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Dynon manifold pressure compatible with Van's pressure kit?

A

alpinelakespilot2000

Well Known Member
I need to hook up my Dynon manifold pressure sensor. As part of my Vans FWF kit I also received their manifold pressure kit. The bulkhead fitting Van's provides has abarbed outlet for ~1/8" ID tubing and the Dynon sensor has an barbed input for 1/4" ID tubing. How do I connect the two? Or do I?

Thanks
 
alpinelakespilot2000 said:
I need to hook up my Dynon manifold pressure sensor. As part of my Vans FWF kit I also received their manifold pressure kit. The bulkhead fitting Van's provides has abarbed outlet for ~1/8" ID tubing and the Dynon sensor has an barbed input for 1/4" ID tubing. How do I connect the two? Or do I?
Click to expand...

The aviation section of my local hardware store (near ice machine plumbing) had a little plastic barb with 1/4" on one side and smaller on the other. Worked well for me.
 
N941WR said:
Use an "AN807-4D ADAPTER HOSE TO UNIVERSAL" fitting to pass the MP line through the firewall to the MP sensor, which you can mount aft of the firewall. This will keep it out of the heat and oil of the engine compartment.

Click to expand...

I used the same type of fitting on the firewall and 1/4" tygon tubing works just fine. Also, buy some of those little spring hose clamps at the auto parts store and put those on the tubing at each nipple. Only problem was the Dynon sensor is very sensitive and the MP gauge fluctuated. I stuck a cigarette filter in the tube and it was rock steady.
 
Webb said:
...Only problem was the Dynon sensor is very sensitive and the MP gauge fluctuated. I stuck a cigarette filter in the tube and it was rock steady.
Click to expand...

Good point Webb. I center drilled a AN470AD4-X (length is not important) rivet with a very small drill bit and put it in the connector on the firewall where the hose attaches from the cylinder head. That solved my MP fluctuations.
 
I used the same combo. I had at first cludged something together but wasn't happy with it. I went to the local NAPA and picked up a little blister pack of "vacuum fittings". I think I paid ~$2.00 for it. It contained the perfect fitting for going from the larger 1/4" tube on the transducer to the small line that connects to the barb fitting.
 
N941WR said:
Good point Webb. I center drilled a AN470AD4-X (length is not important) rivet with a very small drill bit and put it in the connector on the firewall where the hose attaches from the cylinder head. That solved my MP fluctuations.
Click to expand...

I tried a #60 drill and it still fluctuated by 1/2"
 
Webb said:
I tried a #60 drill and it still fluctuated by 1/2"
Click to expand...

Mine still fluctuates but only +/- .3". (I just checked the videos I took while testing the Dynon AP.) For a fixed pitch prop, that is good enough. If you are running a CS prop, then you might need a steadier reading.
 
N941WR said:
Mine still fluctuates but only +/- .3". (I just checked the videos I took while testing the Dynon AP.) For a fixed pitch prop, that is good enough. If you are running a CS prop, then you might need a steadier reading.
Click to expand...

The cigarette filter removed from a Marlboro worked

I also tried a 0.028 restrictor from a fuel injector and it worked. By itself it wasn't enough. With the #60 drilled one I made and the 0.028, it worked.

Ironiclly, the restrictor that was in the engine fitting wasn't enough.
 
More questions...

Van's fitting into the #3 cylinder is not a restrictor fitting. Ideally, should it be?

The premade hose Van's supplies with its kit is WAY too long if all one needs to do is go directly to the firewall aft of #3. Is there any reason I couldn't replace it with a shorter stainless braided hose, like that I got from Pegasus for my brake lines?
 
Jamie said:
I used the same combo. I had at first cludged something together but wasn't happy with it. I went to the local NAPA and picked up a little blister pack of "vacuum fittings". I think I paid ~$2.00 for it. It contained the perfect fitting for going from the larger 1/4" tube on the transducer to the small line that connects to the barb fitting.
Click to expand...
Jamie-are you talking about the smaller barb on the fitting Van's provided in their manifold pressure kit? I think Bill and Webb are talking about a different combo through the firewall using a AN 807 fitting from ACS that doesn't have the small barb--it comes right out the firewall with the same 1/4" hose fitting used on the Dynon sensor.

That said, have you had any indicator fluctuations using the stock Van's kit + the pressure tubing you got from NAPA?

Thanks for your help, guys. Just trying to figure out the best way to skin this cat.
 
alpinelakespilot2000 said:
Van's fitting into the #3 cylinder is not a restrictor fitting. Ideally, should it be?

The premade hose Van's supplies with its kit is WAY too long if all one needs to do is go directly to the firewall aft of #3. Is there any reason I couldn't replace it with a shorter stainless braided hose, like that I got from Pegasus for my brake lines?
Click to expand...

My fitting was. Still had to add another restrictor

Yes on the hose. It's not a high pressure hose so most any will work. I made my own because the supplied one was too long. You could even cut off an end and put a new fitting on it.
 
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