C5 Power Tips II

From: Chris Byrd, C5 Concepts, Inc., (March 11, 1999)

All of the research and development that we have done is on our own in-house DynoJet Dynometer. We have extensive experience with the LS1 and have approx. 600 dyno runs on various Y-body and F-body LS1's. Our philosophy is not based on a quick fix approach to HP, rather we prefer to let our engineering backgrounds dictate a scientific methodology towards any product we sell. Bottom line is this, if it doesn't perform like it claims, then we won't sell it, no matter how much money we might make on it.

1. Air filter assembly: Go with either the TPIS/Donaldson intake or the RM Racing Twin Tube Intake and you won't make a bad choice.

2. Thermostat: We have found that the 6-speeds like running a little warmer than the autos. They produce the maximum HP in the 182 degrees range, whereas the autos like it about 8 degrees cooler. We recommend you use a lower thermostat only if you are using it in conjunction with an Hypertech Power Programmer III or custom PCM programming - to take advantage of a lower thermostat actuation. We found the 175 degree works very good. Stock is 192-194 degrees.

3. Timing Tricker: We use a recalibrated MAT sensor that is not a static resistor, rather a true sensor. We've seen a few HP from this type of mod. Don't expect more than 3-5 HP increase.

4. Mass Air Flow Sensor: We use CNC Aluminum MAF sensor ends. No need to buy a "recalibrated" one for $300+ when you've got a good one already. Our CNC MAF sensor ends flow approx 880 CFM. Result is typically 11 HP, and for $139, it is an outstanding mod.

5. Adjustable Fuel Pressure Regulator: Fuel pressure from the factory is quite fat. We use the autotap software, HUEGO air/fuel ratio meter, and our dynometer to tune in the optimal fuel pressure setting. We have seen up to a 15 HP gain, but 8-10 HP is typical. Won't work on the 99's due to a change in the fuel system over to the F-body style.

6. Headers: We have installed, tuned, and tested both the TPIS long-tube and the B&B shorties. Both produced similiar gains. I recommend either of these header systems. The quality and fit on both is outstanding. We also offer a ceramic coated version of the B&B headers that is very cool and looks awesome!

7. Heads and Cam Packages: Check out our Thresher 450 and Thresher R/R packages.

8. Programming: We have been doing the programming in-house for 4 months now and we are seeing very good gains.

9. Throttle Body: Jury is still out on the BBK throttle body. Don't expect a wealth of HP from an 80mm throttle body. I'd wait for the Accel aluminum intake manifold and throttle body when they come out later this year, rather than a ported intake manifold. The thickness of the nylon may result in compromised structural integrity if ported.

10. Capacitive Ignition Systems: I have never been a believer in capacitive discharge ignition systems. Have never seen one on a C5 that produced the advertised HP gains. Having an electrical engineering degree, I fully understand its concept and don't buy it. If you want to learn more about ignition systems, click on the following link: http://www.magnecor.com/magnecor1/truth.htm

11. Torque Converters: (Automatic transmissions) I personally like the 2900 rpm stall speed.

12. Throttle Body Bypass tube: Been doing this mod on LT1's for a long time. Works well. We also have a stainless steel braided hose kit that not only makes the engine look great, and bypasses TB coolant also.

Players in the LS1 business: C5 Concepts, Inc., Breathless Performance, RM Racing

From: Chris Byrd, C5 Concepts, Inc., (March 11, 1999)