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[snowtrooper1966]

SNIP- ...it also provides forced air to improve performance during altitude drives (not that you'll be crossing the continental divide every day but since the engine isn't starved for air...SNIP

-- John

Hey, John!
At what altitude, does performance start to be altered for our engines?
I live @ 10,000 feet...
Best,
James

[johnnyapollo]

I'm not sure if the ECU adapts to altitude if you're at a fairly consistent elevation - It's when you're a low altitude dweller and you change to high that the mix gets starved of air and there's a noticeable drop in acceleration, fuel economy and performance. My guess is that the ECU would adapt with time by adjusting the mix. If you'll search around on the web you'll see postings by people crossing the divide or doing other high altitude trips relating the issue as a loss of power.

-- John

[snowtrooper1966]

Do you know of any way to confirm/deny your supposition? It would be nice to know for sure if I am not getting all I can out of my Dragon...
James

[johnnyapollo]

I think it was granpabob that first mentioned it - he was the first with an Alpine unit with the actual prototype - he's since changed his username so I don't remember what to search under. He was also the first with a VX at Rubicon.

Here's one of many articles I found:
http://www.4x4offroads.com/4x4-vehic...-altitude.html

Here's a dialog about the altitude effect on gas mileage (on a Prius no less!):
http://www.intuitive.com/blog/toyota...elevation.html

I still don't know if the ECU compensates though. If the VX still feels sprightly to you where you live I'd say that it does adjust.

-- John

[don moore]

I to was ready for a VX but I had to wait fur the money....then it happened..now im a proud owner of the best looking VX in eugene...

[XtremeAaron]

Guys I found a potential LOCAL VX I may take out a loan to buy! Opinions? Going to look at it tomorrow.
Heres some pics and specs:

Price $7,599
Body Style Sport Utility
Mileage 106,187
Exterior Color BLACK AND RED
Interior Color Other
Engine 6 Cylinder Gasoline
Transmission 4 Speed Automatic
Drive Type 4 wheel drive
Fuel Type Gasoline
Stereo AM/FM Compact Disc Playr
Doors Two Door
Stock No. 4450
VIN JACCN57X9X7991973

[WyrreJ]

I still don't know if the ECU compensates though. If the VX still feels sprightly to you where you live I'd say that it does adjust.

I'm no mechanical engineer, but I can't see how the ECU could compensate. The problem is a reduction in the amount of available oxygen and nothing the ECU could do can substantially increase that in a normally aspirated engine.

It could certainly make the fuel mixture less rich to match the reduction of oxygen - so no fuel goes unburnt. I think that would save gas, but would not increase power.

My understanding is that forced induction via a turbo or a supercharger is the only way to compensate for reduced air/oxygen pressure.

[johnnyapollo]

Yeah from some of those posts I read it doesn't seem like it would to me either - I just wasn't sure in my earlier posts.

-- John

[TechnoPope]

Hello Aaron,
PM sent.
Frank