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Porschefile Porschefile is offline
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Join Date: Jun 2004
Location: Austin, TX
Posts: 150
T4 T67's will definitely break 700whp assuming you have all of the proper supporting mods (cams, headwork, aftermarket EMS, etc). Here's a Google cached link to a Supra website with tons of dynos. It's apples to oranges but, it will give you an idea what people with 3.0l i6's are doing with 67mm turbos. It looks like it's even possible to break 700whp with the smaller .68 exhaust side, though that would take a ton of boost and a fully optimized motor as that's got to produce a ton of backpressure. Anyways, Supra guys tend to see 1bar anywhere from ~3.8-4.2k on the non-ballbearing ones. For a 3.2l+ f6 and considering it's ballbearing, it will easily be 1bar below 4k rpm. Transient response should also be extremely good considering it's ball-bearing and a 67mm turbo really isn't that "big" IMO for a 3.0l+ sized motor. Much above ~72mm T4 turbo (T72) and you'd start to see quite a bit more lag (especially if it was only journal bearing) and a much higher boost threshold unless you had a larger motor like a 3.8l. I'm still soooooo tempted to go with a Precision ball bearing T71 GTQ (think they only have the GTS now). The Supra guys have found that going from a 67mm to a 71mm turbo, there is only something like a 200-400rpm increase in boost threshold and spool however the larger 71mm will make considerably more power on lower boost and pull significantly harder on the top-end. Anyways, it will be nice to see some bigger turbo 911's around here! I've been hoping more of us would catch the big turbo bug.

As far as the air filter goes, I doubt if there would ever be room to run a 3" or 4" intake pipe back into the engine bay. Honestly, at the point that you are using that large of a compressor housing, just run a 4" filter directly on the compressor housing and fabricate some kind of air filter shield to cover the bottom of the filter from debris. My Carrera was setup horribly when I first bought it as it was using a horrible little ~2" intake pipe that ran back into the engine bay. Pushing anything like 500+whp and you really need to free up that intake side with at least 3" piping or 4" if you plan to go much higher. You can get away just fine running something smaller, though you'll see increased lag and at the point you are running higher boost for over 500whp, there will also be a definite loss of power if running less than 3". A shield like this would work just fine.
Old 01-31-2007, 06:02 PM
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