corbraeater

I have a set of 17x9.5 rims right now and i going to get a new set of C6 zo6 18x9.5, and i have a mailorder tune. i wanted to know if it would [EDIT] up my computer to use my old hypertech programmer to change the tire size for the speedo

infinitebird

probably yes

corbraeater

yes it will mess something up or yes i can do it

infinitebird

It will mess it up.

2000GTP

Do you know who the mail-order tune is from? You can always call or email the vendor and find out for sure what you can and cannot do with your PCM.

turbo_Z

Right just have the mail order tune adjusted otherwise youll have a worthless hypertech tune.

corbraeater

i havent had that much luck with the vendor, he been helpful but , i just want to adjust for tire size not us the hypertech tune, i just want to know if it will erase the mail tune

guywithaZ

I'm guessing here but the hypertech asks you if you want to use the tune...just hit no and go to the tire adjustment section...as long as you don't tell it to program the comp it shouldn't...I think you should be fine IMO...but I am no expert and could be wrong...

corbraeater

see that what i think if i dont use there tune it wont erase the mail tune, right

infinitebird

Unfortunately it's quite probable that doing anything with the hypertech after getting a custom will screw it up.

http://web.camaross.com/forums/showthread.php?t=406064

It seems to work for some but not others.

madwolf

That is correct. Some revisions did not alter the tune and others overwrite it. Either way, it's a bad idea to combine the two.