95 6.5 Turbo vs. 96 6.5 Turbo

[Crankme69]

Won't the exhaust elbow bolt up from the GM-8 onto the GM-4?

 

[buddy]

Perhaps it will, although Ive never seen a GM8.

There could be a turbine difference but I dont know.

 

[iamdave0887]

Won't the exhaust elbow bolt up from the GM-8 onto the GM-4?

IIRC the wastegate is in the housing in the GM-4 and the wastegate is in the elbow in the GM-8.

The OP's 96 may have the GM-5. Mine does.

 

[Acesneights1]

GM4 isn't a bad turbo. Has more off the line snap.

 

[Crankme69]

Nuttin to compare my gm4 with...but mine will smoke the tires from a dead stop with ease, even more so now, thanks to a recent 10 minute mod :thumbsup:

 

[buddy]

The wastegate has to be before the turbine, so it cant be in the turbo elbow. Both must exhaust into the elbow prior to hitting the turbine.

 

[iamdave0887]

The wastegate has to be before the turbine, so it cant be in the turbo elbow. Both must exhaust into the elbow prior to hitting the turbine.

Wrong. Not sure where you heard that it's not in the elbow. It most certainly is in the elbow.

That's a GM-8 exhaust housing on the left. In Bison's "rebuilding a GM-8 turbo" thread you can see a shot of the exhaust housing/elbow and you can see the WG is in the elbow not the housing.

Closeup.

 

[buddy]

OK, so the gate itself is hinged in the elbow, so it cannot be used on earlier models.

The actual waste path always begins preturbine, and the opening is in the turbine housing. Did GM do that to use a larger turbine in the GM8?

 

[iamdave0887]

OK, so the gate itself is hinged in the elbow, so it cannot be used on earlier models.

The actual waste path always begins preturbine, and the opening is in the turbine housing. Did GM do that to use a larger turbine in the GM8?

Hmmmm....That's a good question buddy. I don't know.

I think it was for better exhaust flow, but don't quote me on that. None of the GM-x series are great in the exhaust flow dept.

 

[Matt Bachand]

GM4 isn't a bad turbo. Has more off the line snap.

Supposedly a lot more heat generation too.

 

[D2 Cat]

Hey Matt, remember the guy who was leading us on with all his truck fixes and ailments? Well he stated he had his turbo tested at a diesel shop in Olathe. I just asked the question about knowing off hand if a turbo is OK, then I just realized Olathe is only 23 miles from my house. I could call up there, to see what it cost to get my turbo tested. I wonder if it really is $75, or if I need it done twice?