I think it may be possible depending on the car, and it's mods. Mine was stock mid-pipes, just the magnaflows, then I installed the bbk x pipe and headers, I dunno, regardless what the Gtech said, as I know from experience they can be off on the MPH often, my car certainly gained more than I ever thought from the pipe...it's just weird no way to explain. At 4k rpm it wants to break the tires loose in second....it's like...out of no where I get a boost of power. I dunno, I need to get all of my other **** installed and then get a tune, and then go from there. Right now it's basically stock it doesnt really matter, I was just really suprised at what an O/R X-pipe did to my car.
That's what I was going to say. Unless of course, by sheer coincidence, my G-tech Comp and the two local tracks here are all off by the exact same amount I still have my old original G-tech as well but it's not as accurate as the new one but it's still not too bad, using it at the track and comparing it to the actual times, it ranges from .05~.2 + or - seconds and is generally 2-3 mph high.
For the record, I gained .2 seconds 3 mph going from the stock six cat system to a catted X-pipe with my current setup.
When I do my tests I do them at the same spot so I know I getting semi accurate times. So I dont do a test on one road then install something and do it on another road. Also I dropped .2 just by running on a cooler day with less humidity(sp?) so those two thing could make a huge difference.
