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RV-14A Vetterman Exhaust

TimO

Well Known Member
I'm getting a bit behind with my online time these days. When pushing thru to the end of the build, I try to stay focused and get too sidetracked. But for a while now I've had the RV14A version of the Vetterman exhaust installed, and recently I finished the cabin heat system, so it's time to post some pictures!

I should warn you, there are many many things in the photos that aren't complete. You'll see many loose nuts, and no hoses have been tightend yet. At the time of the photos the engine monitor was in process of being installed, but today that is all complete. So look at the photos for what they are...just pictures of the exhaust system. I'll post more complete pictures on my website in a few days, as I'm just about wrapped up with everything FWF, and am about to close off the cover forward of the panel and prep the plane for paint.

For those of you wondering "Why" regarding a different exhaust system for the -14, it's simple...the stock system is a 4-into-1 system and with a big IO-390, it will probably suffer some restriction due to not enough exhaust flow. The Vetterman system is a nice dual 2-into-1 system with 2 tail pipes, that is tuned and should give the engine better breathing. It also includes turned down pipes, to help keep the belly from being heated up. While I haven't flown with it yet, I expect the exhaust should do really well. I'm more concerned that the cowl exit area may be too tight and we may have to open that up a bit. Time will tell on that.

The exhaust system does provide dual heat muffs in hopes of keeping a nice warm cabin. While they aren't in place in these photos, I did use the same heat shields as Van's uses, in the area of the fuel flow sender and fuel lines. additionally there will be a heat shield on the pipe below the throttle cable.
My heat shielding will be shown in some photos regarding the throttle quadrant that I should have available by late this week.

The exhaust hangs off the back of the sump, and the tail pipes go up and over the nosewheel hinge point, and into the tunnel. If later it is found the cowl would need more exit area, it would not be too hard to route the pipes under the nose wheel hinge point, and keep that tunnel completely open.
The overall design kind of looks like modern art, to me.

Now on to the pictures. I'll break them down into multiple posts.

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Be sure and let us know how badly the dual pipes bang the sides of the tunnel during startup and shutdown........ ;)

Other than that, the rest of the exhaust and cabin heat installation looks pretty much what is standard in the kit (except for maybe the aim of the hose ports on the Van's heat muffs are better for where each hose needs to go).
 
Clint at Vetterman's did change the angle of the heat muff inlet/outlets slightly after he did mine, so other people should have a more direct routing of the SCAT tubes. If I find a reason to some day, he'll swap them with me.

I'll be curious to see how the exhaust does with the tunnel walls too. There is a good amount of clearance there, actually, but, it's been a while since I've dealt with the 4-bangers. The IO-540 does a shutdown shake too, but I'm not sure if it will be harsh enough that it'll actually touch, on the -14.

The short of it is, I personally dislike the whole "Tunnel" idea on the -14 anyway. I think the cowl should have come down lower and the exhaust should come out the bottom just as it does on the -10. The tunnel itself is an eyesore from the bottom, and being made out of stainless, I don't think I'll paint it because the paint won't stick as well, and even if it did, it's going to have a hot exhaust pipe stuffed into it that would probably discolor the paint anyway unless there's plenty of airflow to prevent it. I guess we'll see after time.
 
Tunnel / Exhaust Clearance

Thanks for posting those pictures Tim. I think Stoney Ware also has a Vetterman crossover exhaust in his -14, of course his doesn't have the nosegear structure to work around, but the pics on his website show the pipes dropping down out of the cowl completely below the tunnel. He had to cut openings in the cowl where they exit. See his pics at http://rvbuild214sw.com/.

I like the idea of keeping the exhaust going through the tunnel better as it seems like a cleaner installation, but I had the same thought as Scott looking at your pics that there's not much clearance there. The pipes on my -8A (which has a 'mini-tunnel') had a lot more clearance than that and they would still make contact with the underside of the tunnel at times...they move around a lot.

I wonder if Vans chose a 4-into-1 design because they thought it would improve performance, or if it was simply because it fits in the tunnel area better? It would be nice to get some performance comparisons between two -14s with the same engine/prop combination but with crossover exhaust on one and 4-into-1 on the other to see if there's any quantifiable difference in exhaust system performance.

FWIW I'll also mention that in contrast to Tim I really like the tunnel design. To me it seems like an elegant and efficient way to reintroduce the engine cooling air into the slipstream and it has less frontal area than it would if you had to further lower the cowl like on the -10 and the other side-by-side RVs. I often thought if I were to do my -8A over again I'd replace the cooling ramp with stainless steel both for fire protection and because it's less likely to crack than aluminum due to the constant pounding of exhaust pulses. And the fact that it isn't painted doesn't really matter to me because you never see it unless laying directly underneath the airplane...not a perspective most people have when drooling on your RV-14 :D
 
Exhaust diameter

Tom,
I like the looks of your exhaust system. One question, what is the diameter of your exhaust pipes. I am putting in a Superior XP400 so Van's system won't fit so I planning on a Vetterman.
Norris
 
I have also decided on a Superior XP400, now being built by Aero Sport Power. I called Vans regarding the Vans exhaust (i.e. will it fit?) and they have no knowledge/information, suggesting I contact Superior. Before getting Vans to delete the exhaust from my FWF kit, I'd like to confirm that it will not fit. Can anyone confirm this is the case?

Also, I see the Vetterman Exhaust installation post by TimO, but that appears to be on a 390, so I assume it was done for other reasons.
 
The short of it is, I personally dislike the whole "Tunnel" idea on the -14 anyway. I think the cowl should have come down lower and the exhaust should come out the bottom just as it does on the -10. The tunnel itself is an eyesore from the bottom, and being made out of stainless, I don't think I'll paint it because the paint won't stick as well, and even if it did, it's going to have a hot exhaust pipe stuffed into it that would probably discolor the paint anyway unless there's plenty of airflow to prevent it. I guess we'll see after time.

Hot exhaust pipes stuffed into it :D:D

Is there any heat shield or insulation to keep the heat out of the cabin?
 
Hot exhaust pipes stuffed into it :D:D

Is there any heat shield or insulation to keep the heat out of the cabin?

Mike,
The design of the exit tunnel on the RV-14 has a double wall with the stainless steel outer surface and an aluminum interior one, with an approx. .75 inch insulating air gap in between the two.

So far heat transfer hasn't been a problem.
 
Exhaust for XP400

I spoke with Clint at Vetterman this morning and confirmed that the Vans RV-14 exhaust will not fit the XP400 engine. Vetterman's design for the XP400 uses 2" pipes in a dual outlet pipe configuration and as a result, the pipes will not fit in the exhaust tunnel, requiring some cowl mods (minor) and a pipe exit similar to the RV-7, forward of the tunnel.

This (along with the price difference) might have swayed me back from Superior to Lycoming, but I'm committed now - oh well.
 
Mike,
The design of the exit tunnel on the RV-14 has a double wall with the stainless steel outer surface and an aluminum interior one, with an approx. .75 inch insulating air gap in between the two.

So far heat transfer hasn't been a problem.

Thanks Scott.
 
I spoke with Clint at Vetterman this morning and confirmed that the Vans RV-14 exhaust will not fit the XP400 engine. Vetterman's design for the XP400 uses 2" pipes in a dual outlet pipe configuration and as a result, the pipes will not fit in the exhaust tunnel, requiring some cowl mods (minor) and a pipe exit similar to the RV-7, forward of the tunnel.

This (along with the price difference) might have swayed me back from Superior to Lycoming, but I'm committed now - oh well.

Since Vetterman is already making an IO-390 exhaust that fits into the tunnel (albeit marginally according to Tim Olson's pictures), can't they do the same for the XP-400? I would think the 400 exhaust could be very similar with minor adjustments (fraction of an inch) for exhaust port locations.
 
Working well...

Regarding the exhaust, I'm pretty pleased so far. Scott may be right in that I may occasionally hit the side of the tunnel with the pipes during startup as the engine chugs to life. I find the IO-390 really tends to start on the rich side and misfire a bit until you get it leaned well enough. So I do think I've heard it hit at least a couple times out of maybe a couple dozen engine starts I've had so far. But, it isn't swinging around and hitting all the time, either.

Once the engine is running though, I'm finding it to work very well. The power and responsiveness are great, and the sound is really cool as well. It doesn't seem excessively loud. The heater I should probably test but it's been too hot here. I did have one heat valve that wasn't fully shutting, and the floor and carpet were getting really really hot on the copilot side. But after tweaking the valve cable a little it seems better now. I'm hoping this translates into a comfortable cabin when it's zero degrees out this winter.

Anyway, so far I haven't found any squawks with the Vetterman exhaust. My biggest concern was how close my throttle cable came to the pipe, but after firesleeve and heatshield on the throttle cable since day 1, I haven't noticed it having any negative effect at all. I'll be watching that closely for a long time to see if the situation changes.

Just thought I'd close the loop on the clearance question. The 2 pipes themselves I moved so they were about 1/8" apart, and whenever I'm underneath they still seem to be in the same spot.

Also, as much as I still think the tunnel is kind of ugly from the bottom, I left it unpainted and it isn't bothering me now. Some day I should cut off the 2 ears that are used for exhaust hangers, as I'm not using them. The stainless tunnel, if it maintains it's color, will just be another silver stripe on the plane I guess, from below. The double walled tunnel actually has worked out very well at keeping the tunnel cool. That was good planning on Van's part. In my RV-10 I had to add tunnel insulation because the heater ports heat the tunnel so hot.
 
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Any updates on the Vetterman exhaust? How much of a price difference is it from the standard kit pipes? Any more pireps on the pipes hitting the sidewalls?

Thanks
 
I did have the pipes hit the sidewall originally, with the dual pipes. Then I got from Vetterman a saddle clamp...it's like a split figure 8 device that goes around both pipes and keeps them in line with eachother and about 1/8" apart. The issue before was that the pipes were free to swing a lot on their flexible mount. With them secured to eachother it's been good now. I'm at 97.7 hours and loving the system.
 
Does that saddle clamp attach to the exhaust hangers included with the fuselage kit or just clamp the two pipes together? I guess I'm wondering if I decide to buy the vetterman pipes if I should attach those two hangers.
 
No, it just attaches to the pipes. My pipes don't go back anywhere near that far to those hangers so on my plane they're useless. If you think that some day there's any chance you'd use the factory exhaust, maybe install them, but I don't see any reason for them and wish I hadn't now.

One thing to keep in mind too...

My Vetterman exhaust went up and over the crossbar on the nose gear, and into the tunnel. I know that other people after me got systems that have the pipes exit the cowl down before that crossbar. This would be a simpler installation. I think they cut some cutouts in the cowl and glassed in some aft facing bumps or something, but I haven't seen pictures myself.
Anyway, I'm not sure if they make both versions now, or switched that that simplified version. It would definitely be easier for them to not have to route up and into the tunnel...but I do like how mine is working now. Mine hangs nicely off the 2 back corners of the sump.
I think either will be better than trying to stuff 4 pipes into a single one that isn't quite large enough, performance wise.

It would be nice to hear more comments from others who have his system. I've had a few offline emails over the past half year or so but haven't seen many people post.
 
I think either will be better than trying to stuff 4 pipes into a single one that isn't quite large enough, performance wise.

Does that mean you have proven with flight comparisons to other RV-14's, that with the Vetterman system you have more HP (and more speed)?
 
Vetterman advertises that RV builders never need to modify their planes to install its exhaust systems. This thread seems to be indicating that is not the case with the 14 14a !! What do those with installation experience have to say ?
 
FWIW, I spoke to Clint today and as of now they are only offering a twin pipe exhaust that does not go thru the tunnel. He said builders will have to cut the bottom of the cowl for the pipes to go thru. Apparently this cleans up all the routing around the nose gear assembly. Personally I think that would look strange having an empty tunnel and pipes sticking my out of the cowl bottom. I guess you could close up the tunnel but what would that do for engine cooling airflow etc?
 
I built my RV-14A with a Superior XP-400. As discussed, Van's exhaust for the IO-390 will not fit on the XP-400 due to Superior's cold air sump. I contacted Vetterman who provided their 2-to-1 by 2 exhaust (each side has 2 pipes joining to one 2" pipe - separate units for each side). I understand this "trombone" design has been used on RV-7s - it adds a loop in one exhaust pipe on each side before they join together to spread out the exhaust pulses. With this design, the 2" pipes are too large to fit in the tunnel, so the pipes must exit the cowl similar to other Van's models - in the case of the RV-14, this is forward and below the cross hinge on the nose gear.

Photos below are:
1. right side
2. left side:
3. view from below:
4. from the side
5. The parabolic cutouts are the only cowl mod I had to make
6. view with the cowl installed

The plane has only flown 13 hours so far, but the exhaust is working great. I was delighted to require such minor cowl mods. I was concerned about clearance between the pipes, the nose gear and the cowl - there is about 5/16" - with engine shake at start up but I've looked at the video of my first start (the most shake I ever expect to have, but that's another story) and while the engine may behave like a wet dog on occasion, the pipes barely move.

Others have expressed dissatisfaction with having built a tunnel that isn't used. I initially felt that way, but now think of it as a cooling tunnel. During my first flight at 25 squared (75% power), the CHTs maxed out at 334 - on a day in the 70s. I now think I will not have any problems in the heat of summer and cowl louvers will be unnecessary.

I did experience some "drumming" on the floor boards, especially at high power settings like climb, but some carpet has helped quite a bit. Observers on the ground have commented the engine is a bit noisier than other RV's. The power is AWESOME!
 

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Cowl flap in tunnel

I have the same setup as Keith Brown (XP400 with Vetterman exhaust), so I also have the empty tunnel. I had previously purchased a cowl flap from Anti Splat Aero so decided to install it in the tunnel. I had read that the 14 had plenty of cooling so thought that I might be able to reduce the cooling drag by installing the cowl flap in the tunnel. Haven't flown yet so no results data at this time. The cowl flap is electrically controllable and I added a position indicator so I can try different settings in flight and immediately see the impact on cooling and speed. If it doesn't work as expected then I'll just remove it.
I'll post results when she flies (should be soon).
Norris Brown (Interesting that Keith Brown and I went the same route though we have never met)
 
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