Tranny gurus: 930 ratios

[Lukesportsman]

I am looking for opinions on a 930 box. It would be used in a lightweight 2300lbish car (future tub) with GT2cams (248I/232E), Carrera or better intake, EFI, and opened up exhaust.

930 box:
1st gear is 15:38, 2nd is 20:32, 3rd is 25:28, and short 4th is 29:23. I have available the stock 32:20 also.

What do guys think about the gear spread? It will be both a street and some track time. The local track is Putnam Park which the fastest I've gone on the straight is 125 (though obviously not in this configuration). That would take me past third gear, but just before braking so don't figure it effect my times too negatively.

Which fourth gear would you guys choose if the above looks good. I realize 3/4 gap would get large, but 1-3 would cover most track time, correct?

Thanks for all opinions

[RarlyL8]

What is your expected torque band and power curve Luke?
I used to run Putnam, great track. Stock Euro gears 2-5 are what I used with my Euro 3.0L SC/915 combo. A 930 trans might be a little long legged if you don't have a lot of torque.
Have you thought about a stock geared 930 trans with an 8:39 R&P? That might be a less expensive alternative.

[Lukesportsman]

Thanks Brian for A response. I sure thought I might get more opinions on this. I would certainly agree that if I were to have one built that the 8:39 would be less expensive, but this is a tranny already built.

Third gear should run out just short of 115. This tranny would give about 150 top at 6500. I haven't actually ran the numbers yet, but the shift points seem very similar to the 915 I have in the 72'. I rarely drive beyond 150 on the street

Yeah, it might be pushing the torque band, but hopefully the hp will hold on to that point.

[Bill Verburg]

just glanced at it quickly, you have huge drops, all ~2k, speed will depend on tires

That is one very oddly setup box for a n/a car

[Lukesportsman]

I guess I left that off, but thought that my signature and the thought of installing a 930 box behind a 2.7 would seem just a little overkill: This would be behind a TURBO application and my fault for not stating that.

Its often said but very true that you can't ask for advice if you don't give enough details. In my lonely mind, I knew what I was asking. I was trying to give cams and weight to determine rpm and engine load, but didn't mention induction....oops.

[mmastro]

Lukesportsman,
your sig states a 3.0 TT ITB...etc. Are you building off of a 930 3.0L or an SC 3.0L? Just curious......sounds like an interesting motor!
What tub will you use? The '72?