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EXP119 Exhaust

The Vans EXP119 Crossover exhaust has a 6 month lead time at the moment. Vetterman can supply an exhaust for the EXP119, but is not a crossover design ... ie Cylinders 1 & 3 exit right side, 2 & 4 left side.
Vans undoubtedly put a lot of effort into designing the the EXP119 crossover installation for good reasons.
Has anyone installed the Vetterman solution for the EXP119, or got knowledge of the pros/cons.
 
EXP-119 Exhaust

Steve,

Not be discouraging, but in my recent experience, the EXP-119 exhaust has a ten month lead time. A word of caution- the heater muff may interfere with your throttle arm forward throw. I discovered this while making airplane noises safely in my hangar, versus in flight, thank goodness. I double wrapped safety wire at each end of the heater muff to prevent it from creeping.
 
If you dig thru Kitplanes you'll find an article on the types of exhaust and rankings from best to worst.
I believe you are asking about the Vetterman equal length 4 into 4 vs a X-over. Performance gained or lost is almost nil between the 2. Disadvantage of the 4 into 4 is muffs for heat/carb.
4:1 is the best for HP but we are not talking huge gains unless you are going to the ultimate degree of cold air induction, etc.
 
Exp 119 exhausr

i bought both to compare them. After reading the article by Marc Cook Kit Planes Dec 2020, about the intro of the EXP 119, the article made mention of “ the new crossover exhaust system sized and shaped to preserve power” I had talked to Clint at Vetterman about making an exhaust for the EXP, he said he could make the trombone style exhaust for the EXP119 and that there would be no noticeable difference in performance. I also emailed Greg Hughes and asked if there was any data on the various system that they tested to determine which exhaust had the best performance. He said there was none that he could provide. The article also said that Vans worked with Lycoming to find the best combination of intake and exhaust for the Exp119. I called Jeff Schans, lead man for the Lycoming Thunderbolt version of EXP 119. He said that there was no data. I asked his opinion about one or the other and he said as long as it fits it should be good, i guess he was referring to the trombone style. Not being able to get any data confirming the performance of either cross over or trombone style exhaust I decided to installed the trombone exhaust from Vetterman. Very clean and easy installation.

Dave
 

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i bought both to compare them. After reading the article by Marc Cook Kit Planes Dec 2020, about the intro of the EXP 119, the article made mention of “ the new crossover exhaust system sized and shaped to preserve power” I had talked to Clint at Vetterman about making an exhaust for the EXP, he said he could make the trombone style exhaust for the EXP119 and that there would be no noticeable difference in performance. I also emailed Greg Hughes and asked if there was any data on the various system that they tested to determine which exhaust had the best performance. He said there was none that he could provide. The article also said that Vans worked with Lycoming to find the best combination of intake and exhaust for the Exp119. I called Jeff Schans, lead man for the Lycoming Thunderbolt version of EXP 119. He said that there was no data. I asked his opinion about one or the other and he said as long as it fits it should be good, i guess he was referring to the trombone style. Not being able to get any data confirming the performance of either cross over or trombone style exhaust I decided to installed the trombone exhaust from Vetterman. Very clean and easy installation.

Dave

One difference will be a slight reduction in cabin heat performance. With the heat muff located that far down the exhaust there is quite a large difference in the amount of heat transfer compared to having it closer to the outlet port on the cylinders like it is with the kit supplied system.
 
Thanks for your various tips/thoughts. I have fitted the Vetterman Trombone Exhaust on my EXP119, and as Dave has mentioned, it's an easy and neat install.
But the Heat Muff/Scat Tube obviously needs a complete rethink ... as Scott says it'll probably be less efficient. I am inputing the cold air downstream, and exiting upstream as per advice in other threads.
Rather than routing the scat underneath the engine from the right air ramp, I am keeping fingers crossed about engine cooling, and taking air from the left aft baffle. If I discover engine cooling is adversely effected during test flying I'll have to adopt plan B!

For more pictures see here
 

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Firing order is 1-3-2-4. The trombone connects 1-3 into the same pipe, and 2-4 into the other. As a result (example below) #3 dumps a high pressure pulse into the pipe before #1 can close, with the same thing happening on the other side. Avoiding this detail is why we use crossovers (joined cylinders fire at 360 degree spacing) or 4 pipe systems (no interaction).

That said, pipe pressures are complex. Dyno or pipe pressure plots would tell the tale. If I recall correctly, Larry sent a trombone to Thomas at G3i for a dyno run, so someone has data.
.
 

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One difference will be a slight reduction in cabin heat performance.
I have the original standard 390 (ExP 129 I believe) but with Vetterman trombone exhaust (originally for Superior XP400). I have a heat muff installed on each side (capturing heat from all 4 pipes) with each muff supplying heat to one cabin side. The heat output is tremendous - I’m in Texas (not very wintery) but have flown in sub zero temps with no shortage of cabin heat.
 
I have the original standard 390 (ExP 129 I believe) but with Vetterman trombone exhaust (originally for Superior XP400). I have a heat muff installed on each side (capturing heat from all 4 pipes) with each muff supplying heat to one cabin side. The heat output is tremendous - I’m in Texas (not very wintery) but have flown in sub zero temps with no shortage of cabin heat.

Just to clarify.... I never said that heat muffs placed much further down the length of the pipes would produce no heat. I said it would produce less of a temp delta than if they are placed closer to the heat source (the exhaust port on each cyl.).

For some peoples situation, this may not be an important factor but for others it might be.
I have never heard anyone say they wish the output of there heater air was a lower temp....:rolleyes:
 
EXP Exhaust

Thanks Dan. It would be good the see the data.
I have the crossover exhaust as plan B if trombone does not perform as expected. Also, It seems that trombone would produce less heat with less piping dissipating heat in cowl and improve cooling over all. Maybe someone knows

Dave
 
I ran the scat tube from the opening on right front baffle under cylinders above intake to a T that runs just behind the oil pan then to each muff.
 

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Not even close to being an expert on airflow for heat muffs. However wouldn't it be easier to heat warmer air? So why not feed the warmer(?) air off the back of the engine baffles? instead of outside air?
 
I would think that taking air from the back of the baffle would risk getting CO/exhaust in the "fresh" ventilation air in the event of an exhaust leak.
 
Except the top of the engine/baffle area is higher pressure fresh air blowing down through the fins, exhaust gases should not be going against the flow. Is there such a thing as cylinder head leak for exhaust gases?

Once again not an expert by any chance that's why I am asking.
 
Not even close to being an expert on airflow for heat muffs. However wouldn't it be easier to heat warmer air? So why not feed the warmer(?) air off the back of the engine baffles? instead of outside air?

The temp. delta between air sourced at the inlet ramp vs at the back of the plenum is negligible and either location is acceptable as an air source for cabin heat (no difference in potential for Co).
 
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