justin allan

I usually live in WI were the elevation is 990ft or so. I just got out to Anaconda ,MT today I will be working here for a while and so I am renting a house. Anyway the elevation is some were around 6,500ft or so. I have just noticed that it takes about a week to spool my Silver B 66 is the turbo on the way out or is elevation to blame. Is there a fix for it? I lost about 12lbs of boost to.(max boost). Truck seems to be sluggish and definatly low on power. What is the fix?

Foxborough

FYI Standard atmosphere pressure at sea level is 14.7 PSI. At 1,000 feet it's 13.03 PSI and when you get to 6,500 the pressure is 6.39 PSI. So the atmosphere is less than half when compaired to Wisconsin.

.boB

You're way off on your numbers. There's less air preesure here at 6,500, but not 6.39. More like 11.5psi, about a 22% decrease. Of course, that varies with barometric pressure and temperature.

http://www.engineeringtoolbox.com/ai...ure-d_462.html

There is a slight differance with altitude changes, but not very much. The turbo has to spin a little faster to make the same boost than at sea level. I live at 6,500'ASL. When I drive across the country, I notice the differance, especially when you first start moving in the morning. But after that the differance is almost imperceptable.

Andy505

I'm in Colorado Springs its about 6000 feet above sea level, when I travel back to Indiana every now and then my turbo spools up a little quicker with a 2-3 psi total increase in boost. egts are cooler as well.

RowJ

I travel from Sea Level to Colo Springs and Denver a few times a yr and have noticed a slightly bigger difference.
When I had a single B-1 turbo, it would loose about 6-7 psi...... dropping from 48 psi to just over 40 psi.

Spoolup difference was noticable, but not serious. But the psi difference was surprising.

At 5000 ft and STP (Standard Temp & Pressure).... the loss is air density from sea Level is almost 15%.

RJ

C Schomer

I don't remember the formulas but to make it simple, you lose about 1/2psi/1k' and a TD loses 1.2%/1k' and you already found out, the turbo spools SLOW! Craig

justin allan

well sounds like elv. is the blame for the performance diff on my truck and not the turbo going south from my trip out here. I use to hit 52 to 54 lbs of boost now only about 40 to 42 lbs. Thanks for the info. Anyone ever dyno at different elv. and see what the hp diff is?

RowJ

I did last May's Charity Dyno in Albuqueque, NM ..... for Familys of Fallen Vets. A little over 5,000'.
I had Mach 4 (150 hp Injectors) at the time.
Best pull was 452.4 hp/874.1 Tq.
Corrected for Sea Level it was 563.3 hp/1086 Tq.

RJ