epitrochoider

Has anyone hooked up a Rotary engine with a CVT (Continuosly Variable Transmission). This would be such an awesome partnership, because keeping a rotary at peak hp rpm means better acceleration, and we all know the rotary can stay at high rpms for a very long time. Ford, Honda, and some other companies make some. Someone on here with money should convert transmissions, and brag to us about how good it was. The only bummer is that shifting is so much fun!

couturemarc

We have one on our formula race car, works great. Took some time to fine tune but the car is much faster than the sequential 6 spd that was in it before.

Railgun

But how much are you going to spend on a CVT that can reliably hold more than...oh...even 320 hp? Read up on it...I think the limit is about 300 for a "standard" version. The Nissan Murano is an example. That's only pushing 245 though. I'd like to see one that can handle the torque and not cost a kidney or two.

couturemarc

Bingo!

We are only running less than 200hp on ours and it was modified from a snowmobile, for higher hp you need something better than that. There are many racing sleds that run high horsepower with cvt's but im not sure what they use to handle that kind of power... its a good starting point though.

Whizbang

cough cough ideas have to start somewhere cough cough

88IntegraLS

300 hp at 8k rpm is not the same as 300 hp at 6k rpm: transmissions and rear ends break from torque, not hp (unless we're talking bearing failure).

The honda CVT from the 90s civic might be a good starting point for a 300 hp rotary with 200 ft-lbs torque. Figure the trans (if designed by Honda) has a factor of safety built into it making its ultimate strength much more than the 100ish ft-lbs torque that the original honda engine came with....

Honestly I think CVTs are a great idea for performance, but they don't seem to sell.

SPiN Racing

The Sidewinder Formula 500 guys that I do a lot of stuff with run a 500CC motor.. well 498.. and they run I believe 9K on a snowmobile CVT.

Now.. thier partner/buddy runs a 3 cylinder 2 stroke that makes over 250 in either CSR or DSR.. dont remember the class.. but its WICKED loud... and runs the same CVT.. only with different weights.

They have been harassing me to put together a RX-7 with a CVT for a long time.. Even trying to get me to put one in EvilAviators 20B. Because they are convinced it will operate un-modified behind a 13B N/A with ANY level of work done to it.
20B they were talking of making some mods to it.

I have watched them LEAVE the other Formula cars at Sebring etc.. with ZERO problem up to thier top end of 120-130.

Now.. as thats a low top end... here are some lap times for those thinking its slow.......

F500 at Daytona.... a Top end favoring track to be sure...and the F500 doesnt have much top end:
2:11.584

Winning EP car?
2:12.352
FP
2:20.020
GTL (GT Light)
2:23.903
SSB
2:24.721
GP
2:26.031
HP
2:26.537
SSC
2:28.084
GT1 (2 times cause the leader checked out)
1:57.102
2:01.210
GT2
2:04.714
2:10.639
T1
2:05.476
GT3
2:10.702
T2
2:14.312
2:20.488
AS
2:12.965
2:15.074

As you can see... having acceleration that is linear does help.
If you go to Mylaps.com and search for SCCA races with Sports cars in the US.. and look through the groups.. you will see that the CVT equipped cars do real well against those with quick shifting sequential dog boxes.

Myself? I like shifting..

couturemarc

part of the problem with snowmobile cvt's is vehicle weight, sleds and formula cars are much lighter than rx7's. Perhaps the newer cvt's can handle this, im not sure....

epitrochoider

I agree with 88IntegraLS. CVT has two limist: rpm and torque. rpm and hp can be limited by the bearings, but low torque limits are what keep CVTs out of so many cars. Rotaries have lower torque, so they should be alright when paired up with some CVT that can handle the power. For example, I bet that Nissan engine has a crap more torque then a rotary. Thats why I would think the match up would be easy. Psh, duh! It is obvious a little tiny snowmobile CVT can't handle a real car's engine. Also, can a Geo Metro engine handle a big block V8 with 500 lbs of torque? NO. SPiN Racing is right, shifting is fun, but a CVT would be innovative, and you could make it fun. It would be sweet to have a shifter **** that just moved in a straight line forward to backwards that controlled the transmission ratio. Then ur still controlling it. Plus, if I installed one, I would keep a manual clutch, with a heavier duty pressure plate!

Railgun

246@4400

James Clarke

So the reason i looked this up was for a snowmobile build. Weird i know. If anyone has any ideas for cooling and making a custom engine mounts. Not sure which platform ill be using as of yet. Also need to find the engine and parts. Any help is greatly appreciated

peejay

Oddly enough, I'd been considering de-AWDing a Subaru CVT for rear drive use. The sticky point is controlling the thing. The algorithms for a drive by cable engine would be weird. They really need drive by wire.