gear.
a 5.3 combo would need 5.13-5.5
6 gear and more boost to have the same pulling power.
I tow a 40' 15000lb travel trailer so i think like that. imagine a Kodiak with an 8.1 setup with an allison 6spd auto.
slight mpg problem vs. diesel, but if you only use it 4 or 5 times a year....
One more piece of data that would be interesting to see is how much fuel each engine was using along the curves and at peak power and torque. To see which engine is making the numbers more efficiently. Bigger displacement at a lower rpm vs smaller displacement at high rpm.
racing is not about efiecency. but seeing the rpms are higher on the 5.3 to get the same power. it probably works out to be about the same.
A 502 vs 8.1 496ci would be a cool comparison
Would be a great race and or comparison! Both great engines.
You can push the 5.3 harder with boost though so you would definitely have to keep it the same for it to be close
You can push anything harder with boost. Both boosted the 8.1 would win all day.
Have a torque converter that locks up at 3500 and my money is on the 5.3.
Joking aside it would be interesting to team up with the guys from power nation and use their test chassis.
So if you put a 42% reduction gear on the 5.3, that will shift the power peak to the same rpm as the 8.1 (6,400/4,500 = 1.42). Put the 5.3 and its reduction gear in a "black box" and put that on the dyno. The "black box" makes (630 x 1.42) = 894 ft lb at 3345 rp m (4750/1.42). The 8.1 makes 850 ft lb @ 3650 rpm so the "black box has higher torque and a wider power band - it will blow the 8.1 away. Richard - perhaps you should replot the power curve for the turbo 5.3. (Just shrink the rpm axis by 1/1.42 = 0.7). Then overlay on the 8.1 curve.
you are free to change your rear end or trans gears as you like
@@richardholdener1727 In your dyno software?
I didn't know I wanted this video till I found it. All of your video do that and I love it lol
I would say no, the 5.3L would hit rev limiter before it could match the 8.1L. The boosted 5.3L suffers from a 36% torque deficit versus the boosted 8.1L, but it's redline is only 16% higher. Based on that it would not be able to overcome the deficit.
That redline of the 8.1 can be massaged a little. I don't remember the name of the shop doing it. But they've apparently got a build kit to make that 8.1L reliably turn 7500
Why over rev it when it's falling hard off the powerband anyways? That's backwards thinking. Big blocks weren't built to make topend power, yes u can sink lot of money in one to do just that, but for all practical purposes for the average Joe a ls or even a small block is way to go. Also they r running a Holley management system, they can set rev limiter. But again, no point in it when it's falling on its face anyway..
Makes me think I want to turbo my 8.1 in my Holiday Rambler RV. Looks like all I would have to do is run 80 lb injectors and an S475 turbo and WALA....800 lb/ft of torque...I bet I would get better gas mileage as well. I don't think my allison 1000 would like it though - its only rated for 625 lb/ft
With the proper gears and converter for the combination should be about the same et,
Would love to see more 8.1 content from you. Thank you for this video. 🙏
Wow Richard! So much enthusiasm here for the 8.1, let’s see what you can do with it.
Knock out the manifold wall, gap those rings and make this motor sing. Let’s see what it’s got!
This was the video I’ve been waiting for.
Congratulations on 200K subscribers ! And one of your best videos ever , even if it is giving me a headache......let's seee......the chicken ? the egg ?
The one that’s faster depends on the transmission and gearing, if you optimize it for both, the 5.3 will be 300 pounds lighter, but you would need a power glide and 4.56 gears, the 8.1 could do it with a 6l90e and 3.08 gears, I’m voting for the 8.1L, even though I own both of those motors, I like the torque of the 8.1L
There's only roughly 130 pounds difference between the two motors. Not sure where you got your numbers from.
@@robking9857 I have an aluminum 5.3L
I enjoy learning what you do.
Something I haven't seen, (maybe I overlooked it) using gen 6 heads on mark 5 and then on mark iv using stock everything else. That includes cams.
I know you have to change to a carb intake, just use the same intake on both engines
I'm looking for stock hp/tq as I don't have the money (disability) to modify these engines.
I have both a mark iv and gen 5 engines that are in excellent shape. (Wreck takeouts)
head swaps are possible with the right head gaskets
@@richardholdener1727 I understand that you have to use the correct gaskets.
I don't have the funds to test these head swaps.
What I am asking is if you have done those tests?
I have a one time opportunity to put the gen 6 heads on either a mark iv or a gen 5.
I am disabled (heart failure) and don't know jow long I have left in this world.
I would like to be able to enjoy my truck before I check out.
If you know where I can find this test, please let me know.
LS with complimentary gearing ove the big block.
Weight is a thing.... cutting weight gains more in a 1/4mile than HP.... its just harder to do after a certain point.
The higher torque will trap more benefit getting off the line which in theory should give it the advantage at the finish line
Of course the 8.1 if it gets traction would eat the 5.3 with the same gearing, and if you change gearing for the 5.3 it should run close to or equivalent to the 8.1! all you have to do is multiply the torque at every RPM level "times" the overall gear ratio till you find a ratio increase that makes average torque equivalent!!! and changing the ratio by that amount should deliver equivalent acceleration!
You are absolutely correct MEGA DITTO'S!!!!
I generally agree but I would like to also have Dino pulls have a time to achieve max rpm. The faster an engine can wrap up to high rpm. Exotics for example with flat plane cranks can rev to rpm so much faster than American V8s. Race car vs drag car rpm range and use. There is not much info in this area on the web because so many variables are involved.
With the same during the 8.1 should outperform the 5.3 in acceleration
Make a test on a stock bore stock 706 head 4.8/5.3 with a 3.9 or 4.0 inch stroke which would make it a ~5.7. see how the torque curve changes with all the stock components on the engine, after that add a stage 1 torque cam on it
please see the video where i compared the stock 4.8l, 5.3l and 6.0l