Thread: Altitude impacts

Wondering if I'm going to run into trouble @ altitude (4500+ ft) on a 91 octane mail order tune from Will @ Overkill. The TCM tune should be just fine, the timing advance is what I'm concerned about, I've heard that people run into problems when using tunes made for sea level vs altitude. I've also heard that more timing can be pulled at altitude to help compensate for the oxygen density losses (indirectly).

I'm planning on feeling it out and seeing how the new ECM, TCM does, possibly get Will to tweak. Shipping and reshipping to get this right isn't the most time effective process. I could probably tweak the tune on a dyno ($$$) looking at another 300+ unless someone knows a cheap dyno tune in Utah.

If altittude is an issue how would it manifest itself?

I'm at 5000 ft, I had a DHP tune mailed in for a 3.4 setup. I bought a powrtuner later on. I wouldn't say you will run exactly into trouble. At the very least, I didn't have any KR with the mail in tune even after I went cammed.

The only thing I noticed with the 3.4 setup and the mail in tune is that the rpm would jump sometimes when going WOT, but not that much.

By the time I bought the tuner I was already cammed and running a 3.25 pulley, the RPM jumping was worse, i took a video of it:

YouTube - ‪gtp2.mp4‬‏

This problem went away when I tuned my MAF table. As for timing goes, I added spark mostly in cruise, but not that much in WOT.


Enjoy your 15 second modded GTP . I hate it when I think of how many mods I have and running 14s.... lol.