Please keep up the awesome work ! Love your videos - your volume of work is like brining free dyno testing to all of your fellow gearhead's projects . Wish you well and God bless.
A GT45 is a 69mm turbo, I’ve never seen a GT45 eBay turbo any larger. Its really interesting to see an old technology 69mm out perform a “Newer” 76mm turbo. Look how important the exhaust flow is on even the 4.8. Good stuff!
@@richardholdener1727 - Compressor: 76mm Wheel Compressor - Turbine: Q Trim .96 A/R Turbine - Compressor Wheel: 102.4mm/76.7mm - Turbine Wheel: Q-Trim 79mm/68.4mm - 3" V-band Hot Side Is this the same turbo you tested? they advertise 800HP on Ebay lol
@@jayallen408 its the outside diameter of the compressor inducer. The small side of the cold fan. Precision does this. Their number scheme is the diameter of the intake followed by the diameter of the exhaust, a 6267 precision has a 62mm intake diameter and a 67mm exhaust diameter. At this boost level on this pretty good breathing 4.8l the gt45 is probably the better turbo. They have a huge turbine housing.
'out perform' at this pressure level. It would be interesting to see the power production at the same pressure output. Any higher, though, and the smaller turbo will become a restriction much sooner than the larger.
Oh yeah backpressure, that was probably higher than spring pressure. The best part about the plots was that any combo made the tracks further apart from the n/a, so thats fun.
The turbos are both pretty similar in size I have both of those turbos actually on my shelf I'm familiar with them. What creates the drawback for the CX racing turbo is that it has a smaller aspect ratio on the hot side. Smaller displacement engines do pretty good with that turbo, and by smaller displacement I mean less than 4.0L. believe it or not I used that turbo on a stock lq4, stock cam and everything. It was AMAZING as a daily driver. 8psi pump gas, made about 550ft lbs at the wheels and almost 500hp. But when I bumped the boost up to 10psi I mostly only gained detonation. Cylinder pressure plus exhaust pressure can get pretty angry together with 91 octane.
@@richardholdener1727 not a massive difference but yes, I feel like it's mostly the tighter aspect ratio on both hot and cold side that limits the t76 the most. You probably know more about this than I do. Love your videos man keep it coming
I know you can't load a dyno that low but I would guess the t76 is better off idle and up to about 3000rpm then the back pressure catches up with it and power start to fall off.
I've got a single cx racing T76 in my 355.. I wanted to go to a gt45 but the outlet is 3.5 compared to the cx racing 3" outlet and I don't have room for exhaust that big between my header and frame
@@richardholdener1727 I would love to see that same test but at a higher boost pressure I've got 3" exhausts for about 3' and then 4" exhaust after that I'm pushing 11PSI .. haven't got it on the dyno yet
This is why I’ve bugged you about the borg Warner K31 turbo. It’s a 71/102 cold side with the 88/77 hotside but it has a 1.28 T6 turbine… it’s rated at 500 HP….. if I bolt this to a heads, cam 6.0 you tell me it will only make 500 hp??
Ive no first hand experience of this turbo but it reads like a large compressor on a small turbine, so thing how that turbine will restrict ultimite performance (as outlayed in this video) Im in the UK so this may not be relevant to you but there was a while where every tuning company was putting massive T4 comressors on small T3 or T25 turbines on ford cosworths. Yes they made loads off boost fast, but my god they didnt make any actual power.
K31 is kind of popular in diesel circles because some come with a factory billet wheel. They are also pretty big. A heads/cam 6.0l is already getting to 500hp level. If i had that turbo, yes, run it. It will be extra spicy. I wouldnt buy it for a heads and cam 6.0l. Its a little smaller than what you could run. If that turbo is for "500hp" its because the 60 series Detroit it came on was 500hp. Its really close to a S471, and even though i cant find a flow map for a K31 the cast S471 that is made by the same company and has the same inducer diameter flows almost 100lbs/m. Its a really healthy size spinnyfan and as long as you arent competing in a 71mm race class it will do almost everything you need.
Richard have you ever done any experimentation on wastegate sizing? Usually I have to depend on the turbo kit manufacturer and where they put the wastegate flange and how they biased the flow. But I've always wondered about sizing differences depending on power, efficiency, even fuel type (alcohol = more exhaust flow).
@@richardholdener1727How would the math be done for twin turbos? I know that with twin turbos your can run less boost for the same power level or the same boost as you did for the single for a higher power level. But I don’t know that math formula.
Definitely need electronic boost controller for this test and they both need to be tested at 17 or 18 pounds of boost to get them in the middle of the map to see what they really do. The GT 45 that had a higher boost output had more horsepower because the volumetric efficiency goes up with boost
@@richardholdener1727 ok, that means the 76 is still bigger, I guess I'm phrasing my question wrong, how is the smaller turbo better or rather what makes the gt45 out perform the t76, I'm currently in the middle of a project on a turbo 5.3 build and am gonna go with a t76 because of a video you did awhile back stating that the gt45 started struggling at like 6-8psi which is where I want to start at boost so I wanted a slightly larger turbo so I can run that 6-8psi without loosing efficiency but here is a video saying the opposite I guess so what exactly is happening here
@@boosted2813 well I think he might have been expecting different boost curves because of the back pressure but it would be best if they were the same too
Slightly off topic, have you ever looked at bsfc and bsac when comparing cams and modifications to get an idea of efficiency. I am looking at the truck Norris cam with it's tighter lobe separation versus maybe something with a 114 but similar specs, l want the sound of truck Norris but am concerned about giving up too much mileage in a daily driver. I'm curious how other modifications affect efficiency also. Thank u
I was thinking by comparing the bsfc and maybe the bsac you could get an idea of efficiency relative to each other.i remember an article years ago where Steve Brule said something along the lines of old school engines were around .51 commonly and modern engines were in the low .4 range. I remember on the Dyno with roots blown big blocks doing part throttle runs checking exhaust temps with ported vacuum advance added in the bsfc was really high, and that carried over to real world efficiency somewhat. I accounted that to the better atomization of the fuel due to the better air draw and volume of air at lower throttle opening.
Bigger turbo equals more "CFM kind of like comparing a a garden hose to a straw 🧃 You can put 60 PSI through a garden hose and threw a straw! But it's called volume. You can flow a lot more gallons through the garden hose at 60 PSI. Then you could on a little straw at 60 psi 😏🙏🏻🙏🏻
@@richardholdener1727 and also at the same time a smaller turbo that can't support the excess exhaust gases produces nothing but heat because it's restricted
@@SawmillerSmith exhaust, intercooler, blow off valve, wastegate, intake and exhaust piping, likely headers. Your factory fuel lines might be fine depending on how much power you want to make.
I believe that part of the power gained in the upper RPM range of a cam that is installed “Retarded” is gained due to the change in force required to open the exhaust valves. What do you think?
nonsence, cause on a twin cam motor, valve springs the same, retarding both cams moves power up the curve. its due to volumetric efficiency at higher RPM's i.e. the momentum of gasses through the engine. this is obv an awesome tunign tool on twin cam motors and imho oft overlooked.
Hey Richard, have any need for a helper? I can help you with some video as well.(20 years entertainment lighting experience) Can’t do my career anymore and want to work on cars/engines, but not as a hobby anymore
@@richardholdener1727 hey richard do you have a video on Waste Gate-BOV tuning I'm planning on running twin turbos on my 1UZ but I don't have budget for an ECU yet So I'm thinking of running 7psi on WG/BOV alone stock ecu I do however have 300Lph pump, 550cc Injectors, and a fuel regulator
The wh1c is pretty small for a v8. The biggest stock compressor i can find is a 56mm fan. They top out at about 54lb/m airflow so it depends on the V8. If you have a stock 260hp mustang gt from 1999 then this turbo might be really spicy for a street car, same deal if you have a 4x4 truck and need to spin some mud. This 4.8 was making ~450 hp before the turbo and even though a wh1c could add some boost, it wouldn't add very much power up top.
I was thinking of using it on a small block mopar 318 over 60 with ported j heads with 2.02 1.60 with a fair cam 484 lift 241 duration at 50 and 108 lobe separation
Also if your intake side is restricted then bigger turbo doesn’t mean better. Head flow is also important and can really effect the end result. Heads that don’t flow well will have better effects with a turbo that doesn’t move a lot on the intake side as there’s less restriction and less turbulence.
@@richardholdener1727 no better flow works better. Sorry if I didn’t clarify. Low flowing head will create restrictions and if you have poor flowing heads smaller turbos will be more effective than a larger turbo
The 76mm is kind of buggered. The Gt45 has a huge semitruck sized exhaust that slows down spool but you might not notice this on the dyno much, especially starting the runs at 3k rpm. The 76 will spool earlier but the intake fan is so much bigger and heavier than it needs to be it might not be much of an advantage.
Richard quick question what’s the best cam for dig/drag racing for a 5.3 I have Tbss intake manifold, cai, 4.10 gears, posi, longtube headers, tune on e85, corvette servo (new subscriber) thanks👍🏻 in advance
Love it! Could you do a comparison between turbos that are more similar in size? like the 76mm vs a VS 7875? Would also love a colaboration between you and Viren Singh! I am really curious on the differnce between all the different versions of the 7875...
How does A/R effect performance? Are these turbos available with different A/R? Probably have multiple videos on this already, maybe same cool side but different hit side.
@@richardholdener1727 3d printed adapters, potentially? wouldn't have to be a modified engine, just to see if they are better than windsor offerings, or maybe you could test it the other way windsor intakes on LS 🤔 sounds like a cheap interesting test
Why there is a change in the boost curve? Because the turbine is too small for a 4.8 lt Richard! A turbine wheel of 74.1/64.6 MM is much more suitable for the 3.8lt V6, and even in for a 3.8 lt is small, actually it's a good size for a 3 lt engine, not more.
@@richardholdener1727 it's a bit weird Richard. A few days ago you turbocharged the 3.8lt V6. It would had made much more sense to conduct this test with this engine. The T76 is so small for a 4.8lt that even if they are some gains in the low rpm range in comparison with the GT45, these are minimal. A test that would had made sense in the 4.8 lt would had been between a single GT45 and two cheap Chinese T3/T04E from e-bay.
Is this why the 45 seems to light off earlier than the 76 also? I was thinking about going the 76 route on a remote mount Astro van with a 4.8. Maybe something a little smaller may be better, not sure at this point, lol.
Your na power is made with a delta of 10.7 psi it idles at 4 psi do the math with 10.7 psi instead of 14.7 it comes out to 41.3 per psi and that almost correlates to your gain that’s why it looks like your motors are beating the formula I’ve seen slightly less than 4psi idle but it’s not worth mentioning
"400hp" 50mm t3t4 and a 4.6L OHC... (not driving at 6000rpm) low boost creep. 1500-3500rpm range? 3psi, "adding a 2L 4 cylinder". "the 74hp 2L as is, was enough to get down the road". 4.6 to 5.4 power with fast response, just have to dial out the transmission kick down with the overdrive off... not compressing 5.4L at idle... "ecoboost", read on a form page not to go past 400lbft... 3psi and boost creeping shifts does it at normal operating range. Always more gas thru the snow plow on farm truck's 360ci, 80's Mopar easier to work on then anything else. trucking not racing
I have personally had a GT45 on a 4.8 in a fox coupe with 355 gears and an 80e Circle D 3600 billet. It was a boring turd from any punch or roll. Once it got up on the pipe....It ran extremely well. But was a laggy turd. I swapped it for a PT 7675 and it was not only a night and day difference, it was complete annhilation of the GT45 turbo. I run a Terminator X. Sold that car and am doing another fox coupe now with a 4.8 and a Rev9 7268 with a th400 I expect easy rolling burnouts and fun. I don't care what the dyno says the boost and drive pressure is of a gt45. It is just too large of a backside to be feasible on a street driven 4.8. Race car, maybe fine, but unless you want to anti-lag every redlight. Stay away.
@@tunerdadtunerdad7927 I'm running a GT45 with my 4.8 sierra swap also with an 80E limited to 7lbs until I upgrade my fuel system/retune. Prior to my convertor change I liked to call it my LazyBoy turbo. Just went with a FTI billet 3500 and now it blows the tires off if I footbrake it anything above 3k. (Mini spool 3.08 and 275 section tires) . But I still think the 7675 would be a big upgrade. Glad to read your input.
@@chrisgallimore9083 Yes....same with mine. I could manipulate it to get the boost up. But just driving it around or punching it from a slow roll...Lazyboi is a great term. A lesser powered Heads cam car would run and hide from me if I wasn't ready. That sucked. I put a Rev9 7268 on a ls6 cammed 4x4 truck and it moves out hard from a dig or slow roll. So for I am going that route on my fox now. I say 500 HP right now is better than 600HP here in a minute or two...Lol
The T76 (aka 76/65) is a great example where the turbine is too small to flow enough, but spools slower despite that since the compressor wheel is so large & heavy. The GT45 is almost the reverse as a 67/78 turbo - a much larger hotside than compressor. The T76 also uses much older tech wheel designs vs the GT45, so it's less efficient at almost any boost and needs more exhaust energy to spool it up. It's just a shitty turbo!
The 1986 Shelby Omni GLH-S was a modified Dodge Omni GLH, with changes made at the Shelby factory. They were retitled as Shelby Automobiles cars sold at select Dodge dealerships. GLH stood for "Goes Like Hell" and GLH-S stood for Goes Like Hell S'more. Just 500 were made.
It's just amazing what the truck LS's can do even in NA trim.
Absolutely loving the volume of info you put out! Old gearhead that has no clue when it comes to turbos-just awesome!
Steve
Please keep up the awesome work ! Love your videos - your volume of work is like brining free dyno testing to all of your fellow gearhead's projects .
Wish you well and God bless.
Exhaust pressure, the first turbo have a lot smaller exhaust side so it got chocked up probably. My guess at least
3 inch exhaust from the rear of the turbo. It wants 4 .
A GT45 is a 69mm turbo, I’ve never seen a GT45 eBay turbo any larger. Its really interesting to see an old technology 69mm out perform a “Newer” 76mm turbo. Look how important the exhaust flow is on even the 4.8. Good stuff!
the T76 is not new
@@richardholdener1727 - Compressor: 76mm Wheel Compressor
- Turbine: Q Trim .96 A/R Turbine
- Compressor Wheel: 102.4mm/76.7mm
- Turbine Wheel: Q-Trim 79mm/68.4mm
- 3" V-band Hot Side Is this the same turbo you tested? they advertise 800HP on Ebay lol
So where exactly do you measure a turbo from to get the millimeter size
@@jayallen408 its the outside diameter of the compressor inducer. The small side of the cold fan. Precision does this. Their number scheme is the diameter of the intake followed by the diameter of the exhaust, a 6267 precision has a 62mm intake diameter and a 67mm exhaust diameter. At this boost level on this pretty good breathing 4.8l the gt45 is probably the better turbo. They have a huge turbine housing.
'out perform' at this pressure level. It would be interesting to see the power production at the same pressure output.
Any higher, though, and the smaller turbo will become a restriction much sooner than the larger.
Really love these short videos! Always so much to learn! Your delivery of the information is always superb!
I see the size of both hot size of the turbos seems to me the small hot side sports up quicker making more back pressure
Boost is just a measure of restriction, overall flow is what matters. The sooner people understand that the better.
Oh yeah backpressure, that was probably higher than spring pressure. The best part about the plots was that any combo made the tracks further apart from the n/a, so thats fun.
I knew I should stay awake in math class for some reason, and this is it!
How about discussing quality and price comparison of these economical turbos.. That's a question I have had for a while
The turbos are both pretty similar in size I have both of those turbos actually on my shelf I'm familiar with them. What creates the drawback for the CX racing turbo is that it has a smaller aspect ratio on the hot side. Smaller displacement engines do pretty good with that turbo, and by smaller displacement I mean less than 4.0L. believe it or not I used that turbo on a stock lq4, stock cam and everything. It was AMAZING as a daily driver. 8psi pump gas, made about 550ft lbs at the wheels and almost 500hp. But when I bumped the boost up to 10psi I mostly only gained detonation. Cylinder pressure plus exhaust pressure can get pretty angry together with 91 octane.
the 76mm has a smaller turbine wheel
@@richardholdener1727 not a massive difference but yes, I feel like it's mostly the tighter aspect ratio on both hot and cold side that limits the t76 the most. You probably know more about this than I do. Love your videos man keep it coming
Im just surprised they spooled at the same rate
I believe the cheaper gt45s have a 69mm compressor. So that shows more how bad the hotside is on the 7665 turbo, for a v8.
I know you can't load a dyno that low but I would guess the t76 is better off idle and up to about 3000rpm then the back pressure catches up with it and power start to fall off.
testing different sized dump pipes would be great too.
He did a while back, bigger made more power even at similar psi
i wanna see this stuff on a STOCK HEAD engine. Not a lot of guys are running ported heads even on turbo apps
you missed the point-that won't change anything
I've got a single cx racing T76 in my 355.. I wanted to go to a gt45 but the outlet is 3.5 compared to the cx racing 3" outlet and I don't have room for exhaust that big between my header and frame
exhaust fitment is always a concern
@@richardholdener1727 I would love to see that same test but at a higher boost pressure
I've got 3" exhausts for about 3' and then 4" exhaust after that I'm pushing 11PSI .. haven't got it on the dyno yet
The GT 45 has MAP groove or slots vs the other smooth bore turbo. Slotted compressor CB overs and bigger exhaust outlet makes more power
TURBO SIZE MATTERS
@@richardholdener1727 so does the compressor cover and wheel
both of those are part of the "TURBO SIZE"
@@richardholdener1727 not at all. A slotted 75mm turbo make more power than a smooth 75mm turbo.
This is why I’ve bugged you about the borg Warner K31 turbo. It’s a 71/102 cold side with the 88/77 hotside but it has a 1.28 T6 turbine… it’s rated at 500 HP….. if I bolt this to a heads, cam 6.0 you tell me it will only make 500 hp??
I have never tested that turbo
Ive no first hand experience of this turbo but it reads like a large compressor on a small turbine, so thing how that turbine will restrict ultimite performance (as outlayed in this video) Im in the UK so this may not be relevant to you but there was a while where every tuning company was putting massive T4 comressors on small T3 or T25 turbines on ford cosworths. Yes they made loads off boost fast, but my god they didnt make any actual power.
K31 is kind of popular in diesel circles because some come with a factory billet wheel. They are also pretty big. A heads/cam 6.0l is already getting to 500hp level. If i had that turbo, yes, run it. It will be extra spicy. I wouldnt buy it for a heads and cam 6.0l. Its a little smaller than what you could run. If that turbo is for "500hp" its because the 60 series Detroit it came on was 500hp. Its really close to a S471, and even though i cant find a flow map for a K31 the cast S471 that is made by the same company and has the same inducer diameter flows almost 100lbs/m. Its a really healthy size spinnyfan and as long as you arent competing in a 71mm race class it will do almost everything you need.
What were the rear A/R of each turbo ? Backpressure.....
Richard have you ever done any experimentation on wastegate sizing? Usually I have to depend on the turbo kit manufacturer and where they put the wastegate flange and how they biased the flow. But I've always wondered about sizing differences depending on power, efficiency, even fuel type (alcohol = more exhaust flow).
I think that might be interesting to test-not sure if I can show what it really does on the engine dyno-might be better on a chassis dyno or street
@@richardholdener1727How would the math be done for twin turbos? I know that with twin turbos your can run less boost for the same power level or the same boost as you did for the single for a higher power level. But I don’t know that math formula.
Definitely need electronic boost controller for this test and they both need to be tested at 17 or 18 pounds of boost to get them in the middle of the map to see what they really do. The GT 45 that had a higher boost output had more horsepower because the volumetric efficiency goes up with boost
neither of these turbos will make 18 psi on this combination
6:01:Backpressure. CX76 had a bigger exhaust housing less BP.
the CX 76 has a smaller turbine wheel-it has more back pressure
Your saying the cx76 turbo is a 76mm turbo but isn't that a bigger turbo then the standard gt45 which is like 66mm?
the GT45 is a 69 mm
@@richardholdener1727 ok, that means the 76 is still bigger, I guess I'm phrasing my question wrong, how is the smaller turbo better or rather what makes the gt45 out perform the t76, I'm currently in the middle of a project on a turbo 5.3 build and am gonna go with a t76 because of a video you did awhile back stating that the gt45 started struggling at like 6-8psi which is where I want to start at boost so I wanted a slightly larger turbo so I can run that 6-8psi without loosing efficiency but here is a video saying the opposite I guess so what exactly is happening here
Should have measured exhaust manifold pressure.
Ya if he was going to test the 2 Turbos that seems like something you would have planned on logging
And close to same boost curve. No really apples to apples if the boost not same
@@boosted2813 well I think he might have been expecting different boost curves because of the back pressure but it would be best if they were the same too
Slightly off topic, have you ever looked at bsfc and bsac when comparing cams and modifications to get an idea of efficiency. I am looking at the truck Norris cam with it's tighter lobe separation versus maybe something with a 114 but similar specs, l want the sound of truck Norris but am concerned about giving up too much mileage in a daily driver. I'm curious how other modifications affect efficiency also. Thank u
Get a Prius already..lol jk..
WE CAN'T DETERMINE FUEL MILEAGE ON THE ENGINE DYNO-YHAT NEEDS TO BE DONE IN THE CAR ON THE ROAD
I was thinking by comparing the bsfc and maybe the bsac you could get an idea of efficiency relative to each other.i remember an article years ago where Steve Brule said something along the lines of old school engines were around .51 commonly and modern engines were in the low .4 range. I remember on the Dyno with roots blown big blocks doing part throttle runs checking exhaust temps with ported vacuum advance added in the bsfc was really high, and that carried over to real world efficiency somewhat. I accounted that to the better atomization of the fuel due to the better air draw and volume of air at lower throttle opening.
Bigger turbo equals more "CFM kind of like comparing a a garden hose to a straw 🧃 You can put 60 PSI through a garden hose and threw a straw! But it's called volume. You can flow a lot more gallons through the garden hose at 60 PSI. Then you could on a little straw at 60 psi 😏🙏🏻🙏🏻
a turbo that can't support the flow, won't produce the boost
@@richardholdener1727 and also at the same time a smaller turbo that can't support the excess exhaust gases produces nothing but heat because it's restricted
I have a 2009 truck with a 4.8 all stock. Can I install a turbo and keep everything stock?
YOU WILL NEED INJECTORS, A BIGGER PUMP AND A TUNE
@@richardholdener1727 OK, doesn't sound like the setup would be to expensive.
@@SawmillerSmith exhaust, intercooler, blow off valve, wastegate, intake and exhaust piping, likely headers. Your factory fuel lines might be fine depending on how much power you want to make.
Don’t forget valve springs if you want to run much boost at all
Want to borrow my new vs racing 7875 turbo and try it on this same test? I'm in Hollister CA
Thnx-I already have VS turbo too
Now that was a good one
I believe that part of the power gained in the upper RPM range of a cam that is installed “Retarded” is gained due to the change in force required to open the exhaust valves. What do you think?
change in force?
nonsence, cause on a twin cam motor, valve springs the same, retarding both cams moves power up the curve. its due to volumetric efficiency at higher RPM's i.e. the momentum of gasses through the engine. this is obv an awesome tunign tool on twin cam motors and imho oft overlooked.
Hey Richard, have any need for a helper? I can help you with some video as well.(20 years entertainment lighting experience) Can’t do my career anymore and want to work on cars/engines, but not as a hobby anymore
Very informative..
Got a question Richard, Can you run a wh1c Holset tutbo on a small block v8 engine and it perform with any real gains?
NOT FAMILAIR WITH THAT TURBO
@@richardholdener1727 hey richard do you have a video on Waste Gate-BOV tuning I'm planning on running twin turbos on my 1UZ but I don't have budget for an ECU yet So I'm thinking of running 7psi on WG/BOV alone stock ecu I do however have 300Lph pump, 550cc Injectors, and a fuel regulator
The wh1c is pretty small for a v8. The biggest stock compressor i can find is a 56mm fan. They top out at about 54lb/m airflow so it depends on the V8. If you have a stock 260hp mustang gt from 1999 then this turbo might be really spicy for a street car, same deal if you have a 4x4 truck and need to spin some mud. This 4.8 was making ~450 hp before the turbo and even though a wh1c could add some boost, it wouldn't add very much power up top.
I was thinking of using it on a small block mopar 318 over 60 with ported j heads with 2.02 1.60 with a fair cam 484 lift 241 duration at 50 and 108 lobe separation
Also if your intake side is restricted then bigger turbo doesn’t mean better. Head flow is also important and can really effect the end result. Heads that don’t flow well will have better effects with a turbo that doesn’t move a lot on the intake side as there’s less restriction and less turbulence.
heads that don't flow well work better with a turbo?
@@richardholdener1727 no better flow works better. Sorry if I didn’t clarify. Low flowing head will create restrictions and if you have poor flowing heads smaller turbos will be more effective than a larger turbo
Good data for sure. What A/R were the 2 turbos?
Back pressure??
Exhaust pressure
Did you log Exhaust back pressure?
I thought the 76 would light off a lot faster than the 45. That doesn't seem to be the case. Is the 45 just better 76 for these 4.8/5.3s?
The 76mm is kind of buggered. The Gt45 has a huge semitruck sized exhaust that slows down spool but you might not notice this on the dyno much, especially starting the runs at 3k rpm. The 76 will spool earlier but the intake fan is so much bigger and heavier than it needs to be it might not be much of an advantage.
Richard quick question what’s the best cam for dig/drag racing for a 5.3 I have
Tbss intake manifold, cai, 4.10 gears, posi, longtube headers, tune on e85, corvette servo (new subscriber) thanks👍🏻 in advance
IS IT A STOCK BOTTOM END AND WHAT HEADS?
Also, what transmission? If automatic, what's the stall?
Is the t76 a p-trim or q-trim turbine wheel?????
Still waiting for a single s366 comparison.
wish I had one
@@richardholdener1727 let’s start a fund raiser for it. Who’s willing to chip in? I can arrange purchasing/shipping.
Love it!
Could you do a comparison between turbos that are more similar in size? like the 76mm vs a VS 7875?
Would also love a colaboration between you and Viren Singh! I am really curious on the differnce between all the different versions of the 7875...
7875 is nothing to compare to a "7664" with literally 80s designed turbine and compressor wheels.
How does A/R effect performance? Are these turbos available with different A/R? Probably have multiple videos on this already, maybe same cool side but different hit side.
Ar changes response much less than a change in wheel size and AR
So how would twin gt45s work on a 5.3?
they will do 1500 hp or more
Richard is right...but it would be pretty laggy for a street car setup
Pure track car/ back of the track type deal.
twin gt35s should do 1200hp imho, would be interesting.
@@denisohbrien cx has t4 gt35s. I just wonder if the exhaust would be a limitation over 1000hp
Back pressure before turbine
You should add in the $250 ebay billet 7875.
link?
Do twins vs big single.
He have before
Would you test LS intakes on Windsor's?
how
@@richardholdener1727 3d printed adapters, potentially? wouldn't have to be a modified engine, just to see if they are better than windsor offerings, or maybe you could test it the other way windsor intakes on LS 🤔 sounds like a cheap interesting test
Can you push up to 1500HP with the 4.8
yes-but stock stuff won't last long there
Exhaust back pressure is a turbo's worst enemy...
I’m in Glendale
Hey Richard....what tubular heads were used in this test?
lots of people sell them
Why there is a change in the boost curve? Because the turbine is too small for a 4.8 lt Richard! A turbine wheel of 74.1/64.6 MM is much more suitable for the 3.8lt V6, and even in for a 3.8 lt is small, actually it's a good size for a 3 lt engine, not more.
I am talking of course for the T76.
that's why I used two of them on the big bang motors
@@richardholdener1727 it's a bit weird Richard. A few days ago you turbocharged the 3.8lt V6. It would had made much more sense to conduct this test with this engine. The T76 is so small for a 4.8lt that even if they are some gains in the low rpm range in comparison with the GT45, these are minimal. A test that would had made sense in the 4.8 lt would had been between a single GT45 and two cheap Chinese T3/T04E from e-bay.
Exhaust back pressure
The GT -45 is a 69/77 and the CX racing T76 is a 76/65. So the smaller hot side on the T76 definitely chokes its performance on this application.
agreed
Is this why the 45 seems to light off earlier than the 76 also? I was thinking about going the 76 route on a remote mount Astro van with a 4.8. Maybe something a little smaller may be better, not sure at this point, lol.
Do you really have to run two wastegate?
only on the engine dyno
Back pressure
Add more boost!
👍
I would say backpressure
turbine inlet pressure . no hassle
Back pressure.
Your na power is made with a delta of 10.7 psi it idles at 4 psi do the math with 10.7 psi instead of 14.7 it comes out to 41.3 per psi and that almost correlates to your gain that’s why it looks like your motors are beating the formula I’ve seen slightly less than 4psi idle but it’s not worth mentioning
idles at 4 psi? the formula only takes into account na power/14.7 psi
You measure power at WOT, that is about 14.7psi/1bar/100kpa absolute on a NA enigine.
I don't see why the idle should matter?
Backpressure
Ford inline 6 turbo test next
X Pipe is NOT Y Pipe
"400hp" 50mm t3t4 and a 4.6L OHC... (not driving at 6000rpm) low boost creep. 1500-3500rpm range? 3psi, "adding a 2L 4 cylinder". "the 74hp 2L as is, was enough to get down the road". 4.6 to 5.4 power with fast response, just have to dial out the transmission kick down with the overdrive off... not compressing 5.4L at idle... "ecoboost", read on a form page not to go past 400lbft... 3psi and boost creeping shifts does it at normal operating range.
Always more gas thru the snow plow on farm truck's 360ci, 80's Mopar easier to work on then anything else. trucking not racing
Hard decision $163 gt45 or $1800 used lsa ? 🤣
AR, Back pressure, exhaust housing size. Now let's compare a GT45 and 7675.
I have personally had a GT45 on a 4.8 in a fox coupe with 355 gears and an 80e Circle D 3600 billet. It was a boring turd from any punch or roll. Once it got up on the pipe....It ran extremely well. But was a laggy turd. I swapped it for a PT 7675 and it was not only a night and day difference, it was complete annhilation of the GT45 turbo. I run a Terminator X. Sold that car and am doing another fox coupe now with a 4.8 and a Rev9 7268 with a th400 I expect easy rolling burnouts and fun. I don't care what the dyno says the boost and drive pressure is of a gt45. It is just too large of a backside to be feasible on a street driven 4.8. Race car, maybe fine, but unless you want to anti-lag every redlight. Stay away.
a 7675 had better spool than the GT45?
@@richardholdener1727 That's my guess with the smaller 3 inch outlet vs the 3.5 on the GT45. would improve response and spool. Just a guess.
@@tunerdadtunerdad7927 I'm running a GT45 with my 4.8 sierra swap also with an 80E limited to 7lbs until I upgrade my fuel system/retune. Prior to my convertor change I liked to call it my LazyBoy turbo. Just went with a FTI billet 3500 and now it blows the tires off if I footbrake it anything above 3k. (Mini spool 3.08 and 275 section tires) . But I still think the 7675 would be a big upgrade. Glad to read your input.
@@chrisgallimore9083 Yes....same with mine. I could manipulate it to get the boost up. But just driving it around or punching it from a slow roll...Lazyboi is a great term. A lesser powered Heads cam car would run and hide from me if I wasn't ready. That sucked. I put a Rev9 7268 on a ls6 cammed 4x4 truck and it moves out hard from a dig or slow roll. So for I am going that route on my fox now. I say 500 HP right now is better than 600HP here in a minute or two...Lol
The T76 (aka 76/65) is a great example where the turbine is too small to flow enough, but spools slower despite that since the compressor wheel is so large & heavy. The GT45 is almost the reverse as a 67/78 turbo - a much larger hotside than compressor.
The T76 also uses much older tech wheel designs vs the GT45, so it's less efficient at almost any boost and needs more exhaust energy to spool it up. It's just a shitty turbo!
Good poop!!!
Backpressure.
👍🏽🇺🇸👍🏽
Exhaust backpressure. Period...
there is no need for the period at the end
Personally I blame squirrels
Shelby Dodge is NOT Shelby Ford
Same guy.
The 1986 Shelby Omni GLH-S was a modified Dodge Omni GLH, with changes made at the Shelby factory. They were retitled as Shelby Automobiles cars sold at select Dodge dealerships. GLH stood for "Goes Like Hell" and GLH-S stood for Goes Like Hell S'more. Just 500 were made.
Wait, this involves math? I'm outta here...
😛
get off your ath and try some math!
hehe 😄
Ubiquitous...
word a day dictionary
Back pressure?
Back pressure
Back pressure?
yes
Back pressure
Back pressure
Back pressure