Any comments using 3.92 final drive ratio on S2000 with supercharger (350hp), the car weigh in just a little over 1000 lbs car?

Thank you

 

Are you specifying 350hp because of the power to weight of a caterham/lotus 7 with a f20/22?

 

Yes sir......F20c
thank you

 

So you have an f20 in a caterham and want to know if you should put a 3.9 FD in the rear? Does the car actually have a supercharger and 350hp? Or were you just using 350hp as a reference as stated above?

 

I'm running 3.90s and they are a hoot at 2600 lbs. At less weight it should go like a bat out of hell.

 

How the hell does your car weigh 1,000lbs, is there no motor or transmission in it?

 

Caterham/7 they are like 1300lbs

 

I have Cosworth 3.92 with QUAIFE rear end, I don't want to spent anymore if I don't have to. I know you guys are using
4.10 or something. The car actually has a supercharger in the 350hp form. The dyno was 342hp @9,200rpm (truncated screen shot) but when we lean a little bit to 11:80 AFR it did a little bit better to 352 hp. Also, 11:80 afr across the board, is this normal afr for some of you in the forced induction? Can I still lean it a bit more?

Just wondering any thoughts on 3.92 with that kind of weight and power. Some will say that 3.90 is ok if you have 500hp but irrelevant if you have lower than 500hp?? why?...........thanks folks

 

well ultimately it would also depend on which transmission your using and tire sizes, but on an S2000 with stock gearing (4.10) the car would be capable of 170ish mph.

with the s2000 some of these guys will go with the 3.9 gear because they are shifting so much and going through the gears VERY quickly with 500+whp. Since your car is so light I can imagine it too would fly through the gears with that much power. The longer gearing will also assist with traction and you'll be able to stay in boost longer and shift less. You'll also be capable of a higher top speed which in your car might be scary. BUT on the highway in 6th the 3.9 will allow a lower crusing rpm, not sure if that will matter much to you though.

IMO your car will likley be stupid fast as it is. Shortening the gearing to 4.10 would only make things more hectic IMO. Reminds me of my 355whp supercharged S2000 with 4.57 gears. YES, the shorter gearing made my car more fun @ lower speeds, but it also meant it was shifting more, and I would be trying to shift into 7th gear @ 145mph. haha.

 

Thanks Grandmaster----that make sense to me. Sorry that I did not mention my transmission was also Honda s2000, only my rear end is cossy.
Some people said I need 4.10 but I'm trying not to spend anymore than I can afford. I will utilize what I got and go from there. Cost me arm and leg already.
As far as the power to weight ratio, the car seems to work pretty good at 3.90 diff.
I have to lower the 4 tire pressure at 15psi to hook up though. http://img152.imageshack.us/img152/6008/7engine002.jpg

How about the 11.80 AFR mapping across the board, is this ok or I can still lean it a bit more to harness few more power?

Thank you again.....