KaiB

For three days this weekend I had a chance to definitively compare the Weiner/Gamroth short ratio tranny to stock units. High Plains Raceway has a long straight (ca. 2200 feet) which follows a high speed bend.

With my tranny, I was easily getting 5 car lengths on a very well driven stock RSA (hi Margie!!!) who was out of the bend faster than I most of the time. 993s had no chance with me, two new Carrera 4S could not pull away and my buddies well driven boosted 930 Turbo only got a bit on me; I certainly had the flexibility to hang with him in the back half (and he is a far better shoe than I)

Marge is a superb shoe and her RSA has suspension done up also, so this is a fair comparison. On my good laps (I bobble at least every other one) I was getting 2 seconds on her - next year after some seat time, it won't even be fair.

The flexibility of the tranny in short acceleration zones was very evident as I was able to get into 4th in many places where others would back off in 3d. Turns 1, 4, and 7 were all 4th gear for me which allowed much easier braking and higher entry speeds (at our level).

I have to say that this mod should be the very first one we should undertake on our cars; it is easily the (as Weiner sez) cheapest 50hp mod a guy can make. No brainer on street cars, and a must for trackies who don't plan to race stock classes.

ThomasC2

Interesting. When you say short ratio, do you mean the final drive or have you changed the gear sets over all?

Thomas

Babalouie

...and where does one get such a nice product

The Stig

Kai - I fear I may have missed a thread on this particular enhancement. Please point us in the right direction if you've already written about this.

Cheers

KaiB

Tranny was rebuilt at Rothsport with shorter 2,3,4 and 5. I'll post the ratios when I get the chance.

Found them, I'll do the GT sets whan I find them.

1st: 3.50 (43mph)
2d: 2.25 (66mph)
3d: 1.684 (89mph)
4th: 1.286 (117mph)
5th: 1.04 (146mph with a 3.333 final drive)

ValveFloat

I am just curious, did you record any lap times? I have some Traqmate data from HPR when I was there in April, and it would be interesting to compare.
Like you say, I was in 3rd for turn 1 and 7, although I would leave it in 4th for 4.

KaiB

Joe, 2:11xx is where I currently am at HPR. I'm still very rough as these are the first two months after a 25 year break for me...the car is obviously capable of much better time than I.

race911

And on the flipside, my regeared faux 993RS is barely a second a lap quicker than my stock class RSA at Laguna. (The regear IS of benefit at Thunderhill and Laguna.) And back when we could only put short ring-and-pinion in the 964s to move them from stock to prepared, the resulting shortened ratios were an absolute disaster at Thunderhill.

ThomasC2

OK, that's what I guessed and that's what I want to do. Just do the final drive isn't good enough. But replacing 4 gear sets is a lot of $$.

If it's OK with you, could please let us know the cost for the parts?

Thomas

Steve Weiner-Rennsport Systems

Hi Thomas,

JMHO, but changing the final drive does nothing at all to address the major liability here; the stock RPM splits are too far apart to keep the engine inside its powerband.

Closing those RPM drops at each shift is really the "magic" at work here. Without question, it IS a lot of money, however nothing else makes the same degree of difference for the money spent.

ThomasC2

Steve, as I wrote I agree with you. Just changing the final drive isn't even an option for me. Just a lot of money for little use. The only way to go is the set up above. We'll see what the bank account says in the future :-)

Thomas

sergiDA

I just regeared mine from 2nd to 5th, purchased the kit from GT gears, Mat Monsoon, Bill Verburg also helped with his valuable advise.

Results are astonishing, not compared times as driven in a new track....the only thing I can say is that I am faster than modern 997 Carreras and starting to chase GT3's ...


Bye

KaiB

the only thing I can say is that I am faster than modern 997 Carreras and starting to chase GT3's

Ditto that! The weekend was my first time to really have a direct comparison and I experienced the same things.

Cost...trade off a set of pretty shiny wheels and tires plus a bit of bling we all talk about here and yer there.

cobalt

I have been considering this change myself. I recently picked up a spare tranny cheap and was planning on regearing it. My concern here is a top speed of only 146 which I am approaching on a number of tracks I drive. What is the happy medium here and would you suggest different ratios for tracks like Watkins Glenn or VIR? The stock gearing always has some part of any track I drive fall short usually third is most obvious.

I was also considering taking the gears from the C2 tranny and using them in my turbo. What do you think of this approach?

KaiB

The 146 I posted above is at 6,500rpm with 25' tires...I think 153 is more realistic. This is also with a 1.04 fifth gear ratio; one could just as easily go to a 1.00.

As we are taking Claudia up to ca. 360hp next year, I spoke with Steve about the gears. He tells me no problem with the stock gear sets - as long as they stay cool enough (we will be installing tranny oil cooling in the car when we get to the next phase).

Of course there are trade offs with any mod - gearing included, but I am so very satisfied and happy with this, I really tend to pimp it. Weiner does also.

At first, I wondered, but find that with the torque we all have aval, a short shift is tremendously successful (as opposed to running all the way up to redline) in many situations...as the short rpm drop keeps me up in the curve. (edit to add: This also really helps relax the engine on hot days)