Anyone running a 64 turbo above 5000' elevation? II said a 64 should do just fine at high elevations. Just wanting to hear from some people with personal experience.

 

What is the scoop on turbos & elevation? Do you need a smaller turbo for thinner air? Last time I was at elevation (stock turbo at that time) I noticed my truck smoked more.

 

I know they run hotter. When I idle down at home it will get to about 400-450 when I shut down. When I go down 2000'-3000' it will idle down to about 350 really quick. With the thinner air do you need less air or more air? Maybe II was right saying the 64 would work I know I can get really hot with any of the smarty programs.

 

You need more air the higher you are,I think. Since the air is thin your turbo spins way faster at high elevation than at low thus causing for turbo failures becase the turbo has to spin soo fast.

 

I'm curious about this too?

Is a 62 better suited to elevation? I run around 5000-7500 ft a lot.

 

You want a smaller turbo at higher elevations. A bigger turbo will give you more heat, smoke, and lag.

 

on the newer trucks the exhaust housing is smaller than it should be and the waste gate opens rather quickly i live at 7,000 feet and the ski run has a road at 11,500 feet on the stock turbo there is not enough noticeable difference between sea level and 11,500 feet to make any difference . if you changed out the turbo to a more efficient one or one to make large hp you will see a noticeable difference and things like turbo bark and black smoke at loaded low rpm , our 91 had i think a 21 cm housing from factory in 91 i changed it to i think a 12 cm housing it has nearly 900,000 miles on it now ,

 

on a stock truck you don't notice much difference... but there is a HUGE difference between sea level and 11.5k!!!!

I'd hang an HT3B or K31 under your stock turbo. Twins are the only way to roll at high altitude

 

When a set of twins say they will support 600hp is that true. It seems they should be able to do more. A silver 62 will do 650. I am leaning more toward twins for this elevation.

 

With twins you get the best of both worlds. The smaller turbo to help the throttle response and the bigger turbo to take care of the top end flow that is needed for horsepower. Twins definately perform better at altitude.

 

Possibly, but will it safely sustain 650? Doubt it.

 

I would do twins...

but, people fail to realize that twins are not the magic bullet/end-all... there are times where I would prefer a single. I converted my last twin truck to single and never regretted it for a moment!

on a twin turbo setup, the top turbo is having to pull air through the big turbo, and the exhaust is restricted by the bottom turbo... so it spools up much slower than if it were run as just a single.

and, unless you're running an external wastegate, all that horsepower still has to flow through the top turbo's exhaust side...

twins are king for low EGT's and a fairly broad powerband... they're great for towing, and they're nice at high elevations. a big single really stinks in the mountains.

my sps62 on my 98 starts making things happen around 1600rpm. sub 3000ft, I don't even watch the pyro... but last summer when I was in Colorado at 8-10+, I had to keep the truck above 2500rpm while going uphill to keep the pryo below 1200*!

the little twin setup that I replaced with the sps62 would walk over the devide and never crest 1200* no matter how hard I pushed it... with the 62, I could spin the needle around so far it would bend against the peg!

but, the little single smacks WAY harder than the twins, and actually gives me a broader usable powerband down near sea level even though it STARTS making boost later, it makes more boost sooner than the twins did a few hundred rpm into their powerband.

BUT... at altitude, the powerbands narrow, and the broader overall powerband of the twins combined with the superior air density they provide over a single wins out in my opinion

 

Thanks Gary, I think I will try and do twins. I am going to get a hold of MPI and see what he comes up with. Even if I did a 62/65/13ss I would still have heat problems up here. I can hit 1700 pretty easy with the 4.2 and TNT. The only hard part is that I have to do injectors at the same time. Luckily I can do lots of overtime.

 

1700? why let it get that hot?

 

1700 won't hurt on a quick 5-10sec burst