Manual Gear Box Modification

Has anyone looked into modification to their gear box to gain speed? As i read somewhere that Porsche put in a (higher or lower? gear ratio) for the 1st & 2nd gear to slow the Cayman S down, thus it cannot be faster than a 911 from 0-60. Any thoughts on this would be welcome.

I would also like to hear people's feedback on this. I have been informed that it would be a simple task of just replacing the first 2 cog ratios, but I have no idea if this is accurate or not? Apparently, even if the CS had the same gearing as the 280hp BS, our cars would accelerate quicker to 60mph. Again not sure if this info I was given is accurate? If so, does that mean the updated BS with 295hp also has had the ratios adjusted against its favor?

Strange that no one has a take on this issue??? Any Sponsors with gear swaping experience out there?

That's because changing gears in a transmission isn't that simple, and certainly not cheap. First of all, you can't just change the 1st and 2nd gears. You will also need to replace the cluster gear that they mate with. The gears need to be a matched set. This would require a complete transmission rebuild. It would be easier to just get a transmission from a Boxster and swap the entire unit. But that trasnmission may have slightly smaller gears to go with the lower torque output of the weaker engine which would put you at risk of breaking the transmission if you get too carried away and shift like a butcher. All of this for a couple of tenths of a second, maybe, from 0-60?

Thanks, that clears it up.

This isn't the first time I've hear this 'allegation' that Porsche rigged the fight by gearing the Cayman higher than the Carrera . So I did a little research to see if it's true. You know what? It totally is. What a Croc (pardon the pun). Take a look at the attached tech info, taken from page 70 of the Cayman product information guide. The Cayman S and Carrera have the same final drive ratio. But the Carrera has a lower first, second, third, forth, fifth and even sixth gear. That doesn't make any sense. In fact, it would be more sensible to give the engine that has less torque lower gearing. Instead, they gave it to the car with more torque. The engines have the same redline, and same wheels, so that doesn't explain anything. Someone might argue that because the Cayman has less torque, it can benefit from the closer ratios. But because the Cayman has a flatter torque curve than the Carrera , flat from 4,400-6,000 RPM, there is no need for close ratios. That really burns my ***. It's amazing the Cayman comes as close as it does to the Carreras 0-60 times. It's obvious to me that if Porsche gave them the same set of gears, the Cayman would smoke the Carrera from 0-60. That's just dirty pool.

Is it possible to change the final ratio? I know that on the M3 a popular mod is to put in 3.91 or 4.10 gears. With a six speed it isn't such a big deal (YMMV). I wonder how hard it would be to do that in the Cayman ?

The Cayman S has a final drive ratio of 3.875. The input shaft to the trans the 1 and 2 gears are part of the shaft so you would have to change the shaft out. I would think that if you wanted to put in a LSD in the trans would have to come out, if you wanted to change gearing then would be the time. It would not be cheap.

Is it possible to swap out the transmision with a Carrera ?

As the engine are facing different ways the final drive as to be in the opposite direction. I'm not sure how Porsche does this either in the design of the trans or actually turning the engine in different directions. I would think its in the trans. So the trans itself cannot be swapped but I would think that the gears are closer to design, but I could be wrong.

I am on the list to get an LSD so I am already planning on going through the expense. It would be nice to change the final drive ratio while the transmission is out.

Yup, like Busman said. If you slapped in a 997 transmission, you would have 6 gears backwards and 1 forward. That might be desirable in a French Tank, but it's not so desirable in a Cayman .

Dropping the final drive ratio can get you there, but it will also reduce top speed, increase cruising RPM and fuel consumption. The ideal scenario would be to get that Carrera set of ratios in a Cayman . I wonder if the differential can just be swapped to the other side in a 997 transmission to make it usable in a Cayman . I suspect that this will be a common mod in 5 years or more after more people have experimented with this.

Where are you getting it from- does it work with PSM?? Bill

The older air-cooled VWs had mounting plates on both sides of the transaxle, where the output shafts came out of the case. It was very simple to unbolt both plates, re-install the diff on the opposite side, and then run the tranny in a mid-engine dune buggy. At some point, VW changed the casting to only have one side plate, and you could no longer use those trannies for mid-engine applications (unless you liked 4 reverse speeds ) I haven't checked, but it's possible that Porsche does the same sort of thing with the current 997/987 transaxles. Otherwise, they would need two different housing castings. If there are plates on both sides, it should be fairly simple to put a 997 tranny in a 987 after moving the diff to the other side. Although, the shifter linkage might not line up correctly. If I remember, next time I'm under the CS I'll take a look.

Fouhahaha!! That is the funniest thing I've read all day. Love it. Hey, at least we'd have RWS (rear wheel steering...like an old Prelude or 300ZX!)

According to the 911 brochure, it has a 3.44 final drive ratio. This is the same info I have found on other web sites. If it is true that the 911 has a 3.44 final drive ratio and the CS has a 3.88, then the CS has taller gear ratios than the 911 , but a shorter final ratio. I am working on the calculations using 3.44 for 911 and 3.88 for CS and to try and determine which car actually has the shorter gear. Does anyone know what the top speed in each gear for the 06' 911 ?