Join Date: May 2002
Location: Kingsland, Georgia
Well you guys made me dig up the Hypertech manual that came with the programmer on a car I set up with it. I changed a 95' Caprice with an LT1 engine. Took out 308 gears and installed 342's, changed tire size to 225/60R 16, installed headers, dynomax dual exhaust, bigger throttle body, performance MAF sensor, bigger injectors, K & N air filter, changed coil spring rate and dropped ride height, and whatever else I don't recall.
Milan is correct on max speed is set for tire speed rating. This can be changed with the programmer.
Here's what else you could do.
Power Tuning - optimized engine spark and fuel tuning based on a 160* Powerstat (thermostat) and premium grade fuel, 93 octane or the highest available in your area.
The engine RPM limiter is increased to 6,000 rpms for the 4.3/5.0/5.7 (auto or manual trans.) 5500 rpm for the 7.4 (manual only)
Change automatic transmission shift points.
Change automatic transmission shift firmness.
Change axle ratio. (automaticaly corrects speedometer and shift points for auto trans.)
Change tire size by 1/4" increments (also corrects speedometer and shift points).
I had good luck with it but had to play around with the power tuning. You can also customize the power tuning and select only certain changes. It made a big difference over stock on the application I did.
Just to add, anybody working on the new cars with the "tire inflation monitors" ? Something else to deal with when you start playing with tire sizes. Chassis module calculates tire diameter I guess from the ABS sensor is the way they are doing it on the Impalas anyway then it sets off a light on the instrument panel if one tire looses 12 psi air pressure over the other three.
Good Luck, Drew
[This message has been edited by drew69 (edited 01-13-2003).]