Everyone wants more power and it seems like there is a common misconception that the best way to go about getting more out of a forced induction application is to increase the boost. While this does the job and is fairly easy to do, the best way by far is to actually decrease the boost. To elaborate on this concept, Richard Holdener at Speed Secrets and COMP Cams teamed up to demonstrate how effectively a cam swap can increase power on a supercharged LS engine while giving some of that boost the boot.
Using an LSX B15 Crate engine from GM fit the bill perfectly for this test. The team upgraded the valve train to a dual valve spring package that allowed for the installation of the Comp cam after getting a baseline for the test. Then, installed a 4.0L Whipple Twin Screw supercharger, dialed it all in with a Fast XFI ECU management system and put the combination on the Dyno.
Running a factory GM LSA camshaft, the engine produced 695 HP and 666 Lb-Ft of torque on 17.6 PSI of boost. While these are impressive numbers, more power is always better.
With an established baseline, Richard installed a Comp 273Lr 54-457-11 camshaft. Despite not being designed specifically for boost applications it performed really well. The supercharged LSXs power output jumped to 751 HP and 692 Lb-Ft of torque. Whats really great about this is that not only did the cam swap produce upwards of 50 more peak horsepower, but it increased the power output across the entire power band and in the process it reduced the boost by almost 2 PSI. What could be better than increasing the power output of your engine across the board while reducing boost levels? Now that is a win-win.
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