Finally - EGTs and pressures of my homegrown turbo

[Eric Deslauriers]

I finally got a chance to wring out my turbo w/ an EGT on. This is appx 15,500# of class A motorhome through a non-lockup TH400 and low rear gears.

The EGT probe is located post turbo in the downpipe and I'm using a VDO gauge/probe kit.

I still need to time it, but here are the prelim #s.

55 down the highway - 450 degrees, 7 psi
65 down the highway - 500 degrees, 9-10psi

I used to completely max out at 80 down the highway (downhill, tailwind, etc.). I haven't tried since the turbo.

Temps never went over 650 EGT while pressure got to the 14-15 range uphills. Either that, or the gauge pegged and I don't know it. (kidding!)

Power is quite good on the low end, but not so good at higher Rs. I assume this is timing related.

As soon as my JeepSpeed Cherokee is "done" I'll start on the 4L80E retrofit project. I'm hoping this will help since I don't like cruising down the highway at 10+psi.

BTW, any thoughts on pushing that pressure for hours? I have a trip coming up at the end of November.

I should be able to take it in for timing next week.

Eric D
83 Southwind 6.2 turbo puller

[britannic]

The combustion pressures are such that 7-15psi of boost isn't an issue - it's a drop in the ocean in fact. What really matters is how much heat is being generated by the fuel injected .

Too much heat (>1100F 6.2L, >1200F 6.5L) and you'll say goodbye to your pistons, head gaskets etc.