LS1 Hop-Ups

If you have the faintest appreciation for musclecars, then you know that most car buffs thought the grim reaper of performance had finally reared its ugly head when electronic fuel injection (EFI) was first introduced in the early ’80s. This was a legitimate concern, because all of the EFI cars at that time were considerably EPA cautious with a focus on gas mileage and emissions. However, over the last 20 years things have changed, and that newfangled technology has now been integrated into the endless quest for more horsepower.

Power Play

What was once viewed as a limitation now allows for greater flexibility in both tuning and maintaining streetability. This didn’t happen overnight, of course, but the lessons learned by aftermarket electronic engineers from the early Cross-Fire and Tuned Port Injection systems have brought us light years ahead with the venerable EFI LS1 small-block. The real question now is...just how potent are the musclecars of today?

The Dyno Doesn’t Lie

The idea was to see what kind of real-world horsepower gains we could generate with only a few simple bolt-ons. Enlisting the help of Mike Taylor and his stock ’99 LS1 SS Camaro, we baselined the SS on the Morgan Motorsports chassis dyno in Reseda, California. Initial numbers revealed an impressive 305 hp and 322 lb-ft of torque. Next we plugged in the Hypertech Power Programmer III (PP3) into the data link connector and waited 10 minutes for the non-reformulated gas (non-RFG) tune to upload into the LS1 computer (see sidebar “Gas Is Gas...Right?”). Back on the dyno, we immediately witnessed the horsepower jump to 312 with the new lb-ft figures reading at 328.

Now for the bigger test. We had Morgan Motorsports install its 20 Rear-Wheel Horsepower Under an Hour package, which actually took less than 25 minutes from start to finish. This included replacing the factory airbox lid, mass airflow (MAF) sensor, and throttle-body with a higher-flowing ’99 Corvette airbox lid, Granatelli MAF sensor, and ported Morgan Motorsports throttle-body. The results were an excellent increase to 325 hp and 334 lb-ft of torque. However, we found that the non-RFG tune was slightly aggressive with minor detonation. Next we tried the RFG tune, and with slightly less timing and a richer fuel curve, our next dyno pull showed that we were only down 1 hp and 2 lb-ft of torque. So to avoid detonation, be sure to use the RFG tune unless you have access to at least 93-octane fuel.

For our final test, we removed the Hypertech tune and allowed the factory LS1 computer to do its job. Interestingly, we found that our power levels increased even >> higher with the numbers peaking at 328 hp and 339 lb-ft of torque. Looking at the air/fuel ratio, it seems the factory computer didn’t lean out the fuel enrichment quite as much as the PP3 tune and was able to make use of the extra fuel for the additional air that was now flowing via our upgrades.

Bottom Line

The LS1 certainly responded well to both our Hypertech and Morgan Motorsports upgrade package. And if you’re running a stock application, the PP3 will definitely give you additional horsepower by adding more timing and leaning out the air/fuel ratio. However, should you decide to step it up a notch and add even more modifications, then the PP3’s other features really make the unit shine. The PP3 allows you to program gear ratio changes into the computer to correct speedometer readings, operate the electric fans earlier, and raise the rev limiter. With automatics, you can control the shift firmness for reduced e.t.’s and to help cure wheel-spin at the dragstrip. Even cooler is that the older LS1 vehicles are already 5 years old, making them that much more affordable. So if you’re looking to either purchase a car or just the potent late-model mouse, follow us, because we’ll be paving the road to true LS1 performance tricks and tips!