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From: Ron Bilyeu of Pro Auto Tech, Fort Myers, FL (March 5, 1999) There seems to be quite a bit of discussion on performance products and their claims. I will try to address as many comments on various products that we produce or have tested. I currently have logged over 300 Dyno runs in the past 24 months on various 97, 98 and 99 Corvettes! Dyno runs are performed at 200 degrees oil temperature and 192 degrees coolant temperature with the stock thermostat and 178 degrees coolant temperature with a 178 degree thermostat. Data acquisition is logged with a Tech II factory diagnostic data tool. We also utilize a high speed air-fuel ratio meter during all Dyno runs. 1. Air filter assembly: The advantage the stock box has is that the vacuum created in the restrictive air box is routed to the fuel pressure regulator at full throttle. You lose that leaning effect (which makes power) on the 97-98 C5 without a fuel recurve line. We have seen additional gains of 4-6 HP with the recurve line. The LS6 Airforce was worth 32 HP on an LS1 that produced 450 HP! It makes more power than no filter at all. 2. Thermostat: We found that the aluminum block LS1 likes 178-180 degrees temperature to make the best power. This has been consistent throughout all of our Dyno testing. Stock is 192-194 degrees. The PCM (Computer) can and will go Close Loop ( that is the computer is controlling the fuel mixture and maintaining an Air/Fuel ratio of 14.7:1) in as little as 100 degrees! The benefit of the thermostat has to do with friction in the engine. The LS1 engine makes more power at 180 degrees than it does at 200 degrees with no ill effects. The factory keeps the temp high to keep the cylinder walls hot to reduce emissions this also increases friction and reduces power slightly. 3. Timing Tricker: The computer has several timing tables to choose from. It likes to stay at the most aggressive timing curve which at full throttle on a 97-98 Corvette is 28-29 degrees of timing. A 99 Corvette has 30 degrees of timing if the air coming in is below 60 degrees. The Timing Tricker basically tells the computer the air coming in is 57 degrees. The difference is 5.5 HP between timing at 24 degrees versus 28 degrees. 4. Max Flow Mass Air Sensor: Fuel and ignition timing tables are based mainly on mass air flow rate. The modified Mass Air Flow Sensor allows more air to enter the engine without the computer adding the fuel to go along with it. This leans the air-fuel mixture and adds a little timing. We have seen gains of 8-20 HP. I have added the Mass Air Flow Sensor to a Lingenfelter 383 and it went from 350 HP to 370 HP on the Dyno! I have added the Mass Air Flow Sensor, Adjustable Fuel Pressure Regulator and Timing Tricker to a Mallett 396 and gained over 20 HP on the Dyno! On our Mongoose packages, we typically see 12 HP gains. 5. Adjustable Fuel Pressure Regulator: Setting the fuel pressure to where the computer is happy, works. You do not want the computer's fuel trimming to go so positive that it will start to add fuel and take away the leaning effect that you created by lowering the fuel pressure. We can tell you where that general pressure is based upon your modifications. However, to be accurate you must be able to read scan data fuel trims and use a high speed air-fuel ratio meter. I would be glad to look at your numbers with my equipment and adjust accordingly at one of the many shows or at my shop here in Fort Myers, FL. 6. Headers: Full length headers are the way to go. These are worth 10 HP to the rear wheels on any combination and the bigger the engine the more power they provide. 7. Heads and Cam Packages: Mongoose 400: 335-340 HP and 339-343 ft-lbs. of torque at the rear wheels. A 99 Corvette requires headers. Mongoose 425 Heads / Cam / Headers / Stage 1: 361 HP and 363 ft-lbs. of torque at the rear wheels. Mongoose 448 Heads / Cam / Headers / Stage 2: 377 HP and 375 ft-lbs. of torque at the rear wheels. Mongoose 500 383 cid / Heads / Cam / Headers / Stage 3: 422 HP and 429 ft-lbs. of torque at the rear wheels. 8. Programming: The biggest advantage is controlling torque management and turning on the electric fans earlier for low temperature thermostats. Gains of 5 ft-lbs. and 2 HP on Mongoose 400. Gains of 8 ft-lbs. and 10 HP on Mongoose 425/448 packages are obtained. We are very close to doing custom programming in house to provide you with programming that matches your combination of performance products! 9. Throttle Body: The intake manifold is 75.5 mm, the throttle blade is 75 mm and the air entry to the throttle body is 72 mm. Early testing of porting the first air entry on a 99 Corvette provided 8 HP and 6 ft-lbs. of torque. We did reach 312 HP on a 99 automatic without headers. Automatics lose 22% through the drivetrain and manuals lose 15-16% through the drivetrain! 10. Nology System with Beru Plugs: The Nology System allows you to make peak power at an air-fuel ratio of 13.5:1 Vs 13.0:1. Your stock spark plugs are 5500 ohms. The Beru spark plugs are pure silver and are .3 ohms! Yes, you can kiss the AM radio goodbye because of electrical interference. We found no problems on FM. We have seen gains close to the Beru with the new Bosch Platinum +4. They are 1800 ohms. Lower resistance wires and plugs increase the spark energy. You do not need increases in spark energy unless you modified the fuel system or increased the cylinder pressure. 11. Torque Converters: (Automatic transmissions) We have seen up to half second improvements in the quarter mile! Pro Torque is the recommendation. 12. Throttle Body Bypass tube: An old ZR1 modification that works on the C5. Cooler air means more power. Real players in the LS1 business who you need to be talking to and asking questions: Tiffany or myself at Pro Auto Tech, Jason Haines at Lingenfelter, Bill Leebans at Lunati, Matt Harwood or Chuck Mallett at Mallett Cars, Jason at Motorsport Technology, Peter or Vaughn at Doug Rippie Motorsports, and Myron Cottrell at TPIS. From: Ron Bilyeu of Pro Auto Tech, Fort Myers, FL (March 5, 1999)
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