Best final drive gear?

[MikeP944]

I want to replace my final drive gear, but I don't know what will work best to increase overall performance. Little help?

[Britwrench]

Overall performance is only going to "improve" by changing the car. Changing the final drive ratios always affects all gear ratios and unless altering the engine torque curve, hp rating, rev band range and a bunch of other things all you actually end up with is a trans with ratios that now don't work with the engine. 944 overall performance is good and that's what the car was designed for. I would only install a chip, which usually increases mid range and the throttle disc, which makes the pedal feel better. After that you will be spending money in not achieving too much.

Your choice and your money. There are only a couple of ring and pinion ratios availble anyway.

What do you want to do with the car and what is your budget? Then ideas can be suggested.

[drfatz]

One thing that can be done (as suggested) is changing the final drive ratio. One must remember that this car was designed to be practical, get reasonable fuel economy, and be able to be driven at low and high speeds efficiently. If your looking for better acceleration then you can change your Ring and Pinion from 3.88 to 4.111. This will get you up in your torque range faster, but it will also shorten all of the gears thus making it a little worse of a highway car. It you were looking for more top end you could change to a 3.375 R&P. However, getting the 944 NA up to its "maximum" stock speed is difficult enough so if you dropped the final drive you would need a runway to get it up there
-Dz

[tifosiman]

Originally posted by drfatz
One thing that can be done (as suggested) is changing the final drive ratio. One must remember that this car was designed to be practical, get reasonable fuel economy, and be able to be driven at low and high speeds efficiently. If your looking for better acceleration then you can change your Ring and Pinion from 3.88 to 4.111. This will get you up in your torque range faster, but it will also shorten all of the gears thus making it a little worse of a highway car. It you were looking for more top end you could change to a 3.375 R&P. However, getting the 944 NA up to its "maximum" stock speed is difficult enough so if you dropped the final drive you would need a runway to get it up there
-Dz

While the above is true, it is not a simple thing to change out the r&p gears in the 944 transmission. It would cost you at least $1500 in materials and labor to have a shop do this work for you, and that much or more for you to do it yourself with the cost to purchase the proper tools and bits. That would be assuming that you could do it correctly yourself. This really isn't something for a shadetree mechanic to try.

[fast924S]

Like I said in another post, I had the 4:111 gears installed, The gear set was approx $900 and the labor for the tranny was $1300, I liked the way the 4:111 gears changed things. I dont use my 924S as a daily driver, mostly just back road fun, I noticed that I was in the powerband most of the time which was very nice and it felt like 2nd and third did pull harder. As for high way use I was at like 4500rpm at 80mph kinda sucked. Also top speed drop to like 125mph. Its not a upgrade for everyone and I only had the 4:111 for approx 2 weeks because they where setup wrong and it blew up. Unless you have some serious mods then I would spend the money on other things like, brakes, suspension, short throw kit, chips, exhaust, MAf upgrades.

Also I would not attempt to do this install your self, This is not like swapping gear in a rear diff on a american car, this is much more difficult and the proper tools and specs are needed and so is a hydrolic press. I usually instll eveything myself but on this upgrade I just didnt have the proper stuff to do it and it seems like the guy who installed it didnt eather