6.5 L compression

BIG MIKE · September 18, 2002

Has any one heard any thing about lowering the compression ratio on the 6.5 diesel to 18.1 ? Saw this on another site, but could not get any info on it. By doing this, the fuel system can be up graded, and the turbo pressure can be increased to 15/20 PSI. By doing this, the 6.5L will develop HP and torque enough to out perform the Power Stroke, and the Cummins used in the Dodge. Also, I would be interested on a cost figure for the parts.

BIG MIKE

CMNTMXR81 · September 25, 2002

The only way to decrease the compression ration would be to make your combustion chamber larger. Putting dish pistons, porting the heads (removing metal from them) or doing a combo of both would effectively increase the combustion chamber side, reducing stroke of the piston travel would also relieve some compression, therefore allowing you to increase boost safely.

Colorado Kid · September 25, 2002

Pistons is it, and this is not a cheap upgrade. You're going to be in for $3,000-$4,000 by the time you do pistons, pump upgrades, turbo upgrades and intercooling. After that you'll have an engine that will make power like a Duramax (well alomost), for a little while.

That other site, if it is www.thedieselpage.com has an article posted right now about a pull-off hill climb. Two very heavily modified (low compression, intercooled, cooling mods, etc.) 6.5's pulled as did two stock D-maxs. It was not nearly as close as the 6.5 owners were hoping. They still have heat (EGT and Coolant) issues. I was there. Go see for yourself. I would consider doing those mods to a Diesel Suburban, because there is no reasonable replacement for one yet. For any other 6.5 equiped vehicle I think I'd spend the money replacing the truck with one of the others rather than trying to make a pony act like a Draft Horse. Just my opinion, and worth what you paid for it at least.