sanderabernathy

Everyone takes issue with the long gearing in the naturally aspirated Caymans/Boxsters with a manual transmission. The solution I see discussed involves an aftermarket company swapping out several of the middle gears such as second, third, and fourth. That's expensive and I would expect it to leave a gaping hole between fourth and fifth or fifth and sixth.

I was wondering why no one mentions changing the gearing in the differential or changing the differential altogether. I'm assuming it's not mentioned changing the differential would cause problems with stability management or torque vectoring, or perhaps the differential is not a separate, easily replaced unit like in a front engine, rear wheel drive car.

I know changing differentials or final gearing on many cars is fairly common so I'm surprised no one mentions doing it to address the tall gearing in the Boxster/Cayman.

Can anyone shed light on the topic?

Thanks

Porsche444

I think the gearing is just great honestly, 2 months, 2300 miles and 1 track weekend so far, car feels just awesome. If I never saw posts about long gearing, it wouldn't be a topic of complaining for me. On the track, it was pretty damn good, so none issue for me in any gear. And even it was, no way would I screw with changing the core of the gt4, take about potentially screwing up car and obvious power train warranty.

sanderabernathy

I see that point of view. It's been debated enough so I'm not trying to revisit that question. It would be fun to hit redline in third though without risking a license though.

I'm just asking why people often complain about the gearing and the only solution ever discussed is changing the gearbox rather than the differential.

I'm not saying it's a good idea to change the differential or the gearing in the differential as I don't know enough to say that. I'm asking why the topic never seems to be discussed as it's a fairly common and straight-forward modification on some other cars.

Porsche444

Power train warranty is what I guess for not changing the diff.

Trying hiting redline in 3rd in a gt3, that's screaming. That's the default nature of porsche and sports car. This is my 4th porsche and I have zero issues with gearing and its the best car I have ever had, enjoy it even more vs my last porsche, 2018 gt3 pdk.

cgfen

Search the 2016 GT4 forum.
Well understood path for differential change, but sadly most vocal vendor recently died.
Any qualified gearbox shop can source and install different differential, that's still about $3k, more if you can't R&R tranny yourself.
Changing ratios $10 - 12K, but "better" solution IMO.

Those that are happy with stock gearing haven't owned a 996 / 997 GT3 IMO.
grin

Craig

Kevin in Scottsdale

I have not researched the exact company, but I've read about a group in the UK that replaces the crown and pinion and shortens the ratios by 14%. I just saw an advertisement on instagram for them the other day. I'm sorry I cannot remember the name, but if you research the issue in the 981 forum, you'll be able to find them. Also, it appears that John from Soul Performance used to work for the race company that developed this same mechanical differential fix, however the owner recently passed as mentioned above. However, John sent out an email that at the right point in time, he may be able to help the company bring their product to market.

We'll see.

sanderabernathy

So there's not a mechanical reason that it can't be done. That answers a big part of my question. Thanks for pointing me in the right direction.

In looking around between posts, I did see aftermarket diffs for the 987 and the 981. Based on the marketing text, the value proposition was that they were limited slip for cars that don't have an LSD or they have an LSD better suited for track use. Vendors don't seem to be singing the benefits of changing the drive ratios but I assume they can also supply shorter gearing better suited to the car. I'm guessing that no one is pushing a 982 solution because so many of the cars have PDK or, in the case of the GT4, they are primarily wrung out on the track where there's less of an issue so there's a limited market.

I realize long gearing is in Porsche's DNA and I can understand why people don't see it as a problem. However, I can drive most of the mountain roads in North Georgia (which has some amazing roads not unlike the area around the Tail of the Dragon) and never approach redline in third. As much as we enjoy shifting a great manual, driving a 40 mile mountain road in 80%/20% in third/second with only an occasional shift between the two leaves something to be desired. Obviously it's less of a problem on the track, but even there half the box goes unused.

I've lived with it with my 981 and I'll probably do the same with my GTS 4.0. In BMWs, Miatas and Caterhams set up for track use changing the rear differential or the gearing in the rear differential is pretty common. That's why I was wondering why I hadn't seen much discussion about it for the 982. I think I have my answer now.

sprocket3

Instead of thinking about 3rd being too tall you could think of how fun it is to downshift into 1st at 20mph. You really use all the gears in this car.

6th gear is already pretty short for cruising down the highway.

rost12

Funny you say that. I own a 996 GT3 as well and out of curiosity noted these maximum speeds last week:
2nd - 84 mph
3rd - 114

pretty much where my 718 GT4 ends up.

Gearing is a non issue. Can it be made shorter and will there be some benefit to it in certain circumstances? Sure.

rost12

Several companies in UK offer crown and pinion mod. Any reputable Indy can do either, really.

An example, reputable guys and I’ve dealt with them before.

RPM Technik

turbo8765

That’s honestly insane even after factoring in a hefty Porsche tax.

Z06jerry

and with only 6 gears, a shorter final drive ratio would prevent the ability to reach top speed.

Denny Swift

Exactly!

.2PDK

spyderphile

Everyone's driving patterns and expectations are different. The driving use cases are different as well. So, will be impossible to have one set of ratios that meets everyone's expectations. It seems, for most of the drivers, the gearing is fine; they're happy. Porsches typically have long gearing. AP mentioned in an interview with Chris Harris that they need to make the gearing work for the Autobahn as well. Spyder (and, Boxsters) tend to get the bad rap because, I think, they are mostly focused on spirited back-road carving. So, shifting quiet often near peak power without carrying too much speed is something some drivers care about. These cars sound the best as you get close to limiter. It is not about having torque (with the new 4.0); but, to keep the Vmax low. And, more than one executive from Porsche did admit that the gearing could have been shorter!

Dropping the Final Drive Ratio is an option. It'll drop the Vmax across the board. I looked at it. The Pinion size is much smaller in that setup. That increases the wear; and, will need a replacement periodically, by a very competent shop. AutoQuest makes one. Changing the gears is a better option since that's one-and-done. Bit more expensive; but, worth.

I'm one of those very tiny group of drivers who think the gearing needs to be changed. I've been talking to GT Gears for shorter 2, 3, and 4 (and, the Mainshaft). I don't care about increased gap from 4 to stock 5. The installation is planned for early summer, assuming I can get the Covid vaccine! For, 982 gen, I'll replace them as well once the powertrain warranty runs out. So, thankfully, for those very small group of drivers, options exist.