I just finished installing a T56 trans in my 3 rotor FD. I just finished and only driven it a few times. The most remarkable difference is the close ratio of the gears. It feels like a much different car.
If you are interested in this installation, there is a thread by Howard Coleman entitled something like "transmission solutions for 500+ hp" that walks you through his install. I pretty much copied his installation and it works remarkably well. His thread should be a sticky.

 

Glad you got her up and running.
Missed seeing your car at DGRR.

Watch out for that kid with his 3rotor rx8. Maybe now you stand a chance...lol


Steve
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I know fast is relative but I had forgot how hard my car pulled. I was telling my son on the way home that your car was one of my favorites at DGRR. I think youy have a great car! I also told him that I would almost be ashamed to open my hood with some of the cars at the show. We'll be there next year.

 

T56 is a really nice solution for those making some power. The later renditions out of an LS2 GTO are much better.

 

I used a trans from an '04 GTO. I think it shifts better than the FD trans.

 

while the GTO T56 has uprated internals i prefer the gearing in the F body trans. both are in a different zipcode than the stock FD box.

consider:


FD................................................ .3.483...............2.015...............1.391.... .....1..............719

F Body...........................................2.6 6.................1.78.................1.3........ .....1..............74

GTO............................................... 2.97................2.07.................1.48..... ......1................8


FD................................................ ........................42.1%.............30.9%... ....28.1%.......28.1%

F Body.............................................. ....................33%................26.9%...... .23%..........26%

GTO............................................... ......................30.3%..............28.5%.... ...32.4%.......20%

translating this to RPM shifting at 8000

FD................................................ ........................4632................5528.. .......5752........5752

F Body.............................................. ...................5360.................5848...... ...6160........5920

GTO............................................... ......................5576.................5720... ......5408........6400

average RPM into next gear

FD...............5416

F Body.........5822

GTO.............5776


while i grant you there isn't a lot of diff between the GTO and F Body there is a huge diff between them and the FD. first gear (3.483!) is pretty much worthless as is the wide gear spacing. given our small displacement, there is often a significant power difference between 5400 and 5800.

i also really like the 2.66 first.

it is closer to the FD second gear whereas the GTO closer to the FD first.

the 2.66 is a wonderful/usable gear on a road course.

the GTO spacing is tighter into second than the F body but who needs it in second? you need tighter spacing in the higher gears. check out spacing into the critical 4th gear...

the GTO finds fourth at 5408 while the F Body sees it at 6160.

the other reason i went w the F body is it is widely available, read cheap. i wanted to see if a boneyard 50,000 mile trans would work behind a high revving rotary. if so, it would open the option to more FD owners.

after 4 or 5 years i can tell you it works. i have shifted at 9000 with no problems.

i do use the GTO shifter relocation which situates the shifter perfectly and is a bolt on.

i am not knocking the GTO option, it does have advanced internals and the Magnum is significantly above the GTO.... just saying that the F Body works fine, has good ratios and the price is right.

howard

 

That is pretty much why the v8 guys like the F body T56 over the GTO T56 as well. I have an F body T56 behind my LS Engine with 3.73 rear gears.

The best track trans would be The F body 1-4 and the GTO 5 and 6 gears, but that is pretty expensive to make work.

 

I think which version of transmission you use, should be application specific. For me being NA 20b, I think the GTO m12 version is best because, NA rotarys need to stay in the higher revs between shifts. This keeps you deeper in the NA rotarys power band. I also think the 6th gear is perfect for cruising on the highway with a 20b's low rpm torque. I can't wait to install one on my car.

 

I went with the GTO because I got a deal with that trans, adapter plate, FD auto bellhousing and driveshaft all from the same source. The hard part is now over now that I have it installed and running....If I want to swap to the Fbody, I can pick one up and sell my GTO and probably not loose money.
I was on the interstate this weekend and was able to use 6th gear. I didnt think I would be able to do so. It drops about 1k rpm from 5th. I was cruising at 70-80 mph. I did notice that in 5th, I was running about 12 'HG vacuum and in 6th I was about 8"hg vacuum. I wonder if this is adding heat to the turbo. water temps were great regardless of gear. Any thoughts on the extra load in 6th gear?