bovien

I have a .2 GT3, which are running a shorter gearing than stock. I'm fairly sure that I have either the RS R/P or a Cup one. (Redline in 6th are aprox 186mph/300 kph)

As I do quite a big part of my yearly miles on autobahn to the Ring, Bilster Berg or some Swedish tracks, I would love a longer 6th, but keep everything else as the lower general gearing really works on trackdays.
Is this possible? I seem to recall that the .1 runs a longer gearing, but is that only in the R/P? Are there other 6ths available for an "easy swap"?

Thanks!

Spyerx

Going off memory,
.2RS had different gearing in the box in addition to a different ring/pinion.
1.GT3, .1RS, .2GT3 all used same gearing
So if you just put a different R/P you'll have overall shorter gearing. So yes, you can change them to match the R/P

bovien

So to keep my shorter overall gearing, but extend the 6th, I would need to go outside OEM?
Does that exist? Probably not. Would only be usable in my specific case or if an .2 RS wanted a longer 6th

audipwr1

You take the car over 186 ? Wow

bovien

Well, had to try it once or twice going through DE to Bilster or Ring.
But much fuss though. My Supra is more white knuckle that the GT3.
Would really like to be able to cruise at lower RPMs though. Annoying keeping 100+ mph for longer periods. .2 gt3 should be better here

Evolved Rs

I thought .2rs had a shorter final drive but taller 6th gear.

Petevb

ilko

According to my research the gearing on the 997-1 GT3 & RS and 997-2 GT3 & RS is the same. They all have a 0.92 6th gear but the 997-2 RS has a 3.89 R&P, while the rest have a 3.44 R&P. The 4.0 uses the 3.89 R&P but 6th gear is taller, 0.88. I am using that 0.88 6th gear in my 993 close ratio transmission rebuild.

Having owned a 997-2 GT3 I didn't find 6th gear to be too short. But my current 997-2 RS could use a taller 6th and when the time comes for a tranny refresh I'll be buying the 4.0 6th gear again.

usctrojanGT3

I got to redline in 5th gear at COTA (around 150mph) in my 997.2RS and when I shifted into 6th the car started to slow down even though I had my foot to the floor. haha

ilko

Hmm, I've done 165mph in mine in 6th and the car definitely had more acceleration in it, but the driver's palms were getting really sweaty... BTW hard braking from those speeds is quite the feeling. You better hope you have a working diff!

Petevb

bovien

Sweet! Thanks

Think you are right about that, come to think of it

I do. Cup. However, only ever do this, if I have 3 lanes and only traffic in the inner lane.

Sweet info. So assuming my gears are stock 1st through 6th, and its only my R/P that are replaced with RS or Cup, I will get a longer 6th by using the .2 RS or 4.0 RS 6ths.

So going to .88 from .92 with a 3.89 R/P gives me 8 mph more in the top. No too relevant, not sure I'll ever go there again. @ 3000 rpm I'll be going 68 mph as opposed to 65 or 102 mph in stead of 98 @ 4500.. Hmm.. Not going to matter a lot regarding getting rpms down on longer cruises.
If it was a free upgrade, it might make sense, but in this case, I think not. Sadly.
The same rpms but with 3.44 R/P in stead (back to stock) gives me 207 mph (not possible, i know) vs 183 @ 8400, 74 as opposed to 65 @ 3000 and 111mph vs 98 @ 4500. Now these are changes that matter.

Buuut I don't think I would be very happy about giving up the gained performance on track.
I don't have any measurements, but the difference in acceleration with the 3.44 vss 3.89 must be quite a lot

brake dust

997.2 redlines in 4th at 148. The gear ratio is different in the RS.

ilko

Pete, you are correct! I had my files mixed up, sorry about that.

The 3.89 R&P makes a HUGE difference from the standard GT3 transmission and the 997-2 RS. Going through the gears is a very rewarding experience and you are ALWAYS at the peak torque. But the 0.88 6th gear is quite short. Here are the cursing speeds in a 997-2 RS in 6th gear:

72mph @ 3000 rpm
85mph @ 3500 rpm
95mph @ 4000 rpm

The 3.8L engine has plenty of torque in the lower and mid range RPM and I think a taller 6th would be better suited for that car.

Meanwhile I just removed the stock 0.775 6th gear from my G50/20 transmission. It is a VERY TALL gear and makes no sense in a lower HP car such as the 993. I practically never used 6th in the 993. But I might put that gear in the RS when the time comes to refresh that transmission.

bovien

Interesting on the .775. Many boxes would be compatible with the GT3's? I would ask a well renowned shop here to do a swap, and they would probably have a bunch of boxes to cannibalize from.

Regarding the R/P, you are saying that the trade off in terms of higher RPMs, wear (?), and noise for long stretches is worth it, as my primary focus on the car is to be able to track it 5-10 times a season.
- and going back, when I only have driven it with the 3.89 would be an impressionable step down in all round accelerative performance?