HighAltitude

I have a 1988 Chevy 2500 4wd pickup with a 6.0 LQ4 and TH400 transmission and 3.42 rear end. Since i live at high elevation (7500 ft) I am loosing 75 to 100 horsepower from the stock engine because of lower atmospheric pressure. It gets even worse when driving up in the mountains as on some passes can loose considerably more HP 10,000 + ft. So basically I am at about 225 HP with this engine. I would like to make up for the HP loss and add some performance parts while retaining reliability and drive-ability.

I am looking for suggestions on sizing a turbo for this engine. I am going to be putting new Gen 4 floating rods, pistons, cam, and a few other minor upgrades. i would like to be able to get 450 to 550 Hp at the crank when it is all done. i have no desire to wind this up much over 5500 rpm and looking for more low end not top end as there is no way I intend on driving it much over 80 mph. I have other more suitable project vehicle if i feel the need for speed.

So what would be the best size range for a turbo that spools up quickly and does not need to perform much over 5500 RPM? I have no problem going to a higher stall converter to help spool up as long as it is not too far from stock speeds so I dont kill low end torque. Not sure how altitude affects boost required but hoping it can be higher volume and not so high on pressure as i am running stock plastic intake hopefully. I know everyone says boost is addictive and the next thing you will be turning up the boost but this is my work truck and i am not going to be racing it or risk breaking the rest of the drive train once it is set at a safe range. When I am done with this one ill be moving on to other project vehicles. Any help would be appreciated.

krazy4

iTrader: (5)

I would run a single BorgWarner S366. It's cheap, it'll spool instantly on the 6.0 and easily support your power goals.

You really only need valve springs for that power level. I would just leave everything else stock and save the money.

HighAltitude

I would have just left it stock but last week started seeing some oil pressure issues. I think the pump or the oring has gone bad but I could hear to much noise the last time I started it from the bottom of the motor. I am going to pull it out and inspect for bearing damage and when i replace the pump so I might as well freshen it up inside while I am at it. It will be mostly stock type parts so the cost will not be too high. It will depend on what I find in there.

Project GatTagO

iTrader: (7)

I agree. Trick turbo and KB Racing both make simple hot side log systems that will most likely fit your older chassis.

Andrew

Lsxford

iTrader: (6)

The on3/vsracing 7665 would work great for you also. Hard to beat the durability of the Borg tho. And I also agree just throw some valve springs in with stock cam and send it. After you get your oil pressure situated of course.