7 More HP??

Today I ordered an oil separator from a company and was told that I should buy the check valve and stand off for the exhaust because it would add 7 HP to the engine among other advantages. I ordered it mainly because I had and liked the direct connection to the exhaust from the crankcase vent on a former RV, belly stayed cleaner. Quite a few early builders equipped their RV's with a connection at the exhaust. This just seems like a very bold statement so I'm asking if anyone out there can verify this. It just seems like if such an inexpensive item would add much HP, this item would be in very high demand and hard to get?? Please help me understand this. Thank You,
Larry

I just finished installing the same air-oil separator today and the vendor made the same horsepower claim to me.

My short test hop today was too bumpy to notice any difference. However, racecar engine builders have known for some time that putting a slight vacuum on the engine does help them produce a few more horsepower.

Expect the installation to take between eight and ten hours.

The designer modeled the separator can after the one he made for his non-standard side-by-side RV. Meaning it is intended to mount directly above the battery on the right side and moving it to the left, away from the battery is a challenge. I ended up mounting mine just to the left of center, partially blocking the prop governor recess.

The other challenge I had was the 90 degree elbow fitting interfered with the engine mount. I had to locate the proper tap and "deepen" the adaptor plug. A 45 degree fitting eliminates this issue but the thing was shipped with a 90.

To accommodate the location I selected, I clamped the exhaust valve on the left exhaust pipe.

Once those details were worked out routing the lines was fairly straight forward.

LARCO said:

Today I ordered an oil separator from a company and was told that I should buy the check valve and stand off for the exhaust because it would add 7 HP to the engine among other advantages.

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And the company would be..?

Please help me understand this.

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The theory says reduced crankcase air density means reduced windage and pumping losses. There is auto dyno data to support the theory, and crankcase evacuation is SOP among racers.

However, theory also says pumping losses become more significant with increased RPM, and our Lycomings are rather low RPM engines. Further, my own pressure measurements say exhaust-driven evacuation isn't very powerful as currently installed on our engines; not much density reduction.

When offered a specific HP claim perhaps you should ask for a dyno sheet.

The theory says reduced crankcase air density means reduced windage and pumping losses. There is auto dyno data to support the theory, and crankcase evacuation is SOP among racers.

However, theory also says pumping losses become more significant with increased RPM, and our Lycomings are rather low RPM engines. Further, my own pressure measurements say exhaust-driven evacuation isn't very powerful as currently installed on our engines; not much density reduction.


Gents,
Mr Horton is correct????..
Unless someone chose to run a scavenge belt driven pump (Auto Verdi is what I run on my blown alcohol, sprint, motors)
Im new to the aircraft engine world, the principles still apply???.

TXTaildragger said:

Gents,
Mr Horton is correct…………..
Unless someone chose to run a scavenge belt driven pump (Auto Verdi is what I run on my blown alcohol, sprint, motors)
Im new to the aircraft engine world, the principles still apply……….

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I run a all aluminum sprint car motor in my experimental and the Moroso crankcase evacuation kit works great for me..

http://www.jegs.com/i/Moroso/710/25900/10002/-1



I cannot confirm a 7 HP gain.. but the belly stays squeaky clean.......

I have one on my -6 and the -10, not because of potential the horsepower gain, but for the slight vacuum pulled in the case. A slight differential will help to reduce the oil seepage that seems endemic to aircraft engines.

I noticed a major reduction in a stubborn seep in my 0-360 at one of the head drains that was there from the first start.

The separator also works very well to reduce oil on the belly as opposed to the first two the -6 had, the -10 has some OIB, but it is still early in its break-in.

The H.P. gain is there, and I also would like to see some real data, but it is not the best benefit.

I'll say it...

I imagine we're talking about Anti Splat Aero's Oil Separator and Crankcase Vacuum Valve.

N941WR said:

I just finished installing the same air-oil separator today and the vendor made the same horsepower claim to me.

My short test hop today was too bumpy to notice any difference. However, racecar engine builders have known for some time that putting a slight vacuum on the engine does help them produce a few more horsepower.

Expect the installation to take between eight and ten hours.

The designer modeled the separator can after the one he made for his non-standard side-by-side RV. Meaning it is intended to mount directly above the battery on the right side and moving it to the left, away from the battery is a challenge. I ended up mounting mine just to the left of center, partially blocking the prop governor recess.

The other challenge I had was the 90 degree elbow fitting interfered with the engine mount. I had to locate the proper tap and "deepen" the adaptor plug. A 45 degree fitting eliminates this issue but the thing was shipped with a 90.

To accommodate the location I selected, I clamped the exhaust valve on the left exhaust pipe.

Once those details were worked out routing the lines was fairly straight forward.

Click to expand...

I just finished the install today. The parts look very nice and all went well but I did not order their install kit as I needed to install mine on the left side as well and the return hose would have been way to short. The exhaust fitting seems to fit very well. Looking forward to a clean belly and 7 more HP. Larry

I'm pretty skeptical of that 7hp gain.

I'm also skeptical. Unless you put a particular engine on a dyno, there is no way you can say that a particular change makes a definite HP change.

I'm not sure one way or the other whether this adds power. But if a particular technology (like reduced crankcase pressure) has been well documented to increase horsepower in engines, then I believe one could predict a ballpark power bump based on RPM, displacement, crankcase pressure, etc.

Would love to see a comparison of the same engine with & without this mod on a dyno under the same environmental conditions.

Let's test it on Dyno, we run every day!

I am spending a small fortune to gain 7hp on our engines. If someone can get company to send me one I'll test it and report results.

We have found A9 treatment reduces friction in the engine 5%, not sure how much this effects hp but we will be testing it once I get caught up for SNF>......

grayforge said:

I'm not sure one way or the other whether this adds power. But if a particular technology (like reduced crankcase pressure) has been well documented to increase horsepower in engines, then I believe one could predict a ballpark power bump based on RPM, displacement, crankcase pressure, etc.

Would love to see a comparison of the same engine with & without this mod on a dyno under the same environmental conditions.

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I googled this and found a dyno test by a car mag. The engine made 897 hp with the crankcase drawn down by 15" hg. A lot. The power went up by 9 hp. 1%.

Windage, ok I get, but the oil will foam, so scavage pumps are needed too. Pumping loss reduction - - a bit of a stretch.

Crank seals don't like suction so the air had better be clean.

The oil separator is good for it's intended purpose. And a good price. Still a good buy if one is desired, even if hp gain is not real.

What is "A9" treatment Kevin???
Thanks,

A9

http://www.aprobertsarts.com/clients/ace/a9-2/

Thanks Reiley, very interesting!!
Cheers,

As Bill Lane indicated;
You may not like the oil seepage coming out of your engine, but you may like less the dirt sucked into your engine thru the seals when running a crankcase vacuum of any great amount.

SHIPCHIEF said:

As Bill Lang indicated;
You may not like the oil seepage coming out of your engine, but you may like less the dirt sucked into your engine thru the seals when running a crankcase vacuum of any great amount.

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Are you being serious?

Yes.
Look at the lip seal with a garter spring used to keep the oil in. It's designed to 'tighten up' from pressure on the inside. My son just replaced the front seal on his RV-4. The new kind that you stretch over the flange.
If there is pressure from the outside (from vacuum on the inside) the lip seal tendency is toward 'looser'. and the airflow becomes 'in' instead of oil seepage 'out'.
Now I don't know how much air will flow in, or how much dust is in the air, but I do know that the more hours SMOH the looser that front seal gets.
So I advocate a slight crankcase vacuum, which, by the way, seems to be what Dan Horton is reporting from this exhaust extractor system. I'm just opining about big vacuum from an extraction pump like the racers mentioned.
In a previous thread, I speculated 2 tap points on the case be used to suck out each crank bay to a pair of exhaust extractors for more power, but Dan pointed out the futility, and I took a look at a Lycoming crankcase.
I have an experimental Mazda rotary that I mess around with, but the 2 Lycomings I take care of, those I keep pretty stock. Especially the wife's. That hummer is completely stock. I owe it to her to not include any hidden 'gotcha!'

Would it be a good idea to just add the separator and see what difference it makes before adding the vacuum valve?