MAP sensor line

[ecorl]

Next question for the EFI guru's: I have a 1/8 line from my manifold going to the boost guage. can i just T-off this line and connect a smaller hose going to the MAP connector on the megasquirt?

[TheSilverBuick]

I don't see why not.

[dieselgeek]

yep, that's a good way to do it.

[JeffMcKC]

I would just say make sure it sees enough volume it can change easy on Pressure readings. In the OEM World Escorts and Tempos had a badd issue with reversion clogging the tube in the intake up they would see high vacuum then the crack of the throttle the high reading was trapped and was slow to bleed off it was a bear to find at first. Its saw high just did not react quick enough to a drop in vacuum because of the restriction I would make sure the source is from a Plenum area and wont see a runner pulse from the valve opening and closing too.

[BKBridges]

Ive burned myself with poor MAP sensor port placement in the past... The progressive opening of multiple throttle bodies really points out how a manifold design and MAP placement can affect performance. On big plenum, big port manifolds like the RB Mopar 6bbl stuff, its not so critical, but for an old school, tripower SBC intake if you dont put the MAP port in one of the outer bodies plenums, but instead on the central body, the signal goes "flat" when you open the outers and its a bear to get the proper enrichment without jacking around with the transients.. IMO even on a single plane intake Id put a few ports in choice locations and test for total "signal" from each one. Use the one with the most (range and gain).

[ecorl]

Hmmmmm, I am on a critical decision point on this one. The top and front of my manifold is basically hidden or too busy for any ports. It has short runners and because its on a v6, the 4-71 blower really covers it up. I have very little space left on the back. There is a 3/8 line that is tapped into the middle of the manifold plenum that I run inside to my boost gauge. I have just enough room on the #6 runner to install my IAT bung. I assume the IAT isnt as sensitive to the issues you guys have mentioned so I can put that in any location. As I mentioned earlier, it would be easiest to just t-off the boost guage line for the MAP. Should I leave the MAP line where it is (source is from the middle of the intake plenum) and put the IAT in the runner or should I put the IAT over top of where the MAP currently sits and re tap the MAP port to the runner? Sorry for the redundancy but I can only do this once.

ed

[JeffMcKC]

I would source from the same place but use 1/4 line then neck it down for the boost gauge the IAT can be stuck about any where.

[ecorl]

I would source from the same place but use 1/4 line then neck it down for the boost gauge the IAT can be stuck about any where.

Got it. Thanks Jeff.