Where to tap manifold pressure sender into

[Gary Wallace]

Wondering where i would get my manifold sending unit to tap into. Lycoming O360 a1f6. Any input would be appreciated

[Bdflies]

Mine was tapped into the primer port of #3 cylinder. Pic attached
.

[Battson]

This seems to be the normal approach. We used #5 on the -540, same difference.

[Gary Wallace]

Awesome as that is an available spot. Didnt realize that was an opion. Thanks so much

[svyolo]

I heard that if you use a single cylinder or intake runner you get a sinusoidal signal as the intake valves open and close. Maybe it is good enough. Not my information. I know on my EFI throttle body they come from the factory just downstream of the throttle body, on the throttle body.

I am just the messenger.

[Rollie]

If you are using digital you will need a damper, which should be identified in the instructions. I missed that during the initial install and got a lot of fluctuations until I re-read the installation instructions and installed the required part. I have no idea if it's required for analog.

[svyolo]

Yeah even taking the pressure off the main manifold sometimes the digital readout fluctuates a bit. Inserting a smaller orifice into the MAP line supposedly fixes it cheap and cheerful. It could be that the same dampener will also dampen out the fluctuations if you used a primer port to measure MAP. I don't know, just guessing.

[zkelley2]

I'm pulling MAP off the #5 primer and I had put a damper in there, .040 hole I think was recommended by GRT. The MAP reading lagged behind the engine significantly, so I took the damper out and now it's close to instantaneous and there's no fluctuations. So, at least in my case, no damper was required on a digital gauge off the #5.

[Gary Wallace]

I spoke with dynon finally. He said #3 primer is good and no orifice or damper required as incorporated into softwar . Thanks all

[svyolo]

Good info about Dynon. I think my engine monitor recommends a small orifice (GRT).

[Bdflies]

Reading all this got me thinking. I did put an orifice at the port, to dampen pulses. I should have mentioned that. Worked perfectly.

Bill

[Battson]

I also used the orifice plug with mine, homemade.

I still see small fluctuations with the Dynon, nothing annoying, just in decimal places. The cause seems to be the tube wobbling, when I secured the tube better it improved the stability of the reading.