Vetterman 4 Pipe Exhaust

[David-aviator]

If anyone is sitting on the fence with regard to pipes, I just want to mention I am very satisfied with the Vetterman 4 pipe exhaust system.

On the last flight the batteries in my noise cancel head set gave up the ghost so it was like in the good old noisy days before micro circuitry and I must say not all that bad. Well, I won't say it was like you can carry on a conversation with your wife, but it was not as noisy as I thought it might be. The Subaru made a lot more noise with no muffler.

Another pleasant surprise was the availability of cabin heat in flight. I am using the 2" baffle exit aft of #3 and run the scat tube over to the #4 pipe where the heat muff is installed. From there it is just a short run to the cabin heat box/valve. At 8500' with the OAT at 37F, it was comfortable as it was during the climb.

With regard to ring seating, I checked the color of the inside of the pipes at the exit today. They are a grey color, not oily or black soot, but a clean looking dark grey. I think I am getting close....but will keep on running hard some more hours.

[tridge]

Dave,
I'm one of those guys on the fence trying to decide between a four or a two pipe system in my 7A IO360 James cowl and plenum.

I'm concerned about proper air flow out the cooling exit with two extra pipes in there taking up space. What engine do you have and are your cht's under control. Hey guys! Any comments on this would be much appreciated.

Tom Ridge

[tin man]

Originally Posted by tridge

Dave,
I'm one of those guys on the fence trying to decide between a four or a two pipe system in my 7A IO360 James cowl and plenum.

I'm concerned about proper air flow out the cooling exit with two extra pipes in there taking up space. What engine do you have and are your cht's under control. Hey guys! Any comments on this would be much appreciated.

Tom Ridge

7A? Can't imagine it making much of a difference with all the nosewheel plumbing in there.
tm

[Mel]

Originally Posted by tridge

I'm concerned about proper air flow out the cooling exit with two extra pipes in there taking up space. What engine do you have and are your chts under control. Hey guys! Any comments on this would be much appreciated.

I started out with Larry's 4-pipe system in '93. That's all he had back then. Switched over to the tuned cross over system in '95. I didn't see any change in temperatures at all.

[David-aviator]

Originally Posted by tridge

Dave,
I'm one of those guys on the fence trying to decide between a four or a two pipe system in my 7A IO360 James cowl and plenum.

I'm concerned about proper air flow out the cooling exit with two extra pipes in there taking up space. What engine do you have and are your cht's under control. Hey guys! Any comments on this would be much appreciated.

Tom Ridge

The engine is a Barrett IO360 180 HP and is running very cool, like the highest CHT did not break 300 in a WOT climb to 8500' last Friday, but it is winter and exit area is much beyond what is necessary for a Lycoming coming off the H6 Subaru. After level off highest CHT was 280, still at WOT for the ring seating procedure.

I don't think cooling will be an issue. One can slice a piece of cowling forward of the bottom of the opening if necessary. It's been reported by guys like Barry in Arizona that really works to increase the exit area.

[tridge]

Okay with all of that, I'm kind of still on the fence, what exhaust...two or four?? I like the looks of the four pipe and after talking to Larry V, he prefers the 4. Told me he has it on all three of his RV's, so with that I'm kind of leaning towards the 4p setup. I'd really like to get some more input from the guys that have that system.

Tom Ridge

[David-aviator]

Originally Posted by tridge

Okay with all of that, I'm kind of still on the fence, what exhaust...two or four?? I like the looks of the four pipe and after talking to Larry V, he prefers the 4. Told me he has it on all three of his RV's, so with that I'm kind of leaning towards the 4p setup. I'd really like to get some more input from the guys that have that system.

Tom Ridge

I chose the 4 pipe system because it seemed to provide for the least amount of pipe clutter under the engine. Now that I've been through the process of routing and hooking up throttle and mixture, that still seems like a good idea.

But some guys like the cross over to 1 or 2 pipes coming out the back. It amounts to a personal choice just like the engine, prop, and color of paint one chooses. The throttle and mixture will go in no matter what.

[Mel]

One thing you might consider if running carburetor. The carb heat system is more difficult with 4-pipe.

[tridge]

Thanks a lot for your help. My first choice was a 4 pipe and I'm going with it.