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View Full Version : So how much is the GM-8 turbo really worth??



Randee of the Redwoods
08-07-2003, 17:11
A previous arguement pitted the GM GM-8 turbo(GM8) against a hipo unit from I think Penninsular(penn). The arguement was about performance of a built engine with low compression pistons, etc, and getting black smoke until the turbo spooled up. The arguement went on to conlcude that the gm8 wasn't a match for a built engine and couldn't keep while the penn unit was better at keeping up but seemed to be built for a performance window. While I'm not argueing this conclusion, I would like to say a few things.
First, I really liked the research done for the writeup, but it should have been obvious that the gm8 wouldn't be able to cut it on a built engine. It was never designed for that type of power output so naturally, even after turning it up, it still was not capable of feeding a low compression engine. I don't have a beef with the outcome here, I just have a question. Since more people run standerd compression, what's the gm8 unit worth? My truck is a 94 and I have finally verified the turbo to be the gm4. The turbo parts I bought for my 6.2 consisted of a gm8 unit(got lucky). It's clearly LARGER than the gm4. Since the turbo arguement was for feeding low compression engines, what's for us standerd compression guys? I ask legitimately(sp) though-is the gm8 a worthy upgrade for the standerd compression engine? If it's worth some extra power(lord knows I can use some), I'll toss it on. I'm planning on some modest upgrades(exhaust, gauges, intake work), so this won't be an overboard engine. But since I already have the gm8 unit, I'm willing to do a full turbo upgrade if it's worth the work.

patrick m.
08-07-2003, 21:20
i too am interested in the responses this topic will receive.
I would like too upgrade from my gm-4, and i dont mind spendind the money to do it, if the outcome is a noticeable increase in overall power.
maybe the guys in the know about this will chime in soon. :D

toyboxrv
08-07-2003, 22:02
I did the same swap on my 94. The original was ok, but had almost 150k and I got a good deal on a new GM-8. I didn't see any noticable change in power or mileage. It may be better, but the difference isn't enough to run out and buy a new turbo unless you think you need it.

rjschoolcraft
08-08-2003, 08:00
The Project Truck runs a GM-8 turbo. It seems to do very well.