Fast xfi altitude change
 

I bought a 408 lsx turbo car with fast xfi 2.0. Now the car was tuned at 3000ft above sea level. Now its at 20-50ft above sea level. I know fast can compensate for altitude changes but would i have to retune the car since the change is so drastic? Thanks

Which Firmware version do you have? 2.01 or 2.05

I'm not an xfi expert, but I have looked at this a little. I don't have a copy of the 2.01 software so I'm not sure if it has any barometric pressure (altitude) compensation.

If you have or upgrade to the latest version 2.05, you have an option to run in load indexed speed density mode. You have to have an extra 1 bar map hooked to one of the aux inputs and reading barometric pressure. Then it compares that barometermetric pressure and manifold pressure and compensates. If you don't add the baro pressure input, it looks at the main map when the engine isn't running and still compensates.

If you have 2.01 and want to upgrade to 2.05, you'll have to populate a few new tables, but not necessarily a whole new tune. If you have 2.05 and just need to add the barometric sensor it shouldn't take a retune.

ok thanks. I was planning on datalogging anyways just to be sure either way. I don't know which version I have I havnt taken a look yet. Thanks

If it does need some tuning, it won't be far off. You can probably turn the adaptive learning on and fix most of it. If you're not familiar with that from FAST, you should look to one of the FAST support tuners for help with settings and advice. Cal Hartline with Hartline Performance provides a support package for users and can help with over the phone and tuning via email if you can't find someone local.

cals tuned a few of my friends cars. Good idea. I'll see if I can send him my tune and see if he can send me a good corrected version. I assume its going to need less timing and more fuel. Thanks again