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Thread: 914 Temps?

  1. #1
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    Default 914 Temps?

    I know this is apples to oranges, but I am curious guys running 914 what are your water temps and oil temps? Hot day long climb? I am running a edge performance turbo 912 and had to mod the naca vent to clear the turbo. Airflow is reduced and wondering how close to the edge temps will be? I am just trying to get a reference to try and decide if other measures need to be made. Thanks!
    Dustin Dickerson

    Building 7ss STI x 2
    Oratex
    29" shock monster
    EP912STI 155hp
    Garmin
    N33TF......FLYING!
    N53TF......FLYING!

  2. #2
    Senior Member aviator79's Avatar
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    Default Re: 914 Temps?

    Hey Dustin,

    My engine is pretty similar to yours - moreso than a standard 914. The differences are yours is fuel injected, and I *think* your TCU is tuned to give you more boost.

    My CHTs are in the green in all phases of flight. My oil temp does get into the yellow during a high-performance climb - I've seen temps as high as 240, which would continue to climb if I maintained 65 mph. If I nose over to an 85 mph cruise climb, they cool back down to ~200 quickly. I have a 205 degree thermostat, so 200 is perfect in my opinion. I suspect at 65 mph, the AOA gives poorer flow through the NACA, in addition to the reduced mass flow rate through the cooler on account of airspeed. This is at ~8000-9000' Density altitude, and around 40-50 deg ambient temperature. The high DA means less mass flow through the cooler, so poorer cooling efficiency.

    I didn't install a coolant temp sensor because the 914 Firewall Forward manual didn't call for one, and I mis-read the 914 install manual. As it turns out, if you're running conventional coolant and "without suffix -01" cylinder heads, you're supposed to measure coolant exit temp. I plan to add the coolant sensor.
    --Brian
    Flying - S7SS

  3. #3
    Senior Member Esser's Avatar
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    Default Re: 914 Temps?

    I just ran into hot ground temps. Like 240 degree coolant. I removed my oil cooler guillotine and made my naca scoop tighter around the rad with aluminum. My temps are much better. I’ve never had an issue in the air except maybe some extended climbs.
    9D97B935-5433-4037-94C2-F0B404223CE3.jpg
    ------------------
    Josh Esser
    Flying SS7
    Rotax 914iS
    AirMaster Prop

    Edmonton, AB, CWL3

  4. #4
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    Default Re: 914 Temps?

    Quote Originally Posted by aviator79 View Post
    Hey Dustin,

    My engine is pretty similar to yours - moreso than a standard 914. The differences are yours is fuel injected, and I *think* your TCU is tuned to give you more boost.

    My CHTs are in the green in all phases of flight. My oil temp does get into the yellow during a high-performance climb - I've seen temps as high as 240, which would continue to climb if I maintained 65 mph. If I nose over to an 85 mph cruise climb, they cool back down to ~200 quickly. I have a 205 degree thermostat, so 200 is perfect in my opinion. I suspect at 65 mph, the AOA gives poorer flow through the NACA, in addition to the reduced mass flow rate through the cooler on account of airspeed. This is at ~8000-9000' Density altitude, and around 40-50 deg ambient temperature. The high DA means less mass flow through the cooler, so poorer cooling efficiency.

    I didn't install a coolant temp sensor because the 914 Firewall Forward manual didn't call for one, and I mis-read the 914 install manual. As it turns out, if you're running conventional coolant and "without suffix -01" cylinder heads, you're supposed to measure coolant exit temp. I plan to add the coolant sensor.
    Thanks Brian for all the info this really helps. I will post progress, but I think we are going to install an oil to water heat exchanger like Thomas recommends. I am dropping my oil cooler all the way down to improve cooling also.
    Dustin Dickerson

    Building 7ss STI x 2
    Oratex
    29" shock monster
    EP912STI 155hp
    Garmin
    N33TF......FLYING!
    N53TF......FLYING!

  5. #5
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    Default Re: 914 Temps?

    Quote Originally Posted by Esser View Post
    I just ran into hot ground temps. Like 240 degree coolant. I removed my oil cooler guillotine and made my naca scoop tighter around the rad with aluminum. My temps are much better. I’ve never had an issue in the air except maybe some extended climbs.
    9D97B935-5433-4037-94C2-F0B404223CE3.jpg
    Thanks! I was going to install the oil cooler guillotine, but I got nervous because the one I was looking at, when fully open still would restrict cooling quite a bit.

    Good idea. I was just getting ready to order some baffling material and do something similar.

    Do you run into oil temps limits on extended climbs or water temps? From what I have read seems like most run into oil temp limits and not water temp limits?
    Dustin Dickerson

    Building 7ss STI x 2
    Oratex
    29" shock monster
    EP912STI 155hp
    Garmin
    N33TF......FLYING!
    N53TF......FLYING!

  6. #6
    Senior Member aviator79's Avatar
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    Default Re: 914 Temps?

    Quote Originally Posted by Shadowrider View Post
    Thanks! I was going to install the oil cooler guillotine, but I got nervous because the one I was looking at, when fully open still would restrict cooling quite a bit.
    From what I've read, the oil cooler door is really helpful on the 912. Your 154 HP fire-breather probably won't have any trouble getting the oil temps high enough.
    --Brian
    Flying - S7SS

  7. #7
    Senior Member Esser's Avatar
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    Default Re: 914 Temps?

    How are you temps now? I'm finding in the summer I can hardly do circuits and I can't do super high power climbs. After mulling over this problem a bit, I decided the oil cooler needs to move. Radiators and oil coolers need a differential of pressure to push/pull air through it. In the oil coolers current location with my NACA sealed around the rad, the air will bunch up around the rad as it flows through the rad. the oil cooler will be surrounded by this air pressure both front and back without much air flowing through it. After all, air is a fluid and fluid will take the path of least resistance. Add the fact that my oil cooler is HOT (Not the best Delta T, not much air flowing through it, and the fact that it's blocking a significant portion of my rad, I think the stacked rads are a bad idea. I'm going to move it to under the gear box.
    ------------------
    Josh Esser
    Flying SS7
    Rotax 914iS
    AirMaster Prop

    Edmonton, AB, CWL3

  8. #8
    Senior Member aviator79's Avatar
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    Default Re: 914 Temps?

    Have you talked to John and/or Paul? They have been running 914s for years on their planes. It would be interesting to know if they have had any cooling issues. What are your ambient temps?

    I haven't flown in a couple weeks - had an exhaust leak to take care of. The new exhaust is installed, so I'll be doing some flying this weekend in 22-25 C ambient temps. If I transition to an 85 mph, 34" cruise climb at a safe altitude, I don't have any cooling issues yet. I definitely can't do 40" and 60 mph for 5 minutes.

    Have you considered a heat exchanger like Dustin mentioned? That's probably way easier than relocating the oil cooler, and I'm not sure the flow will be me much better behind that little cowl opening than it is in the NACA duct.
    --Brian
    Flying - S7SS

  9. #9
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    Default Re: 914 Temps?

    Hey Josh
    We have about 75 hours on my new 914 Speedster now, and heating has not been a problem.
    Winter testing required a shutter system in front of oil cooler to get the temps up. Last flight
    was at 90 F ambient and we saw 175 F in cruise and 187 in 1500 fpm climb. We made a
    rather large naca feeding a duct to a plenum at the turbo. Air is fed to the K&N and blown
    over the turbo and muffler. Oil cooler is mounted in front of radiator to allow max room for
    air to exhaust. All kinda shooting from the hip but it is working so far. I'll try to post a pic of
    the plenum, first time try for this old man
    download.jpg
    Phil Laker

  10. #10
    Senior Member Esser's Avatar
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    Default Re: 914 Temps?

    Interesting. I’ve never heard of the turbo needing cooling air. Your temps seem great! If I climb up 5000’ I hit 240 and it takes 30 min to get below 220 again

    I do have a cold air intake for the air filter. But it’s closed off from everything else
    ------------------
    Josh Esser
    Flying SS7
    Rotax 914iS
    AirMaster Prop

    Edmonton, AB, CWL3

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