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WOW - thank-you! That really sets the tone for what to expect.
You're welcome.
And I cannot emphasize enough the role that BGB has played in Cayman development and racing. From my own product line, if it were not for John Tecce there would be no PDK LSD today. There would be no Cayman gears available right now.
If not for Tecce I would have waited until the Gt4 came out, and then developed the gears in the first couple of years the car was on the market. I don't make what I can't race. If BGB hadn't come to me and said that had to have gearing to beat the factory Mazdaspeed turbos in Rolex, I would have waited until someone like Pirelli World Challenge was willing to consider alternative ratios. But BGB and I had a relationship. We had already won Continental Tire Sportscar Challenge titles together.
When they said we will not win the title without gears and we will race on proptype product in order to get that advantage, I pulled out all the stops to provide them something. And today you guys beneift because I have all the plans and drawings and engineering done that allows me to make full production batches. I wouldn't have absorbed those creation costs if it weren't for BGB.
Here's a look at the GT4 stock ratios vs the base 981 ratios. The base ratios do look slightly better to me. This counters the argument that Porsche kept the ratios stock for cost reasons- they already have the ratios below.
Below would be an aggressive ~4.3 ring and pinion with a taller 6th. Technical issues aside it looks decent to me for an all around box (not a big track only box, which would have significantly taller lower gears):
Below is perhaps close to what Porsche would have done if they'd had complete freedom. Note that speed in most gears is within a couple MPH of what Porsche gave the 997.2 GT3 RS- far lower than the GT4 despite more power. This would help a lot down low without really hurting on the high end IMHO:
I'd personally want something close to this if possible, though perhaps with a taller 6th for cruising. It'd make the car far better at the autocross and far more fun to drive.
Personally I suspect GT car customers will prove different than regular Cayman customers in their buying habits. I'm ready to get a R&P or spare gearbox today, for example, but I wouldn't have been for a regular Cayman (nor would I have bought a regular Cayman to begin with). $.02
I'd personally want something close to this if possible, though perhaps with a taller 6th for cruising. It'd make the car far better at the autocross and far more fun to drive.
Personally I suspect GT car customers will prove different than regular Cayman customers in their buying habits. I'm ready to get a R&P or spare gearbox today, for example, but I wouldn't have been for a regular Cayman (nor would I have bought a regular Cayman to begin with). $.02
I have to confess the discussion of auto-x confuses me. I get a lot of inquiries about lsd work from gt3 owners. Generally when I tell them that my parts aren't considered direct stock replacement under the letter of the rules they don't buy because they don't want to be cheating.
Are gt4 Cayman guys looking at classes to race these cars that allow changing gear ratios and lsd performance?
I'm going to field this one before John Tecce has a heart attack while replying. Porsche has distanced themselves from every single racing Cayman that has ever existed up until right now. For years they actively discouraged teams like BGB Motorsports from building cars and getting them approved for racing. The Cayman has existed for a decade and the GT4 is them finally subtly admitting that while they really want you to love the Carrera best, there's a die hard portion of Porsche owners who prefer the midengine configuration. It's the slightest of nods to the midengine guys even though historically some of their most successful racecars have been midengine.
So, no, Porsche has never sold alternative ratio gears for this gearbox. In fact, you cannot get your gearbox rebuilt. Why? They don't sell synchros. They don't sell most bearings. They don't sell any service parts for these gearboxes outside of a few seals and the differential bearings. If it weren't for the fact that the original 987.1 gearbox was lifted directly from an Audi we would be dead in the water in our ability to provide the above service parts. When we rebuild a race box, we buy the parts from the Audi dealer, not the Porsche dealer. Up until 2008, all the gearbox castings had the 4 rings instead of the P in a triangle. It was an actual Audi gearbox.
And before anyone wastes any energy looking, it was a TDI Audi. The gears in it were WAY taller and longer. There's no off the shelf option to get shorter gears through the Audi angle.
I guess we'll see just how much Porsche intends to support the "GT" in GT4......I wonder if their intent for the GT4 Cup with it's PDK race box is the same with our manual....just replace the whole thing when it needs servicing? Either way, it doesn't look like factory motorsport gearbox parts will even be an option given the PDK rumors for the race car.
I can honestly say I'm glad I'm not even planning on tracking my GT4 in the foreseeable future. Unlike the 996/997 GT3 where motorsport parts were plentiful and proven, we are on page 1, chapter 1 in the factory cayman motorsport era book.
Time will tell, and in the meantime, we have great companies and race teams like you guys, to develop race proven parts and sell to us hacks.
Are gt4 Cayman guys looking at classes to race these cars that allow changing gear ratios and lsd performance?
SCCA hasn't classed the car yet, but I don't expect it to be favorable. For PCA rules vary by region. Here we use a PAX points system to class cars, and a ring and pinion (or to a lesser extent gears, more points) would be worth far more than the points it would cost.
With correct gearing and tires the GT4 would be a top time of day threat in most PCA regions- that's essentially what won the Nationals Parade in 2014. Not even close without a gearing swap...
I was thinking if the 986 5 speed manual transmission is interchangeable with the 987 6 speed ? I also see the gearing is deferent in the 986 2.7 vs the 3.2. Is the gearing the same in the 981 vs the 981s in manual ?
Not that I want to change things around I was just thinking aloud. I owned a 997 C2s during these times and did not keep up with the Cayman model much then.
The 986 stuff is a whole generation older and not compatible. In fact you can't even bolt a 987.1 housing to a 987.2 or 981 engine. The 986 5spd and 987.1 5spd are essentially that same.
The 986.20 01-04 S gearbox is basically a 996 gearbox. Beefy but hard to rebuild. And very heavy.
I also recall AP in an interview talking about some kind of Torque apparatus in the drivetrain or tranny. Toque limiter I think. If this is true and you tune the engine up you could run into a problem?
Last edited by Ochocoronas; 10-03-2015 at 05:21 PM.
After the exhaust and headers, my car made much better power and torque down low but almost identical up high. It looks like Porsche may be limiting the maximum potential, and a tune may unlock it
^^^ I agree. But if Porsche has a torque limiter in the tranny or drivetrain you will need to find how much torque it takes before it starts slipping. Remember you now have LSD and huge rear tires with a lot more power on the same tranny as a 981GTS.
I think a lot of people do not realize how much money and time is spent in reverse engineering by companies. If they build it you are not going to be able to make it better easily.
Last edited by Ochocoronas; 10-03-2015 at 05:21 PM.
I switched out my 3.4l engine in my 12' CR and went with the 3.8l x51 and also swapped gears 3-6. I too have to thank BGB and CTgears for all of their R&D. I rarely drive the CR on the street other than up to Lime Rock but the gear swap was a game changer. I dropped a full second at LRP (was low 58's now low 57's). While the engine may help a little, I believe the gearing was more impactful. At Watkins Glen, both the gearing and the extra horsepower play a larger role. Stupid question but assume the 987.2 gearbox/gears are completely different than the 981.1 box?
In the EVO video (@ 2:36) Preuninger states it has a "Torque Peak Limiter" ?? What is that?
My understanding is that it's a valve in the clutch slave cylinder. It "softens" the engagement speed of the clutch so that side-stepping the pedal doesn't shock the driveline.
09-30-2015, 04:21 PM
