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Was a a bike meetup recently and a guy had an aftermarket slip on exhaust pipe with CAT removed. Was wondering if the will mess up airflow/performance?
Removing Catalytic Converter Question
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If by mess up you mean improve, then yes. 
Joking aside, you will make a lean bike even more lean, by adding a slip-on. You have a few options:
You can get a factory Termi slip-on that comes with a Race "tune".
Lots of other people get a slip on with a Rexxer tune OR
Slip on with Boosterplug (increases fuel in mixture by lying to the ECU about outside temp).
If you search the forums, there are details on all these options.
Joking aside, you will make a lean bike even more lean, by adding a slip-on. You have a few options:
You can get a factory Termi slip-on that comes with a Race "tune".
Lots of other people get a slip on with a Rexxer tune OR
Slip on with Boosterplug (increases fuel in mixture by lying to the ECU about outside temp).
If you search the forums, there are details on all these options.
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If by mess up you mean improve, then yes.
Joking aside, you will make a lean bike even more lean, by adding a slip-on. You have a few options:
You can get a factory Termi slip-on that comes with a Race "tune".
Lots of other people get a slip on with a Rexxer tune OR
Slip on with Boosterplug (increases fuel in mixture by lying to the ECU about outside temp).
If you search the forums, there are details on all these options.
If by mess up you mean improve, then yes.
Joking aside, you will make a lean bike even more lean, by adding a slip-on. You have a few options:
You can get a factory Termi slip-on that comes with a Race "tune".
Lots of other people get a slip on with a Rexxer tune OR
Slip on with Boosterplug (increases fuel in mixture by lying to the ECU about outside temp).
If you search the forums, there are details on all these options.
I was concerned about changing the back pressure, affecting the sensors, etc
It looks like the CAT is attached to the stock muffler, am I right?
Should be an easy swap.
Yes, lean is the way to go, already took off the EVAP cannister
This on looks badass
LeoVince LV One EVO Slip-On Exhaust Ducati Scrambler 2015-2016
Correct, no cat.
The Cat resides in the phat box in front of the rear wheel, the box and tail-pipe are all one unit so by removing the exhaust /silencer will remove the Cat.
Back pressure is of no relevance to this engine as the valve overlap is quite short. On the Panigale engine for example back pressure can help stop the inlet fuel charge from falling out into the exhaust by pushing back before the valve has a chance to shut as the valve overlap (ie. inlet & exhaust open) is nearly a fortnight.
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8 Posts
update: got the Two Brothers slip on on yesterday. It sounds siiiiiick
Ducati Scrambler Comp Slip-On Exhaust (2017)
Ducati Scrambler Comp Slip-On Exhaust (2017)
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192 Posts
Lean is not the way to go. Runs too hot. Not good. There are a lot of warnings throughout this forum warning of damage to the bike. If you do a slip on you should be doing a remap. I wouldn't trust the products that say no remap is necessary.
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Heck, a remap on a totally stock bike would ever freshen the engine up I guess. :eagerness:
But I gotta say, the scrambler seems pretty choked on the intake side; single throttle body and the airbox seems very "closed". More so than on the exhaust side. Hence the results with the MWR Power Up Kit.
The stock exhaust has quite some volume and the cat itself is a big 80mm unit with a three chamber design and some small blowby holes.
I would really like to see an A/F graph from a stock bike, and one with just a slipon with the DB killer installed.
I would never run an open pipe -too loud-, and to make a smaller, lighter aftermarket pipe reasonably quiet, the manufacturer has to build in some "choking" or even a resonance chamber. Chances are they have to choke the exhaust flow even more than on the stock exhaust to get the noise down.
I know from previous bikes that changing just the end can, and nothing else (so no air filter and/or airbox mods) hardly changes the fueling and or power output. And the other way around, change the airbox and the fuelling while leaving the exhaust stock could lead to interesting gains already.
But I gotta say, the scrambler seems pretty choked on the intake side; single throttle body and the airbox seems very "closed". More so than on the exhaust side. Hence the results with the MWR Power Up Kit.
The stock exhaust has quite some volume and the cat itself is a big 80mm unit with a three chamber design and some small blowby holes.
I would really like to see an A/F graph from a stock bike, and one with just a slipon with the DB killer installed.
I would never run an open pipe -too loud-, and to make a smaller, lighter aftermarket pipe reasonably quiet, the manufacturer has to build in some "choking" or even a resonance chamber. Chances are they have to choke the exhaust flow even more than on the stock exhaust to get the noise down.
I know from previous bikes that changing just the end can, and nothing else (so no air filter and/or airbox mods) hardly changes the fueling and or power output. And the other way around, change the airbox and the fuelling while leaving the exhaust stock could lead to interesting gains already.
The problem is, the many warnings on this forum about tuning are as far as I can tell are made by well meaning people who have read other forums who have also read other forums written by somebody who listened to a mate's mate who's never worked on an engine.
The way I can usually tell how much the author knows is when the 'back pressure' statements along with tuned lengths, rich, lean etc get thrown in with no technical explanation of any or all of them.
I've been tuning engines and fabricating exhausts for many years and never have a problem.
I will agree though that a re-map of a stock ecu will always show improvements without the factory compromises.
Anyway to free the exhaust of restrictions will mean no lost power trying to push and sqeeze the elephant up a stair. As far as making the mixture too lean, please will somebody explain HOW? on this particular engine with 11degrees of overlap. Don't waste time explaining a tuned 43 degree engine etc. I already know.
The way I can usually tell how much the author knows is when the 'back pressure' statements along with tuned lengths, rich, lean etc get thrown in with no technical explanation of any or all of them.
I've been tuning engines and fabricating exhausts for many years and never have a problem.
I will agree though that a re-map of a stock ecu will always show improvements without the factory compromises.
Anyway to free the exhaust of restrictions will mean no lost power trying to push and sqeeze the elephant up a stair. As far as making the mixture too lean, please will somebody explain HOW? on this particular engine with 11degrees of overlap. Don't waste time explaining a tuned 43 degree engine etc. I already know.
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Ha, I was reading up on exhausts in general, and ran into a German motorcycle web site that fitted a Zard street legal exhaust to their test fleet bike. Sounded much better without being obnoxiously loud. The bike lost over 4 horses though...
Kind of proves to me the Ducati engineers do know how to make an exhaust that A) keeps the bike decently quiet, and B) doesn't restrict exhaust flow too much. Of course the stock exhaust is heavy (it has to last the bike's life), they did a good job of using the space behind the engine.
At the same time I found this graph. Stock bike vs Rexxer map (both with stock airbox and stock exhaust)
![Text Line Plot Font Diagram]()
(too bad there was no A/F graph...)
Kind of proves to me the Ducati engineers do know how to make an exhaust that A) keeps the bike decently quiet, and B) doesn't restrict exhaust flow too much. Of course the stock exhaust is heavy (it has to last the bike's life), they did a good job of using the space behind the engine.
At the same time I found this graph. Stock bike vs Rexxer map (both with stock airbox and stock exhaust)
(too bad there was no A/F graph...)
"Kind of proves to me the Ducati engineers do know how to make an exhaust that A) keeps the bike decently quiet, and B)"
I'm sure Ducati know more than most about exhausts and definately more than me. On the other hand.
Have you seen the Zard high level ?
That proves to me that Zard know next to f/all. I don't think I've seen such a badly designed exhaust and as for looks it's in the eye of the beholder but for me it looks terrible.
I'm sure Ducati know more than most about exhausts and definately more than me. On the other hand.
Have you seen the Zard high level ?
That proves to me that Zard know next to f/all. I don't think I've seen such a badly designed exhaust and as for looks it's in the eye of the beholder but for me it looks terrible.
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1,231 Posts
I've had 2 scramblers, first was standard and I fitted a sc projects exhaust with NO cat I would say the bike lost most of its bottom end but gained a tiny amount up top, i ended up fitting a booster plug which did help but didnt cure the issue, not good but sounded great. My second scrambler came with a termignoni fitted (with race ecu) and now at 5000 miles it absolutely flies, sounds great, goes great, has loads of bottom and definitely more top, has a proper forward powerband surge that makes it a really fun bike to ride. So I would say if you replace the std exhaust for a race can, to fully benefit you need an ecu upgrade.
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Can't say I have but my ass tells me there's an improvement somewhere, I recon the noise also helps with the overall experience.
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