Quote:
Originally Posted by jr_ss
That is my dynograph and it was between 19-20psi on 93oct. Timing was not extreme.
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Where is the datalog showing exact psi
Our eyes can't tell the difference between 21 and 23 on a typical gauge at the exact instant the engine hits peak torque on a dyno
Also keep in mind that most gauges vary 1-3psi , so unless you have a gauge and a datalog, or two gauge or two datalogs, you don't know what kind of error is in the reading. And there is always error term.
And finally the fact that pressure is highest near the compressor and lowest near the cylinder. If you saw 21psi at the intake through a properly sized intercooler that could very well be 26psi at the compressor. So not only is there error in the gauge, there is variance according the measurement location.
From looks of the graph I think it peaks 22 to 25psi and falls off to 20psi by redline
your original quote was 17psi though iirc and it really fucked this guy up thinking hes going to get 350ft*lbs at 17psi is a joke from any 2.0L
With a small turbine It takes 25-28psi to get that kind of torque out of a typical rwd sr20.
so first you say 17 and now it became 20, suddenly. And I bet its really 23.5 falling to 20 or something. Just be careful with ur numbers. Its very common or typical for people to make several passes, raising the boost gradually to the point where they no longer even know what the boost curve looks like or how much boost they are running. Even I am guilty of doing that while frazzled on a dyno session with my own vehicle. But when you are finished with all that, looking at the graph, don't go online and make up a boost number just because you don't have a recording of what it really was, that guess will get people's feeling hurt when they copy your setup and it only makes a fraction. Better just to say you aren't sure than use 17psi as a go-to guess.