M20E Exhaust

[IvoryM]

Hey guys,

I'm looking for any insight any of you may have on the difference between a M20E exhaust and a 201 exhaust. It was recommended to me to replace my original 1965 exhaust (maybe not original but at least the same style) with a new Mooney 201 exhaust. I would appreciate any thoughts you guys may have on this.

Thanks,

Mitch

[cctsurf]

I have the powerflow exhaust on my m20c and it provides equivalent to the m20e performance...  I'd love to try the powerflow on the 200hp engine: http://www.powerflowsystems.com/products.php?cat_id=5&pid=46

James

[Guest]

Try this, more budget minded than power flow

http://aircraftexhaust.com/nav.cfm?cat=11&subcat=67&subsub=0&as_id=8&mg_id=74&sys_id=121&display=system

Clarence

[wombat]

I just went through my annual and decided not to go with a powerflow exhaust.   I figured that a full replacement of my existing exhaust was about $1,700 but the Powerflow was about $4,600 and I would need to save 500 extra gallons of avgas before that was worth it.

 

While I expect that there is some improvement in performance, I don't think it's as much as their advertisements lead you to believe.  (FYI, a 0 knot speed increase can also be stated as "Top speed capability improved by as much as 6.5 knots at 11,500 feet")  

[cctsurf]

To those who would say it isn't worth it, I reply, "you have to make your own decision."  To those who would argue that there isn't a performance gain, or that it isn't equivalent to the advertised, I'm sorry, but my experience demonstrates differently.  The short field performance of my m20c is equivalent to that of the m20e. Equivalent to a 20hp gain.  It is a noticeable difference.  I also have a friend with a Cherokee 140 with the powerflow and he has experienced a major difference as well.

[Hank]

I just went through my annual and decided not to go with a powerflow exhaust.   I figured that a full replacement of my existing exhaust was about $1,700 . . .

 

(FYI, a 0 knot speed increase can also be stated as "Top speed capability improved by as much as 6.5 knots at 11,500 feet")

I just replaced my muffler & tailpipe for about $1800 + labor. If you can get it done for $1700, jump on it. Wish I'd taken a picture of the gaping hole on the bottom . . . Oops, just noticed you said "exhaust," did you mean "muffler"?

The "zero knot improvement" advertising gimmick is something to remember. How do you tell when a salesman is lying? His lips are moving.

[wombat]

cctsurf:  I'm in agreement with you that each person should make their own decision.    Unfortunately, I find that your anecdotal evidence is unconvincing.  What I do find compelling is the fact that they have not run their exhausts on a dynamometer in comparison to a stock exhausts in order to generate a statistically significant set of test results which would be extremely useful to their sales and marketing department. They have a single result where with the stock exhaust the engine was producing 83% power to begin with and their exhaust still produced less than 100% power.  I do think that they are producing a quality product and their ideas are good, but I don't think that the exhausts are really producing a 10+% performance gain.  I think that the gain that we do get with the exhaust is exaggerated by the placebo effect.  Just like all of the speed mods with speed gains posted on them, the fuel burn savings of LOP ops and an EI and the Powerflow...  If I took all of these at face value I would expect a 30MPH speed increase at 3GPH less.... That would put me 170KTAS on 7 GPH.

 

Hank:  Yes, that was my muffler and exhaust headers.  Everything but the tailpipe.

[bonal]

Time to learn. So I was cautioned that my cruise setting put me at 48 for rpm and MP if I am limited to a certain performance number what difference would having a better flowing exhaust system make. I am very knowledgeable about engines and the importance of flow but in cruise I can't see where anything would be gained. Obviously climb performance could and should benefit but that is such a small percentage of our total flight profile. Short field and high DA I suppose the investment might make sense. If the improved flow could allow me to run 48 and be leaner for a reduced fuel rate then that might make it good but it seems like there would be zero gain in speed unless one were to push into more stressful numbers. Just asking and why on earth is it so expensive these exhaust systems are pretty simple it always blows my mind how much something cost just because it's certified like for an example our hot air box at over a thousand dollars for a stupid tin can with a couple sloppy flaps in it. Geeze Louise

[IvoryM]

I really appreciate all the Information and opinions. Can anyone out there tell me the difference between a stock M20E exhaust and a stock 201 exhaust? Are the stock exhaust systems interchangeable between the 201 and a M20e?

Thanks

Mitch

[Bob_Belville]

June 2012: Installed Challenger Air filter KH pin # CP1176 IAW STC SA01669CHRD; Installed PowerFlow Exhaust System PFS 16201 Generation 2 per STC SA 028871A7. 

 

[Marauder]

June 2012: Installed Challenger Air filter KH pin # CP1176 IAW STC SA01669CHRD; Installed PowerFlow Exhaust System PFS 16201 Generation 2 per STC SA 028871A7.

You're such a handsome devil Bob! Don't know how Nancy has been able to hold onto you this long!

Other than a better sound and increased manifold pressure, what do you think it netted you in increased airspeed? My exhaust is getting long in the tooth and I would consider it if there was some real performance to be had.

[carusoam]

The secret is the T-Shirt that the driver is wearing.

It comes with the video.

If for some reason you are not running full throttle... Then better flow (intake and exhaust) will probably not be a benefit.

For more speed, consider more

-displacement

-rpm

-MP (for the turbo guys)

-airflow (cause you can)

Mooney pilots like this stuff.

Many of these decisions come up when stuff wears out or breaks.

It takes some of the pain out of the decision...

There isn't enough logic for most of us to swap out systems that are working...

It may take a lifetime to get your Mooney to the state you want it in...

Best regards,

-a-

[Bob_Belville]

Other than a better sound and increased manifold pressure, what do you think it netted you in increased airspeed? My exhaust is getting long in the tooth and I would consider it if there was some real performance to be had.

The exhaust system can't help with aerodynamics or parasite drag.

 

I think the comment I made for PFS about MAP would indicate more available power. More power should reduce take off roll, increase balls to the wall climb rate, and increase the altitude at which you can maintain 75% power (or whatever power you like to cruise at) resulting in higher cruise speed.

[carusoam]

+ shiny good looks and no missing/split welds at the tip...

Problems of an oooold C...

Bob,

Did they at least get you a PF T-shirt for the video/Pirep?

Best regards,

-a-

[Bob_Belville]

Anthony, I stopped by their booth because Jim Shafer is always good for a tube of anti-seize lube. They were asking customers for testimonials. Took 5 minutes, they were giving a nice combo pen/light/touch screen stylus. Did I sell my body too cheap?. 

[aaronk25]

So on my J, with the powerflow installed CHTs are down 25 degrees....that's more than they promised me.

At 2,400ft it will run 170kts...that's 8-9kts faster than before. Yes this is on a J but why replace the exhaust with a hotter running slower less efficient system?

Great system.....

[bonal]

That was a nice explanation on flow and as I indicated I understand much about the importance of efficiency in moving air in and out of the combustion chamber. Believe me when I say with lots of experience in tuning racing engines I understand. What I don't understand is if I have to stay out of the red box meaning running at too high of a power setting what real benefit would there be in cruise other than the ability to run more lean and burn less fuel. So here is where you can clear things up. If an engine is turning at 2500 with mp at 22 running at 47 in the safe zone what can be gained with a better flow if I can't turn up the heat so to speak.

Today I was running at 2500 with the throttle pulled back to 22 inches at 5700 ft elevation. Wide open would add another 2 inches but now I think I should limit to 47 when running at lower altitudes. I know once I get really high I can't make enough pressure to hurt things so WOT it is and perhaps this is where a better exhaust system would be a benefit

[Bob_Belville]

That was a nice explanation on flow and as I indicated I understand much about the importance of efficiency in moving air in and out of the combustion chamber. Believe me when I say with lots of experience in tuning racing engines I understand. What I don't understand is if I have to stay out of the red box meaning running at too high of a power setting what real benefit would there be in cruise other than the ability to run more lean and burn less fuel. So here is where you can clear things up. If an engine is turning at 2500 with mp at 22 running at 47 in the safe zone what can be gained with a better flow if I can't turn up the heat so to speak.

Today I was running at 2500 with the throttle pulled back to 22 inches at 5700 ft elevation. Wide open would add another 2 inches but now I think I should limit to 47 when running at lower altitudes. I know once I get really high I can't make enough pressure to hurt things so WOT it is and perhaps this is where a better exhaust system would be a benefit

ISTM that the biggest gain of the PFS is the ability to continue to pull 75% power in cruise at a higher altitude. If the PFS gets us an extra inch of MAP that means 5%+ more power above about 8000'. Even if I want to operate at a max of 65% the PFS will maintain that at a higher altitude. And with a higher balls-to-the-wall MAP you can maintain the desired HP% at a little lower RPM for a quieter cabin.

[bonal]

ISTM that the biggest gain of the PFS is the ability to continue to pull 75% power in cruise at a higher altitude. If the PFS gets us an extra inch of MAP that means 5%+ more power above about 8000'. Even if I want to operate at a max of 65% the PFS will maintain that at a higher altitude. And with a higher balls-to-the-wall MAP you can maintain the desired HP% at a little lower RPM for a quieter cabin.

That's what I thought would be the case. So for normal take off and climb and for higher alt opp's there is some gain and I'm sure even better with an injected engine but not so great for the old o360

[aaronk25]

Put me down in the red box is a myth club. It might apply to he turbo Navajo engine that claim to run in light detonation but in our relatively low compression and timed engines 100ll is over kill.

I cruised the last 1,200 hours prior to overhaul at very high power settings. Ex 4000ft, 2700rpm, full throttle 27" peak or 20rop. 12.2gph. At higher altitudes it's always wot and peak or just barley ROP.

Take a guess what the cylinders looked like after such extreme abuse??? They all met new specifications, not service limits but new. The key I believe is not internal cylinder pressure, but heat. Heat soaked cylinders and cylinder heads kill valves and rings. I always keep CHT under 380 and preferably in the 350 range. Another kicker my cowl flap linkage is now adjusted completely closed right.

This is one of the things I like about the powerflow is when it gets hot out I typically don't have to back off a power setting (going leaner or richer) to keep CHTs in check as for me it lowered temps 25f.

Also important. Get a tube of high temp silicone and seal the baffle area where air can go from high to low pressure areas bypassing the engine. Ex..around alternators, or any seams below and behind the spinner. Made another 20degrees difference. On a J cut 1.25" of cyl #1 vertical baffel and on #4 bend up the baffel 1/2" to steal some air from oil cooler....just a bit.

My cylinders look so good at overhaul we reused them.

In my 77j yesterday I cruised back from Florida at 4-6000ft and cruised at 170-168kts in a J!

100ll is some pretty awesome stuff and it's auto ignite temp is 482f!

In our engines 91 octane auto fuel will start to auto ignite when CHTs get to 355-360f, under high MP conditions. 400f at low power settings.

So I go against the grain a bit but really can one person on this fourm site a example of a engine failing from operating in the red box WHEN CHTs are less than 380f? My guess is engines get wrecked from prolonged high CHTs do to poor cooling designs and redbox opps combined.

So the key to going fast without engine damage is 30 min worth of baffle mods, 30 mins worth of silicone and a powerflow....my opinion only...

[jetdriven]

I finally took that oil cooler ramp baffle off completely. Oil temp is still very low but #4 runs a little cooler now. fwiw I sometimes run 11.0 gph 83% power LOP. It still runs 30-50 degrees cooler than ROP.