The whole thought is that you abandon the TPS sensor altogether, and run the signal from a 2 or 3bar MAP sensor into that terminal on the PCM (Very similar to the wideband logging through EGR signal wire that some have got working on the LSX platforms). What you would have then is a 2 or 3bar MAP based VE table, with PE enables that you can change based on manifold pressure instead of TPS. This would completely change the tune, and I'm certain would require a TON of tweaking, however on a boosted application it certainly would work a ton better than a TPS based VE table. There are a ton of threads on here, and elsewhere on the benefits of a Speed Density tune in a boosted application. This is very similar to the LS1 guys that are running boost dumping the MAF in favor of the SD tunes.Originally Posted by Russ K
A TPS based table doesn't work well in a boosted application because you can be at 10psi of boost between 50 and 100% TPS. This causes problems on a TPS based VE table cause the VE values change, however while when under boost it will be relatively the same VE needed.
However, I'm not sure how this would effect the AE settings, and DE settings since they are also TPS dependent I'm sure, and woul dnow be controlled by MAP instead of TPS. I'm sure it also effects areas like automatic transmissions, cruise, and things of that nature, however my truck doesn't have either of those, so they are not of concern to me.
Here is a VE table based on MAP, and RPM. This one I used in a Typhoon that I was tuning recently with great success. Those trucks are speed density from the factory, so it's a native feature on that PCM.