So i fit a decat mid pipe with my original exhaust and i really like the sound and the volume is just right too.
After a few days i decided fit a aftermarket ECU just to richen up the system hopefully smoothing out the throttle response and add a bit of extra power.
Having spoken to Austin racing and they said "Yes it’ll definitely be better however I’m unsure if you’ll get the maximum potential using the standard muffler."
Coober says "We have a ECU version for de-cat 790, but never sold one, the power loose is huge. The engine was developed to be used with cat.
If you De-cat the 790 then you need whole setup the get a stable power output."
Now i cant say ive felt any huge loss of power in fact my bum Dyno says the bike is quicker.
Both units look identical with a different logo (and i assume a different mapping?)
So i guess im asking if anyone out there has tried a setup like this or has more knowledge about these things than me.
Do i really need a ECU to protect my engine after a decat?
Im kinda leaning towards the AR unit as it gives me room to move in to a aftermarket slipon at some point if i want to. Also the graph looks more linear.
So i fit a decat mid pipe with my original exhaust and i really like the sound and the volume is just right too.
After a few days i decided fit a aftermarket ECU just to richen up the system hopefully smoothing out the throttle response and add a bit of extra power.
Having spoken to Austin racing and they said "Yes it’ll definitely be better however I’m unsure if you’ll get the maximum potential using the standard muffler."
Coober says "We have a ECU version for de-cat 790, but never sold one, the power loose is huge. The engine was developed to be used with cat.
If you De-cat the 790 then you need whole setup the get a stable power output."
Now i cant say ive felt any huge loss of power in fact my bum Dyno says the bike is quicker.
Both units look identical with a different logo (and i assume a different mapping?)
So i guess im asking if anyone out there has tried a setup like this or has more knowledge about these things than me.
Do i really need a ECU to protect my engine after a decat?
Im kinda leaning towards the AR unit as it gives me room to move in to a aftermarket slipon at some point if i want to. Also the graph looks more linear.
this topic is covered in the decat thread
i fitted the coober last night.
Bottom line i think both are correct
Coober claim a decat removes too much back pressure affecting mid range power significantly 4000-8000
AR runs as decat this should produce more power circa 8500 upwards as the higher the revs the less significant back pressure becomes
If this is all true then Coober for road use and AR for Track would make sense.
The only way to be 100% would be if someone want to spend the money and time dyno testing all options on same dyno for comparison
1nd best thing would be get the AR muffler and ATOM ecu, this is a cheaper option then 2nd one, but still good enough since we could assume that decat pipe you have is the same as one sold by AR.
2st best thing would be to get AR decat & muffler system with intake ATOM ecu so you don't have to take bike for dyno-tuning. AR decat with ATOM and advanced map would be best but cost the most, reason is that this system is already setup probably within 90% range of ideal setup.
3rd best thing would be to get programmable ECU and take the bike to some good map tuner with dyno table, then it does not matter what setup you have, but not skilled tuners could do more damage then leaving bike as is.
Explanation...
Soon as you change intake or exhaust parameters you need to revise fueling map for ECU, it would also be good to change ignition timings but that is not necessary if you are not looking for power. You bike is most likely running to lean in low to mid rpms since you have increased exhaust flow (increasing exhaust flow will increase intake flow as well) and your ECU has no way of knowing how big the change is and what to change. Running lean actually increases power since it increases burning temperatures but at the same time it creates negative effects like burn valves and could create knocking (both are bad things for your engine in the long run). Why you need another ECU is because you can't reprogram stock ECU (if you could this would probably be cheapest way but you still need map tuner, dyno table & wideband O2 sensor). Reason why you need to reprogram your ECU is because stock ECU does not measure air flow in the intake or measure O2 in the exhaust which are both needed in order to know how much fuel you need to feed.
ATOM from AR is already set up to change stock ECU fueling signal to work well with their exhaust & intake combinations so you don't have to go for dyno tuning.
Hope this helps, also I don't have 790 duke (will be buying it next year) but I do understand how ECU and electroning fueling works.
Back pressure from catalytic converter might be needed to increase torque in low-mid rpm range (because of the valve timings might be set up to for power at high rpm) but on AR webpage dyno shows this not to be correct, since biggest gains are actually in low to mid range with de-cat pipe they sell.
Thanks for the info guys. @Anril i dont believe the ATOM unit is programmable at all, you just get what you get.
I agree the AR graph looks to me more like a torquey road tune compared to the Coober graph that looks more peaky. Did you take a look at the Coober graph... the one i posted is a bit small you can see it better on their site.
If the AR map and setup is indeed more road biased than the Coober unit i will go ahead and purchase from AR.
@anotheronetoday yeah i thought i would start a new thread to keep the exhaust stuff easier to find as that other thread has all kinds of stuff in it.
1nd best thing would be get the AR muffler and ATOM ecu, this is a cheaper option then 2nd one, but still good enough since we could assume that decat pipe you have is the same as one sold by AR.
2st best thing would be to get AR decat & muffler system with intake ATOM ecu so you don't have to take bike for dyno-tuning. AR decat with ATOM and advanced map would be best but cost the most, reason is that this system is already setup probably within 90% range of ideal setup.
3rd best thing would be to get programmable ECU and take the bike to some good map tuner with dyno table, then it does not matter what setup you have, but not skilled tuners could do more damage then leaving bike as is.
Explanation...
Soon as you change intake or exhaust parameters you need to revise fueling map for ECU, it would also be good to change ignition timings but that is not necessary if you are not looking for power. You bike is most likely running to lean in low to mid rpms since you have increased exhaust flow (increasing exhaust flow will increase intake flow as well) and your ECU has no way of knowing how big the change is and what to change. Running lean actually increases power since it increases burning temperatures but at the same time it creates negative effects like burn valves and could create knocking (both are bad things for your engine in the long run). Why you need another ECU is because you can't reprogram stock ECU (if you could this would probably be cheapest way but you still need map tuner, dyno table & wideband O2 sensor). Reason why you need to reprogram your ECU is because stock ECU does not measure air flow in the intake or measure O2 in the exhaust which are both needed in order to know how much fuel you need to feed.
ATOM from AR is already set up to change stock ECU fueling signal to work well with their exhaust & intake combinations so you don't have to go for dyno tuning.
Hope this helps, also I don't have 790 duke (will be buying it next year) but I do understand how ECU and electroning fueling works.
Hi Anril
I did not have a clean start
I purchase my bike with akro
Then purchased a decat not from AR
Then remove my akro baffle
so having purchased an akro and decat taking the AR complete system approach would have been significantly more money than just buying the coober
Perhaps the real shame is that the coober/atom unit only has one fixed map and that power commander are slow at introducing new kits for new bikes
Hi peoples, I just found another thread about this in aftermarket parts and bits, but I see someone is trying to combine the threads, so apologises if Im adding what is already known or has been discussed...🤔
Anyway, just as a 790 owner, I have the full AR system, with wiring harness, ATOM module and air box mod, and have done probably now over 1200 road miles with it....and I can say it has improved fuelling, as I can now ride it in sport mode almost all the time, without the original low rev snatchiness, and the mid range power has improved significantly, but I’ve have actually forgotten how good the original standard bike was in the 1st place....
I originally just wanted an end can that looked a little better than the original, but when I got my bike in early may there wasn’t anything available other than AR who were still developing the system at that point. I spoke to the guys there, and was told that for the full system (removing the cat) it needed the ATOM to stop it running hot/lean, and for optimum performance with that system they had just tested the air box mod which was the restricting factor in getting more/better air quantity into the bike.
I then got sucked in! Pardon the pun...🙄
I guess, with a new bike, as always there’s a lot of behind the scenes development, and people trying to mix and match pieces, and yes, I would say that the comber ECU is physically the same as the ATOM, and is probably the same part, although unknown, certainly to me, if the mappings are different...but just putting it out there, that at the moment the AR system I have fitted (myself by the way, it’s okay if you take your time, especially with the wiring harness-all very good quality connectors..etc...) does what it says on the tin so to speak...although I’ve not dynoed it, and don’t intend to as it’s made a fun bike even more fun....😁
Sorry for the long post.....Paul
Hi peoples, I just found another thread about this in aftermarket parts and bits, but I see someone is trying to combine the threads, so apologises if Im adding what is already known or has been discussed...🤔
Anyway, just as a 790 owner, I have the full AR system, with wiring harness, ATOM module and air box mod, and have done probably now over 1200 road miles with it....and I can say it has improved fuelling, as I can now ride it in sport mode almost all the time, without the original low rev snatchiness, and the mid range power has improved significantly, but I’ve have actually forgotten how good the original standard bike was in the 1st place....
I originally just wanted an end can that looked a little better than the original, but when I got my bike in early may there wasn’t anything available other than AR who were still developing the system at that point. I spoke to the guys there, and was told that for the full system (removing the cat) it needed the ATOM to stop it running hot/lean, and for optimum performance with that system they had just tested the air box mod which was the restricting factor in getting more/better air quantity into the bike.
I then got sucked in! Pardon the pun...🙄
I guess, with a new bike, as always there’s a lot of behind the scenes development, and people trying to mix and match pieces, and yes, I would say that the comber ECU is physically the same as the ATOM, and is probably the same part, although unknown, certainly to me, if the mappings are different...but just putting it out there, that at the moment the AR system I have fitted (myself by the way, it’s okay if you take your time, especially with the wiring harness-all very good quality connectors..etc...) does what it says on the tin so to speak...although I’ve not dynoed it, and don’t intend to as it’s made a fun bike even more fun....😁
Sorry for the long post.....Paul
Hi DukeAus, no drop in mid/low power, although I wouldn’t have expected that? But the torque power has increased right through the Rev range, and pulls much stronger than before, but as I said in the previous post, I’ve forgotten what the original standard bike was like now that I’ve been riding this system for quite a time, but that first ride was very noticeable...and it still pulling stronger than before (the engine) sitting up at over 125mph (closed road obviously..😳) but I’m sure laying on the tank the top speed would be pretty respectable...
As regards induction noise, I can’t say I’ve noticed any real difference, but the standard air box is quite small and restrictive with a difficult path for the air flow, so the air box mod just relieves the pressure in the box, but with it all mounted under the seat, it’s not like conventional sports bikes with the intakes on the front behind the fairing where the noise is more noticeable...😁
Hope that helps...🤔
Getting airbox and atom should be just as good as whole AR system that they sell. It might not be 100% exact but it should be very close and most important engine will not run lean and you will have sound that you like. Btw there are no risks if engine runs a bit rich, it actually helps with throttle response and prevents engine from running too hot.
There is another thread going here where I said that I don't believe Coober dyno results, since big gains across whole rpm range with just ecu are hard to believe. Many engine tuners said that mapping an ecu can improve engine response but will not make an engine produce more hp, usually gains would be 1-2% at best on some narrow rpm range and for big gains (over 5% gains) you need do more than just changing intake & exhaust. It's hard to believe that car/motorcycle companies do not know how map ecu correctly, if they could sell 110hp engine instead of 105 just with different map they surely would.
Tried to upload my Coober installation guide but this forum restricts files to 20k which is tiny in todays world
so stripped pictures out
contact me if you want proper doc
The idiots guide to installing a Coober ECU to a KTM790
When you open the box you will see a wiring harness and a control box, this may look daunting, but as long as you are careful and take your time, anyone with limited tools and experience can install this.
Depending upon your experience I would allow 2-4hours
You will requires a T30 Torx driver, cutters, cable ties, torch/good lighting
For our USA friends cable tie= zip tie and Gasoline=Petrol
Preparing your bike for installation
I would suggest fitting this when your engine is cold unless you like burning your fingers and if you have a paddock stand use it!
You need to remove seats, body panels and loosen the tank to gain access and carry out this installation
This is my suggested process
a/ Remove rear seat with your Key
b/ Remove front seat by removing the 2xTorx screws located at the rear of the seat
c/ Remove the petrol tank cover, remove the 6xT30 screws (1 either side and 4 at the front) Once you have removed these screws you will find the cover is still held in place by a flange and grommet located either side at the bottom rear above the frame tube.
Gently place your fingers up behind the cover in this location and pull outwards until the cover comes away then repeat on the other side.
Then hold the two front side of the loosened cover and pull apart enough to clear the Petrol tank and take away.
d/ Below the petrol tank on both sides you will see the black plastic outer infill panels these are each held on by 3 x T30 screws, remove.
Behind the LHS cover is the evap filter and the RHS cover the coolant expansion tank you want to gently moves these to one side to get better access (you might need to remove one or more pipe off the evap filter to facilitate this. (Mark pipe(s) to ensure correct refitting)
e/ Next you need to remove both of the inner black plastic infill’s, LHS cut the single tie wrap and undo another 3xT30 screws. RHS cut the 3xtie wraps and again undo yet another 3xT30 screws. Picture below shows LHS inner fill panel with evap filter
f/ At this stage loosen the 2xT30 screws 1 on either side of the petrol tank and wedge a small piece of wood or a cloth at rear of tank to lift it slightly to give greater clearance under the tank for better access.
Correctly identify the required connections
Remember cylinder 1 is on the LHS
There are 6 connections to identify on your bike, so the new wiring harness has 12 connectors 6 in 6 out.
1/ KTM Part number 59039034000 pulse generator KOKUSAN 4K3-A/ This is the (Crank connector) and is located on the front left side between the frame and the radiator, you are looking for a blue two pin connector. As shown right
2-3/ KTM part number 63539006000 stick coil (IGNITION) When you look at the top of the engine you will see the two coil packs (on top of spark plugs) follow each wire back to the black connector which is located on a metal tang, release the connector from the tang to ease installation.
Identify LHS cylinder 1 and RHS cylinder 2 connectors. Picture right shows LHS connector that has been release from its metal tang.
These are easily removed
4-5/ KTM part number 90841123000 FUEL INJECTOR (Fuel) if you look on the top of the throttle body on both sides you will see a fuel injector with its Grey connector on.
Picture right shows the LHS injector connector removed from injector.
These are the most difficult to remove take time and care they will come off
6/KTM part number 63541001000 throttle body on the LHS of the body the throttle position sensor is mounted (ConnectTPS) you will see the required connector plugged into the back edge of this. Picture right shows the throttle body with its connector removed awaiting connection
There is very limit space cut cable ties to give a bit more free play to get both this connector out and connect the new connectors from the wiring harness
The next stage is to install the wiring harness.
Do not connect the black box at this stage
Lay the cable down the LHS of the frame you might need to gently push the airbox over to get the cable neatly behind the LHS seat spigot.
Pop all 12 of the connections between the frame and under the petrol tank neatly to avoid fouling any of the existing cables and connections and pull them through to the RHS of the bike as shown below
This next stage is to remove and refit the connections
Each connector is labelled clearly on the new harness and you have identified the required connectors on the bike.
I would recommend that you remove one bike connector at a time and fit this to the appropriate harness connection and then plug the appropriate harness connection on to the now vacant bike connection, If you do it this way you should avoid confusion and mixing wires.
Do not force any connectors, either taking them off or to plugging them in (forcing a connector may damage it, this is both expensive and difficult to fix)
When all connections are made connect the earth to the battery and plug in the black box to the wiring harness connector and locate box in space in front of battery as shown below
Test your installation
Briefly start your bike to make sure all is good, if engine starts and runs cleanly TURN OFF.
If bike will not start check all connections are full pushed in again.
If bike still fails to start i would replace all original bike connectors and try again
If bike then starts i would suggest contacting your supplier for assistance.
Tidy up
You now need to tidy up the wiring, I would recommend a lot of cable ties for neatness and reliability and to prevent abrasion and vibration
The most difficult panels to replace are the two inner undertank panels, patience and cable ties will win
Do not over tighten the screws hand tight is good enough.
My tool kit was located in the same compartment are the new control box, i found i could still get my tool kit even with the control box in the same location
ENJOY
P.S. These are my opinions and are aimed as a guide, never attempt fitting this if you are in doubt or lack the required skills.
@anotheronetoday thanks for the awesome write up ill PM you for the pics. Did you try compressing the pics to be able to fit them in... maybe even split the guide through a few posts if necessary?
So how does your ride feel with the Coober unit fitted?
You need to remember they are generally working to extremely strict emissions guidelines set out by the EU, they do the best they can whilst staying withing the set boundaries.
Getting airbox and atom should be just as good as whole AR system that they sell. It might not be 100% exact but it should be very close and most important engine will not run lean and you will have sound that you like. Btw there are no risks if engine runs a bit rich, it actually helps with throttle response and prevents engine from running too hot.
There is another thread going here where I said that I don't believe Coober dyno results, since big gains across whole rpm range with just ecu are hard to believe. Many engine tuners said that mapping an ecu can improve engine response but will not make an engine produce more hp, usually gains would be 1-2% at best on some narrow rpm range and for big gains (over 5% gains) you need do more than just changing intake & exhaust. It's hard to believe that car/motorcycle companies do not know how map ecu correctly, if they could sell 110hp engine instead of 105 just with different map they surely would.
The coober results show a 5-10% improvement with standard cat plus exhaust
The AR 3-17% improvement with decat and full exhaust
As previously covered a manufacturer has to comply to emission regulations and plan for poor grade fuels that are sold in some markets
we have the benefit of superior fuels and not complying to emission regulations
so i can easily see a 5-10% improvement for coober and the 17% for AR as they have changed the airbox and the complete exhaust system as well
Very few dyno's are accurate better than 20%
But they all tend to be good for comparisons (before and after mods) so i always look at the before and after rather than the actual measured BHP at the end of the day if your trying to get more that is what you are interested in
Before and after graphs from both Coober and AR are arguable, I can argue that strict emissions are not that strict as you might think if you research VW diesel emissions fiasco that happened not so long ago, that brought to light that every car manufacturer is "cheating" emission tests, motorcycle manufacturers do the same (we know this from bike surging and constant speed and low rpm throttle response). All I am saying is what more then few respectable tuning companies, motorcycle manufacturers and professional racing teams stated many times before. This topic has been argued for 15 years now if not more and since we can't really know, what's the point in arguing?
My opinion is that Coober is great if you like to keep catalytic converter but want to get rid of low to mid throttle response and surging at low speed with steady throttle (both caused by emission control) and unless you will bring your bike to customized professional tuner, AR atom would be best option for de-cat system. And in my opinion power gains stated by manufacturer should not be taken as accurate measurements.
Btw I am not sure but as of recent AR is not selling full system with atom anymore, seams that atom ecu has been removed (hope it's not because of engine failures).
Before and after graphs from both Coober and AR are arguable, I can argue that strict emissions are not that strict as you might think if you research VW diesel emissions fiasco that happened not so long ago, that brought to light that every car manufacturer is "cheating" emission tests, motorcycle manufacturers do the same (we know this from bike surging and constant speed and low rpm throttle response). All I am saying is what more then few respectable tuning companies, motorcycle manufacturers and professional racing teams stated many times before. This topic has been argued for 15 years now if not more and since we can't really know, what's the point in arguing?
My opinion is that Coober is great if you like to keep catalytic converter but want to get rid of low to mid throttle response and surging at low speed with steady throttle (both caused by emission control) and unless you will bring your bike to customized professional tuner, AR atom would be best option for de-cat system. And in my opinion power gains stated by manufacturer should not be taken as accurate measurements.
Btw I am not sure but as of recent AR is not selling full system with atom anymore, seams that atom ecu has been removed (hope it's not because of engine failures).
I use coober ecu and spoke with them few times on the phone, they strictly recommend to keep cat. I think the main reason is not emissions, it is reliability of the engine. As i understand, products sold under coober name must keep emissions due their road permit, their products sold under different name are made for customers with no emission guaranty.
for now i have 4000km on my dash, and i am still happy
Hi Have you fitted your ATOM yet?
first impressions?
I fitted my Coober Kit with ATOM air intake mod
The engine will run down to 2500RPM even in 5th Gear
So i would say better low speed running
to early to say much else
I ordered a cheap slip on for my 790 because I can't stand the look of the stock pipe and stole the SC Project to put on my 890. The bike will be for sale any day now, but for $76, I figured I would give it a shot. Honestly, it's a pretty decent pipe. Considerably lighter than stock, No...
I'm not sure if this makes me a big old hypocrite, but today, despite all my claims that I like a quiet bike, I removed the db killer in my Akra slip-on. Why? When I was at the KTM dealership on Thursday, I heard what this setup sounded like, and it tickled my fancy. Now, that I've done it, I'll...
So, I keep going back and forth between stock, WIngs slip-on, Arka slip-on or full, etc.
I have not seen any good info that I can draw from to make an opinion on the Akra full system so I may be willing to champion the cause. I guess I don't mind spending the money one time if it is the right...
Sectional photo of the Cat Converter.
By removing this completely, and replacing with an available pipe:
*What changes should be made to compensate for this as well as the slip-on?
*Coober doesn't recommend removing the Cat, why? How will it affect the running with the Coober installed...
I'm a stickler for following the service manual instructions, but I'm kind of scratching my head at this bit about using copper paste to mount the silencer clamp.
Is the copper paste for the screw itself? I've never heard of it. Or is the paste for the clamp itself somehow? Any tips...
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