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Discussion Starter #1
I was changing my oil cooler lines yesterday and took a look at my turbo and noticed it was a GM-3 turbo. Now I heard 98 and up should have the GM-8 Turbo? is this true? I have never known much about the turbos and about 8 months ago my turbo went an BD Diesel replaced it. I saw some treads that the GM-3 were for earlier models, so do i have the wrong turbo on the truck?
 

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Yes - the -3 turbine housing is very inefficient, and the compressor housing is inefficient, as well.

The -8 vertical WG controller would not fit the -3 exhaust elbow, which had a horizontal controller bolted to the compressor housing.

Maybe that's an 8 where the stamp was off-vertical, so it looks like a 3?
 

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My 97 had the GM8 turbo......I thought that was the first year for that turbo?
 

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Discussion Starter #4
I know the the wastegate on the turbo is also welded shut. Weather thats a performance upgrade? from them or what they are doing. But I know on the little tag it says GM-3.
 

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Wastegate welded shut is deffinately not a good thing, especially without gauges. These engines can't endure high boost levels especially stock, and if you don't have gauges you could melt down your engine fairly quick.

Just my .02

Jacob
 

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That's very true, Jacob - even wiring one shut in an emergency is hazardous to the 6.5.

dzl, even if you ordered a hi-perf turbo from BD, the -3 does not fit into that category - you may have a bone to pick with them, since your PCM requires a vacuum-regulated wastegate controller.
 

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It pumps up the backpressure in that scrunched-up exhaust elbow - the -5 and -8 gotta smooth elbow.
 

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Discussion Starter #9
well mines got a smooth bent elbow, maybe just the casing is from a -3? im not sure there was a noticable power difference when I put it on, and with the exhaust it whistles pretty good, but like I said I dont know very much about these turbos.
 

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get some pics from different angles so we can take a good look
 

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are the elbows and compressor housings interchangeable, or do they have different impellers also?
 

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Only the shaft and wheels are interchangeable - the exhaust elbow, turbine housing, cartridge, and compressor housing castings are all completely different
 
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