all4spl

So I have a 6.1 lq9 with 15% innovators west crank and 2.75 upper pulley. I have 243 heads stock with springs, Holley Hiram, and tick stage 2 blower cam. Also have 2" headers and 3" catback. I have a proefi ecu and had a zr1 map sensor which was maxed out at 23psi. (Proefi uses 4.5 volts where as gm uses 5 volts) I upgraded to a Holley 5 bar and now it's telling me I only make 20 psi. I put it on the Dyno to make sure that it was reading correct and the Dyno says 20 psi as well. I checked for boost leaks with the compressor and a block off and checked through the throttle body and into the manifold and it seemed good. Also check from blower up to throttle body with a block before throttle body and it seemed fine.

Any ideas?? Also have a&a bracket with the earlier hd tensioner with a 10 run setup. My engine shouldn't be moving that much air to only his 20psi.

MVP'S ZO6

Could the MAP sensor calibration have been off in your tune file?

ss4luck

What sort of boost do you think you're supposed to be seeing? Is it making the power it supposed to?

winters97gt

Boost is pretty much irrelevant. Is the car making power and trapping well?

c5mtl

20 sounds about what it should be...u running a filter ? I made about 21 with a bellmouth .... u shouldn't get caught up with psi numbers.. I'd rather make 1000hp with 15 psi over 25 psi

stevieturbo

Bizarre that any ecu would use anything other than a 5v reference. That is pretty much the world standard for sensor power supplies. Not even sure how some would behave if not fed with 5v.

And have you calibrated the ecu correctly for the sensor setup you are using ?

ie get a Mityvac or similar and test it.

And was the previous setup calibrated correctly in the same manner ? If not, you may not be comparing like for like, and actual boost may be the same before/after anyway.