Carrera GT

A shorter diff gear certainly makes the old 993 Carrera jump out of the hole, but for that car it used to be a tad cheaper. I wonder what it would cost for the 997 GT3.

P.J.S.

roughly $3k delivered for the ring and pinion from guard in 8:33 made by Ricardo

911SLOW

1600EUR from Porsche Motorsport.

cfjan

The one from Porsche is 32:8, though, right?

Carrera GT

I recall the 993 costing about $800, so $3K is just a tad over the top. I wonder what Ricardo asks for the generic part (or what it costs if it goes into a higher powered car, but with a lower priced badge on the steering wheel.)

Last I was heard, someone ordered the factory motorsport part and was told there's none available. I can't say the factory drive train gear components have a stellar reputation, but I've not heard of an R+P failure (not that I'm exactly "finger on the pulse.")

911SLOW

8/32 : )

cfjan

Yeah, so the Guard / Ricardo at 8:33 is probably a more reliable option.. (not perfectly divisible, so less issue of hitting the same tooth on every revolution)

911SLOW

Speaking of missing a tooth, I think that they made a change to the R&P at some point a couple of years ago, I have the older version but haven't researched it much since.

Was the 993 s RP ever that low priced? I think it was more but again I have deleted that part of my drive : )

On Pole

I tend to enjoy mods that I can feel from my seat.

FVD Flash no
200 Cell Cats yes
Motorsport R&P yes!

FFaust

Ok, so now that we're kind of off of the ECU flash, and just to be sure that I'm still following along here:

8/32 is 8:32, reversed is 32:8, which really is 4:1 right?
My owner's manual says: Final Drive 3.44:1

Therefore, when getting a Guard or Ricardo or P Motorsports RP, can I assume that the "desired" goal is for the final drive to go from 3.44:1 to ~4:1? Or a 15.7% SHORTENING of the final drive.

Is that it, huh, huh

On Pole

4:00 to 1
3:44 to 1 stock

just had TRG replace the R&P, LSD, LWFW... and from my first driving impressions it was certainly worth the price of admission. Acceleration is noticably improved throughout, although first gear is somewhat useless as it is really short and will spin the tires without carefull throttle application. It took a little adjustment getting used to the new shift points (speed vs. rpm) but anticipate a nice decline in lap times. Can't wait to get it on the track.

A big thanks to Austin and the folks at TRG. See you out at SP on the weekend.


04 GT3



1st gear is almost useless esp with LWF (redline in less then .5-1 secs) but as u can imagine a fat trq band everywhere(it's now not later). Top speed maybe 175 vs 190. 3rd gear pulls like 2nd gear. I think it will do great in the track with new R/P esp I think original R/P is abit lazy on certain stretches of the track. Regards. Mike



I've close to two years running the 8:32 RSR R&P, RS LWFW, and 3.8 RSR Clutch plate with the street disc.

The gearing in the GT3 is pretty long on the first two gears, but it gets pretty good on the last three gears. Given the stock long R&P, most likely you won't use the last two gears on track days.

I drive most of my local tracks between 3rd and 6th, putting more power to the ground than a stock 3.44:1 R&P GT3, given that my car stays at the higher RPM range most of the time.

The only problem is top speed, which is limited to 179mph on my 335 tires. That's not a problem for me, because the fastest configuration I run (Pocono Long with one infield) requires hard braking a tad under 170mph. I would need to run an oval NASCAR track to be able to reach Top Speed (What's the Top Speed on a road course from a street car in U.S?)

Another benefit is for autoX, the short 2nd is always on sweet spot for the powerband. 1st gear is useless with both the stock R&P and the RSR one. I don't know of anyone downshifting to 1st on the track with a GT3.

Before the short R&P, the car was pretty much a 2-speed car (3rd and 4th) at the track, with the short R&P it's a 4-speed car (3rd through 6th).

Other than improved acceleration, higher speeds and more fun, I don't think the RSR R&P upgrade is worth it.



Some even combine the Cup R&P (32:8) AND closer ratios. Like this guy http://www.youtube.com/watch?v=lJ9s6v8kzdE at Spa. I only have 32:8 R&P and don't ge to use 6th even at the end of the Kemmel straight at Spa, but he does. The only drawback of changing the R&P and closer ratios is that you may find you then have to shift in the midde of a corner : Sergini has to shift to 5th in the middle of Pouhon (the fast double left-hander), I only have to once I'm out of it. Of course Sergini's top speed is unlikely to be much more than 165 mph. How many of us reach such a speed on a track day ? Even at Paul Ricard - which used to have the longest straight in formula 1 - that is not possible anymore. Interestingly enough, Sergini omits the last (straight) part of his Nordschleife clip http://www.youtube.com/watch?v=OW1NO1VSgv4. Would that be because all cars he just overtook in the corners before are then effortlessly flying past him on the straight ?



There are 2 methods by which we perform this mod.

Here's a cut and paste from our soon to be released TRG product guide:

TRG Porsche GT3 Street Production Car Transaxle Upgrading

As Equipped by Factory:
The Porsche 996 GT3 production street car has a tall geared transmission. The stock MPH ratings for each gear of the GT3 are:

Gear MPH
6 190+
5 171.8.3
4 141.7
3 110.1
2 79.6
1 45

Track driving, flying starts, and standing starts benefit from shorter gearing. “Gearing down” lowers top speed by raising the RPM level for a given gear selection, while improving response to power input. TRG changes gear ratios in the 996GT3 to optimize the use of the vehicle on racing circuits. TRG offers 2 options for changing the GT3 transmission gearing. Additionally, a limited slip differential upgrade can easily be added to both of the TRG gearing options.


Option 1
Install existing 5th gear into 6th gear position and replace 3,4,5th with aftermarket gears.

Aftermarket gears are available in race finish; normal usage noise will be more audible than that of the stock Porsche street car gears. While 3-5 will sometimes exhibit a whine or hum, the 6th gear will remain quiet for top gear freeway driving and fuel saving cruising.

Re-Gearing Top Speed Chart
Gear MPH
6 171.8
5 146.3
4 121.9
3 101.1
2 79.6
1 45
$3900, includes parts and labor. May require shipping charges.


Option 2
Remove and replace 3.44:1 (31:9) stock ring and pinion with 4.00:1 (32:8) ring and pinion.

Replacing the ring and pinion of the GT3 transaxle with a 4:1 ratio unit retains the original gears and will not result in abnormal noise. Net effects are remarkably similar to changing and replacing transmission shaft gears with highly regarded reliability. TRG uses the Porsche Motorsports 996 RSR ring and pinion set for best quality.

Gear MPH
6 172.6
5 147.9
4 122
3 94.8
2 68.5
1 38.7
$4250 includes parts and labor. May require shipping charges.


Differential
The stock 996 GT3 limited slip differential unit has no pre-load and is designed with ramping. Ramping means the lock up increases as load is applied to the unit. The stock suspension and tires do not achieve enough load to make full use of the stock LSD unit. The stock unit has no immediate effectiveness, and too much slip can occur during corner transitions. Stock 996GT3 ramp rate is published to be 40/65% lock up at full potential.

TRG offers a preload lock up solution that results in an “always active” LSD unit. While this solution may not be ideal for street driving (parallel parking and rain understeer in particular), the tighter LSD unit can bring down lap times and make better use of the GT3’s drivetrain. Ramp remains; however, lock up begins immediately and is always on.

Add $265 to any transmission re-gear or R&P replacement...."while you're in there".

Recommendations
TRG recommends using TRG 996GT3 suspension upgrade components to enhance communication between driver and vehicle, make better use of the GT3’s capabilities, and limit active alignment changes.
§ Replacing rubberized suspension components with metal connections allows better sensory input from car to driver, and more precise reaction from driver to car input.
§ TRG suspension upgrade components, from bushing removal to full 4 way adjustable damping, improve handling and the ability to effectively transfer power through the GT3 LSD and tires.
§ Active alignment changes occur from rubber flex in shock towers, control arms and toe arms. TRG spherical bearing shock towers and toe links greatly reduce flex and improve road/track feel.

FFaust

Thanks.

That's a lot of typing in 10 minutes

P.J.S.

^ that is it...

I had the PMS 8:32 in my 996-3 and this time around I went with the 8:33 and changed some gears to get more of close ratio box..

The ricardo 8:33 is commissioned by guard from Ricardo... clearly it is a 4.125 r&p... besides the obvious differences, the fact that it "hunts", meaning not the same tooth hits the same gear every 4 turns... reportedly it "wears" more evenly.

That being said I had no issue with my 4.0 in my 996-3 and to my knowledge the new owner tracks it a fair amount and it is still going strong.

IIRC, 996 gt3 stock is 3.44 as is the 997.1 gt3 and .1RS and 997.2 gt3... the 997.2 GT3RS is a 3.89 rear end with revised gears... (which in my opinion, that alone makes the price delta between the two worth it the upcharge if the majority of the use is as a track car).

On Pole is right -- mods that you can feel... switch to either ring and pinion discussed and you will absolutely feel a difference.

deputydog95

Bring it!

savyboy

A friend did this (Install existing 5th gear into 6th gear position and replace 3,4,5th with aftermarket gears) recently along with guard LSD and LWFW to his 2007 GT3 and he is thrilled with difference.