Standard Corrected Power

Big Turbo, Small Turbo, Bi^ürbo Small Turbo

3500 4000 4500 5000 5500

EngSpd RPM SuperFlow WinDyn™ V

Run on pump gas with the small 67mm turbo, the 417 stroker pumped out 766 hp and 815 Ib-ft of torque. That the turbocharged stroker produced peak power at 5,400 rpm instead of 6,100 rpm is a clear indication that the 67mm turbo was running out of steam.

6000 17:19:19

The factory 42-lb-hr injectors were replaced with a set of larger 60-pounders. Unfortunately for us, the turbo kit was capable of supporting much more power than the 60-pound injectors.

This graph illustrates two important aspects of the turbo kit: Turbos offer huge power gains, and the 67mm was (as indicated by the guys at HP and Precision Turbo) indeed too small for this application. Sized for a stock LS application, it managed to produce 766 hp and a whopping 815 Ib-ft of torque. But, it is evident from the shape of the curve that the flow rate was falling off at the top of the rev range, as both boost and power production fell past 5,500 rpm. If you are looking to make 750 hp, this is a good turbo, but if you need more, you'd better step up to something larger. The larger 80mm Precision turbo, made more than 900 hp, but we ran into another limiting factor. Despite increasing the static fuel pressure, our 60-pound injectors were no match for the demand, and we were forced to stop at 913 hp and 925 Ib-ft of torque. The turbo and accompanying kit were clearly capable of supporting more than 1,000 hp, but we'd need larger injectors (75-pour>ders) to do so. Keeping the tune conservative, we were able to run roughly 12 psi of boost to reach the goal of 900 hp. END


Comp Cams; Memphis, TN; 800/999-0853; Dr. J's Performance; Anaheim, CA; 714/943-3404; E3 Spark Plugs; Ponte Vedra, FL; FAST; Memphis, TN; 877/334-8355; GMPP; Warren, Ml; 800/577-6888; Demon Engines; 562/694.2559 HP Performance; Roswell, NM; 575/623-2555; H

L&R Automotive; Santa Fe Springs, CA; 562/802-0443;

Lucas Oil; Corona, CA; 951/270-0154; Precision Turbo; Hebron, IN; 219/996-7832;

Probe Racing; Torrance. CA; 310/784-2977;

Procomp Motorsport; Rialto, CA; 909/605-1123;

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