I know the factory computer will adjust for elevation and other such different driving conditions. It is relatively flat here in Indiana but say when i visit my bother in PA, I go to MN every year, or if i decide to go out to CO hunting. Would my truck still adjust to the differnet terrain with custom tunes or would i have to order a seperate tune for those locations.

05 Lariat Scab 5.4L

 

good question. Never thought of that! and good to plan ahead!

 

Yes it would still adjust. Custom tunes aren't going to stop the computer from "learning".

 

that being said some of us have had problems at elevation using custom tunes with certain pcm strategies

 

How? The tuner should be adjusting for that if you live in some crazy area of the country. The factory PCM will adjust but only to a certain degree. I've never heard of anyone having a problem though. So if you don't mind, explain what happened. I'm curious.

 

ok great, thanks Thump

 

thump, don't have time to go into detail at the moment but here is a link to some conversation...

https://www.f150online.com/forums/sh...ight=elevation

 

I don't know the reasoning behind it, but elevation does matter on at least the performance tunes. Corey asked me about my local terrain when I ordered my Gryphon.

 

Air density ...

 

Yep - and that effects the air/fuel mixture ratio, which can lead to a vehicle running too rich at altitude if it is tuned for sea level. But, you'd think a simple ambient pressure sensor could provide an input to the PCM so that it could adjust for this.

As an aside (some of you will know this, others won't) when you get into high altitude environments, the octane rating of fuels is reduced too. "Ordinary" gas is 85 octane in Colorado and it worked just fine in my 87 octane truck (in spite of the warning by Ford not to use it). Since the air is less dense, there is less oxygen and that translates to a reduced tendency for the fuel to "self-ignite" (detonate) under compresson.

I'm sure though, there are "fine-tune" tweeks that can improve the way the vehicle operates at altitude. I just know I had no trouble whatsoever pulling my trailer up mountain roads at 11,000+ feet using Bill's custom 87 octane towing tune.

- Jack

 

Darkstone, I just read your link and since I've been driving in Colorado probably longer than you've been alive, I agree wholeheartedly that power is reduced at altitude. With reduced oxygen pressure, you have to reduce the fuel input, and that translates to less power.

Back when I was flying, we'd "leap" off the ground in cold weather with high air density. When it was hot (and the air was "thin") or taking off from Colorado Springs anytime, we rolled, and rolled and finally "staggered" into the air.

But, I'm pretty sure Thumper is right about the PCM being able to adjust somewhat for all of this.

You simply cannot expect the same power at altitude that you have a sea level though. A tune cannot make up for the lack of oxygen partial pressure, it can only optimize the fuel mixture. Put a blower on the engine though, and you'll get better performance. (Of course your sea level performance will be better too with a blower).

- Jack

 

HMMM.. so is it safe to assume that a tune would not adjust fuel mixture according to altitude? Even though the PCM would try???? or am i way off?
I think thats why I've been having some odd problems with my custom tunes?? Seeing how I live at sea level.

And please forgive my ignorance and lack of correct terminology.
I kinda own the phrase
I know a little about alot, and alot about little!
Graham

 

Unless the tune was written specifically for high altitude driving, it could not do anything special for you at high altitude. But, I don't see how it would hurt any attempt the PCM might make at optimizing for altitude either.

As I said, I've got a custom towing tune and I live at 2500 feet in the Sonora desert (supposed to get to 107 today). I had no problems using that same tune in the mountains of Colorado with snow all around in the high passes.

- Jack