Installing An STS Rear-Turbo On An LS1 Bird Part IV: Completing The Methanol Injection Kit Install, Upgrading Injectors, Mounting Gauges, And A Spin On The Dyno!
writer: Randall D. Allen
photographer: Randall D. Allen
If you've been following this nut-and-bolt turbo install on an '00 Formula through the first three installments, then you know the Squires Turbo Systems kit is unlike others marketed for '98-'02 LS1 F-bodies. The turbo bolts on where the muffler used to be, offering an almost invisible installation and 5 psi of boost. An optional methanol injection kit can even add more punch to the already potent package by allowing boost to be increased to 7.5 psi without worry of detonation.
We covered the hows and whys of the system already in past stories. This time, we will finish the methanol system install, upgrade the injectors, install boost and fuel pressure gauges to properly monitor the actions of the fuel system and turbo, and finally see what it's all worth on the dyno.
According to Rick Squires, owner of Squires Turbo Systems (STS), "Although this kit can be installed by the enthusiast with average mechanical skills, we highly recommend you work with one of our factory-trained dealer/installers to maximize the potential of your Firebird or GTO and ensure that the system is properly tuned for safe operation. Variability in the fuel injector size that GM provided on the Firebirds and the mechanical condition of the vehicle play a large part in how the car performs.
"We prototyped the system on a stock '99 LS1 vehicle with low mileage, and after a performance PCM tune by Nelson Performance, the car maintained a safe air/fuel (A/F) ratio of 11.5:1 and has been a paragon of reliability. Unfortunately, an almost identical Firebird may not fare as well and could severely damage the engine, if not properly monitored.
"After system installation, we recommend that the PCM be tuned and the car be monitored with either a scan tool such as Autotap or a wide-band O2 sensor equipped chassis dynamometer. Under no circumstances should the owner go out and start ripping on the car before verifying the engine will maintain a safe A/F ratio. If A/F ratios lean out beyond 12:1 on the base kit, either the tune isn't appropriate or the vehicle isn't receiving enough fuel.
"Rather than bundle a generic PCM tune and larger injectors into the base price of our kit, we choose to warn the enthusiast that careful monitoring of the system is paramount to success. Including larger injectors in a kit necessitates a custom tune, but what if the injectors aren't necessary for safe operation or the larger injectors aren't sufficiently sized due to the car starting out with serious modifications to begin with? The base kit provides the foundation for some serious horsepower, and the enthusiast should utilize the resources that our company and dealer-trained installers provide in order to maximize the horsepower and safety."
Follow along as we complete installing the STS rear turbo system on an LS1-equipped '00 Formula WS6 at Real Performance Motorsports and DuSold Designs, both located in Lewisville, Texas. Texas Rear Turbos of Arlington is a factory trained distributor and full-service installer of STS turbo systems. so its employees performed the turbocharger installation. Allen Nelson of Nelson Performance assisted with the methanol injection system and provided expert PCM tuning and vehicle diagnostics.
Testing: On The Street
After completing the installation, Allen Nelson of Nelson Performance downloaded a custom tune using his HP Tuners software suite. Here's what he had to say:
"The STS-equipped LS1s are tuned for a target air/fuel ratio of between 11.5:1-11.8:1. I have found this to be the middle ground for boosted applications for maximum horsepower and safety. Extra horsepower can be achieved by leaning the car to 12.0:1 or 12.1:1, but I have found that in hot conditions, running it on the edge will cause timing to be pulled, thus wiping out the small horsepower gains of tuning it leaner. With Billy May of Texas Rear Turbos piloting the Formula and my HP Tuners software hooked up to record the pertinent engine monitoring functions, we set out for some initial testing.
"The smaller 26.4-pound injectors installed on '00 models ('99s and '00s used 26.4-pound injectors, while 28.8-pound injectors were used in '98s,'01s, and '02s) caused this low-mileage car to lean out. I recorded O2 sensor values of 620s, which are dangerously lean and translate to a 14.9:1 A/F ratio. Had the run not been monitored and aborted before reaching the redline, the engine may have incurred damage.