Taking into consideration torque coverter slippage at WOT, a 5AT with stock powerband (6300rpm peak power) and a 4.08, the top speed in each gear at 6700rpms is roughly:

1st 33mph
2nd 54mph
3rd 80mph
4th 122mph
5th 147mph

The ONLY way you're going to extend the engine's peak power (6300rpms) is by either cams, intake manifold (Cosworth, SSV), and/or heads. The typical bolt-ons will not extend peak power, but rather elevate the power curve. The engine will still peak at 6300rpms and then power will start to drop off dramatically after 6600rpms.

IMO, a 3.7 gear set is as far as you want to go on a relatively stock VQ35DE. When you gear a car too deep, the motor sails through the powerband too quickly and you end up loosing sustained acceleration.

Years ago, my college roommate had a 90 LX notch 5.0 Stang 5MT with a 3.73 gear set (stock was a 2.73) and simple bolt-ons. I had a 94 Z28 automatic with a 2.73 gear and an intake/catback. His car felt FAR faster than my Z28 because it had significantly more torque multiplication. Every gear had significant pull and snap. The Stang did 35mph in 1st, 55mph in 2nd, 78mph in 3rd, and 110mph in 4th. My Z28 did 55mph in 1st, 85mph in 2nd, and 125mph in 3rd. From 0-40, he'd get me by 2 cars. From 40 to 70mph, it was neck and neck. From 70mph to 110mph, he quickly faded into my rear view mirror. His Stang did 14.1s@98mph. My Z28 was doing 13.7s@102mph.

 

Cruise control is completely gone... if I try to set it at any speed, it just blinks.

Nah, my engine isn't a Cosworth block... just the heads and cams. The bottom end is built as well, but definitely not Cosworth.

 

Main Point Its fun to drive

 

old thread, sorry, but if the engine is fully built, with cams, built heads to handle high revs, and the trans has a transgo kit and 3200 stall torque converter, would 4.08s still be too much? i need to decide on what final drive i want to get, thanks

 

^^^ you'll have no top end... but it would be a good 1/8 mile car

 

By top end you mean 140mph+?
I don't care about that
I'm hoping to make peak power over 7500rpm

 

I suspect it will be under 140mph... if you make peak power at 7500, and can safely bump rev limited a bit beyond that, you might do okay in 1/4 mile... otherwise, you probably wont make it in 3rd gear - shifting to 4th will lose time...

Have you looked up the various tables that match speed/rpm to gearing - that might give you a better idea... there are a few floating around in several forums (including this one somewhere)...

you would need to look up formula and calculate to get exact numbers...

 

I'll be ableto set the rev limit to 8000 if I want with dual supertech springs and bc stage two cams. I don't really care about the drag strip, I want the gears for the road course track. I know 4th is garbage, but with gears 4th should be improved, idk

 

Bump, are there others that think 4.08 would be too much in my case? I've decided to not choose a gear ratio until I know where my peak power is, so no gears until I'm tuned. But still interested in what others think about this, thanks

 

I think it's best you first build the motor, see what your numbers are, and where peak power is achieved. If the motor makes peak power in the 7200-7500rpm range, then 4.08s might not be too bad. However, since this your focus is on the fast road course, I'd probably look to a 3.9 gear as the 4.1s might be too short. Short gears are more suited to drag racing. Longer gears are more suited to road racing. You can also vary tire height to increase or reduce torque multiplication rather than using gear ratios.

You might also want to reconsider the 3,200 stall converter too because the only real advantage to the TC is for launching. Without drag slicks, having a high stall TC isn't going to do you much good on the road course. Road course tires don't hook up off the line like real drag tires do.

 

yea, ive decided to wait on the fd gears until i know where my peak power is. plus i want a nice lsd so can do that at the same time after i save some more cash