Originally Posted by Exidous
I probably knew that in 2004.....been a while since I looked that stuff up. lol Thanks. I'll start looking for an S4 TII diff unless something cobra jumps out at me for the cheap. I'd still really love to run 3.72's in europe.
Are you using 5th with a 129 trap or a big tire like the 26" ET street? My 4th tops out at 117 and I am definitely getting there before the 1/4 is up.
Looks like a 26" tire, 3.9 rear and 6600rpm redline will net you ~130 in 4th.
To answer your question, my car has the rev limiter set to 6,800 and I always stay in 4th. Your calculations are correct, since I run a 26X10.5 M/T ET Street I usually pass thru the traps at about 6,600 RPM.
There is actually a way to run 3.73's in an FD pumpkin, in fact if I can find some time, I might be running 3.73's this season! The secret is an uber-rare Mazda MPV: It's got be a 2WD 5-sp which is seriously a unicorn... it took me 2 years of searching to land a diff from one. They share the short pinion length of the FD and have a 3.73 gearset. The only difference is that the pinion diameter is 5mm less... people who are currently running 3.73's usually use a pinion sleeve to make up for the diameter.