ECI IOX-320 Stroker!

[wingtime]

Did anyone see the ECI IOX-340 stroker at Sun N Fun?

They are claiming 185HP in a package thats lighter than a O-360.

It has a few nice features that I found interesting including:

tapered barrel fins
flow matched cylinders
Venturi intake seats
Magnesium oil sump
Magnesium cold induction plenum
4.125" stroke
9.0 compression

Sounds like a very interestion option to me.

[osxuser]

Believe it or not, Lycoming actually has a certfied O-340, I doubt it's in production anymore, but it does exsist. I believe it was originally rated at 170HP. I'd be interested to see detailed pics.

[wingtime]

Yup the ECI rep said Lycoming did have a 340 years ago. I doubt it had a intake set like the ECI engine.

[N184JG]

ECI web site says 100LL only.

[cjensen]

this was a nice suprise at SNF! i talked to robbie about it, and this engine looks like a winner to me. less weight, and more power than the 360. i like it!

[RVbySDI]

I have been looking at the ECI IO-360 as the engine of choice I am leaning toward, but with increased HP and decreased weight over the IO-360 this IO-340 engine sounds like a perfect match for what I am looking for. I love the idea of this engine until manufacturers start talking about 100LL being the only fuel this engine will run on. Why are these manufacturers sticking with requiring 100LL when the FAA has already laid plans for the elimination of this fuel in the near future?

I would like to ask this question as, frankly, I just don't get it. Can someone tell me why I can run a ground based engine at 9.5 to 1 or even 10 to 1 compressions using regular unleaded gasoline but an 8.5 to 1 or higher Lycone "Aviation" engine must have 100 octane low lead fuel? I have been running a six cylinder 260 hp with 9.5 to 1 compression cylinders in my Infinity I-30 on 87 octane regular gasoline for six years now with no visible ill effects. It is still a great running car that continually gets 26 mpg and has never shown any decrease in power when I press the gass pedal.

If anyone can educate me please give me some facts on this mystery of mechanical and chemical engineering that is obviously escaping my mind. I understand that everyone has their own biased opinions about everything under the sun but I would like to have some real "scientific" information to chew on. I truly fail to see why these two applications require different fuel. I also understand that higher compressions require higher octanes at a certain point. But, I was taught that you did not have to worry too much about octane problems, premature ignition, pinging, etc. until about the 10.5 to 1 ratio range on any hot rod engine I was around.

Please no bashing. I am not opposed to learning something the hard way but factual explanations sink into my thick skull much quicker and easier.

Thanks,
RVBYSDI
Steve

[mlw450802]

Originally Posted by RVbySDI

I would like to ask this question as, frankly, I just don't get it. Can someone tell me why I can run a ground based engine at 9.5 to 1 or even 10 to 1 compressions using regular unleaded gasoline but an 8.5 to 1 or higher Lycone "Aviation" engine must have 100 octane low lead fuel? I have been running a six cylinder 260 hp with 9.5 to 1 compression cylinders in my Infinity I-30 on 87 octane regular gasoline for six years now with no visible ill effects. It is still a great running car that continually gets 26 mpg and has never shown any decrease in power when I press the gass pedal.

If anyone can educate me please give me some facts on this mystery of mechanical and chemical engineering that is obviously escaping my mind. I understand that everyone has their own biased opinions about everything under the sun but I would like to have some real "scientific" information to chew on. I truly fail to see why these two applications require different fuel. I also understand that higher compressions require higher octanes at a certain point. But, I was taught that you did not have to worry too much about octane problems, premature ignition, pinging, etc. until about the 10.5 to 1 ratio range on any hot rod engine I was around.

Steve,
The propensity toward 'knock' is dependent on many factors some of which are listed here:
1.) Dwell time at pressure. Lower rpm engines will tend to knock at lower octane ratings (lugging your road engine up a hill in too high a gear at full throttle will knock more readily than climbing the same hill in a lower gear)
2.) Volume of fuel air mixture under pressure. Larger bore engines knock more readily than smaller bore engines.
3.) Combustion chamber shape. Hemispherical shaped heads will knock more readily than wedge shaped heads.
4.) Temperature of combustion chamber walls. Higher tends to encourage knock more than cooler.

There are others but you can readily see the huge difference between your road engine and the lycoming. In each of the 4 points mentioned, the poor lycoming is on the wrong side of the knock equation. Hence they need higher octane fuels to provide safe operating margins relative to knock.

-mike

[osxuser]

Engine efficency is somewhat based on compression ratio. Also once 100LL is phased out, it will be replace with another form of avgas that is lead-free, but still runs in these engines. Most likely it will be 91/96, but could be higher.

[mlw450802]

Originally Posted by osxuser

Engine efficency is somewhat based on compression ratio. Also once 100LL is phased out, it will be replace with another form of avgas that is lead-free, but still runs in these engines. Most likely it will be 91/96, but could be higher.

I agree with this but just want to add emphasis about engine thermal efficiency. It is strongly related to compression ratio and is the reason that BSFC for diesels is better that the BSFC for otto cycle engines.

-mike

[RVbySDI]

Thanks Mike for the information. Your explanations make a lot of sense but raise more questions.

I originally saw the notice for the introduction of this ECI IO-340 and was very intrigued by it. Then I saw that they were requiring that it run on 100LL. This immediatly got me to thinking down those lines I had thought about for many years now concerning the engine choices for airplanes. I am undecided on what I will eventually end up doing with my RV9A as far as engines go. I do want an engine that will provide the best performance related to HP, weight, cost of purchase, cost of operation, ease of maintenance. I want a relatively light engine that will produce sufficient HP to get me in and out of High Density Altitude airports. I want one that will not cost a fortune to purchase or to operate and be low maintenance (as most of the automobile engines that I have owned have been in the last 20 years).

I really think that we in aviation need to get beyond the 1930's-1950's era of engines and move forward with the rest of the world in terms of this engine design. Mike, you mention an interesting point when you talk about large bore v. small bore engines. If small bore engines are not so prone to running low octane fuel such as mogas tends to be, then what fundamental problems are there in placing smaller bore engines with appropriate configurations to produce adequate HP in our airplanes? Why are we locked into using these large bore 4 cylinder air cooled engines? Why not a smaller bore 6 cylinder, or 8 cylinder engine that would produce the same HP and stay relatively within the same weight requirements necessary? Why are air cooled engines "better" than water cooled for aviation (Has anyone noticed how many water cooled high performance airplanes were built during WWII that we revere even today)? What happened to the idea that water cooled engines would work well in the flight environment?

Is the answer more related to mechanical fundamentals such as power output capabilities, weight of the engine or complexity of the design? Or, is it more a result of some psychological attitude toward staying with something we think of as proven and safe (After all, don't we rationalize that we don't want to die behind some unproven technology)?

With respect to weight, could we not utilize new or existing metalurgic techniques to lighten the load (Why not aluminum blocks? Are there other heat tolerant strong metal alloys that would work?). Does that leave the complexity of such an engine as the show stopper? Some would argue that Eggenfelner's Subaru engines are more complex than the typical Lyclone installation, yet, so far, these engines seem to be performing quite well in the planes flying them. Why are they able to use a small boxer 2.5 L engine to produce the needed HP to fly our babies? Something seems to be working with them.

If the answer lies with a fear of death, injury or of the unknown then why are we doing this highly risky endeavor of flying anyway? After all, the rest of the world (especially since 9/11) thinks we are crazy for wanting to fly these "death traps", let alone build them ourselves and then fly in them (You only have to look at the insurance industry to see this. Has anyone looked at the small print on their life insurance policies?). Are we still so lock step entrenched in going down the road most traveled that we cringe at doing something different from what others are telling us is the prudent solution? We are convinced that the only solution to powering our birds is to stay with the "standard" aviation large bore Lyclone engines?

As of yet I do not know what I will do about choosing an engine. I like the Eggenfelner Subaru, if it weren't for the price. I like the IO-360 or this new IO-340 except for the specific fuel requirements that I may have to live with, oh yeah, and the price. I have considered the 290 as I think that would give adequate HP for my needs but there is the weight of the engine compared to the HP output issue with them and the lack of fuel injection (does anyone know of a fuel injected 290 out there?). I have not been opposed to the IO-320. However, comparing the weight, and the price, for the IO-320 to the IO-360 the difference in both is negligable so why not opt for the IO-360?

Hmmmmm, I am seeing a pattern in my perusal of this subject that is bringing up a non-technical question that I also seem to always be asking. Why do all of these engines cost 2 or 3 times more than an engine costs for any other internal combustion application?

Well I see that I am prattling on and on. I am sure the only individual interested in this dissertation is writing it so I will put an end to this. Should there be, however, anyone interested in commenting on my writings I would greatly welcome your opinions and/or thoughts.

Thanks,
RVBYSDI
Steve
RV9A slow build