OK, I have learned that an AR on the exhaust of 1.12, and an AR on the intake .60 is too big. I cannot make enough boost or spool it fast enough. I only get 15 psi of boost with the Garret T04. I am now abandoning that turbo, up for sale too if anyone is interested. I have "plugged" the waste gate on my GM8 and am making 20 psi of boost with it.

Now, here goes what is on my mind. The AR on the GM8 is less than .50, so hows about I machine a new adapter to put the larger .60 AR T04 type housing with the T04 inducer wheel on the GM8? Will the GM8 make more boost?

Will the holset off of a Cummins work? Anyone know bout the Holset turbos?

I've been through what you have just done. Started out with a Garret that was too big, tried a couple others, and settled on the Holset HY-35. It's readily available as a take off from high powered dodges... Grape says for the Garret to work it needs a 60-1 compressor and a .6? exhaust side, this of course needs to be externally wastegated though... IMO a Holset HX-35 or HY-35 is the only way to boost.:ro) When combined with a low compression engine, Heaths program and water injection, it's very hard to get egt's up to 1000. Even without water egt's barely touch 1200. If I could be of anymore help to you let me know.

Justin

Awesome info, thanks. Let me know what kind of adapters are needed. I have made an adapter to go from a GM8 to a T04 flange that works great.
I guess I found out what Grape did with the Garrett. That is OK, it is something learned.
What kind of boost are you getting and did the turbo have a waste gate on it that you could use. Which turbo will reliably put out 25 psi of boost? Thanks for any info, let me know any other inportant model numbers.

The Holset turbos found on Dodge Cummins engines are already a T3 flange, so no adapter is required. On my Holset I could run up to around 25 psi with the wastegate disabled, it was factory set at around 18-20. I ran it both ways just for fun... The wastegate is the common spring loaded pressure opperated canister that runs off of boost pressure. IIRC the choke point of the HY-35 is around the upper 20's to 30lbs of boost. The HX-35 is somewhat higher than that since the common exhaust housing is 12cm^2 compared to 9cm^2 on the HY. Here is a link that should provide some insight to Holset turbos as used in Dodge applications: http://www.dodgeram.org/tech/dsl/FAQ/turbo_faq.htm

Justin

I thought this thread was about building a better GM-8? Not puttin on something else altogether? The 8 can be improved, or so i've heard... still waiting to test though...):h

The gm8's can probably be improved, but there are lots of cheap hx35w's and hy35w's out there from the dodge guys that have upgraded. Personally, I would opt for the hx35 because it has a larger compressor housing to help keep egts under control. The hy35 only has a 9cm housing, it does however spool very quickly, but bottlenecks with added fuel. the hx35 is capable of 35 lbs of boost with a boost orfice, but is factory set between 20 and 26 psi depending on whether it came from a standard output engine or a high output engine. Lots of turbo whine too:eek: :cool2:

What about the down pipe? What will have to be done to the down pipe on our 6.5s to adapt the cummins turbo? Also how would it align with our intake manifold and how would you neck it down to fit to the manifold?

There would need to be a custom down pipe made. I have the resources to make a 3" mandrel bent pipe to fit perfect. I know many people do not have the time or resources to do that. The alignment will more than likely be way off. But for me, I will be puttin my intercooler on this weekend maybe and then alignment will not be an issue.

Those are some serious issues to deal with if anyone were to just try and bolt up a stock Holset turbo.

Can't it be clocked to line up with the intake?
I've re-clocked other turbos before by loosening the 8 or so bolts around the back of the compresser housing and rotating it. Shouldn't a Holset be the same?

the prob is the height of the holset turbo. No matter how you clock it, the output will always be higher than the manifold on the 6.5L because it is a bigger turbo!

Then you will have to find a way to neck down the out put of the turbo to the size of the 6.5L manifold opening. Prob the best way to solve all of this is to fabricate your own upper intake manifold like others have done on here. And don't forget that you will have to make a new intake tube and airfilter assy.

Aahhh, I see.

It can be reclocked like stated before, it just comes down to the down pipe and the intake connection

So how much would it cost to have a new down pipe made? And where could I have it done? I would imagine that they would have to have my truck to make it, unless there is someone that has done it before and knows what to do!

I have made my own downpipe for my Garrett TO4, it turned out great. It only too me about 4 hours to make and about 60 bucks. I made the flanges are my work and then I just got some 3" pipe and 3" J bends and cut and welded it all up.

hmm what type of flange does the holset turbo use?

The intake will line up just fine, as long as the elbow from the dodge appication is choped a little bit. As far as the exhaust goes there were so many different configurations that it just depends on what you get. Every application is different, for mine I just needed functionality, not beauty. For the available fueling options for the 6.5 I feel that the 9cm exhaust housing is more than enough to keep things under control. I wouldn't even waste time messing with the stock IHI turbo, it is just way to small... If anyone ever get the chance to set the IHI and a HX-35 side by side you'll know what I mean.