With the recent results from the Racer-X (and Promax) chips, the airbox mod, and the recent discussions about the header RS Barn is working on, potentially in conjunction with an optimized cat back set-up, I'm wondering what could be ultimately attainable horsepower-wise from our engines. I know the results aren't additive, but it seems that something in the neighborhood of 265-270 hp is probably a reasonable estimate from the best chip/airbox mod/exhaust combination. RS Barn's web site also describes a 3-stage head rebuild, which, in concert the the above mods, would seem to have the potential to squeeze out a few more hp. Combined with some fairly aggressive (and admittedly fairly expensive) lightening strategies, could a coupe (or even a cab, in Flash's case) be brought within striking distance of a 10:1 lb/hp ratio?
Wherever these mods lead, it's heartening that we've come a long way from the days when it was "common knowledge" that it was pretty much impossible to add much hp to these engines. Thanks to Flash, Dave Greimann, Pete from RS Barn and others for their efforts in wringing some extra juice from these engines.
Adding useable hp is possible up to around 300 engine hp. It doesn't come cheap though. The cams, and cylinder head and intake mods with header will put it at around 300. This is with a useable powerband. I know this from engine testing with similar mods. The same parts I'm using with a dual Weber setup produces 325 engine hp. We cannot get there with stock Mass Air and single throttle body. I will be testing different intake with larger Throttle body soon.
Pete
I think Pete said the key words: usable power band. Peak numbers can be misleading if the low end torque is gone. I like the term, most area under the curve.
What is the current "state of the art" as far as HP / Liter?? Anyone? Is it a Honda Vtech something or other? The motor will spin like crazy, but at low RPM it (as my friend from Tenessee says) "won't pull a greasy string out of a cat's ass".
The 968 with the current set of tricks applied should be close to the top? How about BMW 3.0?
Pete, how about trying the Carrera 3.2 throttle body? It seems to me that would help along with an adjustable fuel pressure regulater to richen up the mixture. These along with the chip, air box mod and the header should really work well together. Thanks for your efforts and good luck, bob Blackwell.
[quote name='bob blackwell' date='Oct 3 2005, 08:00 PM']Pete, how about trying the Carrera 3.2 throttle body? It seems to me that would help along with an adjustable fuel pressure regulater to richen up the mixture. These along with the chip, air box mod and the header should really work well together. Thanks for your efforts and good luck, bob Blackwell.
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I'll jump in here with a few data points from my past experience. The most I've seen from a normally aspirated 968 engine that was seriously modified was 300 corrected rear wheel HP. This was a Kelly Moss car that ran in the Speedvision World Challenge series. MoTec injection, slide-valve individual throttles with custom air box, 12 or 13:1 compression, cams, header, head work, etc. That car since has been sold and converted to a 951 turbo engine and runs PCA Club races now. I can scan some detailed pictures of this car and post them later.
On a supposed "stock" PCA club car that I was involved with we got 241 RWHP as measured on a Dynojet. This long block came from Michael Mount and was basically a blueprinted stock engine with a modified intake manifold, throttle body, header, head work, and 5 hours of dyno time mapping a custom chip. We figured around 40 hp over stock. Of course the car weighed in at 2200 lbs, so it was hard to compare it to a street car.
For refence, a stock 968 dyno'd around 204 hp on the same dyno. While not the final word on 968 engine performance by any means, these are actual numbers that I can validate from first hand knowlege.