Squires9914s

is this software similar to Cobb tuning? Or better?

GoKart Mozart

I disagree that lower gearing would make the GT4 less livable. I honestly have never owned a car where I sometimes don't even bother putting it in to 5th or 6th. In fact in many cars I've owned, I looked for an extra gear and it wasn't there. The speeds the GT4 does in 2nd & 3rd especially, are way more than in most cars, even the GT3 and other 911's have lower gearing. It's just crazy tall gearing in this car, which is probably THE #1 complaint. For example, 2nd gear tops out at 84mph, whereas the GT3 does 76mph, despite higher redline. And many other cars are setup to just get above the mid 60 mph mark in second gear, for that "all important" 0-60 time. Don't get me wrong, I don't want to have excessive high RPM's on the freeway, but there is plenty of room to lower the ratio on this gearbox. Ideally you would leave 6th gear ratio where it is at and just change the rest. Sharkwerks changes 3/4/5 which is very popular and I would love to do that, except that I would like 2nd changed as well, and permanently that gets pricey, because 1st and 2nd are on another shaft, requiring a lot more labor.

I also doubt that any one tune is way above the rest. There is only so much you can do. I recently installed a tune from BGB Motorsport via the COBB Accesport. While it is worthwhile to do it, the gains are <10%. Nice, but not earth shattering.

blomman

A tall 2nd is Perfect on most tracks. Have it on my 964rs also and it's what makes it so great according to a c2. But 3-4-5 should be much shorter, thats my opinion.

GoKart Mozart

Purely for track yes, but for street 2nd is too tall.

lee88

Yes BGB are really pros here. I'm fortunate to have John's old GT4 which had X51 plus some custom porting, tuning, etc that he did. That car is 415 rwhp so probably in the neighborhood of 460 hp crank. They can do 4.0L conversions, PDK conversions, etc to GT4s so pretty much sky is the limit.

Petevb

Not correct. In a given gear the lower R&P does deliver more torque to the wheels and hence acceleration. It’s not correct to say that it’s the equivalent of more power, however. If the new R&P lowers 6th gear to exactly the same final ratio as the previous 5th then the two cars will be equally fast over the same speed range. Thus the net result of shorter gearing is that the original gearing will be pulling harder through some speed ranges (ie the top of the original 1st when the modified car is already in 2nd) and less hard through others. This is very different than an actual hp increase which would see the car faster in nearly all cases.

Thus in certain cases, ie 2nd gear on the autocross, the R&P will be hugely beneficial, but in others it will have a very limited effect.

GoKart Mozart

I wrote in theory because I knew it wasn't exactly as adding 19% more power. I suppose it isn't even so in theory ;-). Never the less it makes the car faster. According to Autoquest it improves 0-60 by .4 seconds (probably largely because 1st gear benefits the most), but also in the example they described how Porsche changed the gearing on the GT3 997.2 by 13% over the 997.1 and it improved Nuerburgring lap times by 7 seconds. Although who knows what else they di bewteen the 2 models. Either way, Porsche did it before and it made the car faster on track.

Bottom line the gearing is too tall on the GT4, that is a fact, and shorter gearing would make the car faster in most circumstances, and is one way to get "more power" out of this car, which is what the OP asked, sort of.
There is a reason the Sharkwerks shorter gearing is a popular mod. In fact it is another way to go. They only do 3/4/5. I personally would like 2nd shorter also. I think they would offer it if is wasn't for cost.

Jim Cobb

My friend did some new headers and a tune on his GT4 and then re-geared it as well. This made it a lot faster than mine down the back straight at Road Atlanta, so fast, in fact, that he has to go to 6, and then downshift like a maniac on the short climb up the hill leading down to the infamous Turn 12. Not sure that doesn’t amount to going a mod too far.

Petevb

I’ve been saying that since the car was released, and I’m quite sure Porsche did it intentionally to keep the Carrera faster to 60. See here from 2015:
Link
Very glad the aftermarket stepped up with good R&P and re-gearing options. Just making it clear that re-gearing is very different than actually increasing power.

GoKart Mozart

Agreed, to short is no bueno either. What gear reduction does he have? Did he go with the Sharkwerks 3/4/5 or did he change the final drive. FWIW, at the tracks I go to it would not be a huge issue. Currently I only use 2/3/4 and even if I had slightly lower gearing I might hit 5th on the straight.

Fair enough!

Davin

I ended up going with fabspeed gt450 power package. It came with exhaust, race headers, Cobb tune, IDP throttle body and air filter. The exhaust is way too loud, I might end up going back to stock muffler and keep everything else

ajw45

I think it's great that Autoquest offers a shorter final drive. If I had to do it all over again, final drive plus headers and call it a day, great bang for the buck. That said, the issue is both the long gearing and the gear spacing. The low gears are long with wide spacing, the tall gears short and closely stacked. It probably makes sense on the nurburgring or on some emissions test. In a perfect world I'd like to see 2,3, & 4 shorter and more closely stacked and 6th actually a little longer. I drove the short 3,4,5 set up and it's weird. 2 and 3 are so close it seems redundant. Upshifting to 3 or downshifting to 2 almost feels like you just shifted into the same gear you came from. That said, I can see the potential, the close 3 to 4 is real real nice. Throw in a shorter 2nd and it would be a really sweet set up.

I'm still crossing my fingers that we see a GTgears shorter 2nd/mainshaft get to production but I've gotten used to the stock gearing. Just add more power... Or pdk