The turbo for the 6.5 was smaller in diameter and had a lower boost pressure
than on either the Cummins or the Powerstroke so it wasn't always easy to
hear, but I could barely hear mine at harder acceleration just before the
Cheers - Jonathan
I can't tell yet if is working due to the way it was set up. I bought it and
it had 2.25" exhaust ... yes 2 1/4" that was done by one of the muffler
shops. It was so restricted I don't think that enough exhaust could get out
to spin it up. We removed the clogged cat and put on 3.5" back to the rear
so far, we have to bend up some pipes for over the rear and out the back.
Also replaced the clogged air filter... hoping to see a major improvement.
When we replaced the air filter we also removed the small restrictive air
intake out of the fender. While we had that off we also reached in and spun
the turbo it spun very free with no drag I hope that is normal and good.
When I bought it the guy said it gets bad fuel mileage and low power. I hope
this fixes it all, then we can start throwing extra parts at it.
It is a F code and from what I read that is the H.O. Turbo ??? Does anyone
know what is different in them ?
If you want better exhaust flow overall the key component to replace is the
downpipe from the turbo outlet on the exhaust side to the cat inlet. This
S-shaped pipe had some pretty restrictive bends and was not radius bent from
the factory (it has "crimps" on the inside curves of each bend) and no
matter how much you opened up the exhaust after the downpipe or the cat it
was always the chokepoint for flow. You can find an aftermarket replacement
that has smooth, constant diameter bends and is fairly easy to install.
The other thing to check is the dump valve on the turbo itself. Make sure
it is free and able to move from fully open to fully closed. Disconnect the
vacuum line at the turbo and move the valve rod back and forth with a pair
of pliers. Don't hesitate to clean it up and lube it. A valve that is
stuck open could rob you of power. Since it is vacuum operated check the
vacuum pump (they do wear out and I had to replace mine at least once), the
vacuum solenoids (three on the driver's side of the motor on top) and the
vacuum lines (they like to get cracks and leak).
Cheers - Jonathan
So the 6.5 uses vacumme to operate the wastegate on the turbine????? Thats
dumb...way to go GM. That outta be a boost sensing line to control the
.....FYI its called "mandrel" bent tube that you want for exhaust.
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