IO360 180 vs 200HP

[201er]

I still don't quite understand how the same IO360 engine creates 20HP more when fuel injected than carbeurated. Otherwise the engines are identical right? How does fuel injection make 20 more horsepower?

[Shadrach]

Quote: 201er

I still don't quite understand how the same IO360 engine creates 20HP more when fuel injected than carbeurated. Otherwise the engines are identical right? How does fuel injection make 20 more horsepower?

[N601RX]

All the 180hp engines use a parallel valve head and lower compression ratio. The 200hp engines use an angle valve head and higher compression ratio. 

It also cost more to overhaul the 200hp engine.

[rbridges]

What impresses me more is the speed difference b/t a C and E model.  You wouldn't think 20HP would give you ~10 knots.

[John Pleisse]

Brake horse power and engine bore size don't always add up. It has also been estimated that an IO360-A3B6 with all of it accessories and weight ends up really being 10-12 HP less than rated.

[Shadrach]

In terms of weight, I believe the IO360 is heavier by ~40lbs. 

In terms of speed E vs C.

1) a good C model is a 145kt bird in cruise. On the deck with everthing forward a good one will likely break 150kts.

2) injected engines will do sightly better at lower MPs (high altitude) getting better fuel distribution.

3) The higher C/R bird will always be more efficient and make more power for a given Alt.

4) Ram air. As many experts have stated, the intake on the A,B,C,E,F,G models was less than ideal. With the Ram air, my engine picks up anywhere >1" to a .25" depending on alt, temp and barometric pressure. This is more significant than people think in the 4K-6K foot range. The carbed birds have no Ram Air.

All of the above being said, the 180-200 M20s are all within about a 20kt range give or take a few kts in speed with some overlaping others.

Airfacts Magazine raced and M20E against a Comanche 250 back the mid 60's and the E model walked away from it while down on the deck.  I've seen Cs that will run with Fs and Es that will run with Js. There's more at hand then just 20hp.

[201er]

Well if you put all the J mods on the earlier models, you have a lighter/shorter version of the J so it isn't much surprising (namely the cowl and sloped windshield). Actually what I'm kind of surprised about is that an E modified into a J isn't even a little faster as the result of lower drag/weight.

[rbridges]

good thread.  I knew the IO had differences in valves and obviously the fuel injection.  I didn't realize there were so many internal differences. 

[Shadrach]

Quote: 201er

Well if you put all the J mods on the earlier models, you have a lighter/shorter version of the J so it isn't much surprising (namely the cowl and sloped windshield). Actually what I'm kind of surprised about is that an E modified into a J isn't even a little faster as the result of lower drag/weight.

[KSMooniac]

Quote: Shadrach

Modified they often are... There are some stock E models in existence that will outrun and outclimb stock J models.

[Piloto]

[Piloto]

As per aerodynamic math the speed gain from 180HP to 200HP is 5 kts. However average climb rate improvement is close to 150 fpm. The IO-360 will burn 1.5 gallons less at LOP than the O-360.

José

 

[rob]

My 65C isn't an exceptional model in terms of mods, I have the cowl closure and brake reversal and nothing more. I see 153kts true on a regular basis. I have a friend with an E that is slightly faster, as per the math.