Friday, October 22, 2010

We have a dyno chart!

And the news is not what I'd like to see, but it totally matches the butt-o-meter.

Very low power down low, peaking up high.  Compare to the dyno charts of other 22RETs here

Cruise at 80 in OD is 2900rpm, maybe 45rwhp, tops. That's around 80-85ft/lbs of torque. No wonder I hate it on the road and it's getting poor mileage (for best efficiency, running at torque peak is generally recomended).
There was no boost controller, so no way to alter boost, and it was only boosting 4.5-4.75psi. No idea WTF the original shop thought they were adjusting or measuring. I'm finally pretty angry with them, especially because the tech very specifically told me and the owner that he had set the boost to 7PSI. The chart has 7PSI on it. I needed to buy a boost controller to allow that to happen. The baseline is the best this truck has run since the new engine and turbo have been installed. I'd have noticed 7PSI...

When I got it back from the original shop this time, it was the best it had run to-date.

Today, after the dyno shop tweaked it and added a boost controller, it's running even better, but the screwiness in the power delivery is even more evident now that there's such a big valley-to-peak difference, and over such a short RPM range.
It runs a LOT better higher in the rev band, and I can actually hear the turbo now.

It's still running quite rich on the top end, as evidenced on the chart below.
I've decided to source a DOA 270 cam, ARP head studs, and a cam degree wheel. I'm convinced this cam is significantly retarded. I'm wondering if the head deck height and/or block aren't out of spec, causing this behaviour. It's supposed to be a new head.  OTOH, it was supposed to get a new thermostat, it was supposed to be pushing 7PSI...

Time to do some more Googling.

Cam specs from my original invoice

From my invoice:
Cam specs Int    Exh
Valve lift:   .429 .442
Cam lift:    .275 .283
Duration (SAE)
Valve lash .012 .012
Centerline  105 105
Spread         110
Timing events @ 0.050
Duration     224 234
Rocker ratio: 1.56

Click here for bigger picture
All #s RWHP

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