Gearing Change?

MikeP944 · 01-09-2005, 06:52 AM

This may be a silly question, but has anyone changed their gearing in a 944? I did this in an older Monte Carlo and it was like driving a different car. 5th is a pretty tall gear, so on the highway it shouldn't be too noticeable, but I don't do much highway driving anyway.

Britwrench · 01-09-2005, 08:06 AM

You could put a 924S trans in (has a lower 5th) apart from that anything else is waste of money for a street car.

MikeP944 · 01-09-2005, 08:46 AM

Why would lower gearing be a waste on a street car? The whole idea is to have the car pull harder in every gear, I don't need top end speed, how often do you drive over 100mph?

Harpman2 · 01-09-2005, 09:26 AM

Put a shorter 5th gear in, I've heard of people doing that. Somebody on here should be able to tell you the cost.

Britwrench · 01-09-2005, 01:32 PM

These cars are not designed to pull hard, they are based on the European thought of high-speed cruising and good handling (944 was praised for handling by (I think) Road and Track) so unless you are planning in major modifications, the 924S trans is it.
If you need major "pulling hard in every gear" either a 944 Turbo, 911 SC or Carrera 3.2 (or newer), 928GT is what you should buy.
Of course, you could always buy an Monte Carlo, but the handling, braking and steering is somewhat different. It depends on how you drive or want ot drive.

Taz's Master · 01-09-2005, 01:58 PM

I wouldn't think that a shorter 5th gear would give an improved acceleration until in 5th. The ring and pinion would be the way to go, especially since this is a noted weak link in the tranny. If this mod could be done within reason cost-wise I would be very interested.

Britwrench · 01-09-2005, 02:16 PM

Sorry, cost and any appreciable gain wise, not worth it. As in most things, there is always a trade off. On r&p ration changes without engine mods that usually means that first gear is now not usuable.

For an example; install 215/70/15 tires on a stock 944 and find out that pulling away up a hill is now major clutch trauma because gearing is now too high. Yes, we have a customer's 944 with those tires, on the highway it's ok.

The 924S trans only reduces 5th gear and as I said before, doesn't change anything else. The are not many real (apart from FR Wilks chip) ways of improving the car without, usually not too good, side effects.

I like 944s and have one, work in shop that repairs them but the reality is that what you have is a 944,which is fast but not a car with the capability to accelerate quickly as some people perceive they need even though it will out-handle most other cars. Spend some money on installing the Koni-Sport shocks and MO30 sway-bars and it will go round corners faster than before.

SoCal Driver · SoCal Driver's Garage

How does the 924S trans reduce 5th gear? Ring a pinion? Or is there a reduction some where else in the tranws?

Britwrench · 01-09-2005, 04:02 PM

The gear tooth count on 5th is different, the rest of the trans is the same.

Harpman2 · 01-09-2005, 06:45 PM

the S2 (or 968) added a 6th gear, I heard size wise that added gear fit right between 4th and 5th gears of most 944 cars because their 5th gear was WAY taller than 4th which may have been good design if you live near an autobahn, but not in U.S.

my 2 cents.

Britwrench · 01-09-2005, 07:58 PM

Yes, 968 uses a 6th gear and also a different design transmisison. In that trans 6th is even higher as the torque curve is different (and Audi supplied those gears). Unless you use the car on a long freeway (or autobahn) 6th is rarely used. In other words 5th on a 944S2 is almost the same as 5th on a 968 which has another gear to go.

SoCal Driver · SoCal Driver's Garage

I guess I'm still a little lost on the different ratio 5th gears. Since the drive has to be turned around 180 then there is a ration between the incoming shaft and the shaft that goes to the R&P. Or is this 1:1 and the R&P is actually a different ratio than other NA 944's?

Britwrench · 09:28 PM

No, look at the picture of the trans and you will see. The power goes from the engine to the input shaft, that has gears on it. Then the power goes through each gear as selected and to the pinion shaft. All Porsche did was to change the number of gear teeth on 5th ratio to change it. Much like they also did to other transmissions. The 180 degree is only at the diff not in the gear train. Just seperate the gear sets from the diff and it's a bit easier to visualise.
And yes, the r&p ratio is the same for 924S and 944 models. A better way of looking at it is to compare with the Hewland trans on race cars; each gear set is changeable. This is also possible on some Porsche trans for race use.

bazar01 · bazar01's Garage

The pic above might help.

The input shaft is on top while the output shaft is the bottom that has the pinion gear.

On the left side of the case is the 5th gear set. In this tranny, the input shaft 5th gear has 37 teeth while the output shaft has 27 teeth.

You can change the 5th gear set as long as you maintain the same centerline. You can have a machine shop make any combination you want as long as it maintains the same center distance.

On the 951 tranny, the ratio is 35:29 on a 9:35 R&P
On my S2 it's 36:28 on a 8:31 R&P.
I am not sure about the 924S, maybe a lower ratio on a particular R&P ratio.
Just do the math on your desired final ratio.

SoCal Driver · SoCal Driver's Garage

Got it.