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Jonathan,
Got it. And if it did it would probably have a pretty high header pressure at the expense of heat and unrealized upper end HP.
No one in the vocal set of tuners or fellow 930 owners seems to track pressure differentials. They can offer a lot of clues to where our issues or restrictions might lie.
For example:
What is the residual or exhaust manifold pressure relative to boost?
What is the pressure just after the turbo to determine the muffler's back pressure ?
Same on the cold side:
What is the vac just after the air cleaner to determine its restriction.
What is the differential before and after the metering assembly off idle (lag) and at WOT?
What is the pressure drop between the turbo exit and throttle body (IC and plumbing)?
What is the pressure drop through the throttle body?
All info that should not be that difficult to gather and would hold clues as to where the best opportunities lie.
For example. What if we are seeing 2 psi loss on the suction side of the turbo (air filter and metering) and 2.5 psi between the turbo and intake manifold at 1 bar / 5500rpm (intercooler and plumbing pressure drop). With this we know we need to look at the 2.3 bar part of a compressor map instead of the 2.0 (1 bar) part as to the turbos efficiency if we want to hold 1 bar boost at the intake port. Also that there is opertunity to reduce restriction that would reduce our turbo from haveing to work at the 1.3 bar level for lower intake temps.
In a hurry to sell things or save a buck these basics seem to be disregarded. To bad, a differential pressure gage is not more than about $150. Further, with the current crop of wide band monitors, it would not be tough to add a couple of pressure sensors and log some of the basics.
What if we could find that lowering control pressure with first acceleration reduced intake drag 50% for faster spool. What if the fancy muffler is causing higher than expected back pressure at idle or WOT (my B&B style cost me 10% hp at 350whp). Maybe the throttle body starts adding significant restriction above say somthing like 300whp...
Thus a thought.
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