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Cobalt Cobalt is offline
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Join Date: May 2004
Location: New Jersey
Posts: 1,480
Originally Posted by 911st View Post
Porsche put a very good WG in there cars. As noted there is no reason to replace it unless it is broken. Tial dose not have anything on it.

If you are experiencing over-boost because of a larger turbo, that is a different story.

One of the best muffler set ups for a C2T is a bypass pipe to replace the combination cat/muffler section. The stock muffler can in the righ fender is very open. You can drop a tennis ball in that thing and it will come out the other side.

Going from .8 bar (1.8 atmospheres) to 1 bar (2 atmospheres) adds up to 11% more HP but that is only if your efficiency is not dropping off. (HP/1.8) x 2.0)) This, ((320/1.8)x2.0)= 355 hp with a one bar spring. This will likly triger your overgoost switch so you will have to deal with that.

I like the 3" Magniflow set up a lot to.
Normally and theoretically I would agree with you but more often than not the hp gain is not as much as you are calculation states for the 964 3.3 liter motor. At least from the cars I have seen this done to as a lone modification. Not sure why that is. The engines were known to be strong to begin with had no known vacuum leaks and should produce more but they did not. Basing it on the US spec which started at 315 hp the most power the charts showed for these cars was 335 & 340bhp give or take. However, using your calculation my turbo which started at 355bhp did come in at 333.6 rwhp or roughly 390bhp by just adding a 1 bar spring. So the calculation appears to work for my motor albeit a small % low. What is even more confusing is the 3.6 came with slightly more boost stock so the increase in boost is less than on the 3.3l.

On second thought I don't know who did the tuning on these other cars just what the results showed and that might have an impact if the car was not properly tuned.

Why do you feel a 1 bar spring will trigger the fuel pumps to cut out? This is normally set at 1.1 to 1.2 bar. If everything is working you should not have that much creep
Anthony PCA affiliate '77 member '83 '90 3.8 RS tribute, '93 964 C2, '93 928 GTS 5 speed, '94 Turbo 3.6, M '15 Boxster GTS18 Macan GTS
Gone worth mentioning '71 E '79 SC, '79 built to '74 3.0 RS tribute (2390 # 270 hp), '80 928 euro 5 speed, '74 2.0l 914, '89 944 S2,'04 Cayenne TT '14 boxster, '14 Cayenne GTS many others

Last edited by Cobalt; 02-27-2009 at 05:10 AM..
Old 02-27-2009, 05:07 AM
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