Upgrading Rotax 912UL (80HP) to Rotax 914UL (115HP), experience anyone?

[Ultra long hauler]

Dear all,

I am a Rotax 912UL owner, (80HP) currently upgrading to a bigger aircraft, and therefore I have the 912ULS with 100 horses version in mind.

However, I will have to sell my 80HP Rotax to be able to invest the money into my new machine……….and selling it proves to be rather hard to do!

So somebody called my attention to this site:

Bully Hawk Aero Performance, Rotax Performance and Upgrade Kits (http://www.bullyhawk.com/)

It is about upgrading from 912UL to 914UL, in other words from 80HP to 115HP.

Naturally, they talk about it like it´s the 8th miracle of the world, but I call upon you, experienced aviators; those who know all the tricks in the book and more: "is this really as good as it sounds, considering maintenance costs, reliability, performance & TBO figures"?

For your reference, my Rotax has about a 1000 hours on.


Best regards,


###Ultra Long Hauler###

[Ultra long hauler]

Mmmm, zero reactions……………….


That kind of answers my questions…………….nobody with any experience with this issue!!

Smells like a No No…………


###Ultra Long Hauler###

[BackPacker]

You might want to try the LAA. There's a lot of folks there with Rotax experience.

Also, I seem to recall that Skydrive is the UK dealer with a lot of experience in maintaining Rotax engines.

[Jan Olieslagers]

I can't help wondering what kind of money you can still hope to get from your current 912 with a thousand hours on it. Isn't its full life span limited to 1500 hours?
Sorry to push back on your nice plans...

[patowalker]

Recent Rotaxes 912s have a TBO (time between overhaul) of 1500 hours, not a life span of 1500 hours.

I don't think anybody in this country would spend $8500 to upgrade an old Rotax 912 in order to sell it.

[Flyingmac]

Try here.
Light Aircraft Association :: View Forum - Aircraft Construction & Maintenance (http://www.lightaircraftassociation.co.uk/bbs/viewforum.php?f=4&sid=5e0409e4e01dc21f03556ae0ca26e398)

[Rod1]

“Recent Rotaxes 912s have a TBO (time between overhaul) of 1500 hours”

Nope, it is 2000 hours (TBO) with many passing 3000 on condition.

Rod1

[MichaelJP59]

Not had a conversion, but I have a 914 turbo in my Europa and am really happy with it, nice to have that extra boost for a short take off run. Though of course it does end up heavier than the 912S 100hp.

This conversion kit seems like a reasonable idea, but they do recommend having a full condition inspection before adding the turbo, and the $8500 is just for the kit, installation/inspection is another $2500 + parts. I guess also the warranty would also just apply to the kit parts.

If you can't sell the 912 I guess it would seem reasonable?

[Ultra long hauler]

You might want to try the LAA. There's a lot of folks there with Rotax experience.

Also, I seem to recall that Skydrive is the UK dealer with a lot of experience in maintaining Rotax engines.
Thanks!


Try here.
Light Aircraft Association :: View Forum - Aircraft Construction & Maintenance (http://www.lightaircraftassociation.co.uk/bbs/viewforum.php?f=4&sid=5e0409e4e01dc21f03556ae0ca26e398)

Good link, I didn´t know that forum at all.

I can't help wondering what kind of money you can still hope to get from your current 912 with a thousand hours on it. Isn't its full life span limited to 1500 hours?
Sorry to push back on your nice plans...
No worries………it is a pain though, having to sell this aircraft first.


“Recent Rotaxes 912s have a TBO (time between overhaul) of 1500 hours”

Nope, it is 2000 hours (TBO) with many passing 3000 on condition.
Rod1

That is correct, even the new 914UL get a TBO of 2000 from Rotax these days.

Not had a conversion, but I have a 914 turbo in my Europa and am really happy with it, nice to have that extra boost for a short take off run. Though of course it does end up heavier than the 912S 100hp.

This conversion kit seems like a reasonable idea, but they do recommend having a full condition inspection before adding the turbo, and the $8500 is just for the kit, installation/inspection is another $2500 + parts. I guess also the warranty would also just apply to the kit parts.

If you can't sell the 912 I guess it would seem reasonable?

I guess, thinking about it………my Rotax engineer is my friend and he worked my engine from almost zero hours so if I would travel to the States to pick it up, I´d have the whole kit installed locally for a bit more than $10.000,-.
My heart still tells me to stick to the original plan though………..which was sell the plane, and buy a nice, "0 kilometers" conventionally breathing 912ULS.
Granted, my plan is to fly high up in the Andes but talking to owners of both 912ULS and 914UL…………the advantage is on the 912ULS`s side, I´m afraid.

The 914UL consumes 40% more fuel (!!!) and the power difference at sea level is negligible. In the mountains the 914UL wins, but I have seen several club members that make it up to 6000 meters with the 100 HP Rotax 912ULS………..so why wouldn´t I? Obviously, these trips would have to be planned on good weather days…….but the same goes for a 914UL, and as I said; my non-turbo´d friends take off from airstrips at 3.000 meters with their 912ULS.

The extra consumption every day, every flight; the extra maintenance $$…… I don´t know--> I´m torn.

I´m enjoying this thread though………..any more opinions out there?

###Ultra Long Hauler###

[BackPacker]

It hasn't been mentioned at all, but do you intend to fit a VP/CS prop?

From what I've heard installing an airmaster CS electric prop (or any other for that matter) makes a huge difference, particularly in take-off performance.

And it might be a retrofit that's far easier to fit on a 912UL than the 914 conversion kit.

[MichaelJP59]

The 914UL consumes 40% more fuel (!!!)

I think that's only when you're in the turbo range though isn't it? (I think it's called take-off performance in the manual). Otherwise 914 and 912S have similar fuel consumption. Someone more knowledgeable than me would know the details.

[patowalker]

Nope, it is 2000 hours (TBO) with many passing 3000 on condition.

Oops! Better read the Rotax literature while waiting for the Don Francisco to sign my permiso.

[Catchacloud]

Hi,

I currently run 3 aircraft with rotax 912's in various guises. I have the 100 hp version in my mto sport gyro which gives bundles of power and fairly good fuel consumption. Some of my friends run the 914 and I have to say the turbo is not good. I think it's an old garret they have bolted on. If I was in your position I would look at the 100 hp and forget about any add on turbo kits. KISS - keep it simple stupid. On another note they are superb engines all be it expensive to buy, well certainly in the Uk.

[ChrisVJ]

We have a couple of guys who have converted in our group. The only one I can remember was a 912UL converted to 100hp. (Non turbo) I think that turned out to be not terribly satisfactory.

Most of the guys who have 914s seem happy with them and I haven't heard too much about serious turbo problems.

[Ultra long hauler]

It hasn't been mentioned at all, but do you intend to fit a VP/CS prop?

Ivoprop, Medium…………Inflight Adjustable.

http://www.ivoprop.com/inflightmediummodel.htm

I think that's only when you're in the turbo range though isn't it? (I think it's called take-off performance in the manual). Otherwise 914 and 912S have similar fuel consumption. Someone more knowledgeable than me would know the details.

Well, I don´t know. That is one of my major considerations!
I can´t find any good info on that anywhere……….
Would I be able to save a lot of fuel by running it with at, for argument´s sake; 90%??

Hi,
Some of my friends run the 914 and I have to say the turbo is not good. I think it's an old garret they have bolted on. If I was in your position I would look at the 100 hp and forget about any add on turbo kits. KISS - keep it simple stupid.

Thanks, but I believe the kit I was referring to is with original Rotax parts.
Crucially, the Turbo Computer is Rotax´s………
But yeah, I see your point…………I was hoping somebody had experience with this particular kit.


###Ultra Long Hauler###

[BackPacker]

I can´t find any good info on that anywhere……….

I happen to have an old Europa brochure here with engine info on both the 912ULS and 914UL (but not the 912UL unfortunately)

Between the 912ULS and 914UL the performance figures are remarkable similar with one main exception: the "take off" curve from the 914 is higher in every respect: power, torque and fuel consumption. Obviously that's the time when the turbo is most active.

But other than that the fuel consumption for a given HP seems almost identical between the two. The graphs in the brochure aren't all that good but it looks like the 914UL is even using slightly less fuel (<5% difference) to produce a given power than the 912ULS.

I was looking at the Rotax site and it seems that you can get the original datasheets directly from them. Doesn't that help?

Aircraft - DOCUMENTATION (http://www.rotax-aircraft-engines.com/desktopdefault.aspx/tabid-49)

[MichaelJP59]

On my Europa there is the normal throttle range from 0-100%, then you have to shift the throttle lever sideways through a detent to engage the turbo and use takeoff power (115%). Advice is not to use part of this 100-115% range, you either use full take-off power or just use the normal range.

I normally cruise at 75% 5000rpm for 18-20lph. More patient people cruise at lower power settings.

Seems to be the general consensus is if you are buying new then the 912S is fine for most uses and no point paying extra for the turbo. However the original question was what can be done to uprate the 80hp 912 - can it just be upgraded to 912S spec?

[Ultra long hauler]

Between the 912ULS and 914UL the performance figures are remarkable similar with one main exception: the "take off" curve from the 914 is higher in every respect: power, torque and fuel consumption. Obviously that's the time when the turbo is most active.

But other than that the fuel consumption for a given HP seems almost identical between the two. The graphs in the brochure aren't all that good but it looks like the 914UL is even using slightly less fuel (<5% difference) to produce a given power than the 912ULS.

I was looking at the Rotax site and it seems that you can get the original datasheets directly from them. Doesn't that help?


Thanks for that link…………I don´t seem to be able to get the info I need though. I kind of hope you´re right………….
But others say that on average (normal use--> warm up, take off, cruise and landing), the consumption would be 33% higher than the 912ULS.


Seems to be the general consensus is if you are buying new then the 912S is fine for most uses and no point paying extra for the turbo. However the original question was what can be done to uprate the 80hp 912 - can it just be upgraded to 912S spec?

The way I understand it, no. The 912 UL (80 HP)and the 914 UL (115HP) are the basically the same engines………same block, same pistons, same everything.
The Turbo is the only difference, plus the exhausts and carburetors--> but internally……….same same.

The Rotax 912ULS however………the 100 HP Non-Turbo, is different though.
Different pistons, different block etc, compared to the 912 UL & 914UL, but others may be able to explain better.

Saludos,

###Ultra Long Hauler###

[mmbengt]

On Aircraft - Home (http://www.rotax-aircraft-engines.com) you have all the information you need about fuel consumption etc for the 912 ULS and 914.

I have a 914 in my Dyn'Aéro MCR-M and I see typically exactly the same fuel consumption as with the 912 ULS except for the few minutes during take off where I use the turbo. I have not yet investigated the high altitude performance though.

Best regards
/Bengt

[Ultra long hauler]

On Aircraft - Home (http://www.rotax-aircraft-engines.com) you have all the information you need about fuel consumption etc for the 912 ULS and 914.

I have a 914 in my Dyn'Aéro MCR-M and I see typically exactly the same fuel consumption as with the 912 ULS except for the few minutes during take off where I use the turbo. I have not yet investigated the high altitude performance though.

Best regards
/Bengt

Thanks, nice low winger--> I googled her.
I compared the 912ULS & 914UL´s fuel consumption graphics……..and at 5500RPM they are as good as identical.
After the 5500, the 914´s consumption sky-rockets, for obvious reasons.

Yesterday I got feedback from a local friend of mine though that the overall consumption of a 914 at the club is 33% more than the 912ULS, but flying faster; the difference is realistically 28%, approximately…………

Still quite a lot………..and this goes against the Rotax graphics, assuming you cruise under 5500RPM; only using the Turbo for take off´s or high altitude action.

###Ultra Long Hauler###

[MichaelJP59]

Yesterday I got feedback from a local friend of mine though that the overall consumption of a 914 at the club is 33% more than the 912ULS, but flying faster; the difference is realistically 28%, approximately…………


Unless your local friend uses the turbo a lot more than most people, I fail to see how he can use 33% more fuel. Unless he's always in the circuit, of course:)

[Ultra long hauler]

Unless your local friend uses the turbo a lot more than most people, I fail to see how he can use 33% more fuel. Unless he's always in the circuit, of course:)

I see what you mean.
Let me interrogate him tomorrow and I'll report back.

Regards,

###Ultra Long Hauler###

[Ultra long hauler]

Folks,

for those who are interested:

After running the numbers and the characteristics of both engines (as discussed on here) through my head a few dozen times, and after talking to the appropriate people; I finally have decided to go for the 115HP 914 Turbo conversion kit. (ORIGINAL Rotax Turbo & computer).
I will keep my 80HP Rotax 912 engine which hasn´t suffered any incidents yet, and which seem to run fine! No excessive oil consumption, nothing.

Let´s hope that kit gives me the same performance as it does to the other 914 owners.

KISS - keep it simple stupid.
True!! Very true!!
But the killer argument for me was that where we are; we do actually fly ridiculously high at times. There´s airports at 3.000 meters here, and a few other "obstacles" that go over 6000 meters:

http://dl.dropbox.com/u/3820316/Screenshot%202010-12-11%20om%2018.53.36%20kopie.jpg

And although the Rotax turbo is not designed to maintain the exact 115HP at these altitudes, it will make a difference compared to the conventionally breathing engine!

Unless your local friend uses the turbo a lot more than most people, I fail to see how he can use 33% more fuel. Unless he's always in the circuit, of course:)

Okay, after some more research it turns out that the Turbo´s of the Lycoming´s / Continental´s are primarily there to give you your 100% power at higher altitudes. Correct?
Rotax´s Turbo however makes concessions; it both gives you more power at higher altitude (albeit less than 100%) and it adds a lot of grunt at lower level--> making the handling more "sexy" in the lowlands--> which is where I´m based. The Rotax turbo "works" at any time……….which explains the 25% more consumption, or somewhere around there.

I guess for a lot of UK / US guys on here, the 100HP 912ULS is just fine.
But flying here, I think I pay the extra fuel burn penalty, but enjoy the sexy handling at the beach and more importantly: the extra power when I "hit" the Andes.

Cheers,

###Ultra Long Hauler###

[stormfisher]

Hi Folks,
while we,re out there with Rotax,s my 80 hp 912 has started to use a lot more fuel, used to burn approx 12 to 14 lph at 4600 rpm and after careful check its using 18lph . Have checked the chock is full off after starting also checked idle needle setting, carbie diaphragms ete, and of course no leaks any ideas ?
Cheers

[stormfisher]

Hi Again,
Re the 914 turbo,s I have just delivered four new aircraft to Outback stations here in Oz they all ran well and at 5000 rpm at say 4000/5000 ft and between 25/ 30 deg OAT theY all returned approx 18 lph
Would post a pic but don't know how to do that one my iPad
I,m an old 18000hrs steam driven jock!

[cockney steve]

Please bear the following in mind....I AM NOT AN AVIATOR.


ISTR Rotax engines having a "needle and slide" (Bing?) type carburettor.
Wear in the slide/body can cause air -leaks and allow the needle to fret on the jet...needle -flutter causes uneven mixture, which would probably mean a wider throttle-opening for the same power-output.....(if you've got good CHT monitoring and lean-out, , that eliminates that suggestion.

The english SU carb. attempted to meet emissions legislation by having a main-jet mounted on a bimetal strip, (fuel-temp compensation)combined with a wax-capsule at the jet-base ( ambient air compensation) and a needle spring- biased against the jet (eliminating flutter) Of course, it worked fine for a short while , until the needle sawed the jet-orifice oval and a corresponding wear-mark down it's length.....fuel consumption increased dramatically.
the giveaway, was an extremely rich tickover, with virtually normal full throttle AND LOAD operation. or, if you weakened the idle mix to a satisfactory state, thething would starve and fluff or die as you opened the throttle. new needle and jet was a cure.....similar situation with AMAL motorbike carbs.
HTH.