roxiedog13
Member
I’m checking out several aircraft to purchase, a couple have the carbureted 05 40, just wondering what are the overall pros and cons, also is it expensive to upgrade, is it worth it?
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Carb vs Fuel Injected is there a big difference?
- Thread starter roxiedog13
- Start date
IMHO yes, but remember everyone likes what they chose. The ability to run lean of peak with FI - increasing the range and endurance with standard 60 gal tanks - was the main factor for me. OTOH if you plan to always run best power mixtures then there’s less difference.
A parallel valve 540 in the 250/260 horsepower range with fuel injection will typically burn two gallons per hour less than carb version at 65% power. Based on variants of the Piper Aztec ranging from 1962 to 1976, as well as several Commanche's. some with carbs, some with FI. The Aztec's were all 250 hp, the Commanche 250 and 260 hp.
FI injected engines can be tuned, meaning each cylinder injection nozzle size can be changed out to properly get all your EGT's very close in range. This is has a big advantage over the Carb engines. You cannot do anything except change throttle positions. I think that if you can keep all your cylinder temps in range, you are going to get a longer living engine without too many issues. In my Pacer with an O-360, I have had problems with some cylinders that run a lot richer than others. Plug Fouling and valve issues.
On the other side, Carbs are less complex, less maintenance and you can start you airplane if your battery is dead. Carb heat is other issue you have to deal with on carb'd engines.
On the other side, Carbs are less complex, less maintenance and you can start you airplane if your battery is dead. Carb heat is other issue you have to deal with on carb'd engines.
Look at the automobile world. Are there any cars still being made and sold with carburetors?
Is it worth upgrading would be an individual preference. IF I had a carb that was working, I would not upgrade to fuel injection. IF I needed to buy a carb, I would then consider buying fuel injection system and would need to include the price of a new mechanical fuel pump and a new high pressure boost pump in the price.
I have hand propped everything from J3 Cub to Navajo Chieftain(three bladed prop). If shower of sparks or the current equivalent enough power to energise the shower of sparks is required.
My Pitts with stock 360 parallel valve never had a starter. It did have pressure carb which is easier to start than fuel injection. I have hand propped many other Pitts's that were injected.
My Pitts with stock 360 parallel valve never had a starter. It did have pressure carb which is easier to start than fuel injection. I have hand propped many other Pitts's that were injected.
If you don't have any power, how do you prime the engine to start it? The slow rotation of the hand prop isn't enough action to get the mechanical fuel pump to pump fuel. If your starter goes out but you still have battery power to run the boost pump, then you can start it. If you have no power then, you can't do anything and you are stuck. Thus the carb with a hand primer can get you out of a jam.
Christen combination fuel filter, fuel sump and hand wobble pump. Pitts S1S was type certificated in that configuration.
Early model Bonanza's had hand wobble pumps to prime engine and for emergency use. The Bonanza was a fuel selector and pump combined. Forgot to mention the Christen pump was also a fuel selector.
Dugaru
Well Known Member
Owning a carb engine also frees up reading time. There aren’t 5,437 online arguments about the best way to start them when they’re hot.
Jetmart
Well Known Member
I have started a cold soaked engine on two different occasions when having a failed electric fuel pump on a Piper Aerostar by taking a large medical syringe and removing the fuel line into the spider. Pumped a lot of fuel in using the syringe. I was at a remote airport without maintenance available. I always carried the syringe after the first incident.
I used something similar to this. https://www.amazon.com/Measuring-Individually-Measurement-Scientific-Applicator/dp/B09DCFPHC1/ref=sr_1_1_sspa?crid=1C8NCFCGJ1BW4&keywords=large+syringe&qid=1689065920&sprefix=large+syringe,aps,132&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1
Toobuilder
Well Known Member
With a diaphragm pump most of us use, the pumping “power” is delivered by a spring. The cam eccentric merely cocks the action. “Speed” of rotation only comes into play to determine how many times the spring needs to be cocked to get fuel moving. Much like the trigger on a 409 bottle, a slow pull moves fuel just fine. The fundamental difference in this analogy is the fact that the fuel pump moves fuel when the lever EXTENDS, where the 409 bottle moves fluid when the lever COMPRESSES.
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You can also start a FI engine with no boost pump using diesel starting fluid.
ME! But it was due to having the wrong intake and cowl for our RV-8 to work with the IO-360 we purchased. We bought an engine from a plane that was totaled when the fuselage was crushed by a beam in the hangar that was destroyed by a tornado. 18k for a 400 hour engine with good logbooks was a steal. We already had a carb. Runs like a champ! I can't run LOP with a carb obviously, but all 4 cylinders temps are within 30 degrees of each other. It seems like O-360s that have widely varying cylinder temperatures have other issues causing that such as poorly sealed intake runners causing those cylinders to run a bit leaner.
