C4Russ

So I'll never, I mean never be able to use the car's 160 mph ability. In reality I'll never cruise beyond 90 or so.

So if I were to regear the tranny, what experience do any of us have with doing this with a street car? What kind of improvement can one expect to see for quickening off the line and around town usage. I don't want to do burnouts, I just was thinking that there is a lot of engine torque that could be better used.

dfinnegan

I've been saving info on various gear ratios simply because I read an article on regearing the C4 for road use and my car has been re-geared.

Here are a few bits of info that I've collected. Not what you're looking for, but it's a start.

dougn

i did alot of thinking and calculations on my re-gear for street use. the problems as i saw them were:

the 1 to 2 gap was huge really hampering accleration and general drivability

although 1'st was too low, i opted to keep it because i installed a LWF. i'm glad i did

fifth was too high. cruzing at 80 mph at about 3150 rpms. engine sounds comfortable at about 3500 or 3600 rpms....kind of lugging at 3100

2nd gear was too high for alot of the corners i drive

in alot of situations, 3 was too high and 2 too low

so, based on measured torque and horsepower i came up with the ratios in dfinnegans post. it was designed as a street/sport box. it would be good for tight twisty courses. cruze at 80 mph is at 3700 rpms and it tops out at about 148 mph.

i set-up the cruze rpm because anything over 80 (real mph) will draw the atten of the CHP (red porsche). so i can cruze along at 75 comfortably

re-gearing for track use would produce a completely different box (not a very good street box IMO)....without regard for the 1 to 2 gap, lowering 5th and spacing everything closer

Bill Verburg

here's what you have now, it's really not a bad setup

dougn

if you're really going to cruze at 90, your 5th is good (3600 rpms at 90)....so you really shouldn't change anything

PAOLOP

Bill,
it's a track or street set up?

Ciao
Paolo

Bill Verburg

It is a nice combo/compromise setup.

Reasonable top end
decreasing drops as you go up
reasonably sized drops

of course having the middle-upper gears closer, w/ smaller drops is nicer but it is also harder to accomplish w/ a 5 spd. while retaining a reasonable top end.

ideal gearing is going to be different for everyone depending on use and other mods.

a dedicated track car w/ race engine has differnt needs from a dual purpose car.

PAOLOP

Thank you very much, Bill.
Ciao
Paolo