I just recived my HPP3 for my 98 Camaro Z28. My question is that the HPP3 asks me for tire height, my front tire height is 25.71 while my rear tire height is 25.57 which tire height should i programm for. Also i live in Illinois and and have no clue if the fuel is RFG or not, I dont even know what RFG is, what option should i choose.
Thanks

 

I would guess it wants to know your rear tire height. Most likely is for calibrating the computer for different tire sizes. Mine didnt have anything about RFG?

 

Reformulated Gas - it's an emission control additive package for gasoline - depends on what part of the country you are in.

Houston gets it ...

My understanding is that the newer programmers do not offer that option - dunno why.

The tire size question is strange - did you indicate on the programming that you changed tire sizes ??


I hope rncotton will see this thread - he is the resident HPP3 expert as his car was used as a beta tester for the ' 01 programming if memory serves me correct.


Later !


Britt

 

You want your rear tire height, its the one that affects the distance traveled from one revolution of the driveshaft. If you run 91 octane or better id program rpg anything less i think it might detonate, but im not completley sure

 

Thanks for the replies I found out that Illinois used RFG fuel. I was also wondering how I can figure out what kind of thermostat is installed in my car, I suspect the previous owner might have replaced the stock one. The car idles around 200 degrees and runs at about the 170 degree.

 

Hey,

I have 17s in front and 18s in rear. I too programmed my Camaro w/the HPP3. The reason it asks you for tire height is so your speedometer reads correctly. I did calibrated it based on the rear tires on my 94 Camaro and my speed reading was waaay off.

You need to calibrate it for the FRONT TIRE size because your speedometer is based off of the front wheels. I am absolutely certain this is true. It's not like when you do a burn out your speed reads 80 mph. That's because speed is based off of what the front wheels are doing. If you program it off of rear tire height your speed reading will be off...believe me, I found out the hard way; a speeding ticket.

Les

 

Wow now I am confused a rear wheel drive car and the speedo is connected to the front tires. 2 people say I should select rear wheel size and one says front wheel size. Although what 2001z28Shark says makes complete sense. Does anybody else have an opinion?

 

LOL not on my car, i can run up my speedo in the rain barely movin down the street explain that one, maybe it changed for LS1's. Ive never seen a car that wasnt run off the drive tires or drivetrain

 

Rear tires. The speed sensor is in the tranny. Then the computer adjusts for rear gears and rear tire height to give you the correct adjusted speed. That's the reason it asks for gear set.