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My 6.2L turbo project update

I have a few Q's bout turbos in 6.2 diesels...Do they diminish (spelling) reliability? And would it be unwise to run one in a truck pushing 200,000 miles?? I REALLY want a turbo, but am afraid it will just kill my motor. I do eventually plan on buying another 6.2 to rebuild, then turbo it, just wondering if I could get away with a turbo now, and rebuild later down the road....But I really dont wanna fry my engine cuz its my daily driver too. /forums/images/graemlins/dunno.gif
 
Your supposed to check for compression and head gasket condition. that seems to be the biggest problem in turboing a high mileage engine.

however, if your gonna rebuild a 6.2, ( or, a 6.5!) you might as well lower the compression so you can up the boost. /forums/images/graemlins/smile.gif

Dieselpage has a great article on it, and it shows the 6.5 TD can make as much as a 7.3 or the cummins. Comparing to the new diesels could prove fruitless. /forums/images/graemlins/frown.gif
 
6-29-04 Update:

I replaced the plastic pressure pipe that goes from the turbo to the manifold with a steel pipe. I think I've got all the bugs worked out now! (I burned a hole in one of the rubber elbows I was using...decided that wasn't going to work!) I've added new pics of the pressure system, and here's one of 'em:

http://community.webshots.com/photo/153303040/157778872FIqafD

All the pics showing my progress can be seen here:

http://community.webshots.com/album/153303040IeQyIu

13 psi still seems to be my top boost, which is fine by me. Anything over that would scare me...I'm not sure how much boost my 6.2L can take!

In order to reach that much boost, I'm running at full throttle at near governed engine rpm. Most of the time the boost runs around 10-11 psi under near full throttle.

The highest EGT I've managed to hit is 975 degrees. It will actually go higher than that in overdrive when boost is low, but not when under full throttle. That means I've got more playing to do with the injection pump.

I find it extremely interesting at how the turbo affects EGT's. Before the turbo, I turned up the pump 1/4 turn and was hitting 1300 to 1400 degrees all the time. After the turbo, and with no adjustments to the injection pump, I see 900 tp 975 as max. temps, with cruising temps around 500 to 700.

When cruising in overdrive, the boost is low and the EGT's are higher. Push the throttle down and give it a little more fuel, and the truck jumps into third, the rpms and boost climbs up, and the EGT's actually drop! That just goes to show how much difference a turbo alone can make in EGTs.

Also, although I can't see the tailpipe that well in my mirror, I don't think I'm smoking hardly at all now, whereas before I could leave a smoke screen. I'm burning all my fuel now. Just another indication to the need of IP tweaking!

Casey
 
So does anyone on the board have any pic of the turbo swap on a 6.2 in the early mid eighties trucks using the stock 6.5 parts? I have a friend that just done a non-ac truck and it worked out pretty slick for what he has in the parts. I have two setups for my stuff but both are a/c trucks and it definetly looks like it is gonna be plenty tight. The power difference in his truck is amazing to feel and see how it goes.
 
You can see this isn't the stock AC system. Some tinkering was done. But you're right, the fit between the turbo and AC is very tight.
fa6a6757.jpg.orig.jpg
 
thanks for the picture, what was done to the A/C box? Is the truck 2wd or 4wd? How was the exhaust run out of the turbo inside or outside the frame? What engine 6.2 or 6.5 using the factory 6.5 parts comp? Why the map sensor? thanks again
 
That a 4wd truck, I don't know how the downpipe was run, that's an L65, don't know what the map sensor is for.

The AC dryer was exchanged for one from an S10 (I think) that curves backward a little more and better clears the turbo.
 
[ QUOTE ]
Why the map sensor?

[/ QUOTE ]

The MAP sensor is used for the wastgate controller (located on the drivers side of the intake).
Reads manifold pressure, and the controller varies the vacuum to the wastgate. /forums/images/graemlins/thumb.gif
 
correct me if im wrong- The banks turbo manifold has the turbo in the front toward the radiator-

is the 6.5 turbo manifolds also in the same spot?
 
Yes, the Banks turbo mount is down low, towards the front of the engine close to the radiator.

No, the GM 6.5L mount is much higher, near the center of the engine. This is what causes a/c evaporator housing issues when retrofitting a 6.5L turbo system into the older body style trucks.

Casey
 
Cool beans-

Time to score up some parts then- how reliable are the stock 6.5 turbo's (the GM4's)? And what exactly are the differences between GM 1-8?
 
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