LS2 Small Block Engine Mods Dyno Test- Power Play

In the September issue, we strapped a stock LS2 crate engine to our engine dyno and coaxed 472 horsepower and 505 lb-ft. of torque out of it (see "Great Crate" Sept. '06). Impressive numbers, but as the saying goes, there's no such thing as too much power. What we wanted to know is how easy it would be to get more power out of the engine with some relatively simple bolt-ons. Our test engine was already fitted with stepped race headers, so the exhaling was as good as it was going to get. Now we needed to get more atmosphere into the mill.

The LS2 is shipped from GM rated at 400 hp at 6,000 rpm and an equal amount of torque at 4,400 rpm. The redline is 6,500 rpm, but it's all done building power by 6,000 rpm. Remember that this is an engine designed for an emission-compliant production car, so the camshaft is pretty conservative, and the heads, while excellent in many regards, are designed to flow enough to support this camshaft. The factory LS2 also runs a 65cc combustion chamber and a stout 10.9:1 compression ratio. Our tests would all be done on 91 octane, so we didn't want to jack up the compression. That brought us back to helping the LS2 increase its capacity to inhale.

Dyno TimeWe decided to swap three of the most common parts: the intake, the heads and, most importantly, the camshaft. The Superflow dyno at Westech performance would be the location of testing and we would use the SAE J-607 correction factor commonly referred to as STP. This corrects the data to 60 degrees Fahrenheit and 29.22 inches of Hg barometric pressure. Just like before, we would employ a cable-actuated FAST 90mm throttle body, since our dyno doesn't have provisions for the LS2's standard 90mm fly-by-wire air valve. To control the engine, we would also revisit FAST's XFI computer and adaptor harnesses.

The goals for the engine were to end up with a streetable combination that would kick butt at the track, yet still be a blast to drive on the street. We weren't going for the biggest peak numbers possible, but a good compromise that would be durable, have excellent low-end response, and not fall apart at the top end. Check out the photos and captions to see how it all unfolded.