Been working on setting up an Innovate LMA-3 Aux Box on the S4 to add in some additional sensors and to complement the Innovate LM-1 that I already have. The Aux Box has a number of options for using internal and external sensors. Today I was able to get the RPM input connected and configured as well as the 3 BAR MAP sensor.
The LMA-3 MAP sensor is tied into the wastegate signal line which is fed from the compressor housing, I’m very interested to compare the pressure at the turbo compressor housing with that at the intake manifold, where pressure is measured by the vehicle MAP sensor.
For kicks I loaded up a couple of tunes that run more boost than the stock profile, one targeted around 16 psi and the other just passing 20 psi. Two of the more interesting results from this new configuration are displayed below.
The chart above is the most relevant to the new capabilities offered by the LMA-3, it shows how at lower rpm the pressure losses from the turbo compressor housing outlet to the intake manifold are minimal, but around 4000 rpm at 16 psi the pressure at the intake manifold is beginning to drop below the level at the turbocharger.
The car is presently equipped with stock intercoolers which during the Intercooler Faceoff flow testing were shown to lag most aftermarket options with regard to pressure drop across the core.
The next chart is one that I was interested in just for baseline comparison purposes, to be able to assess some of the larger turbocharger options against the smaller K03’s in the one area that a K03 should have an advantage, that is in spool up at lower rpms. The F4H-BT tune was set to hold 21 psi so as that boost level is approached the boost rise rate slows. If the boost level for the F4H was left higher the rate would have continued along the path it was taking prior to reaching 21 psi.