Manifold pressure in a rotax 912uls

[Jch]

I'm used to flying a fuel injected engine with separate throttle and propeller(variable pitch) controls. soon I will be ordering a Dynon Flight Dek D180 to go with my SS7 and 912uls and Whirlwind fixed pitched propeller) and the order form asks if I want a Manifold Pressure Sensor (which they say is usually included in the rotax engine sensor package). I don't think there is any value to monitoring the MP with my set up. Am I missing something? I also find it a bit unusual that the Dynon d180 Sensor "package" includes only two EGT sensors and uses only the two CHT sensors that come with the 912. Also the package includes a carburated fuel pressure sensor. I'm inclined to add 2 chts and 2egts and I don't know if the fuel pressure sensor is a good idea. I will appreciate any thoughts or comments with someone who is more familiar with these things.

[Jch]

After looking through the Rotax manual and looking at the 912 uls I'm not sure I can monitor CHTs in all four cylinders. Anyone out there have 4 CHT sensors on a Rotax 912?

[Slyfox]

If it means anything , I have the same engine(912uls). I use one CHT(stuck on the meter for water temp). one oil temp, actually 2 sensors for the oil pressure. nothing else. my egt died(1) and I just didn't care when it did work. I never had a fuel pressure. so there you go. Have no plans of doing any more. I fly mine over 100hrs a year. Oh and I have an inflight adjustable prop and have NO intake sensor. I use engine rpm, that one is very important on the rotax in my opinion.

[Dick B in KY]

I only have one (1) CHT sensor, located on the hottest cylinder (right rear in my case looking from the cockpit). You can move the sensor around to see which cylinder is hottest.

Dick B

[kitfox2009]

Hi Jch
I have a 912 UL with a IVO IFA prop. I have round gauges one CHT, one EGT, one coolant temp gauge. I did install an automotive fuel pressure and I do like to see that it is in the 5PIS range.
Also installed a small manifold pressure gauge that I like to use with the IFA. I do have trouble maintaining MP in the 27 inch range at high elevation cruise power though.
I find a few gauges are reassuring that all`s well.
Good luck
Don

[kmach]

Hi,

I believe that a manifold pressure gauge is recommended for an inflight adjustable prop. using it and the tach helps in setting the prop and engine load.

Its not needed for a fixed pitch prop setup.

I have the dynon 120 , it is setup with tach , 2 cht and 4 egt, oil temp and pressure, the MAP , fuel flow, volts and coolant temp sensors. I like looking in one spot for all the info.and really like the audible alerts if something goes out of the parameters set . A fuel pressure sensor would be a good addition !

I don't know of any 912 ULS 's that run 4 cht sensors, they are set up with #2 and #3 cylinders being sensored from the factory.

[Dorsal]

I run my 912ULS with the standard Dynon package, I have MAP and never look at it, 2 EGTs which honestly I also rarely look at, fuel pressure which makes me feel warm and fuzzy, 2 CHTs which seem enough (given one on each side) and fuel flow which I find handy on longer trips. I have also recently switched to the Kavlico sensors which I like a lot. If I were to do it again I would move the Oil pressure sender back to the firewall right out of the gate.

[Jch]

Dorsal, why would you move your oil pressure sender to the firewall?

[Jch]

My order form asks if I need "extension wires for EGT probes" and how many feet? If I want 4 EGTs, how many feet of extension wire should I get? I am getting closer to installing all these things. Still need to educate myself on how to do it and I'm trying to get all the materials together so I do t have to keep sending in orders for small stuff. Thanks for the help. Sure would
like to fly the ss7 to oshkosh and the factory fly ins next year!

[Slyfox]

Dorsal, why would you move your oil pressure sender to the firewall?

for the reason I did. Because of vibration in the engine takes out the sensor

[Slyfox]

in my opinion map reading does nothing for setting the prop. rpm on the other hand. I have the round guage with color code for the 912. very nice and I keep it in the yellow on take off or 5800 area for no more than 3 minutes. after that it stays at around 5200 regardless of the throttle. at least to a point. when I go to land I put full throttle at 5200. than I back off the throttle to 4200rpm than flatten the prop to 5200 about a count of 3 as in 1000-1 1000-2 1000-3, generally that's all it takes. If for some reason it takes much longer than that, it's a sign the prop movement is slowing, I start looking at things, yes this has happened, I found a build up of grease on the contacts where things spin, for the brushes. I leave the prop setting alone and when I go to take off the next time it's perfect for take off. I monitor the rpm and operate the switch for the prop to stay in the yellow, once I level I put it to 5200. done.

[jamesmil]

had the oil pressure sender fail at 3.5 hr,s over the beach. if I had put it down I would have had to remove the wings and get a barge to get it back to the mainland as the beach I was over is an island. climbed until I was high enough to make it back to the runway, by then I knew it was not an oil pressure problem or it would have locked up by then. moved it to the firewall and installed a second manual elec, gage as a backup.
as for the fuel pressure reading I am glad I have it as it showed a low fuel pressure warning after about 2.5 hr,s of flying caused by a vent line restriction from a tye rap that was pulled to tite:eek:

[Dorsal]

Dorsal, why would you move your oil pressure sender to the firewall?

What Slyfox said, see thread http://www.teamkitfox.com/Forums/showthread.php?t=4754

Only time I had a low fuel warning was because I had the main valve off :o wouldn't have made it to take off but was good to know before the engine quit.

[Slyfox]

I never turn my fuel off. On the oil sender. I have the pressure sensor and an on/off switch that turns on at about 35psi. I put that on/off wired into one of my cht guages. so I watch for pressure and for that cht to go to 220. if one goes to zero I look at the other. my butt is covered.

[Dorsal]

I never turn my fuel off. On the oil sender. I have the pressure sensor and an on/off switch that turns on at about 35psi. I put that on/off wired into one of my cht guages. so I watch for pressure and for that cht to go to 220. if one goes to zero I look at the other. my butt is covered.

Normally neither do I, shut it off while swapping out the fuel pressure sender, thought the sender didn't work cause the reading was zero :o

[Slyfox]

oops. can understand. glad you caught it.

[Jch]

Sounds like moving the pressure sensor is a good plan. Where. Could I look for more information on how to do this and what parts are needed? I can also see the value of the fuel pressure sensor from the replies. Thanks all!

[Slyfox]

for ease. call lockwood and get there kit, reuse your sensor. me, I made my own.

[Dorsal]

I used the kit sold by Kitfox

[Dick B in KY]

I had a fairly high temp braided steel line 36 inches long made up at local hydraulic shop with 1/8NPT male on one end for engine and 1/8NPT female on the other for the pressure sender. Relocated to engine mount at firewall on my SS.

Dick B

[jamesmil]

if you move the oil sender to the firewall you should use a fitting that is restricted with a smaller opening where the hose attaches it the engine so that if the hose completely blows off " not likely with an a/n hose with the proper fittings" it will show the pressure drop on the gage but will restrict the discharge of oil from the engine so as to hopefully make a safe landing with power.