Horrible Power at High Altitude

Oct 08, 2003 5 Replies

Got back from a trip to Breckenridge Co a few weeks ago. My 2000 Silverado 1500 Z71 w/5.3L (K&N FIPK, Flowmaster Cat back exhaust) was pathetic to say the least. I drove as a chase vehicle on an OHV ride along with my buddies Jeep Wrangler (I6).



Living in Ca at an elevation of about 200 ft, the truck has tons of power and enough acceleration to keep me more than happy. At 10800 ft elevation, the truck was so underpowered that it would not break the tires from a dead standstill on a dirt/gravel road. It also had a top speed of about 70mph with at least 1/2 mile to get to that speed. The truck was always unloaded while I was there, no cargo trailer or anything.



I raced my friends wrangler and got blown away to say the least. He had his Jeep tuned for high altitude though he could not tell me what that meant. Since I am going to be moving there very soon, I was wondering what, "High Altitude Tuning" consists of. BTW, I have noooo problem taking a Jeep wrangler at sea level.



I understand, less air = less fuel = less power, but this was ridiculous. My Uncle swore I had a 4cyl under the hood. What can be done if anything to remedy this?



Thanks again,



Derek


let's see..............10,800 ft

3% volume of air lost per 1000 ft

so you were operating on 67.6 % of normal air intake

sound normal to me..................the good news is that your fuel adapts will compensate to a degree if you live and drive there for a while

Lost power with the large pipes, unfortunately. We're getting much better results with the Gibson Stainless single cat-back.

Have a great one!

Bush

I don't belive that there's much you can do on the newer computer controlled trucks... You might check with the local GM dealer to see if they have some type of computer update for operation at high elevation which might increase the timing and fuel delivery....

A decent free flow exhaust is a plus at any altittude...

gary... reading your reply made me wonder about my truck... (which i won't name, since this is the chevy group) i live at 357 feet and have been over 10,000 feet 3 or 4 times with no power loss.. do different computers and/or fuel injector systems compensate differently?

yes

some adapt quickly

some, (like our old 86 Ranger) NEVER adapt to more than a 5000 ft change from 'baseline facory' programming

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