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Most HP for the buck.?

miyu1975

miyu1975

Well Known Member
Been pondering engines. In comparing IO 390 to an IO 540 (super 7)...with the 390 price tag at 36,000 couldn't one purchase and o'h a 540 for much less than that and have more HP. Of course then make mods for the bigger engine. It seems there are lots of 540 on barnstormers priced less than 360s even. ???

Thoughts?..pls don't beat me up to bad.
 
I'm with you man. The price of a parallel 540 is less, the cost for six parallel cylinders is less, the weight is only marginally more, and you aren't running the 540 hard at ALL compared for WAY more HP. Low compression still nets you 235HP. I'd do it. I was planning on either a Angle 360 (if I could find one cheap) or a para 540 for the -7... of course that was before this -4 project distracted me :D.
 
The biggest factor is weight. Everything else falls in favor of the 6-cylinder except perhaps overhaul cost - but then even that might be better if the initial purchase price is right for a used engine.

One caution - if you are planning on putting this engine in an RV other than the -10 or Rocket you are moving into the "true experimental" region (as far as weight and balance goes) and also run the risk of exceeding Vne in level flight. This could result in a very exciting ride right up to the moment that some crucial control surface departs the aircraft...

:D
 
osxuser said:
the weight is only marginally more
Click to expand...

Maybe I'm looking at the wrong site, but according to Lycoming's website, the weight of the O-540 is 33-40% more than the 4 cylinder engines. Over 100 lbs. difference.
 
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DATA points for you

TMXIO-540 weighs 410 Lbs and sells for $41,479.00.
TMXIO-390 weighs 308 lbs and sells for $36,850.00
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."
 
390

I purchased a 390 for my new project. I do not believe a 540 is appropriate for the airframe. I know there are a few out there but I'm very confident this was outside of the design engineering.

Use a 390. They are getting around 215hp, maybe more with some work. The weight gain over an IO360 is minimal, performance is excellent and you aren't pushing the airframe.

Just my opinion.
 
mahlon_r said:
TMXIO-540 weighs 410 Lbs and sells for $41,479.00.
TMXIO-390 weighs 308 lbs and sells for $36,850.00
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."
Click to expand...

That doesn't sound like the weights I compared. IIRC a 235HP carbed 540 was within 35lbs of a Angle valve counterwieghted 360....
 
I may be crazy but it seems to me the most HP for the $ is still the IO-375-M1S from Aero Sport. With the same weight as the parallel valve IO-360 and low compression 8.0 to 1 pistons they're seeing 200 HP. ...and all of this for about $10K less than the IO-390's that are being talked about here. (add higher compression pistons to sneak over 200 HP)

I'm not sure but it seems to me that spending 10K more for 35 more HP along with an extra 40 lbs up front isn't as much "bang for the buck" so to speak. That extra weight will likely negate most of the cruise speed gain you see from that extra HP and then you're right back where you started after spending $10K more.

My $.02

- Peter
 
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We aren't talking about 10K more, because you can pick one up for around $15-18K, overhauled. An overhauled IO-360-A would be in the $25K neighborhood. Supply and demand.

There are a few people out there who still can't justify spending $20k+ on an engine.
 
Lycon?

Having owned a angle valve 360, a parallel valve 360, a parallel valve 320, 2 parallel valve 540s(260HP) and a C85-12, if I wanted to balance weight and get the most HP, I would do it with a parallel valve 360. You can port, polish and flow the jugs, increase the compression, balance the internals, install a cold air sump, use tuned exhaust and refine the FI to get it near or equal to the 390 and close to a 235HP 540. Several places can do the jug work and the rest is bolt on and tweak. You may loose some life on TBO, but everything is a compromise. IMHO, Mike Stewart is going to be your best reference on installing a 540 on a RV. His site has some good info. www.mstewart.net/super8/faq.htm

I currently own a LS2 and have a LS9 on order. My 2007 Corvette will do 186 in 1.2 miles and when the LS9 goes in I hope to hit 205. All on the ground. Sorry Todd, but I'm gonna take you in the 1/4 mile, either engine!
 
Hard Knox said:
if I wanted to balance weight and get the most HP, I would do it with a parallel valve 360. You can port, polish and flow the jugs, increase the compression, balance the internals, install a cold air sump, use tuned exhaust and refine the FI to get it near or equal to the 390 and close to a 235HP 540. You may loose some life on TBO, but everything is a compromise.
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Sorry Robby, but I'm going to have to call you on this one. Even if you go 11:1 on a parallel head 360, you won't get more than 200 hp out of it. The engine just won't produce that much power with the existing cylinder head. If you go 10:1 on this engine, you will lose one half of the life of the engine.

If you are a racer and have unlimited resources, you wouldn't care if the engine only lasted 200 hours, but I think at some point you have to evaluate the overall purpose of the airplane, and it doesn't make sense to me to do this in an airplane like most of you are flying. My two cents, for what it is worth.
 
Just my $.02, but I would take a parallel-valve 540 over a hopped up O or IO-360. I'd rather have an engine that loafs all day long than one that has to run hard to achieve the same speeds. A few times I've flown friends' rockets and climbed to 10K and made it there in 3 minutes from ~850msl, then throttle back to a smooth running engine loafing at less that 50% power. It doesn't take much of that to make one a believer.

And factor in the price of six new parallel valve cylinders is less than the price of four new angle valve cylinders.

Last weekend a friend of mine who routinely rides with me to breakfast in the -6 got his first rocket ride, and his first words were "holy cow!"
 
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What Bob said... I'd personally rather derate my load factor to 3 or 4 (within my envelope anyway) and not have to wonder about the integrity on a max'd out "-360" series engine.

Other factor for people like me is price and availability of good used engines. The -540 series used to be a much better deal. Not sure sure any longer though.
 
I would too... in a car.

In all seriousness. An LS2 isn't an option for a side-by-side RV because of wieght... period. Lightened up (i)O-540 has been done successfully. Todd... well we've all followed your thread so... Yeah, I'll take the Lycosaur for now.
 
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Can't argue with an expert, a pretty one at that!

rgbewley said:
Sorry Robby, but I'm going to have to call you on this one. Even if you go 11:1 on a parallel head 360, you won't get more than 200 hp out of it. The engine just won't produce that much power with the existing cylinder head. If you go 10:1 on this engine, you will lose one half of the life of the engine.

If you are a racer and have unlimited resources, you wouldn't care if the engine only lasted 200 hours, but I think at some point you have to evaluate the overall purpose of the airplane, and it doesn't make sense to me to do this in an airplane like most of you are flying. My two cents, for what it is worth.
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Rhonda:

I'll never dispute the opinion of an expert. I thought there is a stock 200HP parallel valve 360 offered by Lycoming, IO-360-A1A. My thought was with some jug work, cam work, tuning the exhaust and CAI, you could at least touch the same HP as a 390 or more. I know you are gonna kill the TBO.

Thanks
 
Hard Knox said:
Mounted on what? Airboat? Quit pulling our leg! Its nearly June 1st, not April 1st.
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If you guys saw how damaged the engine was and its ability to still produce power you would fly behind it too. Bottom line, any engine with electronic ignition or EFI would have been destroyed since the problem had nothing to do with the engine. It was in the way the alternator was wired into the electric system. One wire going to the wrong battery.
 
How many hours?

Todd, how many flight hours are on your RV-10 with the LS2, not counting your taxi tests hours?

As you are aware, many of us have followed your adventure via the two year old thread, "TSweezy?" You've faced many hurdles, but it seems that you are still in the extreme area of "experimental" with the LS2. Many RV-10s have been built and are currently flying, without issue, equipped with traditional aircraft powerplants. These factual numbers speak for themselves.

Good luck.
 
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Nothing to do with the engine....

Bottom line, any engine with electronic ignition or EFI would have been destroyed since the problem had nothing to do with the engine.
Click to expand...
No, bottom line is that your automotive engine installation is way too complicated. Airplane engines need to rely on the KISS principle, that is to say a simple wiring error shouldn't result in a failure that may, or may not, let you make it back to terra ferma in one piece. While they may be "old technology", Lycos will let you put hundreds of hours on then without a major overhaul because of a simple wiring mistake.
Sorry Todd, but seems it may getting close to time to quit making excuses and put a real aircraft engine in your plane. Then you can start enjoying it like you're suppose too!
 
Hard Knox said:
Rhonda:

I'll never dispute the opinion of an expert. I thought there is a stock 200HP parallel valve 360 offered by Lycoming, IO-360-A1A.
Click to expand...
All the IO-360-A and -C series engines have angle valves. The IO-360-B and -M series engines have parallel valves. There is zero relationship between dash numbers of the O-360s and the IO-360s. I.e, an IO-360-A1A is not simply an O-360-A1A with fuel injection.
 
Hard Knox said:
Rhonda:

I'll never dispute the opinion of an expert. I thought there is a stock 200HP parallel valve 360 offered by Lycoming, IO-360-A1A. My thought was with some jug work, cam work, tuning the exhaust and CAI, you could at least touch the same HP as a 390 or more. I know you are gonna kill the TBO.

Thanks
Click to expand...

Robby,

The IO-360-A1A (and all the IO-360-A series) are angle valvers.... The -A1A is the one without the 6th degree counter balanced crank... the lightest one in other words.

The IO-360-B and -M series are Parallel... and 180HP'

Angle valve flows more at RPM... thats all. The parallel head can be ported to help a little, but the angle still flows better.

Any engine I build, I plan on putting angle valves on... Be it a 290, 320 or 360... :) But I'm going for efficiency as well as HP.
 
Really Todd?

They won't eat themselves because of bus low volt...kind of a nice feature wouldn't you say?
 
The best HP/$ is a no brainer: a turbocharged peripheral ported 13B or 20B rotary. It will likely have the best economy and reliability at continual high output levels as well.

Price ~ $5000 depending on engine source, hp 400-500 range, weight in 300lb range.
 
rtry9a said:
The best HP/$ is a no brainer: a turbocharged peripheral ported 13B or 20B rotary. It will likely have the best economy and reliability at continual high output levels as well.

Price ~ $5000 depending on engine source, hp 400-500 range, weight in 300lb range.
Click to expand...

And expected TBO would be??? And of course, who can repair it on Sunday night when stuck 3 hours from home base?

Still, HP/weight/$ IMHO still leads me to the 390. But I could be a little prejudise:)

Allen
 
Yes Todd,

I have even flown for hours behind a lycoming in an airplane with NO ELECTRICAL SYSTEM....shocking isn't it that a properly designed single engine powerplant could start, run, climb, cruise, roll, loop, descend, land, and idle....all without any battery or alternator power at all!

I also flew 45 minutes to land a Cessna 172 (rented) with an alternator failure and the main bus shut down completely.

Once had an intemitent voltage issue in a rented Mooney 201.

If they had voices and could be blindfolded, I bet two lycomings would not be able to tell the difference between and electric or electric free plane.

Though your question surprises me...have you worked mostly with jets? I am struggling to think of a single piston plane where the engine would melt and eat its own internals because of a low main bus.
 
Back on topic a little:

What about a 540 with a nice light fixed pitch prop. Gain back some of the weight penalty, plenty of hp for take off, a bunch cheaper, just as fast as you want in cruise by picking the right pitch???

Cheapest option as far as I can tell from the thread so far. The engine is cheaper, the prop is cheaper, maintanence is cheaper, go as fast as you want by picking the right pitch for cruise.

So what would be the bottom line weight penalty with a wrung out 390 with a CS prop to get the power vs. a 540 loafing along with a FP prop?

Price difference for engine prop combo could be closing in on $15-20k going with a good overhaul 540 vs 390.

I'd love a 6 cylinder in the -8 if I ever get to making progress again, and right now money/budget is getting more and more important???????
 
rtry9a said:
The best HP/$ is a no brainer: a turbocharged peripheral ported 13B or 20B rotary. It will likely have the best economy and reliability at continual high output levels as well.

Price ~ $5000 depending on engine source, hp 400-500 range, weight in 300lb range.
Click to expand...

Ear splitting noise, priceless!

Sorry, I just had to add that. Truth is, a turbo on a rotary should bring the chainsaw exhaust note down to a reasonable level.

Probably the biggest problem I see with putting the (I)O-540 (Yes there are carb version of that engine out there.) in a -7 or -8 is the overall weight penalty. If you check out Kahuna's site, he had to add some weight to the tail to get the W&B to work out. He pegged his GW at 2270 because his empty weight is 1330 pounds. Just something to think about.
 
N941WR said:
Ear splitting noise, priceless!

Sorry, I just had to add that. Truth is, a turbo on a rotary should bring the chainsaw exhaust note down to a reasonable level.

Probably the biggest problem I see with putting the (I)O-540 (Yes there are carb version of that engine out there.) in a -7 or -8 is the overall weight penalty. If you check out Kahuna's site, he had to add some weight to the tail to get the W&B to work out. He pegged his GW at 2270 because his empty weight is 1330 pounds. Just something to think about.
Click to expand...

Unmuffled, a PP rotary sound level is brutal. With turbo and muffler, it will be quieter than most Lycs, but with a little higher pitched sound, more like a race car. I like the sound myself, sorta like a WWII dive bomber. If you use a Renesis side port, the peak power is a little lower, but the sound is much improved.

TBO will be very high compared to most aircraft motors, >2000 hrs. Very low internal stress in a rotary engine as long as it is run reasonably hard (no 25psi boost levels, keep rpm below 7500 rpm). Rotaries in race apps typically last a season or more while recips generally get rebuilt after each race.
 
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Rotaries in race apps typically last a season or more while recips generally get rebuilt after each race.

1. Rotaries that go a whole season racing are in single spec classes where everyone buys one identical engine (at a low tune level) and must run it all season. High Output rotaries, in professional racing series are also rebuilt every race weekend.

2. Pistin racing engines are similar with FF1600 and FF2000 and F2000 Zetec (spec motors) goin a whole or half season without rebuild. FAtlantic toyotas get rebuilt every weekend for pro teams and twice a season for amateurs.

What that has to do with your (completely unsupported guess) claim of more than 2000 hour tbo for an aircraft rotary is truly beyond me. A 12 race season would put less than 120 hours on the whole package.

Please give an example of a rotary going "well beyond" 2000 hours in flight.
 
Jconard said:
..120 hours on the whole package.

Please give an example of a rotary going "well beyond" 2000 hours in flight.
Click to expand...
John,

Ed Anderson has his rotary powered RV-6A (Second one to fly) two hangars down from mine and is a big proponent of rotarys. After talking to him and Tracy Crook about their applications, it does seem as though the rotary, as installed in an airplane will make it past 2000 TBO. This is based on Tracy's overhaul at 500 or 1000 hours, I don't remember which, and the engine showing absolutely know wear. As another data point, Ed has something like 550 hours on his engine now.

Truth is, we really won’t know until someone does make it past 2000 hours.

And no, I have no intention of giving up pistons.
 
Jconard said:
Yes Todd,

I have even flown for hours behind a lycoming in an airplane with NO ELECTRICAL SYSTEM....shocking isn't it that a properly designed single engine powerplant could start, run, climb, cruise, roll, loop, descend, land, and idle....all without any battery or alternator power at all!

I also flew 45 minutes to land a Cessna 172 (rented) with an alternator failure and the main bus shut down completely.

Once had an intemitent voltage issue in a rented Mooney 201.

If they had voices and could be blindfolded, I bet two lycomings would not be able to tell the difference between and electric or electric free plane.

Though your question surprises me...have you worked mostly with jets? I am struggling to think of a single piston plane where the engine would melt and eat its own internals because of a low main bus.
Click to expand...
If it has an electronic ignition and electronic fuel injection controlled by a computer and every thing is suffering from a lack of electricity. That is how. If you want to fly out to Savannah I would be more than happy to show you and anyone else.
 
grantcarruthers said:
What about a 540 with a nice light fixed pitch prop. Gain back some of the weight penalty, plenty of hp for take off, a bunch cheaper, just as fast as you want in cruise by picking the right pitch???

Cheapest option as far as I can tell from the thread so far. The engine is cheaper, the prop is cheaper, maintanence is cheaper, go as fast as you want by picking the right pitch for cruise.

So what would be the bottom line weight penalty with a wrung out 390 with a CS prop to get the power vs. a 540 loafing along with a FP prop?

Price difference for engine prop combo could be closing in on $15-20k going with a good overhaul 540 vs 390.

I'd love a 6 cylinder in the -8 if I ever get to making progress again, and right now money/budget is getting more and more important???????
Click to expand...

Where are people coming up with the information that a 540 is cheaper than a 390 or angle head 360? Are you comparing a new engine to overhauled engine prices? Keep in mind I have no issue with buying an overhauled engine for an airplane, but an overhauled 540 and a new 390 are probably pretty comparable in price. I am generally not a fan of buying a mid-time engine and putting it into a new airplane that you have spent thousands of $$ and hours building unless it has been thoroughly inspected and the history of the engine is a known factor. That's the only way I can thinnk that the option of the 540 would be more cost effective at initial install.

The weight penalty on the engine side alone is 85-90 lbs depending on accessory configuration. What would the weight offset be with fp prop?
 
Rhonda,
I'm going to have to respectively disagree about putting a freshly overhauled or new engine on a new airplane. A mid-time engine has a history. Hopefully a good history, otherwise you probably wouldn't have bought it. A new or freshly OH engine has no history. The other big thing is that a new or fresh OH engine needs to be run hard for the first few hours. This is not the way a new airplane should be flown initially. The initially flight hours for a new airplane should be flown with very little concern for the engine, other than making sure the temps are all in the normal range.
When I first flew my -6, it was with a first run O-320 with over 2500 hrs on the clock. It had a good history and run sheet. I flew it for over 3 years without issues. When I did overhaul it (at over 2800 hrs), all parts more than met serviceable limits and it was still running great. The only reason I overhauled was to increase the hp.
 
rgbewley said:
The weight penalty on the engine side alone is 85-90 lbs depending on accessory configuration. What would the weight offset be with fp prop?
Click to expand...

Rhonda:

Depending on the FP, metal or composite, maybe 30 pound savings over a Hartzell/prop gov combo. If the comparison is to a plane using an experimental composite CS may only see a 15 to 20 pound savings using a FP. Not trying to start a FP/CS Flame, but for some of us weight is only part of the equation in choosing to fly behind a FP prop.

FWIW
 
rgbewley said:
Even if you go 11:1 on a parallel head 360, you won't get more than 200 hp out of it. The engine just won't produce that much power with the existing cylinder head.
Click to expand...

Rhonda, back in about 1988, Monty built up an O-360 for me. It had 9:1, you flowed the cylinders, and added Bendix fuel injection to it.

On your dyno, once we got it up to 2700 RPM, I saw just over 200 HP. I took a picture of the dyno readout; its in a box somewhere... but the engine DID make 200HP.

Monty told me it might make 205 with a few more hours on it, and the cross-over exhaust. So, NICE job BPA, and the parallel valve O360 did crank out 200HP after all.
 
Bang for the buck? Custom M14 and carve your own fixed pitch; 315 hp @2400. If I told you how little money I have in it you would march on Williamsport and burn the building ;)



Hey, bolting it to your RV wouldn't be a bit more experimental than V8's or rotaries. Weighs about the same as a 540.

Sorry, couldn't resist.

Returning to reality.....I find it interesting to see new 390's compared to used engines, overhauled or not, hand grenades or not. Looks like the benchmark.

Now consider long term cost. It's a new, heavy case engine with pendulum absorbers and low compression. Easy on props, easy on starters, likely to accept any future av fuel, doesn't require any airframe mods to hang on a 7 or 8, and will probably make TBO.
 
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I"VE GOT IT!

All the car engine guys and Todd will be happy, its looks similar to an airplane engine, its simple technology, its air cooled and can be built for under $40 per HP.

Most of all, Ralph Nader HATES it!

CORVAIR!!!!

http://www.corvaircraft.com/

Todd could strap three of these on his RV-10 for under 10K.

Just having some fun! Keepin it fun!
 
M14

DanH said:
Bang for the buck? Custom M14 and carve your own fixed pitch; 315 hp @2400. If I told you how little money I have in it you would march on Williamsport and burn the building ;)



Hey, bolting it to your RV wouldn't be a bit more experimental than V8's or rotaries. Weighs about the same as a 540.
Click to expand...

which is why i'm surprised someone hasn't tried to bolt one on an rv10?
If they have an engine mouint and cowling for a rocket, how hard would it be to put one on an rv10? Now we're talking $$/wt/hp that makes sense.

ajay
 
Hard Knox said:
All the car engine guys and Todd will be happy, its looks similar to an airplane engine, its simple technology, its air cooled and can be built for under $40 per HP.

Most of all, Ralph Nader HATES it!

CORVAIR!!!!

http://www.corvaircraft.com/

Todd could strap three of these on his RV-10 for under 10K.

Just having some fun! Keepin it fun!
Click to expand...

I could make a Tri-motor RV-10 and get my multi-engine rating.
 
Hard Knox, props on the way.....

rvprop.jpg
 
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