Stage 2 Max RPM ?

[OneFastT]

I was wondering what kind of RPM you guys are turning through the traps. I am having the car tubbed and am getting rid of my spool and going to a Detroit Locker instead. My new tires are 31x18.50 on a 15" rim. I was running a 3.90 gear in my old rear end and am thinking with the larger tires I will need a bigger gear, maybe 4.10 or so. I am also getting a new converter. The talks I've had so far everybody asks what kind of RPM I am looking to run. In my old Stage 1 motor I never went above 6400 but with the Stage 2 I'm thinking around 7300-7500 sounds right. What do you guys think.

Thanks,
Jason

 

[John Wilde]

Jason,

If you are back halving the car why are you putting a locker in it?
With the taller tires you should still be ok with the 3.90s.
The rpm you gear the car for will depend on the heads you use and how fast you need to go.

With the stage 2 heads you can make power to 8200 easy.
With the stage 1 type heads you are better off under 7500.

Turbo motors like a load on them, so going with less gearing
seems to help them MPH.

We run a 29.5 tall tire and a 3.89 gear and go through in the low 7s. We are going to try a 3.70 and maybe a 3.60 or 3.50 later in the quest to hit upper 170's to 180mph.

 

[OneFastT]

John,
Thanks for the reply.

I had a spool with my old setup. The car is still driven on the street occasionally for car shows, cruising...etc and I always felt the spool was to hard on tires and rear suspension parts. My new setup has a 4-link. Would you stay with the spool knowing the car does see the street? I drove my dads car that as a similar setup and the locker felt a lot better. I'm sure the spool offers better performance off the line but will it eat up parts more?

The heads are fully ported stage 2 heads used with the ATR Stg 2 headers, steel crank, ported intake to match the heads, 88 turbo, 90mm TB, 3.5" THDP. My goal is mid to high 8's.

Thanks,
Jason

 

[John Wilde]

Jason,

We have run a locker down to 8.39 @ 166.
A spool is being put in after the next PSCA Race.
If you are going for max performance and some
street driving the spool is what we want.
I guess it will really depend on how much street driving
there is.
If you really want a detroit locker we will probably
have a 35spline unit for sale in 3 weeks.
It was in the $700 range when I bought it.

Your cars sounds awsome!!!

Let me know how the PT88 works with
the ATR Headers. I was affraid that they
would position the turbine housing too
close to the valve cover to allow easy access.

In regards to the down pipe, I would tell you that
a 4 inch or 4.5 inch would work better.

Send me some pics of your ride if you get a chance!

 

[opeltwinturbo]

The Opel shifts at 7600 and usually goes through the traps at 7300-7350. Tires are 32X14 and gears are 4:10. Good luck.