CarbonRevo

Ok, so there has been some debate about my S2. I have had this car to a speedo indicated 143mph in 4th gear. I'm running 285/30/18's out back. These equate out to be about .4" shorter then stock 225/50/16's in circumference.

To the topic though, I have had many upon many people disagree with my car doing such speeds. Even with my car doing a speedo indicated 70mph in 2nd (hitting the limiter though). My car indicates 80mph at 3200rpm in 5th gear. I have used the clarks garage method for finding speed in a certain gear at certain speeds, and this formula says I should be 78.09mph. So for sake of argument, my car is off 2mph at 80mph.

Since I have had my car at ~70mph in 2nd gear at about 6500 revs, we can say this is really maybe 67-68mph. However, a S2 trans at 6500rpm in 2nd gear with my tires should only do 60mph.

Other things were my car doing 39-40 in 1st, 102-103 in 3rd. A S2 trans is said to do 35 in 1st and 89 in 3rd at 6500 revs with my tires. My car is off these targets obviously, but would my speedo really jump from 2mph off at 80 to 13-14mph off at 102-103?

My car has done 39, 70, 103, 143 in 1st-4th gears...and a turbo does 39, 69, 102, 139 in 1st-4th at 6500 revs. So it's obvious to see my car is close to turbo figures.

The main question; were turbo trans available without a cooler? I have no cooler lines or anything and the trans appears stock, and no known change over to a turbo trans. However, my car doesn't line up with S2 trans figures.

Also, is there anyone running 285/30/18's that can give me an rpm number at 80mph in their car?

I do realize a GPS would tell the story, but the car has the front bumper off currently for probably another week. So I can't do that as of right now. But even with calculating the speed the clarks formula says compared to what my speedo says, I'm not off by much even at 80mph.

And lastly, is there anyway to tell if it's a turbo trans besides looking at the code on TOP of the transmission? There are a bunch of numbers and words on the passenger side of the case, but I don't know what they mean.

Thanks!

RPHARRIS

Your tach may be off too. That would have an impact on your measurements. I'm pretty sure that mine reads about 200-300 rpm too low at redline.

CarbonRevo

But the needle is barely into the red when I hit the limiter, which S2 redlines at 6400 and then limiter at 6480rpm +/- 20rpm. So the needle should barely be into the red before it bounces, and it is barely into the red.

jyoon

yes the turbo trans was available without a cooler.

CarbonRevo

Damiza- What tires are you running?

facboy

+1

PorscheDoc

You have a 951 transmission in your car.

CarbonRevo

Ahh...lol, this does explain a lot, and sums this topic up.

Any idea as to why? Was it installed at the time of the clutch? Maybe a LSD unit?

Also, I'm getting a lot of noises out of this thing. I don't know if it's the trans or TT bearings, but noises aren't good. Whines a lot when coasting and off the gas, but if you give the right amount of gas, it goes away. I'll probably have to take you for a ride some time to show you what it is exactly.

PorscheDoc

It was pulled because he thought it was making noise, which then of course didn't cure the problem and so the clutch was replaced. More than likely it is the torque tube bearings whining a little.

It is a standard open diff from an 951, no LSD.

2bridges

get numbr off top of trans case (mirror on a stick) and then you will know what you have (LSD or no LSD)

2bridges

Sounds like doc has the scoop

CarbonRevo

Ahh boo! lol

Yea, sounds like a fun project for next winter!

Keithr726

A lot of 944s make this whining noise in gear off gas. I once heard it was because of a defective design. My 951 and my old 944 both do it along with 3 others I've been in/driven.