Jabiru ram air installation - Zenith Aircraft Builders and Flyers2024-03-28T22:48:32Zhttps://zenith.aero/forum/topics/jabiru-ram-air-installation?commentId=2606393%3AComment%3A303721&x=1&feed=yes&xn_auth=noI'll try it at 2900, but I'l…tag:zenith.aero,2013-08-12:2606393:Comment:3037212013-08-12T17:28:22.330ZJohn Austinhttps://zenith.aero/profile/JohnLAustin
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<p><span>I'll try it at 2900, but I'll have to have an air to air refueling :)</span></p>
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<p>It'll only be about 6 gph @ 2900 ... hey, after burning 14 gph at cruise with the 206's IO-540, <em>anything</em> in the single-digit range looks good to me! ;o)</p>
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<p>I don't think <em>any</em> high-wing flows the tanks equally - I see about a 2 gal imbalance from full to empty, which I consider not that bad! </p>
<p>John</p>
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<p><span>I'll try it at 2900, but I'll have to have an air to air refueling :)</span></p>
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<p>It'll only be about 6 gph @ 2900 ... hey, after burning 14 gph at cruise with the 206's IO-540, <em>anything</em> in the single-digit range looks good to me! ;o)</p>
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<p>I don't think <em>any</em> high-wing flows the tanks equally - I see about a 2 gal imbalance from full to empty, which I consider not that bad! </p>
<p>John</p> John,
I agree with the shavin…tag:zenith.aero,2013-08-12:2606393:Comment:3038982013-08-12T16:32:27.067ZDr. Edward L. Olds IIIhttps://zenith.aero/profile/EdwardLOldsIII
<p>John,</p>
<p>I agree with the shaving of the baffles. I'll try it at 2900, but I'll have to have an air to air refueling:)</p>
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<p>I have a fuel flow issue to work on today. The right wing tank does not seem to feed equally? Will do a flow test.</p>
<p>Ed</p>
<p>John,</p>
<p>I agree with the shaving of the baffles. I'll try it at 2900, but I'll have to have an air to air refueling:)</p>
<p></p>
<p>I have a fuel flow issue to work on today. The right wing tank does not seem to feed equally? Will do a flow test.</p>
<p>Ed</p> I think one of the first twea…tag:zenith.aero,2013-08-12:2606393:Comment:3039582013-08-12T00:54:05.313ZJohn Austinhttps://zenith.aero/profile/JohnLAustin
<p>I think one of the first tweaks I did was to aggressively shave the baffles above the cylinders of #! and #3. Both of them ran cool, so I wanted every bit of air going back to #5. Those baffles are totally shaved flush with the top of the duct in my engine. I "think" you've already done this, but I also extended the inboard end of the baffle above #5 to force the air down over the cylinder fins rather than let it bounce off the back of the ram air duct.</p>
<p>In cruise, my #4 is now usually…</p>
<p>I think one of the first tweaks I did was to aggressively shave the baffles above the cylinders of #! and #3. Both of them ran cool, so I wanted every bit of air going back to #5. Those baffles are totally shaved flush with the top of the duct in my engine. I "think" you've already done this, but I also extended the inboard end of the baffle above #5 to force the air down over the cylinder fins rather than let it bounce off the back of the ram air duct.</p>
<p>In cruise, my #4 is now usually the warmest (but normal). There is only a bit of baffle left above #4, so I'm tempted to add a little back to try get the CHT spread even tighter.</p>
<p>If you only got to 355, at least that was within continuous limits. If you keep running and breaking-in that engine, I'll bet it comes down. If that 355 @ 2800 remains stable, try cruising at 2900 or even 3000 and see what happens. I found that the cylinder cooling improved, but the oil temps would start creeping up. That was resolved with the oil sump duct, which of course, you already have installed.</p>
<p>John</p> John,
I've done exactly what…tag:zenith.aero,2013-08-11:2606393:Comment:3036612013-08-11T23:45:52.206ZDr. Edward L. Olds IIIhttps://zenith.aero/profile/EdwardLOldsIII
John,<br />
I've done exactly what you did, plus I did re-jet the carb at Pete's instruction. I have the smooth hose/vane, but still have the issue.<br />
I flew today and had #5 running at 355 at 2800. The others were 50 to 100 degrees cooler.<br />
I'm going to shave the last air dam over #3 down to nothing and play with the plate in front of #1. We'll see what happens.<br />
Ed
John,<br />
I've done exactly what you did, plus I did re-jet the carb at Pete's instruction. I have the smooth hose/vane, but still have the issue.<br />
I flew today and had #5 running at 355 at 2800. The others were 50 to 100 degrees cooler.<br />
I'm going to shave the last air dam over #3 down to nothing and play with the plate in front of #1. We'll see what happens.<br />
Ed Ed,
I'm sure you know this, b…tag:zenith.aero,2013-08-09:2606393:Comment:3030112013-08-09T14:16:45.299ZJohn Austinhttps://zenith.aero/profile/JohnLAustin
<p>Ed,</p>
<p>I'm sure you know this, but rotating the carb is to balance the "swirl" of the mixture <em>distribution</em> between left and right cylinder banks, but of course does not overall enrich the mixture. I found that by installing a smooth-bore 90 degree bend (rubber radiator hose) from the airbox and installing the vane insert, my EGT spread was extremely tight (usually less than 50 degrees over 6 cylinders!) and rotating the carb was not necessary. If you installed the vane insert…</p>
<p>Ed,</p>
<p>I'm sure you know this, but rotating the carb is to balance the "swirl" of the mixture <em>distribution</em> between left and right cylinder banks, but of course does not overall enrich the mixture. I found that by installing a smooth-bore 90 degree bend (rubber radiator hose) from the airbox and installing the vane insert, my EGT spread was extremely tight (usually less than 50 degrees over 6 cylinders!) and rotating the carb was not necessary. If you installed the vane insert <em>after</em> previously rotating the carb, I'd straighten the carb and see if it affects #5 positively. Also, Pete emphasized that the vane insert be installed with one of the internal vanes exactly vertical relative to the Bing's intake.</p>
<p>There are various after-market "Hacman" valves that can be used to vary the mixture on a <br/>Bing carb (as I understand it, they alter the flow in the air balance tube between the airbox and carb and "trick" the Bing's altitude compensation), but I have <em>zero</em> personal knowledge and it would seem a questionable solution as it might introduce a new set of problems! The only way I know to richen the mixture would be to re-jet the carb. That might be a temporary solution to run a little cooler 'til the engine fully breaks-in, but if I were you I would consult with Pete about that. Of course, it seems problematic to deliberately run way over-rich just for the sake of one cylinder if the other 5 are "happy."</p>
<p>John</p> Jerry,
Mixture is hard to cha…tag:zenith.aero,2013-08-09:2606393:Comment:3029122013-08-09T13:52:44.782ZDr. Edward L. Olds IIIhttps://zenith.aero/profile/EdwardLOldsIII
<p>Jerry,</p>
<p>Mixture is hard to change on this engine, what did you do? I've already turned the carb @ 5 degrees as suggested by Pete.</p>
<p>Ed</p>
<p>Jerry,</p>
<p>Mixture is hard to change on this engine, what did you do? I've already turned the carb @ 5 degrees as suggested by Pete.</p>
<p>Ed</p> I suspect you are running too…tag:zenith.aero,2013-08-09:2606393:Comment:3028802013-08-09T01:07:48.098Zjerry nicholshttps://zenith.aero/profile/jerrynichols
<p>I suspect you are running too lean. At 7-8GPH, I stay cool. Try carb heat to richen the mixture and see if the CHT's and EGT's don't fall.</p>
<p> </p>
<p>My advice is worth what you paid!</p>
<p>I suspect you are running too lean. At 7-8GPH, I stay cool. Try carb heat to richen the mixture and see if the CHT's and EGT's don't fall.</p>
<p> </p>
<p>My advice is worth what you paid!</p> John,
Yes, I did extend the d…tag:zenith.aero,2013-08-07:2606393:Comment:3024452013-08-07T19:18:53.595ZDr. Edward L. Olds IIIhttps://zenith.aero/profile/EdwardLOldsIII
<p>John,</p>
<p>Yes, I did extend the duct down behind #5. I will try out the ramp again. I have to do a fuel check to see if I'm still at 5 gph, my Dynon is showing more.</p>
<p></p>
<p>One of the guys who helped a lot on my build has decided to go with a 750 also. He was looking at an RV, but after OSH, he is ready to get going as soon as he sells his Challenger.</p>
<p>Ed</p>
<p>John,</p>
<p>Yes, I did extend the duct down behind #5. I will try out the ramp again. I have to do a fuel check to see if I'm still at 5 gph, my Dynon is showing more.</p>
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<p>One of the guys who helped a lot on my build has decided to go with a 750 also. He was looking at an RV, but after OSH, he is ready to get going as soon as he sells his Challenger.</p>
<p>Ed</p> Darn it, Ed, you've about use…tag:zenith.aero,2013-08-07:2606393:Comment:3024982013-08-07T17:36:12.036ZJohn Austinhttps://zenith.aero/profile/JohnLAustin
<p>Darn it, Ed, you've about used up my bag of tricks! HA! When the ramp was installed, was it used in conjunction with the raised air dam (to cover more cylinder fin on #1) and curved ramp over #1 barrel? If not, it might be worth a try to reinstall it. (Although I don't have the ramp installed, that's the configuration the Zenith demo has).</p>
<p>I don't remember, did you extend the duct down the backside of #5 cylinder fins? That seemed to help on my 3300.</p>
<p>I never fill beyond about a…</p>
<p>Darn it, Ed, you've about used up my bag of tricks! HA! When the ramp was installed, was it used in conjunction with the raised air dam (to cover more cylinder fin on #1) and curved ramp over #1 barrel? If not, it might be worth a try to reinstall it. (Although I don't have the ramp installed, that's the configuration the Zenith demo has).</p>
<p>I don't remember, did you extend the duct down the backside of #5 cylinder fins? That seemed to help on my 3300.</p>
<p>I never fill beyond about a quarter of the hash marks on my oil dipstick.</p>
<p>5/hr seems reasonable fuel burn to me!</p>
<p>I had a great time at AirVenture! The weather was perfect and although (to me) it seemed that overall AirVenture attendance was relatively light, there was a huge turn-out for the Zenith builder's banquet. At the Zenith display, I think I let my enthusiasm get away from me ... I "sold" at least two people on getting a 750 kit!</p>
<p>John</p>
<p>N750A</p> John,
You are correct, they w…tag:zenith.aero,2013-08-07:2606393:Comment:3024942013-08-07T14:38:20.245ZDr. Edward L. Olds IIIhttps://zenith.aero/profile/EdwardLOldsIII
<p>John,</p>
<p>You are correct, they were 214, 216, and 215! The #5 EGT was 1349, 1301, and 1345 at the cruise RPM's I noted. I took off the ram airs and checked for debris and there was none. And yes, the patented John Austin oil cooler is working fine.</p>
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<p>I have retorqued the heads and they were fine. I also had the ramp in before, and it made no difference. I have the vane in the carb and am using the wooden prop. I have my oil up to the half way mark on the dip stick, so…</p>
<p>John,</p>
<p>You are correct, they were 214, 216, and 215! The #5 EGT was 1349, 1301, and 1345 at the cruise RPM's I noted. I took off the ram airs and checked for debris and there was none. And yes, the patented John Austin oil cooler is working fine.</p>
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<p>I have retorqued the heads and they were fine. I also had the ramp in before, and it made no difference. I have the vane in the carb and am using the wooden prop. I have my oil up to the half way mark on the dip stick, so I'll take some out.</p>
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<p>I was burning around 5 per hour at 2800, so we will see what happens. </p>
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<p>Did you have a good time at OSH?</p>
<p>Ed</p>