Quote:
Originally Posted by s346k
that's what i'm trying to figure out. 94 on his car and 94 on mine have to be different. i know weather will affect density etc. ill find out soon enough, i think i'm going to swap the intake & tb while leaving the stock air box in place. see what i get. then swap out the stock air box for a rotofab while still on the dyno. hope the tuner is ready for a day of slow car bullshit haha.
i'm trying to get real person numbers. i am very skeptical of any numbers that shops and vendors post.
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I am really glad you are stepping up and saying you're not trusting vendors and "tuners". They are making a fortune as long as people keep taking their word for it and don't question and verify.
I have also asked around on the HP Tuners forum and elsewhere as to the best ways of doing what you are trying to do here. Unfortunately no one seems to be interested in trying to use the built in engine sensors we have at our disposal for free to gauge performance. I will say I have way more faith in these than I do some "tuners" dyno.
I have been using the APC (cylinder airmass, dyn airmass, etc.). GM has named the PID like a million different things over the years. I have given though to just using the MAP sensor as well, however my questions are the sensor is at the top of the manifold subject to the plenum pressure. Is there a significant pressure gradient in the manifold? Is the MAP sensor only indicating pressure drop of the throttle body? or is the intake runners included? I would think looking at the MAP sensor would only give us the restriction and pressure drop from the TB and everything upstream.
Here is mine, ill try to go back and get a log before heads/cam for comparison and add it to the graph as well:
Also in your logs does your barometric pressure increase at WOT? I always take my baro readings at a non WOT point in the log otherwise they get aritfically skewed or increased at WOT. I am guessing pressure is leaking into something somewhere. The thing is this happened even when stock so I'm not sure what's going on.