O360.... Squeeze out more power?

Unit74

Unit74

Final Approach
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Unit74
Any way to squeeze this for more juice? O360 A4M is what I have. Power Flow doesn't make anything for it. I have all of Knots2u speed mods. Any way to squeeze this berry for more go?
 
Unit74 said:
Any way to squeeze this for more juice? O360 A4M is what I have. Power Flow doesn't make anything for it. I have all of Knots2u speed mods. Any way to squeeze this berry for more go?
Click to expand...

Add a turbo or supercharger?
 
Assuming you're talking about your PA28, and your real goal here I'm guessing is more speed more than anything.

Legally you have restrictions. There are electronic ignition options that will help your altitude performance by advancing ignition timing. Consider one of those. I think around $4k to buy the unit, then whatever your A&P charges for install. You could also swap the prop that's on there for a coarser pitch prop. Hurts your takeoff and climb slightly, but helps your cruise.

As far as the airframe, pay very close attention to drag. What antennas do you have? Can you switch to internal or something less draggy? Your external beacons/strobes are big source of drag that can be reduced. Last (but not least), look under the cowl and seal things up very well. So far this has gained me several knots on the 310 and I'm thinking it will gain more when I'm done, as there's a lot left.

Legalities aside, there's always 10:1 pistons or throwing in an IO-390 (or just angle valve cylinders on the 360). But neither of those are legal.

Or, you could buy an M20F, which will go faster without any speed mods or attention to detail than your Cherokee will go with all the speed mods and attention to detail. Until you start pushing the 170-200 KT realm, getting a different plane usually makes more sense. In my case, I'm working on de-dragging the 310, but there's really not another option that will do what I need to faster.
 
I have been researching the idea of stepping up to a Saratoga or A36, but I just don't want to get rid of this Archer. It will fly 129kts all day and if I could squeeze a few more out, I'd probably be convinced to do the interior, paint it and drop in a 540 and gpss roll stering.


I really only need 5 seats 2 times a year, so I'm thinking keeping it and getting the speed up would seal the deal. For the times I do need the seating, flying commercial would probably cost OA less than owning a PA32 or A36 over the course of the year.

What is this ignition you speak of? And to have the prop repitched, what are the costs and what kind of speed increases? Right now I can climb full fuel and two passengers at 400lbs just under 1k FPS. With just me, it climbs pegged at 1k best rate.
 
Unit74 said:
I have been researching the idea of stepping up to a Saratoga or A36, but I just don't want to get rid of this Archer. It will fly 129kts all day and if I could squeeze a few more out, I'd probably be convinced to do the interior, paint it and drop in a 540 and gpss roll stering.


I really only need 5 seats 2 times a year, so I'm thinking keeping it and getting the speed up would seal the deal. For the times I do need the seating, flying commercial would probably cost OA less than owning a PA32 or A36 over the course of the year.

What is this ignition you speak of? And to have the prop repitched, what are the costs and what kind of speed increases? Right now I can climb full fuel and two passengers at 400lbs just under 1k FPS. With just me, it climbs pegged at 1k best rate.
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What sort of speed increase are you looking for? You're going to get a few more knots if you're lucky and potentially spend a fair amount of money doing it. I don't see how getting 131 knots instead of 129 knots is worth much of any time or effort personally.
 
There are a couple of electronic ignitions out there. Here's one:

http://americanpropeller.com/ignition.htm

Just over $3k. No idea for speed increases exactly, but you'd probably get a few knots. It'll also increase performance at altitude moreso. It sounds like you could do fine with a more cruise-oriented prop. Are you operating with the throttle wide open in cruise or not? If so, no benefit.

Read up some of the drag articles and start looking under the cowl.
 
Unit74 said:
I have been researching the idea of stepping up to a Saratoga or A36, but I just don't want to get rid of this Archer. It will fly 129kts all day and if I could squeeze a few more out, I'd probably be convinced to do the interior, paint it and drop in a 540 and gpss roll stering.
Click to expand...
There's not much more you can do with that engine. You could get the cylinders ported and flowmatched the next time they're worked on. You could get a Powerflow exhaust system. You could replace your air filter with a K&N Challenger air filter. Doing all that might add 10-15 HP to your power output. But even an extra 15 HP is unlikely to improve your speed by more than about 3 knots.

OTOH, as Roy LoPresti has repeatedly shown, you can get much greater speed increases by drag reduction than by spending the same amount on power increases. Low-drag antennas, clean-up kits (like those from Knots2U or LoPresti), and other similar improvements are much more likely to give you significant speed increases.
 
Unit74 said:
And to have the prop repitched, what are the costs and what kind of speed increases?
Click to expand...
Repitching the prop with greater pitch will not give you any speed increases unless you are currently hitting redline RPM before reaching desired cruise power. However, it will reduce your takeoff/climb performance. The only way to get more speed by repitching the prop is to reduce pitch so the engine can spin faster and develop more power -- and that works only if you're reaching full throttle before reaching desired cruise power (highly unlikely) or you don't mind going well beyond the RPM redline (not a real good idea).
 
Ron Levy said:
Repitching the prop with greater pitch will not give you any speed increases unless you are currently hitting redline RPM before reaching desired cruise power. However, it will reduce your takeoff/climb performance. The only way to get more speed by repitching the prop is to reduce pitch so the engine can spin faster and develop more power -- and that works only if you're reaching full throttle before reaching desired cruise power (highly unlikely) or you don't mind going well beyond the RPM redline (not a real good idea).
Click to expand...

Thanks Ron you saved me from writing that post, and you probably said i better than I would have.

Brian
 
Unit74 said:
Any way to squeeze this for more juice? O360 A4M is what I have. Power Flow doesn't make anything for it.
Click to expand...
That's apparently an airframe issue more than an engine issue. I have an O-360-A4M with long-stack PowerFlow in a C-172. The only PA-28-180s that qualify are the old blunt-cowl models with aft-mounted mufflers. Muffler geometry must be the issue.
 
You can add power all day. It'll cost you a lot to do. You'll gain some climb rate. Any minimal speed difference will make no noticeable change to the time it takes to get anywhere.

The airframe is the issue and the best way to fix that is to get a different airframe entirely.
 
I missed the later post clarifying that his PA28 is an Archer, and Powerflow doesn't make one for Archers.
 
You could try a K&N air filter for about $200.

I picked up a couple of inches of MP on take off with one. Very cheap power.

You can also try a little MMO in the fuel and see what you get.
 
Ron Levy said:
Diluted fuel.

But the K&N Challenger filter did give me another half inch or so MP at full throttle on my O-360-A4K (close relative to the OP's -A4M).
Click to expand...


Thinking it might help compression a little.

More compression = more power. :dunno:
 
Ted DuPuis said:
Assuming you're talking about your PA28, and your real goal here I'm guessing is more speed more than anything.

Legally you have restrictions. There are electronic ignition options that will help your altitude performance by advancing ignition timing. Consider one of those. I think around $4k to buy the unit, then whatever your A&P charges for install. You could also swap the prop that's on there for a coarser pitch prop. Hurts your takeoff and climb slightly, but helps your cruise.

As far as the airframe, pay very close attention to drag. What antennas do you have? Can you switch to internal or something less draggy? Your external beacons/strobes are big source of drag that can be reduced. Last (but not least), look under the cowl and seal things up very well. So far this has gained me several knots on the 310 and I'm thinking it will gain more when I'm done, as there's a lot left.

Legalities aside, there's always 10:1 pistons or throwing in an IO-390 (or just angle valve cylinders on the 360). But neither of those are legal.

Or, you could buy an M20F, which will go faster without any speed mods or attention to detail than your Cherokee will go with all the speed mods and attention to detail. Until you start pushing the 170-200 KT realm, getting a different plane usually makes more sense. In my case, I'm working on de-dragging the 310, but there's really not another option that will do what I need to faster.
Click to expand...
I have to ask, how much gas could you have purchased with the same amount that you spent on upgrades? I don't see the worth in aviation.

A K&N CAI will pay for itself within a few months. I can't imagine how long it would take to pay off those upgrades for the 310.

txflyer said:
You could try a K&N air filter for about $200.
Click to expand...
That's absurd.
 
Is the KN filter that much better than the Bracket currently installed?
 
Cpt_Kirk said:
I have to ask, how much gas could you have purchased with the same amount that you spent on upgrades? I don't see the worth in aviation.

A K&N CAI will pay for itself within a few months. I can't imagine how long it would take to pay off those upgrades for the 310.
Click to expand...

Actually I didn't go into details of what I've done on the 310 so far. The ROI is a couple hundred hours on most of it for my utilization. Going through the cowls and sealing leaks is whatever a tube of Permatex Ultra Black costs.
 
Ted DuPuis said:
Actually I didn't go into details of what I've done on the 310 so far. The ROI is a couple hundred hours on most of it for my utilization. Going through the cowls and sealing leaks is whatever a tube of Permatex Ultra Black costs.
Click to expand...

Gotcha.
 
Like everyone else said, decreasing wind resistance is more effective than increasing horsepower. Maybe clean up the outside a little or switch to a retract/ faster airframe. I think you'll spend tons of money to squeeze out a few knots.
 
Seems that way....

A five place Bo would be great, but hauling around 4 empty seats most of the time is my biggest hold back. If I trade up, it's a Bo or Saratoga which has been on my mind. My Archer is about as loaded as they come sans all glass and a step up would actually be a step down in panels. I can't afford what I have in the Archer panel if it were in a Bo. Makes it a tough call to sell her.
 
I do have the Challenger/K&N air filters on the 310. Not sure how much of a difference they made, but several other changes were done on the plane at the same time that could've impacted speed in one way or another.

Speed and drag reduction can be addictive. Ultimately the easiest and cheapest thing to do in most cases is buy another airplane. But it also depends on what you're doing. For example, in my case the 310 is a pretty optimized plane. Other than an Aerostar, the only way to go faster is Jet A. Both are not cheap. A 340/414/421 might be a hair faster, but block times end up being about the same because of the extra time in climb. Fuel burn way higher.

Reducing drag will help the engines cool better, let you go faster, and if you also do weight reduction, that improves OEI safety. Lots of things you can do that are cheap if you take the time to look for them. Yes, improved cowlings like what you find from LoPresti or the experimental crowd are things that most of us can't benefit from, but there are lots of other things that we can.

I think if you have a Cherokee and want more speed, you'd be best off going for an M20F, but I can also see why you'd want to keep your Archer if you're otherwise happy with it.
 
Unit74 said:
Seems that way....

A five place Bo would be great, but hauling around 4 empty seats most of the time is my biggest hold back. If I trade up, it's a Bo or Saratoga which has been on my mind. My Archer is about as loaded as they come sans all glass and a step up would actually be a step down in panels. I can't afford what I have in the Archer panel if it were in a Bo. Makes it a tough call to sell her.
Click to expand...

A Bo is an efficient airframe and gives you the 5 seats (or 6 in an A36), so a real upgrade. You can then make it more efficient. Plus some Bos can run MoGas, which is a nice benefit if it's available in your area.
 
Lancairs show how well reducing drag works. That same O-360-A4M in a Lancair 360 will do 200 KTAS on the same fuel as the OP's Archer does 129.
 
Ron Levy said:
How would adding kerosene (that being essentially what a "naphthenic hydrocarbon" is) to your avgas improve compression?
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Anything that fills the micro-pores of the cylinder bore wall is going to help out with compression IN THEORY.

You're either an MMO devotee or you ain't.

I can lead you, but I can't make you drink. :redface:
 
txflyer said:
Anything that fills the micro-pores of the cylinder bore wall is going to help out with compression IN THEORY.
Click to expand...
Even assuming that theory is correct (which I do not accept without proof), what makes you think the addition of naphthenic hydrocarbons to your avgas will "fill the micropores of the cylinder"?
You're either an MMO devotee or you ain't.
Click to expand...
You make it sound like it's a matter of faith rather than science, and that I'm ready to believe. I'm just not ready to believe MMO will do any of that without a scientific basis and independent research to back it.
 
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txflyer said:
Anything that fills the micro-pores of the cylinder bore wall is going to help out with compression IN THEORY.

You're either an MMO devotee or you ain't.

I can lead you, but I can't make you drink. :redface:
Click to expand...

Absolute and complete bs. And this is the polite way to say this.
Take this from someone who actually does this for living
 
mtuomi said:
Absolute and complete bs. And this is the polite way to say this.
Take this from someone who actually does this for living
Click to expand...


Anyone can call BS on a forum and claim to be an expert.

Maybe you're full of ****. Who knows?

I never claimed any absolutes. I said try it and see what you get.
 
Unit74 said:
Seems that way....

A five place Bo would be great, but hauling around 4 empty seats most of the time is my biggest hold back. If I trade up, it's a Bo or Saratoga which has been on my mind. My Archer is about as loaded as they come sans all glass and a step up would actually be a step down in panels. I can't afford what I have in the Archer panel if it were in a Bo. Makes it a tough call to sell her.
Click to expand...

Forget the number of seats. Pencil out the cost per mile for each for the number of seats you want to use. I suspect you'll find the bo is cheaper on that basis even including higher insurance, mx reserve, etc.
 
Unit74 said:
Any way to squeeze this for more juice? O360 A4M is what I have. Power Flow doesn't make anything for it. I have all of Knots2u speed mods. Any way to squeeze this berry for more go?
Click to expand...

Mill .030 off the the both the case and cylinder mating surfaces.
 
Performance Airmotive and Atlee Dodge produce a "Hot Rod" Cub muffler that's gutted and uses an enlarged outlet (STC approved). The benefit is reduced back pressure/better breathing. The result is lower CHTs and greater rates of climb although most of us don't see much difference in static RPM, which is the laymans's method of judging power increases with fixed pitch props and no MP instrument. Would it be legal for you to gut a muffler and enlarge the tail pipe? Not exactly, but that hasn't stopped guys from doing it.
 
Henning said:
Mill .030 off the the both the case and cylinder mating surfaces.
Click to expand...

It would be far easier to just buy 10:1 pistons and throw those in.
 
Originally Posted by Henning
Mill .030 off the the both the case and cylinder mating surfaces.




Ted DuPuis said:
It would be far easier to just buy 10:1 pistons and throw those in.
Click to expand...


Agreed..... And finding pushrods to get the proper valve lash will be
"interesting".....:rolleyes:.....;)... Actually that would be proper hydraulic lifter preload...:yes:
 
Sounds cheaper to sell than get into all that. I'd prolly go for it if I was Experimental though. Sounds like a sleeper plane!
 
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