Exhaust development work

[A1VW2NV]

Matt, I was exhausted just reading your through your adventure. I'm pretty sure we all agree that your dedication is appreciated. Nothing ventured, nothing gained. Right?
After gutting my stock muffler, my butt dyno swears there is a bit more hp. And a better tone too. However I have not yet loaded the Akra map, so I'm sure to be running quite lean. My airbox and lid are still stock at this point, and for good reason. I intend to have the Akra map loaded when I take the bike in for its first service. I'm getting the impression that I'll be content with the new tune, my gutted muffler and an air filter and lid mod. I'm not opposed to buying the pcv but I'm weary that it will be worth it.
Joe

 

[dingdong]

Hi Matt, I came across this thread because I was thinking about having a custom exhaust made. You're being way too hard on yourself regarding the test results. First of all I think the effects of a slip-on are a little overrated. The low-end gains on Run25 are most likely from the pcv correcting the factory's very lean conditions. The loss in the top-end is because you're running leaner than stock in that area. I'm basing this off chad's dyno charts from his pcv thread. The fact that you're running lean with his pcv map probably means you're flowing better than whatever configuration the map was developed for. I wouldn't give up on your exhaust development. People want more options for exhausts in stock location, so I think it's worth the effort.

Btw, the info I was looking for when I stumbled on this thread was the header pipe ID/OD. Would you happen to have that info? Thanks.

 

[Formula390]

Hi Matt, I came across this thread because I was thinking about having a custom exhaust made. You're being way too hard on yourself regarding the test results. First of all I think the effects of a slip-on are a little overrated. The low-end gains on Run25 are most likely from the pcv correcting the factory's very lean conditions. The loss in the top-end is because you're running leaner than stock in that area. I'm basing this off chad's dyno charts from his pcv thread. The fact that you're running lean with his pcv map probably means you're flowing better than whatever configuration the map was developed for. I wouldn't give up on your exhaust development. People want more options for exhausts in stock location, so I think it's worth the effort.

Btw, the info I was looking for when I stumbled on this thread was the header pipe ID/OD. Would you happen to have that info? Thanks.

I'm working with Tyga with their exhaust development these days. I just didn't have it in me to keep working at it and started working on the other projects... namely the steering damper and RAM Camera mount system. That led to the Tyga upper triple... and then I got smacked with the Armored Truck... So my days these days are doctors appointments and order fulfillment, but not much in the way of additional parts development. Development takes WAAAAAAY more time than I think a lot of folks think it might. {shrug} Plus the market for the exhaust is something I just don't fully understand. Folks are apparently buying the Werks exhaust, something which WILL hinder performance (unless someone wants to produce a Dyno graph showing stock vs Werks back to back runs and prove me otherwise) just like the PowerCones do. The system length just isn't remotely correct... just as my design was. My longest design showed that's the way it needed to head, but that's as much length as I could get without doing the whole switchback stuff the stock exhaust does... or go outboard like the Akra, Arrow, or Yosh pipes do. It's the only way to get the necessary system length.

I STRONGLY suspect that if you unzipped a stock exhaust, removed the CAT and the white baffling packing, and welded it all back up, you'd match the Akra or Arrow performance. I'd also bet that it would soundly pummel the Yosh, Werks, and PowerCone exhausts. Soundly. The stock exhaust would then also be "noisier" as requested, and would be more free flowing to match the Akra pipe and it would match it's top RPM spinup and likely hit exactly the same HP numbers. This is all theory tho. I'd need a donor exhaust to work with Chad on to do those tests. We thought we had located a donor exhaust, but it never materialized... and we all got busy... so work on that stopped.

As for the ID/OD numbers. Sorry, I just don't remember. I looked around for my notes... and they are SOMEWHERE here in the office, but I couldn't find 'em.

 

[dingdong]

As for the ID/OD numbers. Sorry, I just don't remember. I looked around for my notes... and they are SOMEWHERE here in the office, but I couldn't find 'em.

No worries. Thanks for looking.

 

[ToraTora]

Matt, I think the developers of tech don't realize how long something takes, because if they did they'd never start down that road. You have to be very optimistic about these things and their schedules.

Hope you are feeling better. I finally got some good riding in today. Lots of pain where I was hurt, but the riding was wonderful--tomorrow is probably going to suck. lolz You'll get back to some level. Maybe not 100%, but enough to start enjoying the road again.

 

[regular_guy]

An armored truck!? Damn man I hope you get better soon.

 

[msquared]

I'd need a donor exhaust to work with Chad on to do those tests. We thought we had located a donor exhaust, but it never materialized... and we all got busy... so work on that stopped.

Matt, if you want my stock exhaust I would be happy to send it to you and Chad. Its not like I plan on putting it back in or anything.

 

[Formula390]

Matt, if you want my stock exhaust I would be happy to send it to you and Chad. Its not like I plan on putting it back in or anything.

Thank you. Yeah... let's see if we can make that happen. I can gut it and weld it back up, then get it mailed up to Chad for some dyno tests, and see if we can get a easy HP gain proven out for the community!

Thank-you.

 

[Major]

Thank you. Yeah... let's see if we can make that happen. I can gut it and weld it back up, then get it mailed up to Chad for some dyno tests, and see if we can get a easy HP gain proven out for the community!

Thank-you.

I would be very interested in this option

 

[CDN Duke]

Thank you. Yeah... let's see if we can make that happen. I can gut it and weld it back up, then get it mailed up to Chad for some dyno tests, and see if we can get a easy HP gain proven out for the community!

Thank-you.

Well, I managed to get some dyno time this weekend, and tried the stock everything with Acra map, and everything the same with a gutted catalytic converter. The gutted cat smoothed out the curve slightly, didn't cause any new issues, leaned out the bike .25-.5 of a point, and bumped the horsepower appx .5hp. The dyno guy speculated that we increased the flow, which helped the power, but probably lost a bit from leaning out from the high 12s to the low 13s. He said in his experience, the singles like around 12.8 which was where we were running with the stock exhaust.

It should be noted that this was a pretty new exhaust with the cat, so a bike with 20K miles will likely be a little worse for flow. With the new exhaust, removing the cat is a small enough gain by itself that I probably wouldn't bother, but at least it didn't hurt anything.

Also, I was very happy to see that with 89 octane, non-ethanol fuel, my AFR was a very flat, stable line which was pretty much spot on for where I wanted it. Throttle response is good and nice and smooth as you are just rolling it on. Very easy to control.

If I get a chance, I'll try to post up some graphs a little later.

-Sean

-Sean

I think this is the direction I'm currently headed - remove the cat from the stock exhaust... If it gets .5hp more on top of Akra map, plus is a bit louder to boot, that works for me. I was really hoping for a greater weight savings as well though...

 

[Diploman]

I would like to see someone replicate the OEM exhaust in aluminum or carbon for weight reduction. Also the bottom panel should be made removable, so fiberglass packing can be renewed/adjusted. Instead of the current exhaust port on the right, a SuperTrapp-style outlet with adjustable numbers of discs could be fitted to the bottom of the lower panel, so both exhaust note and back pressure could be adjusted. But absent such a theoretical upgraded version of the OEM exhaust, I will stick with the stock unit. If a successful de-cat conversion at reasonable cost could be developed, I would be interested.

 

[Formula390]

I would like to see someone replicate the OEM exhaust in aluminum or carbon for weight reduction. Also the bottom panel should be made removable, so fiberglass packing can be renewed/adjusted. Instead of the current exhaust port on the right, a SuperTrapp-style outlet with adjustable numbers of discs could be fitted to the bottom of the lower panel, so both exhaust note and back pressure could be adjusted. But absent such a theoretical upgraded version of the OEM exhaust, I will stick with the stock unit. If a successful de-cat conversion at reasonable cost could be developed, I would be interested.

For your new exhaust design, with those features.... No. Freaking. Way! An exhaust like that would be possible to build but in no way even closely approximating something affordable. There's ZERO economy of scale, and the costs alone of building the jigs and fixtures wouldn't be recoverable without selling a thousand exhausts, something which is just not possible.

For the stock exhaust rework, removing the baffling and cat, is far more possible. I've torn apart two exhaust cans bow, and THINK I've figured out the best way of doing the disassembly, rework, and welding it back up. Here's the problem tho... It's probably at LEAST six or seven hours of work. There are a LOT of welds holding the internals together, and many of them have no simple way of removing them to get the can apart. It's also going to use up a lot of materials to do the job. I went through at least four angle grinder discs for each, plus metal hole saws are needed (two sizes), and the plasma cutter. It's possible to do, but honestly it's also likely not something which could be done economically, especially when compared to the costs of buying a new exhaust.

The stock exhaust is a masterful work of VERY complex engineering.

 

[Diploman]

The stock exhaust is a masterful work of VERY complex engineering.

Matt, I agree, entirely. The OEM exhaust is so well done that those who attempt to create alternatives are often frustrated. You have done admirable work that serves to substantiate how good a job KTM did on this part. My proposal was just a pipe dream, or maybe a format for someday doing a one-off custom job. You are quite correct: This is not something that lends itself to profitable mass production.

To date I have seen no aftermarket exhaust that tempts me to abandon the OEM unit. But it could be improved.

 

[Deleted member 452]

I have the same crazy dream as Diploman since steel exhausts are heavy & rust (catalytic convertors create water as a byproduct of the catalyzation process).

 

[Ryanthegreat1]

I have the same crazy dream as Diploman since steel exhausts are heavy & rust (catalytic convertors create water as a byproduct of the catalyzation process).

Burning hydrocarbons always results in the byproduct of water.

The catalyst primary reactions do not result in water unless there are unburned hydrocarbons in the exhaust stream.

https://en.wikipedia.org/wiki/Catalytic_converter

1. Reduction of nitrogen oxides to nitrogen and oxygen: 2NO[SUB]x[/SUB] → xO[SUB]2[/SUB] + N[SUB]2[/SUB]
2. Oxidation of carbon monoxide to carbon dioxide: 2CO + O[SUB]2[/SUB] → 2CO[SUB]2[/SUB]
3. Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: C[SUB]x[/SUB]H[SUB]2x+2[/SUB] + [(3x+1)/2]O[SUB]2[/SUB] → xCO[SUB]2[/SUB] + (x+1)H[SUB]2[/SUB]O.

 

[SneakyOwl]

My proposal was just a pipe dream

Probably the best pun this forum will see

 

[Diploman]

Sneaky! Glad someone got it!

 

[Deleted member 452]

Burning hydrocarbons always results in the byproduct of water.

The catalyst primary reactions do not result in water unless there are unburned hydrocarbons in the exhaust stream.

https://en.wikipedia.org/wiki/Catalytic_converter

1. Reduction of nitrogen oxides to nitrogen and oxygen: 2NO[SUB]x[/SUB] → xO[SUB]2[/SUB] + N[SUB]2[/SUB]
2. Oxidation of carbon monoxide to carbon dioxide: 2CO + O[SUB]2[/SUB] → 2CO[SUB]2[/SUB]
3. Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: C[SUB]x[/SUB]H[SUB]2x+2[/SUB] + [(3x+1)/2]O[SUB]2[/SUB] → xCO[SUB]2[/SUB] + (x+1)H[SUB]2[/SUB]O.

Interesting, I always assumed it was a byproduct because you can see moisture come out of the exhaust when starting any modern car. That and I ran catalytic converters with aluminized steel exhaust and it always rusted a lot faster than in the old days before catalytic converters.