964TT

Everything is going smoothly. Might do a little cylinder head revision and looking at a better option instead of the 993 GT1 Evo cams.

Rebuild starts next week.

The only thing which is much harder than anticipated is finding a bigger chargecooler which fits the available space.

To be continued

evoderby

You might want to have a try here: http://bellintercoolers.com

The company's founded by Corky Bell, author of "Maximum Boost" https://www.amazon.com/Maximum-Boost...rds=Corky+bell

I still must have a copy somewhere here in Amsterdam, if you want to I can look it up for you to borrow.

Edelweiss

Hi Thomas,

just by the way - the 993 GT1 engine was a water cooled 4V engine; 74,4 x 95,5 mm, eta 9:1.

The cam you are running is a GT 2 evo cam.

This is the latest Porsche Motorsport two valve turbo cam and already a very good profile.

On the more modern engine layouts, with higher static compression ratios, like in your case, you should react on the dynamic side with a cam profile that generates a suitable lift at TDC.

On this way you reduce detonation / pinging tendencies also.

Also a charged engine likes flow !

Look at it like you look on any normally aspirated engine.

With good ports and very important good valve seats you can go down with boost and have the healthier engine or you keep the boost level and gain mid pressure, torque and power as well.

Best regards,

Dirk

964TT

Thanks Dirk!

Lets take care of that with the new cam!

964TT

Ha! I wrote them an email yesterday!
I had already found the website through Google.

evoderby

Cool! Look forward to seeing what sort of solution they can come up with....

Undutched

Happy I could help out

Let me know what you come up with, with regards to the chargecooler. Although I will admit I do want to run a big wing

Edelweiss

Thanks for the contact to Thomas also from my side !

I like cool and unconventional dudes with a vision ...

Best reg.

Dirk

964TT

Okay, it has been a while. But back to the original question why I started this thread. Boy, a lot happened since then! Haha

I'm back on the gearbox issue. The 964 turbo box was okay and took the beating without a problem but I always felt like the gearing was off. So I started wondering about a 993 6-speed, but those are so hard to find and can they take the power? But then it was suggested to me to look at GT3/GT2 gearboxes. A small change to the chassis and the cable control is actually not such a big issue if you get a really great transmission in return.

So this is what I am exploring now. I see the holy grail for me would be a nice G96/88 GT2 gearbox, which has almost the same ratios as the 993 G50/20!
But of course is stronger, has the H pattern and steel syncros.
But very hard to find. Much easier to find are the GT3 gearboxes, but those ratios are a bit shorter. And with my 850Nm this seems a bit silly. Am I right here? There is quite a difference in the ratios of the GT2 and the GT3, obviously Porsche did this with a reason.
So would it be sensible to change a GT3 gearbox to GT2 ratios?

Any feedback here would be greatly appreciated.

964TT

Just found out the 996 Turbo G96/50 is exactly the same as the GT2 but without the oil cooling system but perhaps just needs a little modification for taking out the 4WD part?

These can be sourced new for a good price so this could be a nice solution.

964TT

Okay the modification is no problem I just found out. So the choice is between a 996TT box or a more aggressive GT3 box.

964TT

On another note, just picked up the last engine parts in Germany and finally we can start putting everything back together.
Very curious for the result of the new parts. The gorgeous new custom heads, rockers, pistons, conrods and cams.
Lower compression ratio of 8.5:1 and 4.0L

964TT

Old rockers VS new rockers

964TT

Heads and pistons

R6XTERRA

looking good, can't wait to see it come back together.