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August 7, 2005
Intrinsic Performance FI cams - first result
Ron from Intrinsic Performance posted the first dyno results for their supercharger-specific cams on Oside JimC's Acura RSX Type-S equipped with an 11psi Comptech SC, Jackson Racing race header, 650cc injectors, Hondata K-Pro, Injen CAI and Comptech 2.5" exhaust. The dyno comparison was done at Church Automotive in Torrance, CA, on a DynaPack. Power went from 324 to 343 at the hub, and torque from 218 to 225 ft/lb. Most interestingly, the IPS cams almost completely eliminated the boost drop usually seen at the VTEC point. This means up to 3 psi more boost between VTEC and midrange, and additional boost even at high rpm.
These results seem to affirm Ron's earlier prediction: "As you may know already, overlap allows boost and fuel to blow right through and ignite a good portion of the mixture well out of the combustion chamber through the exhaust. This causes high EGT's. This is very bad. So, for a proper FI camshaft to perform well - overlap must be reduced or eliminately completely. This is what IPS-Kpsi's were designed and engineered to do. Moreover, the ideal FI cam profile will have significantly larger lobe area conducive to boosted application. And because there no longer exists an overlap condition, the pressurized intake charge will see less restriction at the valve due to the greater amount of valve lift realized with IPS-Kpsi cams. Lastly, the result from meticulously analyzing valve motion and harmonics, IPS-Kpsi cams allow Volumetric Efficiency to scale exponentially under boost, with superior valvetrain stability. We'll see torque curves and HP powerbands hold very strong past their peaks, unlike what is seen with stock camshafts. FI amplifies the engine's natural ability to make power." Ron further stated, "The benefit from overlap in an NA engine helps with cylinder filling at mid to high rpm. I think by the time you hit this portion of the powerband while SC'd, the blower will be doing what it does best. Therefore, I feel it will be an non-issue and that part-throttle driving (SC bypassed) will not incur any downsides other than the inherent parasitic losses seen with a SC installed." OsideJimC, the car's owner, reported, "I'm pleased to report no loss of driveability. Under light throttle the cams are very tame, no bogging and again partial throttle response is excellent. One thing my G/F mentioned, the car is quieter under light/medium throttle. Even WOT seems a little quieter, my theory is without the overlap less intake charge is burning in the exhaust, a very interesting by-product."
So this is a very interesting development. An earlier test with special Crower supercharger cams did not yield good results, and the general recommendation is to use the stock cams with supercharging unless the exact right cams are available. Looks like we now may have those.
Posted by conradb212 at August 7, 2005 1:58 PM