I've been watching a stock exhaust on eBay for the purpose of modification. Any modification to it will change the power delivery and require fuelling changes. Without fuelling changes you risk blowing the engine.

 

I have to add that I wouldn't do what they did though, that's just heresy, might as well run a straight through.

 

can u suggest me a cheap / safe / good exhaust system?
i'm very much happy with the duke 390 except the exhaust note!
:crying:

 

There are lots out there that'll make it sound better. If I were you, I'd look at getting a PowerTronic and air filter first though.

 

I totally agree with all the comments above, Noise does not always = power & as mentioned changing the exhaust may not give you more power, More than likely with more flow you main gain power higher in the RPM range but you might actually lose needed torque & power down lower in the revs, This is the tricky part that needs to be worked out by a good exhaust manufacturer

1 of the main advantages though even if you dont gain any power is the weight loss, The stock catalytic converter is rather heavy so dropping the weight helps your power to weight ratio overall which not only helps acceleration but also braking & handling, Probably barely noticeable to most unless you are racing & going for those extra seconds per lap etc

I am waiting to get my hands on the new Austinracing Hi Slung GP1 exhaust as soon as it is available>

https://www.facebook.com/pages/Austinracing/654737234631379

 

don't forget the famous tunable Supertrapp

SuperTrapp: Performance Exhaust


These really work as advertised. I've had one on my Mini Cooper S for along time and will install one on my next motorcycle (last bike was a 2 stroke.)

 

i'm happy with the speed, not looking for any kind of performance boost..
only looking for a better exhaust tone...

 

The creators of the 390 Duke, KTM, designed a compact, mass-centralized exhaust system that was carefully synchronized with the ECU's fuel mapping. As MalJohann notes, any change to the exhaust will perturb the air/fuel ratio programmed into the ECU: and this could lead to an excessively lean condition which could seriously damage your motor. KTM has approved the Akropovic exhaust as an aftermarket upgrade. But to use this exhaust also requires the ECU remapping reflash KTM offers.

I think your best bet is to leave the well-designed stock exhaust alone and not worry that it has a civilized exhaust note, as Mechanical_Vandal advises. A 390 Duke is never going to rumble like a Harley!

The Duke exhaust is one of my favorite features of the bike. It is centralized, compact, unobtrusive and effective. It does not require hanging a conventional-style can off the side of the bike - in addition to requiring a remap, this arrangement interferes with saddlebags, precludes (or burns) a pillion, creates extra aerodynamic drag to slow you, and is waiting to be mangled if there is a crash. The "cheap/safe/good" exhaust you are seeking is the one you already have!

 

After much research and consideration I've decided to go with the SuperTrapp S/C Elite 10" stubby in the OEM location in place of the original exhaust. This, only because I can adjust fueling with my aftermarket piggyback ECU, but having a flow adjustable exhaust will certainly help too.

http://www.supertrapp.com/product_sections/detail.asp?CatID=30&ItemID=443-2011

 

After much research and consideration I've decided to go with the SuperTrapp S/C Elite 10" stubby in the OEM location in place of the original exhaust. This, only because I can adjust fueling with my aftermarket piggyback ECU, but having a flow adjustable exhaust will certainly help too.

SuperTrapp: Performance Exhaust

MJ! One more thing for you to review for us! Will look forward to your install!

 

I'll be interested to see how this works for you. If you can fit it in the OEM location, it will retain all the "packaging" advantages of the original, plus likely lighter weight. Possibly might gain a HP or two if the fueling can be sorted. Nice choice!

 

4” Disc S/C Elites are a 3.5” body diameter which tapers out to a 4” opening. They’re available in a 10” length body with a 2.00” (50.8mm) inlet diameter (ID).

This is smaller than the original, and because its the same shape all around and exhaust gasses exit at the opening around its diameter, you just rotate it until the mounting bracket lines up (may need to bend the bracket a bit, but its SS so bending is fine) to the mounting point on the frame.

Also, in case you missed it, the exhaust can be tuned to your bike, or in combination with a piggyback ECU to how you want the power curve to look. Essentially because the discs are separated by a gap, by adding more discs at the opening, you increase the size of the opening. It helps to think of each disc you add as making another hole in the exhaust, or making the current one bigger.

Have a look at their FAQ: SuperTrapp: Resource Center

[EDIT] My thanks to @flyboy2160 for putting me on to the Supertrapp exhaust! [/EDIT]

 

I like that "tuneable" concept. Thank you for being the Guinea Pig! Hope it turns out to be a valuable upgrade. If so, I might emulate...

 

Buddy of mine had Dual Supertrapp's on his 1985 V-Max and a Dynojet Stage 3 carb kit done at local Dynojet facility here and when they had it on the dyno his neighbors started coming over to see what the H**L he was tuning ! I rode it and next to my K1300s it was the fastest bike I've ever ridden. Was definitely the loudest by far !

 

I like the GPR underbody exhaust.
looks even more compact and simpler than the OEM.

https://www.youtube.com/watch?v=UzMyanqmy0I

 

This thread seems to perpetuate the myth that an open pipe or one with less internal obstructions merely needs fueling changes to outperform the stock design. It is not nearly as simple as that and even reputable companies only sell replacement systems that are dyno proven to produce the same power as stock. They may claim slightly more torque in parts of the rev range but can almost never produce significantly more top end power.


The standard exhaust is designed to have an effective length which is matched to cam timing and other engine parameters and it operates in a resonant way which is completely broken if you remove its internals or replace it with an open pipe.


The exhaust design of this bike is one of its best features for exactly the reasons described above and in my opinion even the factory approved alternative is no improvement except for a better sound.

 

I love where the stock exhaust is situated, would happily keep it. But.....it's not loud enough. And my main reason is safety. Nobody can hear you.

 

If you want to be heard for safety, a better alternative to a loud exhaust is to fit a good set of aftermarket horns, such as FIAMM, Hella, Denali, etc.

 

Hi Johann,

Any updates on fitting your SuperTrapp ?

 

I'm curious to see how the Supertrapp muffler works, too.

 

Inquiring minds want to know, Johann! The pressure is building....
We know you have other priorities, such as the O2 sensor. But if the SuperTrapp works (without being obnoxiously loud), and the fuelling can be correctly mapped with a piggy, I think many would be interested in that mod.

Despite its rather stifled tone and ample mass, the stock exhaust is so well engineered that - as Binoy the PowerTronic guy affirmed - it is extremely difficult to find any aftermarket exhaust that can beat the stocker for power.

 

Inquiring minds want to know, Johann! The pressure is building...

[DISCLAIMER] Super busy on all fronts of life at the moment, so projects and participation on the forum is less of a priority and not so desirable time allocation wise. I'll let you know how it turns out when I get to it, but there's no reason it shouldn't be the perfect tunable and tucked away solution. [/DISCLAIMER]

 

Unless there's a after market that tucks up like the stock I'll wait...

That said, very interested in the install...

 

GPR Ghost...

 

I ended up buying a stock exhaust for peanuts from a guy who'd ditched it for an aftermarket one. The plan is to use it for experiments to see if anything can be done to improve the tone while making the least changes to the existing design, but life is getting in the way of being able to spend much time on it.

I have done some exploratory keyhole surgery already to see what the innards really look like & have some ideas to try... just need the time to do them.

 

Maybe IXIL will design a muffler similar to the one they build for the FZ09 that has a carbon cover with a side exit which resides in the original location. If and when I pipe my Triple this is the way I'm going.

 

One drawback of any aftermarket company making a compact underbody similar to OEM is the short header length and its detrimental effects on power. I fully understand not wanting a can hanging off the side, but we're making over 40% more power in the midrange with the MIVV, so that's a trade off I'll gladly accept. It's just too fun.....

 

Aesthetics be damned for you guys pulled out on the dyno in my opinion. Now if it was only 1-2hp gain that's another story.

 

Any update on modifying the stock exhaust?

I have a PowerTronic, K&N filter, and need to open the exhaust up. I too like the location of the stock exhaust. I'm about to just weld something up myself and use a muffler from something else.

 

Howdy,

No update from my experiments. Life is getting in the way of fun stuff at the moment....

 

Too busy waxing your new ride ? >