FlyingMonkey Posted June 7, 2022 Report Share Posted June 7, 2022 Hey all...my engine is juuuust about to hit 1000hrs, so technically "mid-time". This got me thinking of the future and what to do when the engine is tired out or if it has a sudden failure. So if I needed a new engine... What would it take to put a 912iS into a CTSW? I know it needs a redundant electrical system and dual batteries to be safe. I'm not sure if the plumbing of fuel, coolant, and oil lines is the same or close enough to be only a small issue. What exactly would be required to make this work well and be safe? Just a thought experiment. Quote Link to comment Share on other sites More sharing options...
Madhatter Posted June 7, 2022 Report Share Posted June 7, 2022 Why would you get rid of reliable carbs that are simple without the complexities of electronic fuel injection and their added components, not to mention cost? Quote Link to comment Share on other sites More sharing options...
Anticept Posted June 7, 2022 Report Share Posted June 7, 2022 A heck of a lot of work. I believe it's possible... but it's a HECK OF A PROJECT. The 912iS has two major requirements: A header tank, and a strong fuel pump. In the CTLSi, these are installed in the tail, with the header tank hanging on the BRS column, and the boost pump along the left bottom of the cargo bay and composite layups over top with access panels. There is also the fuel test valve which is installed with a hole drilled through the bottom of the tail back there. You'll be buying a new engine mount as well. Not 100% sure if the T-mount also has to be replaced. You will need to either buy a new, or modify, the upper cowling to increase clearance for the fuel rails. You will need to modify the fuel system so that it is rerouted to go from the wings and going back to the tail header tank. You will also need to install a vent line that returns to the wing tank so that air can be purged from the header tank. If you have a fuel flow meter, you will have to either install a second one and use a differential flowmeter, or instead pick up off the fuel flowing into the header tank from the wings. You will need to add indicators so they properly display lane warnings from the injected engine computers. There was also a manual switch for something relating to the lanes but I am forgetting what that was right now. If you have an EMS D120, you will have to reconfigure and rewire it to work with the 912iS sensor packages. I will be flat out honest: I think the best choice if you wanted to retrofit and get rid of carbs, I would be looking into a throttle body injection instead. Throttle body injection would work with the same engine, same fuel system (except possibly the need of a boost pump for a CT), and tuned correctly, would probably be a little more efficient. If you're comfortable with it, you can also use a single TBI to supply both sides of the engine, or just use a 2 TBI setup which would probably be nearly a drop in replacement. You still will probably need a fuel return line to the wing tanks though and depending on how you set it up, you might have to replace the gascolator too with a pressure model. It won't hit the levels of multiport injection efficient, but the simpler setup means it's much easier to tune and troubleshoot, and it's something I personally have been thinking about. https://www.kitplanes.com/de-carbing-the-rotax-912-uls/ https://www.rotecaerosport.com/tbi Quote Link to comment Share on other sites More sharing options...
coppercity Posted June 7, 2022 Report Share Posted June 7, 2022 Our new CT Super Sport injected has a more simplified fuel system compared to the CTLSi. There is no longer a header tank, fuel is returned to the selected fuel tank, the fuel selector control is now located just aft the throttle quadrant. Fuel pumps are on the engine side of the firewall where the start battery normally is, and the gascolator is back where it originally was on the carb engines. With this configuration it might be possible to retro a 912is a little easier. Eric Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted June 7, 2022 Author Report Share Posted June 7, 2022 1 hour ago, Madhatter said: Why would you get rid of reliable carbs that are simple without the complexities of electronic fuel injection and their added components, not to mention cost? As I said. Just a thought exercise. I like to explore all possibilities. Quote Link to comment Share on other sites More sharing options...
Warmi Posted June 7, 2022 Report Share Posted June 7, 2022 If I could , I would exchange my 912 ULS for IS version on the spot … oh well, maybe on my next plane. Quote Link to comment Share on other sites More sharing options...
GrassStripFlyBoy Posted June 7, 2022 Report Share Posted June 7, 2022 I'd sell the bird and buy a newer one, not that it can't be done but looks like a major hassle. I'm looking to upgrade to a low time Super Sport a few years old in a few more years, limited supply but I can hope. Might do a LS, but Super is the wish list. I have to admit the LS I flew back from CT a couple months ago was darn comfy having that shelf space, but I'm still in the SW camp. Quote Link to comment Share on other sites More sharing options...
Anticept Posted June 7, 2022 Report Share Posted June 7, 2022 2 hours ago, coppercity said: Our new CT Super Sport injected has a more simplified fuel system compared to the CTLSi. There is no longer a header tank, fuel is returned to the selected fuel tank, the fuel selector control is now located just aft the throttle quadrant. Fuel pumps are on the engine side of the firewall where the start battery normally is, and the gascolator is back where it originally was on the carb engines. With this configuration it might be possible to retro a 912is a little easier. Eric Did something change with iS engines in regards to the air tolerance? It was my understanding that the reason for the header in the first place was to keep air out of the injection system because bubbles can jam the injectors. Quote Link to comment Share on other sites More sharing options...
Bill3558 Posted June 8, 2022 Report Share Posted June 8, 2022 If I was going to change engines and your experimental, why not go with the 915? I have experience in both the carbureted 912uls(my crashed 2008 N121YT) and my current 912Si. Power is the same, but fuel burn is better. Matched with E-prop I’m getting 123-125 knots at 5400 rpm pulled back to eco mode 4.6 gph. 2013 CTLS with tundra gear. It’s a very efficient machine. Quote Link to comment Share on other sites More sharing options...
Skunkworks85 Posted June 8, 2022 Report Share Posted June 8, 2022 914, Need to add a naca duct, and change the exhaust location to the pilot side. Other than that? I think there is an electric fuel pump for the boost referenced pressure regulator. Fyi, the Gutmans posted a picture of a new LS on facebook with the 914 in it, I have requested to see under the cowl.. Quote Link to comment Share on other sites More sharing options...
Towner Posted June 8, 2022 Report Share Posted June 8, 2022 I agree with the 914 idea! Having a turbo would be a huge benefit. I have to go above 10k feet to go east. Even if I go around the higher stuff, I’m traveling over an hour south or 2 hours north to get around it and still should go up to at least 7.5k. From CA to the Rockies is a lot of high altitude stuff and the turbo would be a huge benefit. Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted June 8, 2022 Report Share Posted June 8, 2022 I'll stick to the carb engines. Too big a pain on the 912iS engines. Harder to find anyone to work on them, you need a $1400 dongle, a laptop computer. That's just to do an annual and heaven forbid someone has to trouble shoot a lane light issue. Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted June 8, 2022 Author Report Share Posted June 8, 2022 Thanks for the feedback guys. I'd probably just stick to the 912ULS, I know the engine well and I can fix a lot of problems in the field. As for the other engines: 915: No way that a CT would stay light sport with that engine, plus weight, plus $36k...too rich for my wallet. 914: Turbo is nice, but I'm mostly a flatlander and spend most of my time under 5000ft MSL. I also worry about a turbo being an expensive point of failure. Quote Link to comment Share on other sites More sharing options...
GrassStripFlyBoy Posted June 8, 2022 Report Share Posted June 8, 2022 I sometimes wonder if going the route of 80HP UL would be an option for me down the road, I see some of these engines low time and fraction of the price of the ULS / injected engines. The performance would drop but I fly solo and from low elevations, it's already a rocket ship. Buying lower octane fuel might afford some flexibility, such as the 89 rec fuel or just the cheaper auto grades. Couple this with an Eprop and maybe the end result is still a decent package. Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted June 8, 2022 Author Report Share Posted June 8, 2022 22 minutes ago, GrassStripFlyBoy said: I sometimes wonder if going the route of 80HP UL would be an option for me down the road, I see some of these engines low time and fraction of the price of the ULS / injected engines. The performance would drop but I fly solo and from low elevations, it's already a rocket ship. Buying lower octane fuel might afford some flexibility, such as the 89 rec fuel or just the cheaper auto grades. Couple this with an Eprop and maybe the end result is still a decent package. If it were a lighter engine I'd say "maybe", but I think the first time you tried to get off a short field on a hot day, you'd hate that 20% less horsepower. You can always get better fuel economy, just throttle back. at 4000rpm you probably burn 3.5gph. You can always use less horsepower than the engine can make, but you can never use more... From this document:https://rotax-docs.secure.force.com/DocumentsSearch/sfc/servlet.shepherd/version/download/0685c00000CxbZNAAZ?asPdf=false It looks to me like the 912ULS makes the same power at 4600-4700rpm as the 912UL makes at 5500rpm (about 73hp). If you fly your 912ULS around never exceeding 4700rpm, including takeoffs, I think you'll talk yourself out of this pretty quickly. Quote Link to comment Share on other sites More sharing options...
Skunkworks85 Posted June 9, 2022 Report Share Posted June 9, 2022 The new CTLSt, this with a CS prop and ifr, I'd be set Quote Link to comment Share on other sites More sharing options...
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