hallo,
I'm not good at all with engines so a need your help before asking to a maintenance center...
I have a Lyc o540 B2C5 engine. 235Hp. I would use this engine for experimental airplane. What changes a maintenance center can make to get the most of the hp?
Apart from the cost, it would be useful to install an injection instead of the carburetor?
thankyou for yor help
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1st, as being used on an Experimental Airplane, YOU can do anything you want to it for HP and making it more Durable!!!
2nd, Fuel Injection does not really make You more HP, it gives You a better Starting Engine, a Smoother Running Engine, and Better GPH!!!
3rd, any Engine's Life(Hours) is only as good as the Fuel Octane used, so you don't have Detonation Problems, Max Rpm's used also affect what Prop You can use, Basic Engine 101 Maintenace done, What Type of Oil is used, what kind of Heat it is subjected too, and what Type of Parts you use!!! Today, You also have many different Engine/Exhaust Coatings You can use, that don't really make more HP, but can make your Engine more durabile!!!
Building Engine's for more HP is basically the same. What Max Rpm's you want to run, What Size of Intake and Exhaust Valves you Run(What is the Max Size your engine can use), Cylinder and Head and Intake Porting(Air Flow Ratio or AFR), Carb Size(CFM) you run, your Stock Cam Spec's Lift and Duration vs what you want to you run to make more Hp. The are usually (3) Types of Cams, Solild Lifter, Hydraulic Lifter, Roller Lifters, what is your Stock Cam and does anyone make other Types for your engine?
So Sadly, most Airplane Engines just don't have many Performace Parts built for them, You have to have them usually Custom made, or even make them yourself, or Adapt other Parts to work. So let's look at some of your Engines Spec's below. Also, I don't know what your Airports offer for Fuel, but with in 50 mile radius Circle's around me, only 1 out every 21 Airports even carry 87, so 100LL is your only choice of Fuel!!! 87 Octane is good for only up to maybe 9.0cr. I can tell you may new 1979 Chevy 350 v8 with 9.6cr would knock on 87 Octane when you went to pass someone, at lower in town Speeds/rpms it ran fine.
Lycoming O-540-B2C5 engine
overhaul, exchange & shock load repair
Lycoming O-540-B2C5 specification
Model: O-540-B2C5
Manufacturer: Lycoming
Aircraft: Piper Pawnee
Horsepower:
235
Compression ratio: 7.20:1
Configuration: 6 Cylinder
Fuel system: Marvel Schebler Carburettor
Propeller: Variable Pitch
Rotation: Clockwise
RPM: 2575
541.5 cubic inch (8,874 cc) displacement
So from the Peak Flow/HP Calc
http://www.mk5cortinaestate.co.uk/calculator3.php it says at 541.5 cubic inch at 2575rpms and if just 90% efficient, 363CFM and can make 242hp is possible if Designed and Built right! The Cont O-200 was rated at 2750rpms for a 2000hr TBO, so I would use that as my Max Rpms. So since 100LL can handle any Compression 7.0 to 12.0 that is what I would use. 100LL does have a 5 year Shelf Life also if your in the outback. 87 has a 6 month shelf life. Check what the CFM Rating is of your Marvel Schebler Carburettor is?
Porting can add 10-15% more HP.
A Good Tuned Exhaust can add more HP.
Using Bigger Intake/Exhaust Valves can add more HP.
Just Raising Compression does add more HP, but not as much as you think! Example on a Skidoo 670(669cc) 2 Stroke, 11.5cr 112hp bump up to 12.5cr 122hp made a 10hp difference. As the CC/CI goes up, the Hp gain also goes up. To really make lot's more Hp you need to use a Bigger Cam, bigger Valves, bigger Carb, higher Rpms used, etc! All of which can affect your total Engine Service Life in Hours!
A Turbo Option is also one way to make much more HP! As Normal Carbed Plane's go higher they make less HP! Your 235hp at Seal Level is 70.5hp less at 10,000ft. With a Turbo you have the same HP at both.
Your 541.5 cubic inch at 2575rpms if Designed and Built right with 1lb of Boost = 287hp and 431cfm
Your 541.5 cubic inch at 2575rpms if Designed and Built right with 2lb of Boost = 305hp and 458cfm
Your 541.5 cubic inch at 2575rpms if Designed and Built right with 3lb of Boost = 324hp and 485cfm
Your 541.5 cubic inch at 2575rpms if Designed and Built right with 4lb of Boost = 342hp and 513cfm
If it was me, and Money was no object, I would use a Variable Boost Turbo and Fuel Injection. Depending on it's Hours now, if it needs Rebuilt now. I would use all of the different Engine Coatings to Reduce Heat, Friction, Corrosin, in and on your Engine. Just using Ceramic Coatings on Piston Tops, Head Combustion Chambers, Cylinder Exhaust Ports, and Exhaust, can lower your over all Temps by 20%.
"Design and development[edit]
https://en.wikipedia.org/wiki/Lycoming_O-540
Generally these engines produce 230 to 350 horsepower.[1] They are installed on a large number of different aircraft types.[2] Their main competitive engine is the Continental IO-520 and IO-550 series.
The AEIO version was developed for high-performance competition aerobatics aircraft. Starting at 260 hp (190 kW), the power was then improved to 300 hp (220 kW). The AEIO-540 family has achieved tremendous results in competition aircraft such as the Extra 300, CAP 232, and Zivko Edge 540."
Just My 2 Cents
Rich