tosha

Hey guys, does anyone know if a 991.2 GT3 manual 6-speed gearbox can be mated to a 7MT 991.2?

mic_crispy

Not really helpful, but the cost of the tranny alone is probably astronomical.

rugu6869

I found a used one from a 2018 GT3 with less than 5K miles for $10K.

That being said, I highly doubt the bolt pattern is the same.

911.

Theyre not too bad. See them in the 9-10k range on ebay with under 10k or less miles. Figure by the time youre all done as said (after selling 7MT) youd be in it for about 8-10k. Maybe 2x the swap of a LSD upgrade.

OP maybe reach out to the tuners, APR and Scott at Softronic might be able to steer you in the right direction.

polobai

Anything is possible with enough time and money-you may be able to have an adaptor plate fabricated or even swap bellhousings to make it work. The only way to know is to have the two trannys side by side and take some measurements. Many people do tranny swaps on other platforms (Nissan CD009 6 speed on a 2jz for example using an adaptor plate for example).

ClassJ

Given the gear ratio differences coupled with the 7500 rpm limit of the 991.2 it would shorten the legs of the car quite a bit which is usually not a good goal for turbo cars.

Maybe its me, or the T shifter, but I spent a few hours in my T Saturday driven back to back with another car that had 6 speed transmission. Frankly, to me its basically a 6 speed with an extra gear I don't use.

The only time I have ever had to think about shifting is if I do use 7th, and downshift, I have to mentally think which gate I am trying to go into.

polobai

To me, although the 7 speed in the 991.2 feels good, the 6 speed in the gt cars feels GREAT. Coming from a gt4 myself, its one of the things I miss on that platform. Now would I swap in a gt car 6 speed tranny-not worth it to me-but kudos to whoever is able to see that project through!

Mike3015

I can't find the post but I did read here on Rennlist that the top speed for a 991.2 7MT is achieved in 6th gear. The 7th gear is an overdrive gear strictly to achieve the vehicles EPA rating. I can't remember the last time I've had my 7MT in 7th gear.

That being said, I would think you could find a solution with the right CAD drawings and someone good at 3D printing in aluminum. Would love to see and read about your progress.

Mike

Joec500

I doubt the bell housings would line up and I am sure there are tricky things with the electronics, like calibrating the throttle position sensors etc. Doesn't really seem worth it UNLESS you are really know what you are doing and have fabrication skills.

ClassJ

Ran the ratio math for GT3 trans in the 991.2.

Compare the MPH at 7500 RPM columns. Certainly changes things. The GT3 gearbox is configured for higher redline.

GT3 makes peak power at 8250 RPM.

991.2 carrera makes peak power at 6500 RPM.

All of this could lead to a hampered top end if one cares about such things.

jfischet

just get a numeric shifter and cables

rugu6869

He's interested in the LSD part of the swap - so performance for the car, not just the shifter feel.

I have the Numeric shifter/cables. They are stellar!

911.

I saw the LSD was 2.5K give or take. Are those installed prices?

The Ox

Agreed! Mine were installed last week (South Shore Performance, Freeport, NY), can't say enough good things about them and the change form stock.

Norge911

Not possible. Everything behind the crossbar where the tub ends is different from a base/s/GTS/turbo vs GT3. See Porsche PET diagram.

in addition, engine case for GT3 is much different than regular 911 and therefore different mounting points.

look at other models with 9A1 and 2 architecture, ie GT4 transmission should be able to fit but still lots of work.