55wagon wrote:Can NOT explain it but I burn 9.8gph in my 180 at 23 squared.
With bushwheels and bubbles and all kinds of dirty stuff hangin on it I average about a 135mph at 9.8 gph at that setting. Not bad mpg.

Do you have one of those high-lift dashboards? Or maybe one of those magnetic gizmos that wraps around the fuel line?

jomac wrote: ...but if u think u want to run mo-gas, i wouldnt do a big bore...the 360's and such do that better i believe...i know u CAN run mogas, but not sure why ....the chance of issues is much greater, and i see a bunch of motors that end up getting 1/2 the hours with mo-gas...i know, some do seem to make it work...

The previous owner of my 180 put on almost all of the 1150 hours SMOH it had when I bought it last fall using mogas, except on trips when he couldn't get it, and it's never even had a cylinder off. I put the last 600 hours on the old O-300 in my old 170, and the first 1100 hours on the new engine, all burning mogas, and never had a fuel-related issue. Put 800 or so hours on my C150/150TD burning mogas too. Not sure which "issues" you're referring to, but in 28 or 2900 hours of mogas-fueled flying I don't think I've ever had any trouble that can honestly be attributed to mogas use.

Ok, so does a IO-550 in a Wagon count as big bore enough? Mine lives at 10,000-11000 msl and all I can pull WOT is around 19"map and usually run 2300 turns sqeaky LOP. Plugs are clean and cylinders/valves bore scope clean. It likes running at those settings. Friend of mine has an A36 with a 550 and runs with same results. YMMV

RockHopper wrote:Ok, so does a IO-550 in a Wagon count as big bore enough? Mine lives at 10,000-11000 msl and all I can pull WOT is around 19"map and usually run 2300 turns sqeaky LOP. Plugs are clean and cylinders/valves bore scope clean. It likes running at those settings. Friend of mine has an A36 with a 550 and runs with same results. YMMV

And I don't have any problems running my IO-520 at 25" MP (or less if altitude is above 3000' at WOT) and 2300 RPM LOP at 11 GPH. Super smooth.

Guess I'm showing my ignorance here, but not quite sure what you mean hotrod. I'm assuming its jokingly but went right over my simple mind.

I don't claim to be anything above average in the brightness category but I do know my motor's running great.
Plugs stay clean between cleanings. Oil looks like its dipped out of the bottle at 40hrs and exhaust pipes look great.
I run around 320-350cht and low 1400's egt. I do run the piss out of it from time to time as well. Don't baby it all the time.
First motor for me to run lop. Always been wary of it but I figured I'd give it a shot. The way I figured; if I make to tbo ill have payed for the entire motor in fuel savings. And if I start having problems... Well then ill know for sure what works and what doesnt from personal experience. So far I've saved about 8k w zero negative effects and plenty positive. So even if I crap a few cylinders I'm still money ahead. We'll see how it goes.
Better quit talking now before I go crank it up and drop a valve with my luck. Adios. Off to find some wood to knock on.

Sounds like if the engine temps are kept hot enough and mixture is right then low power settings should be fine.

RockHopper wrote:Ok, so does a IO-550 in a Wagon count as big bore enough? Mine lives at 10,000-11000 msl and all I can pull WOT is around 19"map and usually run 2300 turns sqeaky LOP. Plugs are clean and cylinders/valves bore scope clean. It likes running at those settings. Friend of mine has an A36 with a 550 and runs with same results. YMMV

I only have the A36 Power Chart but that looks like ~10gph? That's a lot of engine but still close to the same weight as the 520. I'm fighting the gear-head in me and trying balance weight and HP. 300hp on a BH would be insane

55wagon wrote: Guess I'm showing my ignorance here, but not quite sure what you mean hotrod. I'm assuming its jokingly but went right over my simple mind. .

Yup, just kidding you- guess it fell flat.
However you're running that engine, it sounds like it's producing good results.
Your fuel burn is for sure about as good as it gets for the power produced.

I use both 100LL and mogas. Just before annual, I'd been running mostly av gas and higher power settings on long x-country flights. At annual, the plugs showed a fair amount of lead fouling. That doesn't happen with mogas and at $2.99 per gal vs $6.00, I don't miss running 100LL and only buy it when I have to. The last fill-up was 55 gallons of mogas and cost $165 instead of $330 for 100LL.

Nearly 1000 hours SMOH on the O-540 running low power settings mostly; no issues and great fuel economy. Average cruise is about 19 squared. Carb heat or power is added to keep CHT's above 300F in colder temps.

Can NOT explain it but I burn 9.8gph in my 180 at 23 squared.
With Bushwheels and bubbles and all kinds of dirty stuff hangin on it I average about a 135mph at 9.8 gph at that setting. Not bad mpg.

I use less in my O-360. It is very hard for me to think in gallons per hours but with the help of Google I have arrived at 9.8 USG = 37 LPH.

I have a Dynon engine monitor, do all in my power (cocking the throttle plate just right, a whisker of carby heat, experimenting with RPM versus MP) and leaning until at least some of the cylinders are lean of peak. I burn around 33 litres per hour for a cruise of 95 knots in my Scout with 32 inch Bushwheels. Courtesy of Google again this is 8.71 USG per hour.

I am running around 2450 RPM and 23" MAP most of the time for this power and keeping the CHT's under 360F most of the time. I have a (self imposed) redline of 380F (Manufacturer gives an astonishing 500F) and my engine seems to love it. Virtually no oil consumption, perfect compressions every inspection, no metal in filter. I also run Cam Guard although I doubt this does anything for fuel consumption.

If I loiter around at 2200 and 19" MAP I am using around 26 litres per hour. A fthrottle wide open climb is 66 litres per hour and a 25 squared full rich climb is around 52 LPH.

It is interesting to watch the engine monitor, a full throttle climb results in widely varying CHT's and EGT's but cocking the throttle plate slightly and reducing RPM to around 2550 results in near matched CHT's and EGT's.

I have done one of these courses http://www.advancedpilot.com/onlinecourse.html and highly recommend them. An eye opener for operators of piston aircraft engines.

Best economy is around 3500 feet or less, at higher altitudes I need to burn more fuel to keep the CHT's down or put up with a bit of a "lean stumble" and get all cylinders lean of peak. MOGAS is better for lean of peak operations then our 100 LL avgas.

I think Bob Barrows ran his O540 at 19 squared. My IO520 counter weight arrangement/prop combination has no RPM restrictions. With Gami injectors should be on PAR with Bob's O540.

Bonanza Man wrote:My Bonanza has a 520(285 HP) and I will run it at 19"/2100 when I want to let my friends 182 keep up with me. That's 45% and I lean it to 8.5 GPH. I will also use 19"/2300 and 10.5 GPH.

Phenomenal!

I got about the same numbers at Aussie Bob in the O360 Bearhawk. The frustrating thing was Blackrock could go faster on less fuel in his O540 Bearhawk. I'm not looking at the Lyc O360 at all. Mostly I'm looking at the TCM IO360, the IO520 and keeping the Lyc O540 in the back of my mind. Before I go with one of the big engines I want to be sure I can run it at low power frequently.

This has been helpful, thanks guys.

Zzz wrote:As long as you're leaned properly for the power setting, I don't see why it would be a problem. You hear concerns of plug fouling or temps not being high enough, but these are functions of mixture.

Right?

Right*

*From my limited experience, and a whole truckload of research...

I am about to ask the opposite question, Jon. So this has been interesting

OK not really a big engine. TCM IO-360 in my C170B.

I used to commute pretty frequently between Concord and Palo Alto (KCCR KPAO) in the San Francisco Bay Area.

Typically used climb power to 2000 ft then pulled it back to 20" and 2000 and leaned aggressively. Climb on direct course, cross the hills, descend to 1400 to go under OAK class C, call for transition through KHWD class D which is under the OAK class C then cross the bay to PAO.

Always ran 100LL. Was typically 1 hour on the hobbs round trip, about 20-25 min flight each way depending on wind mostly. Did this hundreds of times over a 4 year period with no problems, no plug fouling, nothing of concern in oil analysis. Burn was about 7 to 8 gallons round trip.

http://www.avweb.com/news/pelican/pelicans_perch_84_mixture_cht_194816-1.html

Long article but well worth reading, digesting, then reading again.

Below are my "Cliff notes" regarding mixture that guided me through 2900 hours on my NA IO550 with individual EGT and CHT indication. (Still should read the article and also look up some of Mike Busch's blogs or webinars. Better yet, take the Advanced Pilot Seminar: http://www.advancedpilot.com/

1. Avoid the "red fin".
2. You can't hurt it below 65% power. i.e. peak or either side of it is OK, so sometimes when want or have to fly high (say 11,500 or higher), it's OK to go on the rich side a bit to get max output.
3. Don't target anybody's specific CHT or EGT recommendations. Go by how many degrees LOP you are.

c170pete wrote:OK not really a big engine. TCM IO-360 in my C170B.

I used to commute pretty frequently between Concord and Palo Alto (KCCR KPAO) in the San Francisco Bay Area.

Typically used climb power to 2000 ft then pulled it back to 20" and 2000 and leaned aggressively. Climb on direct course, cross the hills, descend to 1400 to go under OAK class C, call for transition through KHWD class D which is under the OAK class C then cross the bay to PAO.

Always ran 100LL. Was typically 1 hour on the hobbs round trip, about 20-25 min flight each way depending on wind mostly. Did this hundreds of times over a 4 year period with no problems, no plug fouling, nothing of concern in oil analysis. Burn was about 7 to 8 gallons round trip.

Thanks Pete. The IO-360 is the route I'm hoping to go...if I can find the right deal on one. After talking with a local part 135 guy I trust I've backed off my IO550/520 idea. It was his opinion that the 550 would not get along well at really low setting, the 520 would probly be ok but he thought the I/O470 would be a better choice.

Pierre_R wrote:http://www.avweb.com/news/pelican/pelicans_perch_84_mixture_cht_194816-1.html

Long article but well worth reading, digesting, then reading again.

Below are my "Cliff notes" regarding mixture that guided me through 2900 hours on my NA IO550 with individual EGT and CHT indication. (Still should read the article and also look up some of Mike Busch's blogs or webinars. Better yet, take the Advanced Pilot Seminar: http://www.advancedpilot.com/

1. Avoid the "red fin".
2. You can't hurt it below 65% power. i.e. peak or either side of it is OK, so sometimes when want or have to fly high (say 11,500 or higher), it's OK to go on the rich side a bit to get max output.
3. Don't target anybody's specific CHT or EGT recommendations. Go by how many degrees LOP you are.

I've read that article and thought it had some great info. Your cliff notes are pretty much the same as what I've picked up but I haven't been able to put it to practice.

I posted the following in the other thread as someone cross-posted my post in this thread over there and I replied. (I'm getting SO confused!)

Re: Aggressive LOP power settings -540

mtv wrote:
A couple points:


And, of course, Continental gave bad information on fuel flows.

You can run your engine however you like, but I think there are some valid reasons not to lean these engines aggressively at high power settings.

And I am a firm believer in running many engines LOP, as long as it's done intelligently.

MTV


Well put. Traditional ROP recommendations put cylinders right smack in the middle of the "red fin". If you're going to run rich, the new consensus of the really smart guys (not me), is to run very rich, like 120d ROP.

The Red Fin.



My "other plane" is a Cirrus SR22 with a normally aspirated IO550 with GAMI injectors. On the Cirrus Owners and Pilots Association Forum (COPA) over the eight years I've been active, there has been a lot of discussion and now with a large fleet (around 6,000 Cirrus out there) and millions of hours and a lot of data, it was found that a lot of the turbonormalized SR22's were needing cylinder work at 800-1100 hours. When they first came out (2007) the sales and marketing hype was a 200 knot plane. Too many were operated at 85% power, basically WOTLOP (wide open throttle, lean of peak).

At the same time, the majority of the fleet of normally aspirated SR22's, like mine, quietly were making it to TBO and beyond (2960 hours in my case). The takeaway was that the NA birds were being run mostly from <65% to 70% power. (For example, 90% of my SR22 flying is cruising point A to point B WOTLOP at 10,500 to 12,500, where it can't make over 65%.) Probably 90+% of the Cirrus operators run lean of peak the majority of the time. The difference was the TN ships were just being run at too high a power.

With the low altitude type of flying many on this forum enjoy, the conclusion would seem to be that it would be a good idea to pull the power back for LOP ops. One of the reasons I bought my modified 1964 182-G seaplane (now a backcountry plane) is that it has an IO550 with GAMI injectors and a JPI with individual EGTs and CHTs so I can run it like my CIrrus engine. The difference is that down low I pull it back, to say, 21" MP and then lean to about 20d LOP.

Oh, BTW, with this setup I lean "brutally" for taxiing and ground ops.

Pierre

Yeah i get it hotrod...470 and smaller motors run mogas all the time...im referring to 520 and bigger like my T540...cheap gas just does not build HP like avgas...nor is it very clean...just sayin...like whee said, with the power pulled back, the 540 motor is quite efficient and has some xtra juice when u need to get off in a few hundred feet...im routinely off in 4-600'on lower loon and such...i think a 540 for his project would be a really good choice...low power settings with the mixture dialed works well for me...50-70 mph quite a bit...fuel is definitely a personal choice for most...!