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Snubber (MAP restrictor) Location

macrafic

Well Known Member
I have an aisle 360 with 2 PMags and a Garmin G3 system. My flight data sent to SAVVY is indicating fluctuating manifold, pressure at low RPMs. Basically, every flight, that fluctuation occurs at taxi (TO and Ldg) and descent.

Their suggestion was to install a snibber. My question is where this snubber should go. I have Van’s 3-port manifold on my firewall that is fed MAP from the intake of number 3 cylinder. One port of that manifold then feeds both P megs (using a t- connector) And another port feeds the transducer, which, in turn, feeds my G3X.

Do the pmags need a snubber? I have posted this question to eMag Air and I’m waiting for an answer. Just hoping someone else on this site knows the answer quicker. Does the G3X need a snubber? The answer to these two questions determine where I locate the snubber. there are three possibilities:
1. On the input to the manifold to benefit both the Pmags and G3X
2. At the output port for the Pmags, benefiting only the mags
3. At the output port for the transducer, benefitting only the G3X.

Anybody have this configuration and know the answer?
 
Garmin says between the hose and the sensor.
But that was too hard for me so I put it in the cylinder head as Tom suggests.
I had significant MAP variation even at cruise power.
If you put it at the cylinder end then everything downstream will benefit from it
Cheers
 
G3X Touch only...

Determined that RPM of 2400 and below caused some undesirable MAP readings. I installed the Omega Engineering PS8G snubber between the Kavlico/Sensata P4055 MAP transducer and the 3 port manifold.

I spoke with Klaus (I have dual Lightspeed Engineering - Plasma IIIs) about the issue, and he indicated that it was not necessary to have a snubber on the line going to the ignition controllers.

I've been flying this aircraft for close to 250 hours and everything seems to be fine -- no crazy MAP readings at low RPM and no strange ignition advance events.

I do notice that there is a bit of lag between changing the throttle and what's reported on the G3X map -- not terrible, but noticeable. Maybe I'll move the snubber and see what happens...maybe I won't...
 
There must be lots of variables I guess. Hose lengths/diameter/construction etc.
I put 1000h on my 7 with exactly the same setup and never noticed any MAP fluctuations.
Yet the IO540 was all over the place. It’s now nice and steady, but agree there’s some lag but it’s no problem.
I find I’m pretty slow with the throttle and more deliberate in my power settings with the 10 than the 7. Maybe I’m just paying more attention.
 
Decision Made

I heard back from EMag; they do not require a snubber. Given that, and some thoughts that installing the snubber at the cylinder port makes it more prone to plugging, I am going with the same option Brian did. It will be installed between the 3-port manifold and the MAP transducer.

Thanks for everybody's thoughts! And Happy Thanksgiving!
 
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