I have a 1984 CUCV M1028 diesel truck. Its not like most other diesels you see on the road. This thing is powered by a GM 6.2 liter V8 N/A IDI diesel motor. I plan to take the heads off and install 6.5 Turbo heads with diamond pre-cups and the 6.2 valves. The Intake manifold and both heads are going to be heavily ported and polished. The largest factory turbo is a GM-8 turbo. Due to the motors in-ability to handle much boost over 15-16psi and a usable power band stopping @ 3,600 RPM, I was thinking of using 2 of these GM-8 turbo. Each one running off each bank in to a common intake manifold. Should spool pretty quickly, and provide enough CFM to give me a nice, fat torque curve. The problem I have is that I cant find any info out there on the internet as for as compressor and turbine maps. can any one help me here?

 

I don't have the maps for this either, but I might want to go a size or two smaller instead of doubling the turbo sizing from stock.

 

Well in stock condition, the turbo can be pushed to 20 psi but any thing beyond that and efficency drops off fast; IATs going through the roof. From what I understand the compressor is similar to a HX35, but the turbine wheel is much faster spooling. I was thinking with some porting of the exhaust housing, porting and polishing the heads and intake manifold, and building a set of stainless steel log style exhaust manifolds will give maximun flow rates and utilize the thermal energy in the exhaust. With the factory set up, the turbo lights by 1,200 rpm.