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RV-14 Engine choice

In addition to the reciprocating assembly weighing more due to the stresses of higher compression ratio and torque, the combustion pressures are much higher than gas engines and this requires a much stronger cylinder head and cylinder walls to contain the pressures. Light duty Diesel engines such as the Mercedes and Volkswagen aluminum block engines weigh roughly twice what a similar sized gas engine weighs. Light industrial application diesels such as the Cummins 6B series weigh three to four times of a similar displacement size gas engine.
 
The Superior XP 400 makes 205 HP on auto gas. If you get the high compression version it is 215, but Avgas only.

I was just on the XP website and they say auto fuel is prohibited in the XP-400. They also only list a 415 HP version. If you are correct with auto gas currently at $2 a gallon and avgas still over $6 a gallon, sign me up for the XP-400. On the XP engine portion of the website they say XP engines are certified for auto gas and they don't make an exception for the XP-400 as the Home page does. Has anyone talked to Superior about this and have a definitive answer?
 
R409 Efii is the perfect Rv14 engine

Although my R409 is 45lbs lighter than 390 or 400 put two alternators instead of two backup batteries and you will have an engine that was designed to run as low as 90 octane fuel. Ethanol? NO problem new chamber in AX50 cylinder running at 17 degrees advance, will eat it up!

If you want to see how sweet this engine runs come to San Luis Obispo KSBP and we'll go fly my RV8 with R409 and 91 pump gas all you want.:D

Price is still a bit higher but hey, 230 hp and over 40lbs lighter than a Lycoming 390 or Superior 400 doesn't come for nothing! Price with Dual Efii fuel and ignition R409 $47,850.00.

@ $2.oo per gallon savings over 2400 hours @10 gph, just paid for the entire engine?..:cool: Did I mention 230hp!!!


2lifz47.jpg
 
Unfortunately IMHO mogas with 10% alcohol is what is going to be used to save GA. Any special fuel will not be cost effective in future,with various EPA and transportation issues. Tomcatrv4
 
How picky would the aiframe be in terms of where the weight goes?

I mean, if I put an R409 in, and want to make up some weight, does the position matter a whole lot?

Can you hang weights in strategic locations to make up enough weight for example? A second battery could give you 15-20 pounds, but obviously the mass isn't centered in the middle of your engine ...
 
R409, Angle 409, 91 auto fuel form local shell?

How picky would the aiframe be in terms of where the weight goes?

I mean, if I put an R409 in, and want to make up some weight, does the position matter a whole lot?

Can you hang weights in strategic locations to make up enough weight for example? A second battery could give you 15-20 pounds, but obviously the mass isn't centered in the middle of your engine ...

Yes it matters, but in my experience adding weight is far easier that removing. Until the first RV14 is completed we won't know exactly the flexibility we will have on the engine. My R409 weighs 285lbs compared to 331lbs for lycoming 390 we tested in the same configuration. (btw, the 390 only made 205hp on the same dyno we saw 234hp on my R409) I have only the rear 20 amp alternator so the first thing I would add would be the 40mp alternator up front. This 12 lbs right behind the prop maybe all that is needed to keep cg well forward. Build a nice cooling plenum instead of the rubber baffles and I cannot imagine you wouldn't be right there.

Keep in mind that if the RV14 MUST have a 330lb engine to make it work we can still kick Lycoming and Superiors arrrrssses with angle valve cylinders and the same beefed up 409 lower end. Yep, 230+hp:D, but lets start with 285lbs and all the benefits of AX50 technology first.

I hadn't actually flow the latest version of the AX50 cylinders and optimized pistons with 91 auto fuel so yesterday I climbed up to 6k and stabilized at 24' and 2400rpm on left tank full of 100ll and then switched over to right tank with 91 auto fuel from local Shell. Just as we saw on the dyno the only noticeable change was a slight increase in cht's, 6-8 degrees. This made sense since the lower octane fuel has more btu's. I increase the EFii mixture 3% and everything stabilized back to original temps.

I never lost one knot of airspeed………offer is still available to come fly this monster with me anytime until I sell her.:cool:
 
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How picky would the aiframe be in terms of where the weight goes?

I mean, if I put an R409 in, and want to make up some weight, does the position matter a whole lot?

Can you hang weights in strategic locations to make up enough weight for example? A second battery could give you 15-20 pounds, but obviously the mass isn't centered in the middle of your engine ...

It is nothing more than a basic weight & balance calculation.
If you reduce the arm distance by 1/2, you need to double the weight value

If you install an engine that is 35 lbs lighter than recommended, you have to make some level of adjustment if you want to have the same handling and baggage utility that the prototype RV-14 has.

If we assume that the engine weight reduction is centered on the engines CG (about 36 " fwd of the wing leading edge), then you would have to add about 70 lbs, centered on the firewall battery location (about 18 " fwd of the wing leading edge) to get the empty C.G. back to being similar to what it would be with the recommended engine.
 
Sounds like a four bladed metal CS prop is called for to help with the CG and to absorb all the extra power. ;)
 
Certainly sounds like less weight further forward would be easier than more weight further back ... not sure I'D want 70 pounds hanging on my firewall!

A heavier propeller, alternator(s), a front mounted governor maybe (I'm no expert I'm this stage, just guessing).

Opens up options at least ... But I'm not sure I could afford an R409 :p By thew time I get around to it, the R410 will be out anyways!
 
I'm not as brave as others and intend to conform to the prototype, but +$40K for an engine for a 2-seat experimental aircraft doesn't go down easy. I'm hoping that by the time I'm ready to purchase the engine Van's will have worked out a deal with Lycoming given the positive response to the RV-14 introduction.
 
I'm not as brave as others and intend to conform to the prototype, but +$40K for an engine for a 2-seat experimental aircraft doesn't go down easy. I'm hoping that by the time I'm ready to purchase the engine Van's will have worked out a deal with Lycoming given the positive response to the RV-14 introduction.

Lycoming is already selling the IO-390 for less than the angle valve IO-360. My new IO-390 arrived from Lycoming a few weeks ago. I ordered it through Vans during the Oshkosh show when they were offering a discounted price of $33,500. Still not cheap but it's new and its proven, and parts are available if you should need them.

You could always buy a used angle valve engine from a Mooney, Arrow, Seirra...

The ECI engines are really nice, but when you look at all the facts such as compression ratios vs HP output and price then the Lycoming starts to look better. The R series cylinders may be the way to go if you go with a parallel valve engine and money is not an issue.
 
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UL520is

I am in the final hours of my phase 1 testing on a non RV aircraft. I have the UL Power UL390is (160hp) and I am so impressed with the it I will likely never install anything else in my future builds.
If you need a 200hp, full fuel injected, fadec, electronic ignition, 100 lighter than the io360, runs on mo-gas with up to 15% ethanol (if desired) then check it out. The UL Power team will work with you to design you FWF kit (mount). I know they are currently puting it on an RV 4 and will be flying it soon.
 
Aerosport Power IO-382 'Wildcat'

I noticed on Aerosport Power's post about the 382 that they listed it as being suitable for the -14 so I asked them about weight, since it's a parallel valve engine. Here's the response from Gerard Poitras (posted with his permission):

"You are correct that the IO-382 is a stroked parallel valve 360 engine. It basically uses a Superior 400 crank in a 360 roller cam engine but needs slightly larger cylinders than the normal parallel valve 360.

The dimensions are slightly smaller than the 390 engine. The 382 dimensions are: 19.7? high x 33.7 inch wide x 32.7 inches deep (long). The weight of the 382 engine is 302 lbs (due to the counter weighted crankshaft) compared to the weight of the 390 Lycoming 308lbs. The horse power of the 382 is 202 HP as compared to the 210 HP for the 390 engine. This 382 engine also has a cold air sump as standard equipment.

The trump card is that the IO-382 is $33,500.00 USD base price (with Slick Mags). This price is $2,000.00 less expensive than Van?s best price on the Lycoming 390 (Van?s ?Sun N?Fun? sale price was $35,500). We also offer engine and prop bundle pricing ($1,000.00 off the price of the engine when bundled with a Whirlwind prop).

Bottom line is that you will not have to attach lead to your firewall but you will be able to put some of the saving either to your cockpit or back into your pocket."​

I wonder where the W&B would come out on a -14 if you used an engine a bit lighter than the 390 and also a lighter composite prop. Hopefully Vans has designed it so that the 390/Hartzell combo puts you near the forward end of the CG range. Scott do you know?

Thanks,
 
Is there any way to get a look at the weight and balance data from Van's prototype 14? It would sure help out in our planning for our builds and answer some of these questions.
 
Continental 6?

I wonder if the Continental IO-360 would be a good fit as an alternate engine with equivalent power. From my very cursory searches, it is a around 12 pounds lighter than the -390. At one point, the RV-10 was going to have an IO-360 option. I have no idea how much it costs to buy a core and overhaul one, but it might be worth looking into.
 
6 cylinders, I'd presume:

- the size of the engine probably not quite right when compared to the 390 ... would it be longer? All that tubing on top could also be a problem ... might have fun fitting that cowl ...
- that 6 cylinders cost a bunch more to overhaul.

Pretty common engine in general ... could be an interesting avenue to investigate ...

There's also the -AF for those worried about 100LL availability, though only 180 HP ...
 
I haven't seen specifics for the Continental -360, but I do know that IO-520s and such are a bit cheaper than the Lycoming counterparts.
 
If you already had a good Continental IO-360, and you felt like spending an extra year building the firewall forward it might be an attractive option for you.

On the other hand, the Continental IO-360 is the most expensive normally aspirated engine in aviation, they cost about $48k new and parts for them are also very expensive.
 
Lycoming and other engine options

Hi All
Now that Vans Oshkosh 2015 lycoming specials are online, link here
https://www.vansaircraft.com/pdf/VansSellSheet_Oshkosh.pdf

Vans built the rv-14 for the io-390 and thus they don't provide information for other engine choices.
But other then these forums how do first time builders obtain details that help us plan our power plant? By the way these forums are great, I'm not taking a shot at anyone.
I know the RV-14 was a new model from vans, I am progressing well with my kits, and due to dollar/currency pressures i may need to buy our engine soon or lock the dollars in US$.

I have a lot of experience with automotive engines and I fly certified aircraft. Id like to go with electronic ignition but id have to retrofit if I buy the IO-390, sigh.
I know Most LAME's prefer magnetos but mechanics said the same about automotive engines 20 years ago. Ie mechanics would say "you wont get spares in the middle of no-were, best stick with points and don't buy electronic ignition..."
I also find information provided on elec ignition misleading as a failure with one vendors ignition system seems to be used to bunch all ignition systems together. The P-Mags seem to present a great safe alternative, again the other ignition products also look great.

I may purchase an io-390 engine via the Vans special but I am concerned Vans don't provide the engine with "options" such as alternators, belts, pulleys or an exhaust. Id also prefer these options are pre-fitted to the engine but I'm not sure this is possible before crating for delivery?

Vans do not yet also offer the firewall forward kits, again making planning hard.
Weight and Balance data is also sadly missing, again making informed choices difficult.

I have been sent some great information from aerosport on the wildcat 382.
But id like to hear from other RV-14 builders please, who may be more advanced on fitting a IO-390, wildcat 382 or a titan? What is the general opinion regarding RV-14 engine options for weight and balance, baffles, exhaust and cowl clearances please?
I have not seen any examples of RV-14 engines fitted other then the RV-14 tail dragger with the IO-360.
 
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Rocky,

As a fellow Aussie I feel your pain. I suspect that many RV14 builders will be looking at the IO-382 or IO-375 to save some weight. At $35k the IO-390 is probably not that much more expensive than the 382. The big drawback to the 390 for me is the cost of replacement cylinders (and possibly other specific parts) if you ever need them.

The IO-375 can be built from a core by changing the crankshaft, cam and pistons so you could save some money there.

I don't think having the accessories installed is an issue as you would only need to remove them to fit the engine - and they will probably not come installed at all.

I have a set of PMAGS and love them, but it is true that any of this stuff that needs to go back to the US for repairs will ground you for 3-6 weeks, so worth considering.

I'll let someone else comment on W&B if they can. It might be too early. With other models it is possible to get the engine mount changed to support moving the CG around. I.e. the O-320 mounts are longer than the O-360 for the RV7.
 
Although I'm not building yet, I've been struggling with the same questions ... and the same US dollar exchange issue!

Whatever options they do not give you with the engine, will be in the firewall-forward kit, of that I feel fairly confident. Since the engine I believe gets basically shipped from Lycoming directly, that's the way they have to do it.

You can probably find a shop that will take that Lycoming and parts of the FFW kit and further prepare it for you should you so wish ... doesn't *have* to be a clone for you to get that service.

The 382 + 200RV combo and the rebate that you get with it is certainly a very appealing option in theory. The different dimensions on the engine from the 390 could cause some experimenting to be required ... though van's now has experience putting an angle-vale 360 on a -14 ... how different are the 382 from the angle-valve 360 in terms of size and fit? (Obviously the cylinder head and rocker covers are different, so that will affect baffling).

Otherwise, you can be the experimenter, or wait to learn from someone else's experiments!

'tis frustrating, but the cost to pay of launching a build into a new model like this, and one reason I may yet go back to a -9A ...
 
Have you considered the Superior XP 400? It is angle valve engine very similar to the IO 390 and Superior will install the P Mags during the build.

Don
 
Have you considered the Superior XP 400? It is angle valve engine very similar to the IO 390 and Superior will install the P Mags during the build.

Don

Ly-Con did the same for me, added the PMags and other enhancements for performance and economy on a brand new Lycoming IO-390. I spoke to all of the major players last year at Oshkosh and they had the best product for the price and a great reputation. Recommend them strongly. I went with the Lycoming engine, so hopefully Van's baffles will match up exactly.
 
Fitting a 382 wildcat

Thanks guys, you have provided some great engine options.
I am keen to see pictures, has anyone fitted the Wildcat 382 (or any engine for that matter) on an RV-14 yet? I know its early days on finishing kits but I also know how fast some of you are a building :).
I've seen the RV-14 tail dragger but no detailed pictures of the IO-360 engine fit out.

Also I know the 382 Wildcat is a very simular size to the IO-390, is anyone able to provide details on how well the Vans supplied baffles would fit the 382 wildcat?
Anyone see any other issues I should consider before I stray from the IO-390?
 
Even though the HP ratings and weight are very similar, the IO-382 is a parallel valve engine. The -14 firewall forward kit was designed for an angle valve engine. You would need to fabricate or modify the baffeling at a bare minimum.

What props are apporved for use on the IO-382? Is it approved for Mogas? What is the torque rating at typical cruise RPM? What are the advantages vs the IO-390?
 
"What props are apporved for use on the IO-382?"

I don't know about approved, but I believe ASP is promoting a package with the Whirlwind 200RV with the 1000$ combo discount, much like Van's does with its Lycoming and propeller combo purchases.

"What are the advantages vs the IO-390?"

cheaper to purchase and, more importantly, to overhaul, most likely. IO-390 cylinders are very expensive as I recall. Also ASP will offer options on the engine you would not normally get by buying a 390 from Van'S such as having it delivered with electronic ignition and other customizations.

As a side note, I was reading that the IO-390-A3B6 has limits on timing that could make it less EI friendly (though I'm no expert, I could be wrong, but that'S the way I read it) ... I think the timing issue was being talked about on a Mooney forum.
 
Here it is, read through some of this if you're curious about the timing issue ... maybe someone with better knowledge than I could clarify whether that means issues with EI ...

http://mooneyspace.com/topic/5426-a3b6d-vs-a3b6/

Reading through the thread on the Mooney forum, I'm pretty sure they are talking about the IO-360 variants. The IO-390 is mentioned, but the subject of the thread is the is the IO-360-A3B6D vs A3B6. I know there are guys running electronic ignition on the 390 on various homebuilts (RVs, Glastars, etc) and haven't heard about any problems. Regardless of what engine I put in my -14A, it will definitely have dual electronic ignition. That's what I have on my RV-8A and will never go back to mags. I consistently see at least 1 gph lower fuel burn than magneto-equipped RVs, which translates into longer range, plus easier starting and less maintenance.
 
Ah, you may be right, sorry about that ... I know there's a 390 STC for some Mooneys, hence the confusion ...
 
"What props are apporved for use on the IO-382?"

I don't know about approved, but I believe ASP is promoting a package with the Whirlwind 200RV with the 1000$ combo discount, much like Van's does with its Lycoming and propeller combo purchases.

"What are the advantages vs the IO-390?"

cheaper to purchase and, more importantly, to overhaul, most likely. IO-390 cylinders are very expensive as I recall. Also ASP will offer options on the engine you would not normally get by buying a 390 from Van'S such as having it delivered with electronic ignition and other customizations.

As a side note, I was reading that the IO-390-A3B6 has limits on timing that could make it less EI friendly (though I'm no expert, I could be wrong, but that'S the way I read it) ... I think the timing issue was being talked about on a Mooney forum.

So the only "real advantage" so far is the IO-382 currently costs $2000 less than the IO-390. All other "advantages" are speculative without facts or data. Some of the stroker engines are only approved for use with a composite prop. A composite constant speed prop usually costs considerably more than a blended airfoil Hartzell, which may erode the cost "savings" of buying the IO-382. Furthermore $2000.00 cost difference over the cost of the build is minor, and may end up costing more by the time you get the engine installed due to modifications involved. Then there is the fact that angle valve engine cylinders run much cooler than parallel valve cylinders, will the IO-382 have cooling issues that take months to sort out? Then there are unknowns such as detonation margins and torque curves for the IO-382.

There is always the option of buying a good serviceable angle valve IO-360 and installing it. Vans designed the airplane around an angle valve engine and there are lots of used angle valve engines to be had.
 
"All other "advantages" are speculative without facts or data."

There is nothing speculative about saying that ASP will deliver you an engine with your choice of EI, flow matched cylinders, the colour of your choice, whatever options you might choose, etc.

Whether or not you value these things is of course entirely up to you, but those are some advantages that someone, somewhere may value.

It is true we don't have all the data on the engine, but then, I never speculated on it either.

It is true that after the headaches of applying modifications to fit the 382 in a -14(A), you may be no further ahead at all, at least the way things look now. Maybe someone will develop and sell a baffling kit for the -14, for example, and make the cost more acceptable? Who knows ...

Options are nice, that is all.

That being said, I just saw a few 200 hp IO-360's for sale on trade-a-plane in the 25K range, so it is nice to have that option as well!
 
Cost is not the only factor in the decision process, Lycoming products have proven very robust.
As said by kamikaze another appeal for the 382 wildcat includes the supply of a complete engine with 1 or 2 alternators and P-Mags fitted. Plus options such as cold air induction sump and inverted oil again pre-fitted.

The problem with the Aerosport recommended Whirlwind 74 RV composite prop is that asking locally I found the composite would be hard to maintain and may require shipping it out of the state (Western Australia) for inspections.
I have requested information on the supply of a Hartzell blended airfoil prop and what limits may apply for the 382 wildcat. This is a key component in the selection process.

Also does anyone know the limits for the 74" Hartzell blended airfoil prop when fitted on the Lycoming IO-390?
Vans has published a paper http://www.vansaircraft.com/pdf/Hartzell_c2yr.pdf on test results and some limits for the 72/74" Hartzell blended airfoil but it only mentions the IO-360, not the IO-390.
But here http://www.vansairforce.com/community/archive/index.php?t-9843.html it is stated "It is also approved on the IO-390-X engine with NO PLACARDS (all -390s must have dampers according to Lycoming)." It being the 72/74" Hartzell "BA" prop.
 
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"All other "advantages" are speculative without facts or data."

There is nothing speculative about saying that ASP will deliver you an engine with your choice of EI, flow matched cylinders, the colour of your choice, whatever options you might choose, etc.

Whether or not you value these things is of course entirely up to you, but those are some advantages that someone, somewhere may value.

It is true we don't have all the data on the engine, but then, I never speculated on it either.

It is true that after the headaches of applying modifications to fit the 382 in a -14(A), you may be no further ahead at all, at least the way things look now. Maybe someone will develop and sell a baffling kit for the -14, for example, and make the cost more acceptable? Who knows ...

Options are nice, that is all.

That being said, I just saw a few 200 hp IO-360's for sale on trade-a-plane in the 25K range, so it is nice to have that option as well!

Stoney bought a factory new IO-390 through Lycon and they gave him credit for the mags and installed dual Pmags. There are many other Lycoming dealers who sell new Lycoming engines other than Vans, some of these dealers are engine shops and they can do any mods that you want done to you're new engine. The cheapest place to buy a new Lycoming is though A.E.R.O.
 
Ly-Con

Stoney bought a factory new IO-390 through Lycon and they gave him credit for the mags and installed dual Pmags. There are many other Lycoming dealers who sell new Lycoming engines other than Vans, some of these dealers are engine shops and they can do any mods that you want done to you're new engine. The cheapest place to buy a new Lycoming is though A.E.R.O.

When I was looking for an engine last year at Oshkosh, I checked with all major players. Ly-Con did have the best price at that time. I know they had some good pricing from Lycoming, as Van's did. Base price was $31,000. Then I switched to PMags. If I would have stopped there, it would have come in less than Van's price. However, for better performance and fuel economy, per their recommendations I did a few other mods. They were fair with me and price wise, they had the best price with mods as well. They connected everything and ran it two different times on their Dyno machines. I'm no engine expert, I asked people that know better than me and I am happy with the choices I made. Now if I can just get an engine mount to get it up off the garage floor...
 
Yes Stoney has been extremely helpful and the specs for his IO-390 engine are very impressive.
I have also asked for a quote from lycon (last week) on a simular IO-390 setup to Stoney's, but no response yet.
 
14 Engine Choice

Since the taildragger version has been flying there has been some discussion of the possibility that the IO-360 taildragger version is faster that the IO-390 tri-gear.
 
When I was looking for an engine last year at Oshkosh, I checked with all major players. Ly-Con did have the best price at that time. I know they had some good pricing from Lycoming, as Van's did. Base price was $31,000. Then I switched to PMags. If I would have stopped there, it would have come in less than Van's price. However, for better performance and fuel economy, per their recommendations I did a few other mods. They were fair with me and price wise, they had the best price with mods as well. They connected everything and ran it two different times on their Dyno machines. I'm no engine expert, I asked people that know better than me and I am happy with the choices I made. Now if I can just get an engine mount to get it up off the garage floor...

Did they tune the P-mags to your engine? Meaning, I hope they didn't leave the jumper out and did some pulls on your engine.

You can adjust your P-mags to match the recommended timing of your engine with the EICAD program from Emag or with our EICommander.

BTW, Barrett now has an EICommander and as soon as they wire it up, they will offer custom P-mag tuning.
 
Great discussions...very helpful. I'm sure there is no such thing as a "better" engine for all builders, just a "better" engine for individuals who may have different priorities. I will probably not use the IO-390 unless it can be built to run on MOGAS. The XP-400 can be built to run on MOGAS (less horsepower), So can the ECi 370. However, the IO-390 is the gold standard for the RV-14 that everything will be measured against (IMHO).
 
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Since the taildragger version has been flying there has been some discussion of the possibility that the IO-360 taildragger version is faster that the IO-390 tri-gear.

This is very high on Rian's (chief engineer at Van's) list of things to determine - I'd expect numbers fairly soon. The RV-14A was down for scheduled post-Oshkosh maintenance today - I was flying the -14, and hoped to do a head to head test now that it has all its fairings, but it will have to wait until the -14A is back together - then we'll know for certain!

The -14 gave us very respectable performance in cruise - typical RV numbers.

Paul
 
Great discussions...very helpful. I'm sure there is no such thing as a "better" engine for all builders, just a "better" engine for individuals who may have different priorities. I will probably not use the IO-390 unless it can be built to run on MOGAS. The XP-400 can be built to run on MOGAS (less horsepower), So can the ECi 370. However, the IO-390 is the gold standard for the RV-14 that everything will be measured against (IMHO).

I did a fair bit of research before deciding on the Lycoming IO-390. The Superior XP-400 currently IS NOT approved for Mogas. I did find some old information from Superior released in 2006 that stated they would be making a 8.5:1 compression version that would be rated at 210 HP and approved for Mogas, but it looks like that engine variant was never produced.

The other "wish list" item that I had for an engine was the ability to run Mogas. Premium ethanol free Mogas really does not save you much money where I am located since ALL of our fuel around here is E10 unless it is a specialty "Marine/Boat Gas" fuel, and it is very expensive and often only 89 or 91 octane. The RV-14 is designed for an angle valve engine and it would be a major change to instal a parallel valve engine. There are no angle valve engines currently being produced that have compression ratios low enough to run Mogas. When Lycoming announced that they were going to certify the IO-390 a few years ago, they said they would produce a low compression version (195 HP) that would be Mogas compatable, this engine never came to be. I called Lycoming and spoke to one of the powerplant engineers about this. He told me that testing showed that the comustion chambers in the angle valve cylinders are more efficient than a parallel valve cylinder head, but the angle valve cylinder head has less margin for detonation for a given compression ratio than a parallel valve cylinder. The lower compression, lower HP IO-390 version was never produced because it only produced about 190 HP and Lycoming felt that due to power to weight ratio and cost that it would be marketable since there are many stroker/high compression experimental parallel valve engines available already in this power range (although they cannot use Mogas either).

I also had a conversation with the engineer regarding detonation margins. He told me that all Lycoming engines, including the experimental versions (excluding custom racing/aerobatic engines) are tested and built with compression ratios that allow them to meet certified engine detonation margins. I already knew this and asked his opinion on some of the aftermarket hot rod engine detonation margins, specifically the ECI and Superior 400/409 engines. He stated that because the 400/409 series of engines are stroker engines that use a standard bore cylinder with a longer stroke crank, they would have even less detonation margin. This is the reason why lycoming went to the larger bore cylinders on the IO-390 instead of higher compression ratio or longer stroke to get the extra HP and torque.

The last question I had for the Lycoming engineer was the future availability of lower compression pistons for my IO-390 in the event that Avgas may not available in the future. He said that custom pistons could be easily made, and that the pistons Lycoming made and tested for the Mogas compatable engine could be easily put into production. He said that he knows of some IO-360 angle valve engines being run on Mogas that have not had issues and that the IO-390 has better detonation margins, but he could not oficially reccomend running Mogas with stock compression pistons. I am not too worried about 100LL going away soon, but I wanted the factory to have options.

I bought the Lycoming engine for several reasons. #1 cost, the Lycoming was about $14,000 less than the ECI Titan angle valve IOX-409. ECI/Titan does not add the cost of the ignition system to the base price, Lycoming does so look at the pricing closely. The IO-390 also cost slightly less than the Superior XP-400. #2 ECI/Titan claims 230 HP on thier 409 engine, this is at 10.5:1 which is pushing the limits of an air cooled engine already. Same engine with 8.5:1 (which ECI says can run Mogas...Lycoming IO-390 is 8.9:1) makes "about 200 HP". The Superior XP-400 claims 215 at 8.9:1 compression which is the same compression ratio as the IO-390, and the extra 5 HP is not a significant advantage, and may be due to the OPTIONAL cold air sump.#3 I
Hnestly do not believe the ECI/Titan with 10.5:1 will make TBO on the top end, much less the possible cooling issues that come with such high compression. If you buy the ECI/titan 409 with 8.5:1 compression you are back to angle valve IO-360 power for ALOT more money. #4 Lycoming is still around and will be for a long time to come. Superior and ECI/Titan engines have been sold or gone out of bussiness in recent years. With a Lycoming engine you will be able to obtain parts years from now. Will you be able to get parts for a Titan 409 or XP-400 in a few years?
 
I too have been challenged by the lack of engine options for the RV-14A. I too want the flexibility to use mogas. After doing some comparison shopping at Oshkosh, I pulled the trigger on the XP-400. The cylinders are the same dimensions as the IO-390 so the FF kit should work with the possible exception of the exhaust as the cold air sump is standard on the XP-400 and not the IO-390. The price was competitive with Van's special pricing. I bought the engine without fuel or electrical systems (which you can't do from Van's) so I can install the Protek Performance EFii system. According to Robert Paisley 9.0 or less compression ratio engines can operate safely on mogas with the EFii system. I went to Oshkosh with the intent of buying the IO-390 and a Hartzel prop to get the best pricing, but ended up with the XP-400. I intend to use the Whirlwind 74RV due to all the disclaimers and RPM "avoid" areas with the Hartzel. The package should be about 20 pounds lighter and will shift c.g. a little aft. I'm thinking it will help offset the weight of the nose wheel.
 
I too have been challenged by the lack of engine options for the RV-14A. I too want the flexibility to use mogas. After doing some comparison shopping at Oshkosh, I pulled the trigger on the XP-400. The cylinders are the same dimensions as the IO-390 so the FF kit should work with the possible exception of the exhaust as the cold air sump is standard on the XP-400 and not the IO-390. The price was competitive with Van's special pricing. I bought the engine without fuel or electrical systems (which you can't do from Van's) so I can install the Protek Performance EFii system. According to Robert Paisley 9.0 or less compression ratio engines can operate safely on mogas with the EFii system. I went to Oshkosh with the intent of buying the IO-390 and a Hartzel prop to get the best pricing, but ended up with the XP-400. I intend to use the Whirlwind 74RV due to all the disclaimers and RPM "avoid" areas with the Hartzel. The package should be about 20 pounds lighter and will shift c.g. a little aft. I'm thinking it will help offset the weight of the nose wheel.

Sounds like a great set-up and should make for an efficient and smooth running machine!
 
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