964TT

Thanks! I'm going to keep really good track of the built this time so I'll post the progress.

Okay, back on my thoughts about the gearboxes.

Here is what I have now:

964 (965) Turbo 1991-94

1st gear: 3.154
2nd gear: 1.789
3rd gear: 1.269
4th gear: 0.967
5th gear: 0.756
Ring and pinion: 3.44

And this is the gearbox I'm looking at:

996 Turbo 2001-05

1st gear: 3.82
2nd gear: 2.05
3rd gear: 1.41
4th gear: 1.12
5th gear: 0.92
6th gear: 0.75
Ring and pinion: 3.44

Now, I was recommended by CMS to replace the 1,2,3rd gear with the ones of the 997 GT2. 3rd is a weak point anyway and the GT2 is a bit longer in the gearing.

997 GT2 2007-09

1st gear: 3.15
2nd gear: 1.89
3rd gear: 1.40

Looking at those numbers it seems that the new box would be a nice upgrade from the 964T box. Slightly shorter gears and a more strength. I'm just assuming it will feel a lot more solid as it is a newer design. Anyway it will be a new box. I can transfer my Guard LSD as well, this is nice.

It is very difficult to decide though, I could also just go for a straight up GT3 box like the G96/93 (which is relatively cheap from Porsche new)
But this is a box made for higher RPM (my max is 7100) and I would not have a high top speed (not very important). Would it be more fun to drive or is it too much with 850Nm on this GT3 box?

996 GT3 1999-03 Japan

1st gear: 3.82
2nd gear: 2.05
3rd gear: 1.41 (steel synchro)
4th gear: 1.12 (steel synchro)
5th gear: 0.97 (steel synchro)
6th gear: 0.82
Ring and pinion: 3.44

mf_rsr

9m put a GT3 box in the last RSR backdate they did I think? So defo can be done. Another benefit is less HP drivetrain loss plus lighter maybe?

But defo go with TT ratios otherwise you'll be slower as you change gears all the time! Could you perhaps consider 6th gear as an overdrive too, leaving you 5 effective ratios to play with?

Heads up there is a G96/88 on uk ebay right now...

964TT

Yes, I know its not a problem to install. Just trying to figure out which box would suit me more.

Thanks for the heads up on the G96/88, I noticed it on Ebay too. But with rebuild that one is quite expensive. For less money I get a brand new 996T box...

964TT

Porsche Motorsport vs Clevite coated bearings. I think I'm going to use the coated ones.
Unless someone on Rennlist has really bad experiences with these...

964TT

Engine in parts, oil pump won't fit exactly this time. The previous (turbo) pump was fine but the new GT3 pump needs a bit more space...taking a bit away in the engine case

964TT

More parts ready for assembly

sander97C2

Wow, well done sir! air-cooled ****. Where did you source those rockers if you don't mind me asking, they appear to be with ones Pauter sells that are DLC coated. Nice pieces.

964TT

Haha, thanks!

The rockers are Pauter, they look super slick. Light, strong, slippery as hell with that special coating.

964TT

Crank polished, everything ready for assembly. Removed the power steering from the engine, it's going to the front.
Found a RSR electric pump here on Rennlist which somehow felt more in line with my project than the Mercedes A Class pump.

porsche993gtrsr

who is doing your engine work ? And does he have experience with this kind of builds ?

964TT

The guy working on my engine has a good 30yrs of experience, maybe more. Are you looking for something similar?

HiWind

looking great ... love the detail shots and the thought into the gbox

in the cylinder pic above are those stock gasket rings? what year is your engine?

964TT

Thanks man.
Those are machined in the cylinders and heads. The cylinders are 102mm Mahle, originally a 3.8 set.
With the first turbo build in Germany by TTP they did the rings. Engine is from 1990

964TT

And so it begins. GT3 pump installed, looking great.
I wish I could build this engine myself, something I will certainly do at a later point in life. When I look at some other threads on Rennlist I'm always jealous at the work people do themselves. There is something to be said about knowing really everything about your car.

NineMeister

I have a 993TT 6 speed gearbox in stock if you still want one?