Engine upgrade uptions

G-Man

G-Man

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AirmanG
Wildly spitballing here, so bear with me, please. Let us consider the popular IO-360, making 200hp. What options are there to increase that to ~220 hp? Experimental aircraft.

If you're experimental, can electronic ignition get more horsepower and better fuel economy? How much of each?
What's involved in a custom header for an aircraft?
Does an aftermarket turbo make sense?

How cost-effective is an IO-390? Specifically, the AEIO aerobatic version. Does it have to be bought? Can it be built from good used parts? (Can I get an AEIOU version for the whole range of vowels?)

Are there six-cylinder motors in the right power range?
An O-470 seems it would jump fuel consumption 4-5gph for a 15% power increase. Is there an IO-470?
 
The TSIO-360-KB is 220 hp with a 5 minute limit. Heat is the real problem here. Franklin made a NA, carved 210 hp that I think is a six. Parts are a little difficult to find.

There is an IO-470. I know nothing about it.

High compression pistons may be available for the lyc 360. Probably be cheaper than blowing it.
 
G-Man said:
Wildly spitballing here, so bear with me, please. Let us consider the popular IO-360, making 200hp. What options are there to increase that to ~220 hp? Experimental aircraft.

If you're experimental, can electronic ignition get more horsepower and better fuel economy? How much of each?
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EI will get you more efficiency, but not more power.

The way to get 10% more hp is to raise the compression ratio slightly, do some intake work on the cylinders, and spin the engine a few RPM faster.
 
The trend among builders of high compression Lycomings is to use a counterbalanced crank, so just adding high compression pistons isn't the whole answer. My EX IO-400 dyno'd at 220hp with API's latest fuel servo (added 5 hp) and Pmags. That engine (pretty much a clone of the IO-390) uses 8.9-1 compression, angle valve heads, and does have a counter balanced crank.

The TSIO-360KB is a 6 cylinder Continental engine. The IO-470 is a great engine and rates at 265hp. Not many are used these days. It was the original engine in early model C-185s but was replaced by the IO-520 in the mid '60s and most older airframes have been upgraded through the years. I have a friend with an IO-470 in a 185 and he loves it for the fuel economy versus his IO-520 airplane.
 
The early Debonairs and late '50s/early 60s Bonanzas also had various models of the IO-470 in them.
 
A lot of times people talk about rated horsepower, when what they really care about is part throttle horsepower (i.e. better cruise speed and/or better climb). So what are your goals? Better takeoff, better climb, faster cruise?

Being in Colorado, electronic ignition will help you to some degree almost immediately. They start to advance timing at 24" typically, which is more or less manifold pressure on the ground. The higher you go, the more the improvement. So that would be worthwhile in your case. Rated power (sea level/2700 RPM), no, it won't make a difference. You will get more power for the same MP/RPM/FF with electronic ignition (once below 24"), but how much more depends on the specifics of what altitude etc. you're flying at.

Higher compression pistons will help you get more power all the time. That would be worth doing, especially up at your altitude. 10:1 is probably where I'd go vs. the factory (which I believe are 8.7:1).

You can bore out the crankcase some and put on IO-390 cylinders, or just get a 390. Problem with 390s is that they are expensive and hard to find. If you want just the cylinders, Lycoming is the only source (same is true for angle valve 360 cylinders, although they're more common to be found used), and they're expensive, plus the machining work. But you gain an extra ~30 cubes, and there's no replacement for displacement.

You can port the cylinders and do a 3-angle valve job. More flow = more power.

You can put on a tuned exhaust. If done properly, you will see a slight benefit from that.

Baffling. Make sure your baffling is super tight. Cooler CHTs = more power, especially on angle valve Lycomings. There's a significant power loss as you approach redline CHT.

Ultimately what we all want out of our airplanes isn't horsepower directly, but performance. The engine is one part of that. The propeller is another part of that (which propeller are you looking at? Could you get a better/more efficient one?), and the airframe is the rest. Minimize weight, remove as many antennas as you can (or make them internal antennas), get rid of strobe lights other than the minimum. Etc etc.

The 470 would be a consideration provided that weight isn't a concern and you wouldn't have too much power for the airframe.
 
The best way to get more power on an experimental is to turn the engine faster. The racing guys and aerobatic guys routinely turn 3100 rpm to get max performance. My IO-550 makes 30 more hp by turning 200 rpm faster. Electronic ignitions and such are more for efficiency than power and from what I hear it's not really worth it unless you are piecing an engine together from scratch.
 
What airframe? Bigger engines are bigger. Angle valve cylinders are bigger. Creating a nose bowl and cowl to fit engine and airframe can be a lot of work. And in the end its the prop that makes the airplane go so any engine choice should include some consideration about what prop you'll use. My Cub gets the IO400 and a Whirl Wind 200A composite constant speed prop. The combo is known for being turbine smooth and very thrust worthy but its heavier than a 320. My airframe is extended 2' aft to balance the added weight on the nose. Imagine what a heavier 470 would require!
 
Cooling drag is big - tighter baffles as suggested, make sure inlet/outlet are not oversized, round out the inlet / outlet inside the cowl to better decelerate / accelerate the airflow. Look at what LoPresti does for something somewhat similar.

Gap seals. Fairings at the wing root, any strut attach, etc.

I know a guy with a O-290 T-18 that can keep up with most O-320 T-18s - just a LOT of attention to a LOT of aerodynamic details.
 
I think the gain from an IO-360 to a 390 can be 35 hp, at least that's what's advertised. As it was explained to me, the IO-360 is short of the 200 hp commonly listed.
 
IO-360 is rated at 200hp. IO-390 is rated at 215hp.

Higher compression generally provides higher volumetric efficiency so better power to fuel ratio. That’s why upgrading an o-320 from 150hp to 160hp (achieved by increasing compression ratio) usually provides better fuel efficiency.
 
Stewartb said:
IO-360 is rated at 200hp. IO-390 is rated at 215hp.

Higher compression generally provides higher volumetric efficiency so better power to fuel ratio. That’s why upgrading an o-320 from 150hp to 160hp (achieved by increasing compression ratio) usually provides better fuel efficiency.
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I don't wanna be stuck burning blue gas so lower compression is more desirable to me, even if I have to burn a bit more.
 
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