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  #1  
Old 01-18-2019, 10:48 AM
pa38112 pa38112 is offline
 
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Location: Clarksboro, NJ
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Default Heat Muff Orentation

I was just sitting at the table playing with the new heat muff that arrived today from Vans. I bout a second to put in series. I never thought too much about the orientation of the excentric mounts. I have always placed the inlet/outlet ports on the high side. I'm starting to think that they should be on the low side. - Does anyone have data to support the delta T one way or another?
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  #2  
Old 01-18-2019, 10:56 AM
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rvbuilder2002 rvbuilder2002 is offline
 
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The flow velocity is high enough that I don't think port orientation matters.
What does matter is pipe temp and time exposure to the hot pipe(s).

The best performance comes from having the muff(s) on the hottest portion of the pipes possible.
There is also performance gain from ganging two muffs together in series.
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  #3  
Old 01-18-2019, 11:08 AM
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wirejock wirejock is online now
 
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Default Heat muffs in series

Quote:
Originally Posted by rvbuilder2002 View Post
The flow velocity is high enough that I don't think port orientation matters.
What does matter is pipe temp and time exposure to the hot pipe(s).

The best performance comes from having the muff(s) on the hottest portion of the pipes possible.
There is also performance gain from ganging two muffs together in series.
I would love to see photos of two heat muffs in series. Anyone?
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  #4  
Old 01-18-2019, 11:32 AM
pa38112 pa38112 is offline
 
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I'll have one by the end of the weekend, but I always forget how to post photos on there. I'm doing one per pipe. I have not figured out the scat runs yet.
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  #5  
Old 01-18-2019, 12:43 PM
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rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by wirejock View Post
I would love to see photos of two heat muffs in series. Anyone?
It is standard on the RV-14(A)
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  #6  
Old 01-18-2019, 01:22 PM
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dwrichey dwrichey is offline
 
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[IMG][IMG][/IMG]

Not in series, but one muff off cyl 1, and the other off cyl 4. The airflow is in series, combined they work almost too well.
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  #7  
Old 01-18-2019, 03:27 PM
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rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by dwrichey View Post
[IMG]

Not in series, but one muff off cyl 1, and the other off cyl 4. The airflow is in series, combined they work almost too well.
Seriesed airflow is what I meant. It doesn't matter if it crosses over to the other side of the engine. Just so all the flow passes through two heat muffs.
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  #8  
Old 01-18-2019, 03:59 PM
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rzbill rzbill is offline
 
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Quote:
Originally Posted by wirejock View Post
I would love to see photos of two heat muffs in series. Anyone?
Hi Larry,
I have an M1B in my 7A. Heat was anemic with single muff on #1 ex pipe. I had Rick Robbins make a short muff of my design to go on #4. Additionally, since I was blocking the majority of my oil cooler anyway, I picked up the input air from the back of the cooler. So, the flow is: cooler, #4 muff, #1 muff then cabin.

All this did make an improvement however like Scott said, pipe temp (egt) makes a big difference. I can't run low RPM over square LOP in the coldest winter days and expect the heater to keep me warm. Push some flame into the exhaust with RPM or ROP and the heater will keep up when it's COLD.

Sorry for no pics. Expercraft.....

RIGHT. Made it home to real 'puter. Here is a link to my older VAF post on same subject with images until they disappear due to Expercraft. Look quick.

http://www.vansairforce.com/communit...78&postcount=6
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Last edited by rzbill : 01-18-2019 at 06:27 PM.
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  #9  
Old 01-18-2019, 04:57 PM
RV7 To Go RV7 To Go is offline
 
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Sorry no pics but I run 2 muffs in series on my O360 powered 7 with the Vans supplied Vetterman exhaust. The muffs are both installed reverse flow (discharge out closest to the prop) and hooked up in series (discharge of one flows into the inlet on the other) to a single heat box. I now get much more heat in the cabin than with the single muff. Barely warm with the single muff at -6C last winter. This winter at -10C (coldest so far) and very comfortable under full overcast. FWIW.

Al

Last edited by RV7 To Go : 01-18-2019 at 04:59 PM. Reason: configuration
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  #10  
Old 01-18-2019, 05:15 PM
Scott Hersha Scott Hersha is offline
 
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Location: Cincinnati, OH
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Agree with Scott, two in series is the way to go, at least for the RV8. I did that on my first RV8 with a Vetterman crossover exhaust and I had plenty of heat in the winter. On my new RV8 I have an AWI four into one exhaust and just one heat muff - and its not enough, so I?ll be trying to figure out how to add a second muff in series with the other one, although there are some space constraints in my installation. With two heat muffs in series, it shouldn?t be a problem.
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