jetdriven

You could try setting 2" more MP than you wish to run, doing the "big mixture pull", then setting it 50 LOP. You can make the power on the lean side of the graph. We have found that 50 LOP in a NA lycoming IO-360 might be too far. So lately, we run at 15-25 LOP. Side note, the advanced ignition timing lowered our peak EGT from 1585 to about 1500. So, peak EGT is the same temperature as the "Old 85 LOP". FWIW. More reason that the EGT number itself does not matter. Quote: jlunseth Thanks for the suggestions, they are all the same thoughts I have had, but right now I have one new cylinder replaced at annual last year and it is too far off the others to try LOP. Hope to be back at it when this year's annual is completed in a couple months. But the nontuned induction system is still an issue. Raising the MP some amount (such as the 2" suggested) does not have the same effect in the cylinders at the front of the induction system as it does those in the back. Thus, you can't simply add "x" inches and expect that all of the cylinders are going to stay at whatever your LOP setting is in degrees. Further, GAMI/APS recommends running turbos 60 LOP if over 65%, so you have to go deep into LOP territory to protect the engine, where the chances of being able to run smoothly are not very good.

Jim, the biggest scare I had from buying a 231 was the 40K or more overhaul cost vs. ~20K for a Lycoming. Dividing that by the expected 1800 hr TBO vs 2000 hr, that was a little more than twice the engine expense. Thats assuming nothing goes wrong. Of course, if you need to fly high, you need the right machine.

JLunseth: Try adding 2" of MP back to the engine after setting LOP. Or, add the 2" before crossing over from ROP to LOP. You should be able to run the same airspeed, and a lower FF while LOP. Quote: Shadrach If you're losing speed than your not running the same hp, which in theory you ought to be able to do if well below critical altitude. It takes more MP to do it, but that in in of it self should not be detrimental.

I enjoy the same safe airframe, just with a gallon an hour less. In 2000 hours, I save 10K in fuel costs. I actually fly a little slower, and thus 15K, or nearly a free engine. Free engine. Run LOP. I like that.

Those are turbo engines. So is the engine is a Bravo but for some reason they won't run LOP no matter what. First, check the plugs, spark plug harnesses, mag timing. Intake seals at the pan, intake tube gaskets at the head. NO leaks. Do an in-flight GAMI spread test. Then, keep track of which injectors came from which cylinder. Use 4 separate jars to keep them in order. Clean the injectors in Hoppes #9 gun cleaning solvent or acetone overnight. I used 3 days. I shook them and riled them up every time I walked by them. Blast them out with compressed air, then rinse again. change the solvent until there is no little specks at the bottom of the jar. Some have reported over at BeechTalk that using an ultrasonic jewelry cleaner with a stainless tub is best. I didn't have one. Use an ear scope to view inside the injector. I must be perfectly clean. Reinstall injectors. My #1 was leanest and my #4 was richest, I exchanged those injectors for each other. I left 2 and 3 in their original spot. Our GAMI spread went form something like 1.2 GPH to less than .2 GPH.

John, thats prettty close. .43 is a good average number I have .448 from somehwere for 50 ROP on the IO-360-A. LOP drives it down to .40 or .39. When climbing, BSFC is going to be higher due to extra fuel for cooling, so that could be .50. Full rich for takeoff is measured at .54 on ours. It varies with compression ratio and engine architecture. IO-360-A are 8.7:1 C/R. Quote: johnggreen These numbers are interesting. OK, now does anyone have the numbers on specific fuel consumption. The "rule of thumb" on most normally aspirated engines is .43 pounds per horsepower per hour. So at 200 HP, that's 86 pounds and at 6 pound fuel, 14.3 gallons per hour. How does LOP affect that figure? I'm pretty sure somebody on this forum has that number. Jgreen

Sorry to hijack your thread. Here is some discussion on the Challenger oil flter. I am interested in it, we did 4 oil changes this year, http://www.piperowner.org/forums/topic.html?id=86686

Don't ever plan on painting your airplane after applying that stuff

I don't know. The airplane picked up around 5 knots but that was also done at the same time as the 25 degrees timing. I would guess, it helps some, 2-5%.

The Donaldson filter flows more air than a Brackett but filters better that both the Brackett and the Challenger. They are made of synthetic paper now, so they go a little longer. P/N is 13-0234. You also need two AN3-25A bolt and AN960-10 washers. The Brackett ones I had were too short I'd go a little longer and use an AN3- 27A bolt. It has no housing, it is a metal box with the filter inside it. Its also in the parts catalog, so PMA replacement.

Yes we switched out the brackett. The brackett was 15$ and lasts a year, the Donaldson lasts 3 years or 500 hours whichever comes first. It's 100$. So 50$-60$ extra over 3 years.

Someone at the mapa convention said a female test pilot did all those spins and they were a non-event.

I think he meant challenger oil filter. I switched to the Donaldson air filter and our wot ff increased 1 gph. Presumably the higher airflow.

Fort Collins is on the front range north of Denver. Its the same as Texas except the ground is 5500 feet out there. Not very far west is where the mountains start. Your biggest change is going to be a major loss of horsepower for takeoffs, anemic climb performance, and higher true airspeeds for takeoff and landing. Keep it light and dont get behind the power curve. It will be a fun trip.

Try pulling the cabin air knob all the way out, and then cracking open the cabin heat slightly to modulate the temp.

I think the probes are supposed to be 1.5 to 2" from the head. Our j takes a type k egt probe from Alcor, all 5 of them. There is a type J also.

Sounds more like a Lean Mean grilling machine. Had to say it! Quote: txbyker My vent is fixed in one position, no adjustment. Its a Lean Machine, not sure if it is different. I tried moderating a bit but my cabin heat at its lowest puts out a lot of very hot air. I think I will try to make a deflector out of lexan.

Our 3rd partner want to repaint the engraved letters on those switch covers. Does anyone know how to do that?

A 12" long piece of 1.5" PVC with a notch cut in one end makes a good fuel valve turner. Dowel rod glued in the other end aligned with the notch gives more leverage and makes it easy to identify the orientation of the slot and valve.

A wierd theory, but our 3rd partner though the tail was providing a net UP force because the elevator is down, creating a cambered horizontal tail. But that cannot be. So, perhaps, the stabilizer is at a negative incidence in cruise flight and the elevator flies 'down" to offset most this negative incidence. Still a net down force at the tail. ??

I did forget to add in my long winded rant, that I do switch tanks before startup to the fullest tank. If already on the fullest tank I cycle the valve to the other tank and back to verify its working.

Nope, in an early J at least, the microswitch in the throttle quadrant triggers the horn. It activates below about 1/4" of throttle. Quote: xftrplt I agree, at least in my 231. When I bought 888BC, the horn came on too early for my taste, and, neither knowing nor careing what the specs were, it was an simple mechanical adjustment, unrelated to MP, to "correct" it. Maybe on NA engines it's different.

"or cruise, using the Figure 10 dial presentation, all one needs to remember is to lean to peak EGT for best fuel economy unless this puts the EGT into the yellow arc, in which case the mixture should be enriched sufficiently to keep the EGT in the green." LOP or ROP? Richen her up until the EGT is in the green. Never mind them CHT's, they are in the green at 450F. No problem! NO discussion of BSFC. It is the greatest around ~15 LOP to 50 LOP. You don't have greater range because you are flying slower while LOP. You also fly farther because BSFC is greater. IE more shaft HP per lb/hr of fuel. In the photo.... Where is the 50F LOP data? its missing!

I disagree. Minimum BSFC occurs ~15-50 LOP. Thats lb of fuel per HP per hour. Flying slower is more efficient. Flying lean of leak is more efficient combined with flying slower. Still, you cannot get the same NMPG flying slower ROP than the same speed LOP. Re: hot exhaust valves. I would like to see a single data point referring to hot exhaust valves as a trigger for preigniton. I can see a burned valve feather edge glowing hot, but not a proper exhaust valve. Detonation is the premature lighting of fuel due to exceeding the coimpression-ignition (octane) resistance of the fuel. Preignition is caused by a hot spot in the chamber. Re: 65% power EGT. Our peak EGT at 65% used to be ~1590 at 65% power. Now, with 25 degrees timing, its 1500. So, for all the naysayers out there saying we are harming the engine, the exaust enjoys 90 degree cooler temps. More horsepower too. Of course that heat now goes to the cylinder fins. That is still manangeable. Lycoming recommends peak at 75% power and below. We use LOP up to 10.0 GPH, which is 75% power.

I know from testing the fuel gascolator in an early 201 drains at the rate of 10 GPH.