Quote:
Originally Posted by tscdennab
One problem is that when BMS did a dyno without the airbox lid (so no filter at all), the N55 lost about 20whp. It seems the presence of a MAF sensor in the N55 does make aftermarket intakes difficult to do.
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The N55 MAF is in the oval intake tract so close to the filter box that any change in the shape of the pipe or filter will change the way air flows in the MAF.
any turbulece change will induce a different MAF reading for the same air flow, the DME is fooled and less power could result.
Maybe JB3 os procede could correct the altered (by the intake) MAF reading.
Unfortunately the N55 can't rely only on the TMAP sensor (N54 does) to calculate the air flow (this is the engine CHARGE) because there is no throttle blade, so no way to measure the vacuum in the intake manifold when running in the N/A phase (light gas pedal input)