6.5 Turbo Question

[Big Ray]

Subscribed

 

[Barrman]

Sorry I didn’t elaborate about the fan clutch. The HMMWV has a line off the power steering pump go to a solenoid which is supposed to turn the fluid pressure on or off to the fan clutch Depending on engine temperature. Pressure on disengages the fan clutch.

Air is supposed to be used when trying to service or remove the fan clutch according to the HMMWV engine TM.

TM9-2815-237-34. Page 2-10. Steelsoldiers.com is probably the best place to get an excellent TM about the 6.2/6.5. 8th grade reading level with drawing and exploded views.

 

[KirsL]

18:1 pistons if you want to go above 12 psi boost on a regular.

Experience has taught me that a turbo with a drive pressure that's close to 1:1 actually works better on a stock compression engine. The GMx turbos, sure drop down to 18:1 since they have crazy drive pressure ratio around 2.5:1.
An HX35 or 40. Or HE351 turbos work very well on these. I've had a hx35 on mine. Currently I have a s54 from Quadstar Tuning. Basically a hx35 purpose built for a 6.5. Works very well.

The only 18:1 pistons I would ever recommend if someone wanted to go that route, would be GM marine pistons. As they move the wrist pin up to lower the piston down in the cylinder.
Any of the ones you see where they machine the top of the piston I wouldn't trust. Based on how much material is being removed.

18:1 engines also really hate cold starts. Even in warm air temps, a cold engine had to be allowed to warm up.

I still have a full balanced 18:1 setup. And I'll use it in a project at some point.

But for normal daily use, stick with stock compression. You'll be happier.