[:'(]So here goes the story. I have an 08GT500 and i recently installed a Evolution Perf. tune and jlt intake to the SLP LM axle back i had. The problem i am running into now is that the car feels a lot faster then what the speedometer says. The speed limit is 65mph around here and everyone drives 70. if i cruise on the highway at 60mph i still pass almost all the cars. my car used to never have an exhaust drone until 70mph but now its at 60mph. it seems like i am passing everyone when i am going the speed limit or less. just wondering if anyone has had or heard of any similar problems. trying to get a hold of a gps unit to double check. you know that feeling you get when you know your speeding and you dont even have to look down. yeah i get that all the time. talked with Fred at Evo and he said he never heard of it. please help before i get a speeding ticket.[:-] perhaps someone with similar mods can post what speed they hit at the top of each gear. im not crazy i swear[:'(]

 

Do you or anyone you know have a handheld GPS? If so, the GPS has a MPH gauge. I had the same problem after installing new tires and gears. I had to use my tuner to correct it. It is still off by about 2 MPH, but that is fine with me.

 

might be easier to have someone pace you and compare speeds

 

Stock tires and gears?

You could do 60 mph for 1 mile, should take 1 minute, at least you'll know if your going faster.

 

yea have ur buddy set his cruise at 60 then call him and match speeds....

 

so im back with some news. i got a gps unit and found out that the car was off by 10-12 mph depending on speed. i called fred at evo and talked to him andhe said put it back to stock and see what happens. i did just that and sure enough the speedo is dead on. The tune caused the problem. called fred again but he hasnt returned my call yet. i knew i wasnt looney.

 

FINALLY FIXED ER! so i sent to tuner back to Evolution and they reflashed there program and I checked the GPS again and that fixed it. Thanks again Evo for helping me out with the problem. just some glitch i guess during programming.