P-Mag manifold pressure connection

[papamike]

Hi,

I have the Dynon manifold pressure sensor and 2 P-mags. Do I just tee the two p-mags together with the manifold pressure line off the engine, then put the one line into the Dynon sensor? There's only the one input to the sensor.

TIA...

[azflyer21]

Yes, one line off cynlinder #3, then teeing off to both mags and the sensor. Here is a picture of the tee at the mags https://webuildplanes.com/kevins-rv-...final-plumbing. I got my firewall forward hoses from Aircraft Specialty and they supply all connections.

[N941WR]

Yes, they can all be tied together; however, you want to make sure you have some type of restrictor installed in the line before your P-mag connections.

We have discovered that some EFIS's will "smooth" the MAP readings in their software and some wont.

What happens to the P-mags is that they can get different pressure readings and set the P-mags to different timing. None of this will harm you plane but aren't maximizing the efficiency of your P-mags.

Also, remember to time them correctly for your engine. The standard timing is a bit too aggressive.

[TS Flightlines]

We typically use a -3 hose off the #3 cylinder. To connect to a Dynon MAP sensor, we use a short piece of DTL6000 hose crimped to a -3 Male AN fitting that we make. The rubber hose on the MAP sensor fits tight and leak free. Because the sensor has a plastic tube stub thats 1/4 OD, you would have to adapt a -5 teflon hose, then the teflon is stiff and doesnt seal that well over a beaded tube. The rubber hose isnt sexy, but it sure does work.

Tom

[John Tierney]

I ran a braided hose from the engine (#3 Cyl.) to one of the ports on the Van's transducer mount on the fire wall. Then went to the hardware store and got various tees and adapters to connect from the transducer mount to the Dynon MAP sensor and to the PMAGs.
https://shop.vansaircraft.com/cgi-bi...ct=va168-va188

[rv8ch]

I got some model airplane T fittings, some rubber hose, a connection to a bit of braided -3 hose to cylinder #3.



Couple more pictures here:

http://www.rv8.ch/manifold-pressure/

Would be great if these MP sensors were a bit smaller and happy to be under the cowl. At least the PMAG fittings were quite easy to hook up. Mine came with hose that I didn't use, I found something a bit more heat resistant. Probably not needed, but why not?

With about 1 hour of ground running it's working great!

[avrojockey]

Originally Posted by N941WR

Yes, they can all be tied together; however, you want to make sure you have some type of restrictor installed in the line before your P-mag connections.

We have discovered that some EFIS's will "smooth" the MAP readings in their software and some wont.

What happens to the P-mags is that they can get different pressure readings and set the P-mags to different timing. None of this will harm you plane but aren't maximizing the efficiency of your P-mags.

This ^^^^^^^

I had fluctuations in my MAP readings on my G3X and just lived with it until I installed my P-Mag then I installed a snubber to smooth out the MAP variance. This is what I purchased...

Brass, 1/8 NPT Male x Female, 0.004" Orifice Diameter, PN 3820K11

I thought a .004 orifice might be too restrictive and cause a lag in my MAP indication, but it worked great! My MAP indication is rock steading and responsive to any power change. I did install it at the stock Van's transducer manifold rather than at the #3 intake to limit the possibility of the orifice becoming plugged. Then I used the plugged MAP tap to install a 1/8" NPT to 1/8" Male barb to connect my my PMag MAP tubing.

[rv8ch]

Originally Posted by avrojockey

This ^^^^^^^

I had fluctuations in my MAP readings on my G3X and just lived with it until I installed my P-Mag then I installed a snubber to smooth out the MAP variance. This is what I purchased...

Brass, 1/8 NPT Male x Female, 0.004" Orifice Diameter, PN 3820K11

I thought a .004 orifice might be too restrictive and cause a lag in my MAP indication, but it worked great! My MAP indication is rock steading and responsive to any power change. I did install it at the stock Van's transducer manifold rather than at the #3 intake to limit the possibility of the orifice becoming plugged. Then I used the plugged MAP tap to install a 1/8" NPT to 1/8" Male barb to connect my my PMag MAP tubing.

Never knew what they were called - thanks!