Quote:
Originally Posted by toast
https://www.ft86club.com/forums/show...postcount=3357
You need to be able to weld or have someone make you an aluminum box with a vacuum nipple attached. Buy a second map sensor (they're like $20 for a plain one) put that in the manifold where the tmap sensor is and mount the tmap in the box. Connect box to the SC manifold in the back (either T the vacuum port that goes to the bypass valve or change the source of the bypass valve to the brake booster line and just run the manifold nipple right to the aluminum box). More involved but even better is to get a second tmap sensor, split the wiring harness so that the temperature comes from the sensor in the manifold and the pressure comes from the box.
The point is to get the pressure reading out of the intake runner - since it is a pipe with moving air and a periodic plug on one end (the intake valves) a resonance condition gets set up in the runner above 4k rpm. The tmap sees this and the ECU tries to adjust fueling *for all four cylinders* based on this. That wobble in pressure might be real for that cylinder but 1) the fueling response will have a phase delay and 2) the phase of the resonance in all the other cylinders will surely be wrong.
I can say this mod make the car feel a LOT better and when I shared this with Zach he sent me a new tune to take advantage of it and it then got even smoother.
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Why a second tmap instead of a plain map sensor used for pressure reading only in the box?