Serge944

You know whats funny? I was reading the latest excellence where they compared GT2 VS GT3 RS... When I saw Overbeek's time around Laguna in the GT3 RS, I immediately thought, "Potter did it a second faster in my car."

Backmarker

That was my reaction too, the lap times did not seem that fast and watching the videos it seems like (jvb) was driving conservatively

What really surprised me though was that he instructs with TMR like I do, I had no idea...

mooty

i met johannes many times on track, very friendly and courteous. he doesn't push it on track with us for sure. but if you tail gate him, he will dump you....oh..say in about 3 turns, he's gone.

Serge944

Christmas came early! What do we have here…



997 Cup heads!





997 cup intake port.



996 street intake port.



Close up comparison.



Exhaust side.



997 exhaust ports.



996 exhaust ports. Not much to see here…



Side by side.



Parts for a full engine rebuild, including the oversized gaskets for the 4 liter.



ARP rod bolts, of course.

SH || NC

Just incredible, pure, pr0n. Did you plan on doing the 997 Cup heads from the start? What prompted this?

aussie jimmy

wow. **** indeed.

loworbitsi

What differences are from the Cup heads to the stock ones? Larger valves? Port & polish? I see some casting differences, but why new heads when the stock woulds could get the machining process done to them?

I very much enjoy this thread. Eye candy information overload.

Serge944

I don't think you can just go out and "buy" the engineering that goes into the heads. Some yo-yo spent a lot of time figuring out where to put all those little scratches in the ports.

As far as differences go, the ports are different (intake is substantially larger), the combustion chamber is different (I still need to take pics of this). I think the valve sizes are different, but I need to double check.

In a nutshell, there is a hp advantage in the 997 head. Ported-to-match intake manifold, 997 82mm throttle body, 997 street headers, and 997 cup car muffler will also be used.

Similar changes yield an extra 35hp between and 996.2 and 997.1 without increasing displacement and only a minor bump in compression.

cfjan

I am afraid to ask what kind of $$$ are we talking about on that Cup head...

Serge944

$2250 each, complete assemblies.

cfjan

Okay.. not as crazy as I expected, but still $$$..

This is gonna be a monster!!

Backmarker

Ah crap now I'm worried about our next track day together...

I'll bring some banannas for your mufflers

Backmarker

It just occurred to me that the reference may be too obscure, so for the youngins out there:

http://www.youtube.com/watch?v=HktV2yGtLv8

SRL

Amazing build, and thanks for the detailed comparison on the heads. One question, why'd you decide to rebuild the diff yourself instead of just sending the unit to Matt for rebuilding? I don't mind diving into an engine build project but when it comes to building diffs I like to leave it to the guys that do it all the time.....of course, I suppose you could be one of those as well!

Thanks again, the pics are great!

Serge944

The machine shop.




They does a lot of work for Flying Lizard Motorsports. When I was picking up my parts, he was modifying some RSR sway bar arms. Here are some brake hats in process for the Lizards.



The machined case. The sleeves extend about an inch into the case so it had to be opened up for accommodate the 4.0 liter sleeves.




Here’s the cylinder head and case mated together. The machining process was such that it provides a seamless transition from the cylinder housings to the case.



The cooling channels had to be enlarged to allow proper flow.



4.0 sleeves are test fitted.




Here you can closely see the finish of the Nikasil coating on the cylinder walls.



While waiting for the machine work to be completed, the coolant pipes were welded. As many of you know, the glued pipe interface has become a well documented Achilles heal of the GT1 engine. The welding isn’t going to win any beauty contests, but is functional.