Load Measurement for Tuning a BMW S62: MAP or Throttle Angle

[Herrubermensch]

M1 Tune has a delightful toggle in setup between using MAP or throttle angle for load on the Y-axis in the VE table. In the M1 Tune setup webinar, Motec suggests that when tuning an engine with individual throttle bodies, MAP resolution tends to be poor and throttle angle is the best approach for load. Many an S62 has been tuned with Motec ECUs, maybe even an M190 or two! My question is: What did people use to determine load, MAP or throttle angle? The S62 has two pipes running underneath each bank of TBs from which vacuum/boost for the fuel pressure regulator is taken and the vacuum connection for a BOV, if the engine is supercharged. What is the experience of those who of have tuned S62s with a Moted ECU? Will a MAP signal taken from the two pipes connecting all the TBs be of sufficient quality to use for load in the VE calculation? There HAS to be some wisdom out there on this topic. Thanks.

--Peter

[galanos]

Peter,

I have no Motec, but three Pectels on three of my M3 twin turbos.

Map will work best.

Get the map signal from bhind 8 tbs.

Map cause even in 3rd gear @ 3600 rpm boost will vary. You cant have the same boost in 3rd gear or 4th or 5 th gear. Depending on where in power band you go wot, boost will change even with the S/C.

BTW, did you get an intake manifold or using stock intake manifold?

[Herrubermensch]

Thanks. Stock plenum, but the aluminum-topped version to avoid cracks, all openings welded up, with a v-band flange for the BOV (actually, a custom mechanical pop-off valve).

Of course, boost measurements come from the same place on an S62, viz., the pipes beneath the throttle bodies, so there is no difference in that regard. The question is a priori throttle angle or MAP signal to determine the Y-axis in the VE table. Are you saying you receive a MAP signal with good resolution when measured from underneath the TBs on your M3s?