911racer

Why whould they only be used with a turbo or S2 box. Where did that info come from.

The only difference that I am aware of with the turbo/S2/S box vs NA is that the pinion bearing is different and there is some slight differences with the pinion shaft.

Can anyone else weigh in on that one? Erine, any thoughts on that one ?

I have big plans of my own for next year in GTS 1. I have some ideas for a gearbox too, but I am going a different way.

Ed

bgiere

According to California Motorsports and Albin you'd need a turbo/S2 box...said NA box won't work. Supplier I got them from had originally thought they would fit the NA box but was mistaken...That's OK with me as now I'll keep my current box with a short 5th and LSD as a spare and build a new Turbo-based box.

911racer

Did they say why. Call them back and ask about the S box. I have two.

333pg333

Ok so if you can use a Turbo box, then perhaps the cheapest way to create a short ratio setup is to do the S2 ring and pinion swap. Basically this shortens the final drive by about 15%. I have this on my turbo and it is definitely better on the track. Obviously we're talking about different engine power but I think this would be largely immaterial. Whatever you do, don't go to a turbo box without changing either the gear sets or the r&p though. Way to long for an N/A setup.
Here's some recent video to give you an impression.
http://www.youtube.com/watch?v=GSyWaQq972g

Oddjob

The S/S2/Turbo are the same gearboxes. The N/A has different pinion bearings and a few of the input shaft bearings. I have never worked on an N/A trans to compare, but was told by a reputable "expert" that the N/A gearsets are narrower and not compatible with the larger turbo gear sets - but apparently the 5th gear sets are interchangeable, so maybe just 1-4 are not (?).

The S would be a good donor for the short gearset, as it has the 3.889 R/P (which is the same ratio but different part numbers than the N/A box). Its a slightly stronger R/P and will not be as prone to failure as the N/A R/P. Could also use an S2 3.875 R/P box, but the S2 boxes and R/P are worth more because the Turbo guys want that setup (the S2 R/P is strong enough for 951s).

With those Albin gears, stock diam tires, 6500 rpm, youre looking at 60mph in 2nd, 77 in 3rd, 100 in 4th, and 123 in 5th. Thats pretty close ratio, could run out of top end on several tracks, and would be a lot of shifting - but would be fun.

bgiere

I'll give them another call in the AM. Need to get clarification on which box will work with these gears.

M758

personally I would go look for audi 4000 parts. Given the power of of the NA id bet they would take it just fine and be alot cheaper than Porsche stuff. (I beleived the NA box is right out of a Audi 4000).

onefastviking

Some parts interchange with 5cyl 4000 models and Audi 5000 models of some years. Also interchange with some early 924 5 speeds. It's a Audi 016 gearbox.

onefastviking

Joe,
Are you going to the NASA Nationals ?

924RACR

Right - just avoid the '79 5-speed. I'm running a factory 951 LSD in my 2.0L 924 - bolted right in (plus of course re-setting the diff)...

M758

Yep. I will be one of the 31 944 spec cars there. I hope I can do well. Last year I raced there with 25 other 944 spec cars in "friendly" race. I got 3rd and 4th overall in the two races and had Pole on Sunday's race on the 4.5 mile track. All that with 15-20% leak down on 2 cylinders (one reason I went from pole to 8th by the first turn). I have fresh motor now so I hope to be near the front this time around. We shall see.

onefastviking

Great ! I will come by your pit area and say hello. Or feel free to come by ours, you can find me in the garages where they will be having the GTS meetings, just ask around for Viking in that area and you'll find me. Look for the car in my avatar.

See you there !
Viking

M758

I will be in the 944 RV area just off the west garages.

See you there.