964 Carrera 2 - Bi-turbo built by TTP in Germany
 

Hi,

This is my first post here after reading the list for years!

I am having my 964 C2 engine rebuild to a twin turbo by TTP in Germany.
Result should be close to 550hp. I am looking into gearboxes at the moment and thought a 965 (G50/52) would be a great option. Stronger, better ratios and a LSD.
Car will be street/track but 85% street.
Any ideas are welcome and some advice on LSD ratios would be great!

Best,

Thomas

Welcome Thomas, sounds like an interesting project!

I'm no expert, but I've heard the 993 6 speed gear box may be the better option. I don't know if the 993 TT gearbox is different from the standard 993 6 speed.

Wow - subscribed.

Yup and early 993 six speed has slightly closer gears than 964 with a tall 6 - IIRC.

Pictures to get us going would be great. Please.

Wow - 600hp in a C2! Sweet!

Thomas, change your title to "need help with gear ratios on a TT".

Hopefully Bill Veburg will catch the title and pipe in. He is a great resource when it comes to the different gear options. He usually posts shift charts listing MPH and the corresponding RPM.

I built a custom 915 gear box years ago for the street/track and Bill was a huge help.

Good luck with your project :cheers:

Thanks. I did a whole intro which got deleted and I had to login again so I'll redo that soon. Trying to figure out how it all works.
I'll post some pics as well.

My understanding is that a six speed is not desirable in this case as you have plenty of power anyway. I could even get away with just a longer 5th and installing a LSD in my current gearbox but I like the idea of a stronger box, which the 965 box is.
Obviously the 993 TT gearbox is for 4 wheel drive and heavier I thought. Not sure if that would be beneficial over a 965 box. But I have no clue honestly and would love some serious advice.

I'm thinking that with 600 hp, the G50/52 ratios would be ok.
Someone over on P/P is running a 6 speed G50 (non turbo) box with around 600 hp and reported no durability issues when I asked him about it.
I think Turbokraft has built some turbo engines with that 6 speed 993 box. Call Chris; he's really helpful and can guide you.
You could source a 993TT box, but from what I hear, it won't be cheap.
Good luck. Sounds like an interesting project.

Hi Thomas,

I have a short 6 Gear G50/21 of a 993 in my 964 and feels like having 30hp more in the back. They are rare and the prices in Germany for them have been getting high in the last time.

But I think the last gear is a little too short for your 600hp.

Good luck with your TTP project.

Here are some photos of my C2:

I am still trying to find out how to work this system. Wanted to put some info with the photos but I'll explain some here instead.

The dampers are Intrax 4-way. They will be installed next week with the rest of the suspension goodies. Not all is pictured here but basically it is the full 993 treatment in front, 935 in the back.

Front lip (RUF) is coming off, don't like the looks. Rear roof spoiler and the wiper as well. instead the nice RS glass.

Front hood, engine lid and rear (RS) bumper are being exchanged for carbon fiber parts. They are going to the body shop next week or so.

Interior will be RS style, black. I don't really dislike the light interior, it kind of grew on me but it is just not as clean as black will be. I want it to be all business. Seats are custom made copies of the 964 RS seats made out of carbon fiber. They look great and my seat is actually fitted to me. Black leather with alcantara cushions. Center console will be black leather with alcantara gear shift and hand brake.
The rings on the gauges will come off as soon as I have a moment, they are in the body color now.
Doors black leather RS style.

LSD - talk to Matt at Guard Transmission ... They make a beaut
Or you can just get internals from him to tweak your existing.

Car looks superb!

I ended up buying a 965 gearbox. Great strength, good ratios and a LSD.
Brought the car to Germany two weeks ago or so.

And some more photos of the progress

Radiator in the front for the water cooled intercooler.
Luckily nobody will know I'm (partly) water cooled.... haha