S3 E40. We road test the 670 Predator Renault with the new exhaust and Comet 94C clutch
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- Опубліковано 26 вер 2024
- Season 3 Episode 40. Jimbo finishes the custom exhaust on the two cylinder Renault and then modifies the COmet 94C clutch for better performance.
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Jimbo
The walls in our new studio are bare, if you want to send swag please send it to:
Robot Cantina
207 S. Sedgwick Ave
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Point the exhaust straight out the back to take advantage of that sweet 2.5% horsepower boost from the exhaust thrust.
*stares in P-51 Mustang*
It's a thing.
Some gas turbine engines (turboprops) in aircraft ie the Garrett TPF351 have exhaust thrust augmentation ~100hp IIRC.
Also, zoomie headers of nitro burning funny cars and top fuel dragsters make effective use of exhaust to create substantial downforce. Jimbo could create a twin system (with a balance tube) and angle them like that LOL.
@@ThePaulv12 Yeah, I remember reading that the Allison engine of a P-51 produced so much punch with its exhaust, it actually gained forward thrust.
May have been the Supermarine Spitfire, though. It's been a while.
@@SamwiseOutdoorsin general all wwii fighters had same exhaust thrust in the ball Park of around 100hp but we talk about engines with displacement from 20l too around 70l
Haha.
Wow, I didn't know that about old airplanes
The tension of a battery going dead, the clutch and its iffy shifting, I was on the edge of my chair the entire episode 🎉
❤it! That hour gained at time change probably enters into the equation.
Cliff hanger, I know!!
I feel like peak Robot Cantina would be putting a supercharged predator engine in a AC Cobra Kit car for performance testing.
With a kubota porsche 356 in the barn
Peak Robot Cantina would be putting it in a real one
I like the Briggs powered full size '69 Boss Mustang.
A Shelby predator motor.
I'd throw $50 towards it!
Love your content Jim. Lots of fun. CVT weights and spring and or ramp needs to be adjusted to match the power curve of the engine. There should be some old sled racing guys around to help. It is a bit of black magic!
No Black Magic. There's Predator engine power charts add Comet clutch charts online to set it up properly. I love the Internet because I have a powerful thirst for knowledge and it's at my fingertips. While I'm working during the day, my brain is always thinking. So when I think of something I want to know more about, I write it down and make a list. Then at night I go down all the rabbit holes and learn. Maybe I'm the only one that does it I dunno.
I do the same and so do some other people. I think we are a different breed of nerds lol
@@MrDaniel1052 LOL Indeed
Unequal length headers might work in your favour. This being a V2 engine with unequal firing intervals.
@@MrDaniel1052 That's why guys like us are a little smarter than the average Joe! LOL. Plus we can hold conversation with just about anyone.
The CVT seems to be performing normally, although some tuning could still get you some performance. At WOT, it should hit top RPM and stay there until you lift your foot. You shouldn't be dropping rpm as the CVT upshifts.
This channel is like an adults version, of Saturday morning cartoons.
Pure enjoyment.
Thanks Jimbo!
nailed it
The thicker, more rigid belt saps power compared to the old setup. I had the same experience when I changed from a normal to a reinforced belt on my scooter.
And with all the power the predator engine puts out, that could mean a bunch.
Do belts need to be broken in? Get more flexible over time?
that was also my first thought.
It's hard to believe there is no perfect set up for this combination. I'd complain to Harbor Freight. Dear Harbor Freight, I find your 670cc engine to be unacceptable to power my 1960s Renault. I expect satisfaction!
I built a flathead Briggs made a big cam took a little off the head and decked it ported and polished it did a little oil system work then put it in a pretty much stock lawnmower and changed the belt and put more spring pressure on it it had separate gas and break but I needed to oil the kevlar belt too let it slip when I wanted to shift it would only last so long tho then it would grind really bad from a stop and not stop when it was in gear sometimes it wouldn't come out of gear but it was super hard to stall even at idle I think I only stalled it once cause I flipped it 😂
having to change so many things at once can make it difficult to figure out just what needs to be changed to get back to where you were. As always the journey is entertaining, thanks for taking us along for the ride.
2:12-Well Jimbo, you just proved unhirable as an engineer for many auto manufacturers by actually taking into consideration the ease of removal of your designs. How disappointing. 🤣🤣
So glad it's Sunday again and Jimbo is back with another video!
Thanks man 👍💪✌
Love watching these projects come to life! I'm a snowmobile guy at heart, would love to see what a 2 stroke snowmobile engine could do in an application like this!
I really like how you walk through the variables of the process
Can't wait to see the bigger carb on the car now that the CVT is working!
May be worth to give 2nd gear a try since the overdrive capabilities of the new cvt. May be able to run to 50 in second now.
I figured I wasn't the only one thinking this. 👍 I would imagine that the overall gear ratio has changed quite a lot now between the larger CVT where 2nd gear would be quite beneficial.
I am guessing that the gearing might not allow 50 in second gear.
Agree. I'd try it.
@lovemye36 original cvt would not. Ran out of range. But if I remember correctly he said the new torque converter had a much higher ratio at top end range.
I appreciate that you want the pipes to be smooth and uniform diameter so people won't criticize you and say your work is ugly, I totally understand wanting it to look good for the video. Those primaries could probably be quite a bit smaller without costing much power if any or could have wrinkles, dents or spots where they are smaller diameter to make your equal lengths. Engine Masters with David Frieburger did a test on a Mopar 440 where they purposefully crushed down the primaries on the headers a bunch, equal and unequally, beginning with either 1-7/8 or 2" primaries, it had basically zero effect on power, that engine has 8 cylinders that are each 900cc, 7.2L ÷ 8, so in all likelihood you could have probably made that exhaust less pretty to get your equal length and it probably wouldn't have effected anything much. Who knows what primary lenght, what primary diameter and what point you place the Y pipe would produce the optimum performance, perhaps the combination that produces that absolute highest peak power might produce less average power or power under the peak than a different set up which could end up producing better acceleration than an exhaust that generates the highest peak number? I realize that is not something that you could really get in there and find out with no access to a dyno and not unlimited time and money. It's cool to think about though. Love your stuff, I watch every week. I was in Brazil from August to Nov and your show was a nice treat every Sunday morning so I could hear someone speaking English and messing with engines to keep me entertained, thank you 😊
As much as the episodes themselves, I've really come to enjoy listening to the music track at the end... You caught me off guard with the 'DOH!' 👍😉🤣🤣🤣
😎🇬🇧
I noticed that the old speedometer on this car goes to 100. Seems like a good final goal for the project!
100 km/h
@@webmasaledefinitely mph, top speed was 135kmh, or 85mph.
@@Jan-ny8hn since it was imported from Europe(first episode), it does not have mph.
@@webmasaleThe european speedo goes to 150 kmh. This is an american (or more likely UK) speedometer in MPH. Probably replaced since the driver is on the left.
@@Jan-ny8hn if it's an aftermarket one could be anything, he said it was imported from Poland. I did check pictures and all go up to 100km/h at least on the 70s model.
Yay! A cup of Joe and Robot Cantina! What could be better on a Sunday morning? 😊👍🏼
I was so excited for this one. Maybe once you change to dual carbs and those new belts soften a bit you'll get better results.
Great video as always Jimbo. :) Your editing just keeps getting better and better. The pacing of this video was a bit slower than some of the others and I actually quite liked it. The modern YT pacing is really rushed, whereas this video felt a lot more like a natural conversation chatting with you while sitting in the passenger seat. I especially like that you included a little bit more lead in and lead out with each scene, giving us a chance to walk along with you to the car, around to the back, climbing into the driver's seat, and so on. It feels a lot more like actually being there, rather than an action-packed montage. Both styles are fine and you do both well, but the more natural, casual pacing just seems more appropriate for this kind of a project. I watch every Sunday and I look forward to next week. :)
Gotta agree getting better and better and the pacing is great.
You should get some cheap sawdust/mdf panels or thin metal sheets to cover the underside of the car as much as possible and cover up the front grille from behind (could just use cardboard and tape for that). Cars didn't really have flat floors until the early 2000's and they make a massive difference to lift and drag especially. With how little power that engine makes combined with how much every accessory running off that engine saps the power it could make a sizeable difference for pretty cheap. Just leave a bit of an opening at the back to pull air in to cool the engine and leave the top open to exhaust it back out so it doesn't build pressure in the engine bay.
Also, if you can, 3D print a long-ish (150-200mm) trumpet for the big carb when you eventually get back to it. You can print a mounting point slightly below the top of the trumpet and keep a bit of clearance out to the sides of the top of the trumpet to fit an airbox thingy so you can keep the filter while benefitting slightly from intake resonances.
Consider adding some vents to the back of the interior as well, or just opening the rear windows very slightly; would help pull air back out the car to keep yourself cooler in that old cabin.
Your videos make me beyond happy.
Regarding the CVT, have you tried starting in a lower gear to force the RPM higher to advance the CVT faster? (And I realize this may be a dumb question. I just don't know, so I'm asking. LOL)
Sundays are so sweet with Robot Cantina in the feed.
Hi Jimbo,
Just so you know. Equal length headers only work on a two cylinder engine, when the firing interval between the cylinders is 360deg. Since this is a V-engine. One exhaust tube should be a bit longer than the other.
What should be the same is the intervals when the exhaust pulses reach the collector.
Nevertheless great content as always.
A lot of the stuff you test is applicable to my project car. It's a Fiat 126 from 1973 with a 2cyl, 650cc engine in the back.
Maluch. Getting rarer by the minute
Someone get this man an exhaust bender, he can literally do everything else.
exactly what i was thinking, this man needs a rouge fab sponsorship!
Sunday mornings with Jimbo are great!
Awwwwe yeah! Coffee and Cantina time 😎 hope you had a good week, Jimbo! Cant wait to see what you got up to.
I like the grader just driving down the road like it's no big deal 🤣
Softer spring might help the cvt to shift earlier keeping the engine in lower rpm for more torque.
That, or heavier pucks :)
OK, the "D'oh!" at the end there made me grin.
Am I the only one who noticed the boxer engine sound with those unequal length headers? I was super excited for the engine sound when you mentioned that and it did not disappoint 😎
Appreciate your Videos. I like the way you test every change to see what effect it has on the cars performance. Looking forward to more tweaking on the Renault and Diesel Insight Videos.
The CVT should idealy keep the engine in the same rpm (rpm where the engine has the most power)all the time while excelerating
Basic CVT tuning, known by any kid messing with his 50cc scooter
I love that old Renault.
Hey, the lone wolf 9000 made an appearance lol
I think the newer drive belt setup is doing pretty good considering the rotational mass of it
I have a Daff 750 which is a very similar style car. “Daffodil” invented the independent centrifugal clutch drive. Eventually it became Volvo. Mine has two centrifugal clutches, one for each rear tire. They were ahead of their time and out performed the drive systems of the day in all weather conditions, especially since most roads were dirt. The independent drive would allow each clutch to spin at different rates for traction. However, they were not popular because folks were used to shifting gears and didn’t like the automatic type transmission. It has a 2 cylinder motor with horizontal cylinders. There really is nothing to it. You can drop any motor in it and bolt it to the four bolt drive shaft or run a jack shaft and you’re off to the races. The master brake cylinder isn’t much more than what comes on a scooter😂
I wish I was closer, I’d give it to you. The body is shot, but the drive system is good😊
This is the quirkiest of all car channels and i cant get enough.
He should have a bumper sticker, my other car is powered by a cement mixer! Lol
Jimbo you would be my favorite neighbor that I would share my top shelf bourbon with and tinker in the garage!
Ain't even watched the video yet but I'll just go ahead and say it was awesome because I already know it will be!
This testing takes me back to my days as a test engineer. Keep up the good content 👌
I love this little Renault project. I certainly don't find the videos "meh."
To get nicely matched primary pipe lengths, try using a collector box rather than a "Y" branch. The pipe ends can then poke into the box independently of each other, the ends don't need to be level with each other and you don't have to use strange convolutions to match the primary length.
The outlet to atmosphere can then leave on any side of the box that suits. Simplifies things no end.
Space shuttle command to launchpad over... bzzt, launchapd clear and the air filter is on place. Roger, starting the countdown sequence now !
He sure gets you invested.
I need to start going to bed so I can get up to watch your videos on Sunday morning instead of staying up all night. :D
MUCH LOVE FROM INDIANA!!! Keep up the good work!😁
Enjoy these. Feels like what ill do when I'm retired. Keep it up!
Your videos are the best way to start a Sunday morning thanks for sharing
This car performs allmost like new from factory with oem engine😂. Great work
Keep these coming, this has become my sunday morning ritual!
I see the next project is sitting out back. A twin predator powered bus. 🤣🤣
lots of crazy work into this
Thanks for the weekly fix!
Thanks for another great video!
I love the fact that we can hear the engine over the exhaust finally. It sounds like it is starved for fuel (As you mentioned Jimbo). Also these have no torque at low RPM. I realize there is transition time to shift but I think you are currently at a point where a start in 2nd would work better to get momentum as the engine RPM would be more in the proper range for peak torque despite the time loss of the extra shift transition time. Best part is we get to see what you did in another week and live vicariously through Robot Cantina!
Why did it take me so long to see that “BFE” sticker? Love it!!!!
🎉
Still need a downdraft carb and tune the extractors. Tuning the CVT was first on my list.
Wen tuning the extractors, make the volume of each pipe, the same as the volume, or twice the volume of one cylinder.
Glad to see the project getting back out of repair mode and back into testing things
Thanks for another banger of a video Jimbo! Have an awesome week!
Hey Jimbo just found your channel! Love the content!! Saw the Arrow H picture in the video. Greetings from Nashville KS 👍
I would definitely think the dual carbs would be the best setup for this build. Also might try a lighter main spring on clutch to increase rpm gain speed..
Olov Aaen clutch tuning manual will be a big help to you.
Instead of making header primaries the same length, I think you could make the 2nd pipe (exactly/roughly) 1/2 the length of the first pipe.
Another complete Sunday with the latest RC video! Winning!
ANOTHER great show , i'm a V8 peddler , but love watching this quirky stuff . if i tried to do that , i would get a fine
This is really interesting and your incremental approach is great. Swapping back and forth between the Renault and the Honda is also very enjoyable seeing the progress on both. 😊
need to put a go pro pointed on the CTV when driving
a few ways to make both exhaust the same size: 1 - connect both above the clutch and extend the new pipe out; 2 - make a circle of sorts on the passenger side (both would probably require you cut a 90º into smaller angled segments or cut slits into the pipe and sort of bend it); 3 - make a muffler like the original one, but hollowed inside (like a glass pack, but just metal tubing)
11:49 looking at how that belt is moving and how it’s all positioned I believe that motor needs to come forward towards the front of the car about 1/8 of an inch. If you look at, where are the belt is riding right before you rev the engine with the transmission in neutral, there’s a gap between the belt in the backside of the poly but not the belt in the front side then as you’re rubbing it, you can see the belt tips back rather than riding perfectly straight. Wouldn’t cause any performance issue but overtime may stress the belt and make it wear out a tiny bit faster.
And yet another riveting episode thank you for dragging us along with the ups and downs of experiences of seeing what can be done maybe next time you should leave us at the shop the Renault would be lighter without 140,000+ in the car!
Sweet!!
Thanks again, looking for the next one
Think it's time to go and up the rpms. Those cvts I don't think were ever intended to move a car, obviously they are holding up and this comet one seems like it would be able to hold up to more power with that much weight. But I think the clutch wants more ripms, with the how slow its changing ratios under load compared to how it did with no load. After all bigger cvts are usually put on things like snowmobiles which rev quite high. I know you can change weights and make the clutches engage sooner or later etc... but it would be like making a stock snowmobile cvt that has a 4500 stall engage at 2k rpms. It would work yes but the rest of it was designed for more rpm so you end up with a slow start. Or in this case a good start but something isnt happy when the cvt tries to change ratio. If I had to guess I think the engine just isn't turning fast enough for the clutch and isn't putting out enough power to overcome the lack of rpm.
I am excited to see how the CVT performance changes when it comes time for an aftermarket camshaft and the torque curve of the engine changes, and makes power at higher RPMs.
Brilliant,really enjoyed,thanks for the video.😊
Thanks again for another Sunday morning video, up here in the great while north it's getting colder and colder and darker and darker every day, just like where you are, ever thought of moving further south? I'm nowhere near anybody's expertise level here but I'd like to see a tachometer showing the rpms to see how the engine goes faster and slower through shifts, but meh. Keep it up Jimbo, great editing skills.
Maybe the heavier duty torque converter simply has more built-in friction with larger belt mating to pulley faces etc...and will always be a bit slower??? They have infinite ratios but friction is still part of the math. I've never fine-tuned them but I've seen others do it. Just throwing that out there. The little motor sounds so smooth. I can't get a cross-country in the little car out my head,...provided it had some kind of air conditioning, lol. Cheers.
I loved the missile launch system panel to start the engine
Next big upgrade has got to be the 999cc big block and if that goes well maybe a fun road trip 👍
This thing is running way smoother now. Looking forward to seeing this thing with bigger carbs.
The engine sounds like it's operating around 2000-2500rpm during the acceleration. That means it's producing only half of its maximum power. I'm quite sure that if the transmission can be tuned to keep the engine around 4k rpm, the 0-50 time will be well below 20s.
The engine is out of its peak torque band on the high end, that's why it struggles there while pulling strongest in the mid range. Factory carbs. Long tube intake runners will help the top end but you'll lose some low and mid range. It's all a compromise based on what you want from the motor.
Replace the centrifugal clutch weights with lead ones that should really give it a kick the heavier the metal the faster it should pick up
Anyone else chanting "come on baby" in their head while watching the speed and timer climb?
briggs 570 28hp 5500rpm redline bigger carb 28mm with accel pump , bigger cam , no governor .,,
after market conrod ,, milled head ,,9.2:1 Comp ratio ,, spark advance flywheel keyway
used briggs muffler exhaust head flange with 1 inch stubs . adapter to 1 1/4 flexi pipe ,, then onto
2 into 1 muffler . . Biggest advantage was heat removal by mounting muffler out side of body .
I have a stainless steel mesh screen folded into an engine cover
You can bend pipes.
It's probably more than you care to do but you could very easily bend those pipes with minimal tools. You can pack the tubes with dry sand and weld both ends shut. Then you get the pipe red hot with oxy-acetylene and carefully bend it without it kinking.
And old school trick is cutting some "V's" half way through where you want a bend then bend the pipe and weld the slits (now closed "V's) shut.
The more narrow the with and the higher number of "V's," the more open and smoother the inside of the bends will be.
@@jamesstoy8967 that's not ideal though, lots of rough spots inside the pipe when you do that. I mean you could do all your bends with pie cuts, but it's a lot of welding and nowhere near as nice as a properly bent pipe.
@@ExtraFungus It ain't the prettiest. But for someone without a pipe bender and/or a way to heat it, it's an option.
@@jamesstoy8967 but it defeats the purpose of trying to build a better exhaust.
Performance 670 does offer an alternator kit that works off the flywheel side of the engine and if I remember correctly the alternator is a 60 amp unit.
Comet 104 clutches are the most common clutch in a snowmobile. Good past 100 HP. One of those would have given you growing room lol!
Maybe it would be a good test to now revisit whether shifting the manual transmission from 2nd to 3rd is better than it was before?
I seem to remember that David Vizard has said something about equal length tubes are not always what you want. You want the exhaust pulses timed equal, meaning that on a odd fire engine, or an engine acting like a odd fire, the tubes need different length tubes to manage that.
David Vizard. Wow, I haven't given him a thought in ages. The David Vizard section of my performance library starts with a book about tuning the Ford 2.0 4 cyl SOHC engine written in 1984. Is Mr. Vizard still up and running?
@@oddshot60 the pinto book is one I should get🙂
Yes he is still uploading to UA-cam regularly😁 He sometimes struggle a bit with words because of a brain surgery, but he still is brilliant.
I think he's still working on a head from the collaboration with Richard Holdener .
@@espenschjelderup426 I had no idea he was still writing. I'll have to give him a look. Next somebody will bring up L.J.K. Setright.
My daily driver is a CVT, and I agree that that unit was slow to glide through the range.
Jimbo, if I'm not mistaken the pucks and the shims on the spring are to tune the CVT with the torque curve of the engine. if you can calculate the torque peak and tune the CVT to use that rpm to go over the range then you will get better acceleration and top speed.
awesome project
Lol! It just never ends, hunh? Lolol! Thanks for sticking it out, though. Once you get this one and the Saturn squared away, I suggest doing something fun with a Plymouth Prowler! In the meantime though, enjoying this journey with you. Frustrating, but fun! 😊
man just listening to the vid i couldn't tell the engine was over reving at all, but adding weights and bringing the rpm down made a huge difference!
I just would put twin pipes, simple fix!