Craig:

I am currently building a 965 and am dealing with some of the same issues. Of course I am changing from a CIS system to Motronic, but that has its own issues. Anyway, I have found that bigger is not always better. Unless you are making radical changes to your intake, using monster turbos like Chad (GT40's) or 35's which I would be surprised even if his engine could maximize the AR on those turbos. I was wondering if you could use twin K27HFS turbos on the 3.6 engine. They flow a massive amount of air. The spool with proper exhaust is around 2800- 3000 RPM. I am a much bigger fan of low end response than crazy top end.

Craig

 

 

IM USING A GT35R ON A BUILT 2 LITER MOTOR... evo 8... and this thing is the funnest thing to drive.... yes it spools at 4K.... but I have FUEL CUT OFF at 10200 RPMs. SO WHO CARES ABOUT REDLINE ...LET ALONE LAG...
I HAVE 6K RPMS OF POWER.
so here... I now Im to a set of 2 gt35rs on my tt... fully built motor and GT3RS heads.... redline will be 8500...
ist not like we are putting gt35rs on a stock motor..

 

I'd like to see someone slap a single T66 or T88 on a P-car, like the Supra guys do. I have no idea if anyone does single-T setups. But I have seen a T88 hit 30 PSI and let me tell ya, it's somethin' else.

A turbo is never too big on a drag/dyno queen/highway monster car. On a street car, its another story. Building a car is all about trade-offs, not maximizing everything.

 

it all depends on what you like - what i've found is that one likes what their car does best

when i was bpu+++ w/ my supra, with full boost by 4400rpm, while dropping 3-4 psi by redline, i thought it was the best car for all situations.

when i upgraded to a single, and got full boost by 3900rpm, and sustained full boost to redline, i thought it was the best car for all situations. but i didn't care for taking off quickly (no traction); instead, highway runs became my preference.

when i upgraded to the 996tt, and hit full boost by 2800-2900rpms, i think it's the *ultimate* street machine - traction, instant response, & go! i now *love* zooming through the city stoplight to stoplight.


i don't think i could go back to a turbo that spooled above 3200-3300rpm - i love the mod-ability of a turbo car, i love the rush of the turbo kicking in, but i fear i don't want to wait too long for it.

- chuck

 

The Porsche ECU doesn't allow that. Even turning off PSM,
the ECU won't allow gas and brake at the same time...
Joe

 

Markski,

What type of valves did you go with on the GT3R heads? The stock GT3R valves are titanium and they are rated for 30 hours by Porsche MS. In addition the titanium valves aren't exactly friendly to with the combustion chamber temperatures of the turbo.

 

Here is the graph of a GT35R on a 2.8l (6 cylinder) motor running 8.5:1 compression via a headgasket (the 572whp run was on 20 psi, and the 635whp run is on 25psi.

 

I forgot to mention the above GT35R had a .82 AR. If you guys were talking about the .63AR GT35R, then I think thats a good turbo for the 996tt : It would make full boost by 2800rpms and 1 is capable of nearly 450whp(x2 =900whp on the 996)

For that matter a GT30R, as Craig already has, seems like the best turbo option out there as it is works for great peak numbers yet a great drivability.

 

I know.... either sodium filled or the other way ... im just constrained by time and I need this running so not sure I can afford to have Mckenzie do the work... I wish... Im awaiting on the answer myself.
its a GT3 RS head.. not sure if it different form a GT3 R head ?

 

yes its a .63 A/R for faster spool

 

At this point, I'm most interested in seeing how far the GT700 (GT28's?) cat be pushed with some of the new things coming down the pipe: head work, cams, intercoolers etc.

 

There are many ways to spool a big turbo(s), as mentioned before brake boosting and juice for one, but if you want to get advanced, 2-step, anti-lag and other such methods exist, most are built into a standalone like EMS. All work on the same basic principle;

miss spark, retards timing, add more fuel get the EGT's way up

and that spools the turbo under no load. You can build over 20psi at starting line even with GT40's.

btw: i wasnt really serious about my first post, i figured thats obvious.

 

I have anti lag on my evo 8 via a standalone ecu

 

No difference in valve size between R and RS head. If memory serves me correctly R head is 38 and 43mm. Cup 38 and 42mm. Turbo 32 and 35mm.

What can housings are you using?