GrantG

7th gear would be inappropriate for either of those endeavors (6th would be the choice).

Larry Cable

hopefully "sport" mode will exclude 7th ... like sport mode on other PDK equipped cars...

wizee

Maybe the GT4 RS will get a different final drive ratio to make the seventh gear useful. Bringing seventh closer to sixth would make it an ideal next gear for performance if the engine was powerful enough or the final drive were different. Suppose the RS has a redline of 8400 RPM, and they give it a 4.50 final drive instead of 3.62. That would give a redline in 7th around 330 km/h, and the first two gears would be set up to give C8 Corvette like 0-60 times.

Archimedes

Agree, which is why the question. Why do people get so excited about a lower 7th gear that allows you to hit top speed in that gear? It seems entirely irrelevant as I'll bet almost none of these cars will ever see anywhere near top speed in their lifetimes.

halfmonkey

It's not that the majority of people are going to run out their cars to the top speed but it's more of maybe trying to have an understanding of how Porsche may have designed/programmed/engineered the transmission to perform or maybe extract/guess some other changes that Porsche may have made to the PDK transmission that they may not have publicly released yet.

It's like asking how much weight do PCCB save and how much weight do forged wheels save? Most people won't even be able to tell the difference from saving 1 to 2 pounds let alone 10-15 pounds unless your name is Michael Schumacher or Lewis Hamilton so if we can't tell the difference or be able to extract maximum performance from the weight savings, then why should Porsche sell it right? Just making a point that it's not necessarily about the majority of people extracting max performance or using the feature to the max but maybe just having an understanding of it. That's why we're all here to ask questions and help others with their questions.

wizee

If they changed the final drive ratio such that top speed is hit in seventh (in addition to shortening the seventh gear slightly as they already did), this would allows gears 1-6 to get more tightly spaced for speeds below the top speed. This would allow substantially better 0-60 mph times, and keeping the engine closer to max power at all speeds.

Larry Cable

+1!

agreed

Archimedes

But that's not what we're talking about, we're talking about only 7th gear. The discussion was, given the first six gear ratios are set, 'oh boy it would be so great if 7th was shorter so the car could hit top speed'. Which, again, my question is why? Why would one ever want that? It's totally useless and would only increase the chance of drone on the freeway.

Rennolazine

The only time im going to ever use 5th or 6th gear is in the first few hundred miles just to make sure they work and to keep me away from 8 grand. After that the car will live in gears 1-3, occasionally 4. Even on the freeway. So pdk would just get me into 4th a little more easily. Lucky enough to have other cars for commuting or for chick driving..
again, i was really shocked how fast this car is with the manual. Its not gt3 level aggression but if you spin the **** off the motor its plenty fast.

SpeedySpidey

Yes, what is the reason that the final ratio isn’t the solution?
It used to be in the muscle car era where if your Muncie wasn’t matched up with 4:11’s, you were not going anywhere.

Greg_STL

My*guess* is a that it has something to do with top gear usage for good gas mileage. With the old 7th gear, the car would only be doing 2000 rpm at 70mph. So even on most interstates in the US, you would barely be able to use 7th gear. On the older turbo models, being in that low RPM range was not as bad because that is where all the torque was. The old 2.5 turbos were at 430 N-m at 2000 rpm where the 4.0 liters are somewhere around 340-ish. With the new gearing, you are only at 60 mph at 2000 rpm. Given that they probably need to be in the top gear to get the best mileage - you might have had to strangely enough go to a less tall top gear so it could be used at all in the test. At least I could understand the need to do that. I think marketing it as a performance benefit is just that - marketing. But who knows - there might be some other information out there I am missing.

eXpensiveGears

I posted this on the other gearing thread as well. I have a feeling if you could get a taller 6th (topping out at 175-180) along with the AQ Final Drive, you would have the 'perfect' GT4 MT gearbox?

wizee

Sixth topping out at 175-180 mph would definitely be an improvement over 163 mph, and be pretty good, but RPM would still be higher than ideal for highway cruising, and redline in sixth would be lower than achievable top speed. A sixth at 195 mph on the other hand would hurt acceleration going up to the top speed unless fifth were also lengthened accordingly.

My idea of perfect gearing in km/h (mph) would top out at the following speeds:

• 70 (43.5)
• 110 (68.4)
• 150 (92.3)
• 200 (124.3)
• 260 (161.6)
• 330 (205.1)

My alternate idea of perfect gearing would have first gear going up to 90 km/h (56 mph) instead of 80 km/h (50 mph), and leave all other gears unchanged. People had a hard time understanding how lengthening a gear would make it better, but hear me out. A somewhat longer first gear would not hurt acceleration since it'll still be above the limits of traction for most of the rev range. In fact, it'll improve acceleration since the engine would be giving full power between 80-90 km/h instead of being outside the power band in second. However, by reducing the gap between first and second, one could stay in first gear longer on back roads and autocross. Furthermore, downshifting to a 90 km/h first gear would be something one could do a lot more often than downshifting to an 80 km/h first gear. Also, bringing first gear closer to second would reduce synchro wear when downshifting to first. Perhaps my longer first gear idea is actually better than shortening gears 2-5, because it'll leave tightly spaced upper gears for optimal high speed acceleration.

GrantG

Well, if they geared 7th as a performance gear (hitting top speed at peak horsepower in 7th) some might be assuming that the other 6 gears would be lower and closer together which makes for far better performance across the whole speed envelope (as is done with PDK-S in the GT3). There is no evidence (yet) that this was done here.

eXpensiveGears

All great points. I'm wondering if someone would want to develop a final drive that could mimic the gearing you stated above, obviously with the cruiser 6th gear as well.