iT'S OK FINISH THE 1/4 MILE IN OVER DRIVE?
i RUN THE CAR ON OD AT THE TRACK BECAUSE THE 4 GEAR COMES IN 30-50m BEFORE THE FINISH LINE AND I'M AFRAID THAT IF I RUN IN D I CAN BURN THE 3rd GEAR, I THINK THAT MY PROBLES IS THAT I NEED A TALLER TIRE. WHAT DO YOU THINK?
1994 Z28 a4
150 NITROUS
4.11 REAR END
275/40/17 ON A 8 INCH RIM. I THINK MAKE A 25.75 OUTSIDE DIAMETER

 

I think you definetly need a taller tire or a gear swap down to 3.73, 4.10-4.11 is too high a gear to run N20 on a 26 inch tire.

 

So you start from 1st, go to 2nd, then 3rd, then to OD?

I thought *never raced* you just do it all from OD..

 

Grease had the same problem last year minus the nitrous inclusion.

28" tire - but everything i've read says that the 4.11 gearing is a bit much for N20 applications - you run out of gearing too fast.

 

That Means That I Need A Tire Taller Than 28 Inches?

 

You need to figure out what you expect your trap speed to be, and what you expect to cross the traps at. Then we can tell you the best size tire to use with those gears.

A 28" tall with 4.11 gears will trap 118mph @ 5800rpm, which is the rev limiter on a stock F body LT1 IIRC.

 

How fast are you running?

How tall are your tires?

What do you normally shift at, and what is your engine's redline?

Try plugging some #'s in this gear calculator and see how far off you are ... might mean bumping up the redline a little, or if you have to, swapping to 3.73's.