Scorpion exhaust map clarity

You don't give any details of the bike in question but here's some general info you might find useful.

Popping on over-run is usually caused by fresh air entering the exhaust system and igniting unburnt exhaust gases. There are two main causes for this:

1. Leaks in the exhaust system itself often caused by poor installation and lack of exhaust paste at the joints;

2. The Air Injection system is still in place,so fresh air is injected just after the exhaust valve.

 

So it will have Air Injection as well. The popping shows up more when you fit an after-market can because they are more open anyway.

Re-check the joints for leaks and fix them first, then go for an AI removal.

Just a thought, when they remapped the ECU, did they un-tick the box for AI as that would make the AI-ectomy a bit easier?

 

+1 on what Dave says, but if they've disabled the AI on the map they should have also blocked the pipe between airbox and the AI valve. (haven't looked under the tank on my Speedy yet but I'm assuming the setup is the same as on the Sprint1050 I had a while back - I fitted the Triumph TOR can to that - used one of the kids marbles to block the rubber pipe, but make sure it's big enough to not find its way back into the airbox!)
I assume it's just a slip-on and you still have the standard headers and cat fitted?
I would hope Serket give advice on whether it is designed to run on the standard map or not, probably worth contacting them to find out. Several manufacturers advertise their slip-ons as being suitable to run as standard, and if you Google the subject you'll find many are of the view that slip-ons are ok on standard (modern ECU's are self adjusting within set limits), only needing a remap for a full system.
However you're getting into a grey area when removing the baffle IMO.
As Triumph don't provide a map for other after market exhaust I'm assuming your dealer has used the Triumph map for the twin Arrow slip-ons, which might not be entirely suitable for your silencer. If they've used the map for the Arrow low-boy (which is visually more similar to yours) I would suggest that's a bad move, as that Arrow system is complete with modified headers and more performance orientated - and would probably give an over rich mixture as you describe.
As Dave says the popping (many owners see it as a +) is air in exhaust related so not specifically related to combustion mixture. I believe the AI is there to remove un-burnt fuel which could damage the cat, but I stand to be corrected on that one.

 

My understanding is that if you block the AI system but leave the O² in place, the bike with run more lean and my logic is this:

1. The O² sensor measures the exhaust gases plus the AI fresh air (if still in place) in the headers. This value is then sent to the ECU to calculate optimum fuelling.

2. If the AI fresh air is missing then the exhaust gases measured will be changed. This MIGHT mean the measurement shows the bike as running rich and the ECU leans things out - OR it might mean that because the exhaust flow is not receiving fresh air, then there is no after-burning of any unburnt fuel so the O² sensor receives just normal exhaust gas without the the removal of any un-burnt fuel - so it will tell the ECU "you're running rich" and the ECU will lean things out.

 

Hi Dave, (again)
Can't fault your logic..........but then I was confused, when SAI is disabled it's usually on a "performance" tune so why would you wan't to lean the A/F?
So I did a bit more digging, if I (now) understand correctly SAI only operates on small or closed throttle, so not really affecting the main map, and I guess the only significant benefit is stopping the popping on overrun. However it seems SAI's primary purpose is to maintain low emissions and for the cat to work at optimum, so therefore not a good idea to disable it if the cat is still in situ.
(The TOR can on my now departed '08 Sprint1050 also replaced a link pipe which contained the cat, so instructions I followed were sound, even if I didn't appreciate it at the time).
My digging was done here and here. (Most other searches related to cars which seem to be a little different in concept.)
The informative bit -
"The way AI works is…the the TPS tells the ECM the rider has let the throttle return to idle. O2 sensors go into open loop and don’t talk to the ECM which defaults the A/F mixture to a baseline map based upon information from the air temp sensor."

Going off on a tangent.... I've used the throttle balancing feature of TuneECU to good effect several times on the Sprint and SWMBO's Daytona, but as far as I know there's just one manifold pressure sensor connected by pipes to each throttle body. So how does that work!??
Only thing I can think is that it times the readings in sync with the firing order, any ideas? Difficult for an aging mech. des. engineer like me to get his head around the speed of electricery (I'm used to a good old set of vacuum gauges me)

 

Hi Col_C - it's really easy how the MAP works once one understands what the MAP does and what the crank sensor does.

The MAP sensor measures ambient air pressure constantly; the crank sensor sends signals to the ECU about the position of the crank constantly.

So as you can imagine the ECU is programmed to take signals from both sensors microsecond by microsecond. So the ECU is permanently making minute adjustments to the injector timing and duration based on the sensor information continually provided.

Regarding the function of the AI and O& sensors they are primarily pollution control devices and the bike will work perfectly well,even better without them.

For example, these devices are designed to provide information to the ECU at specific operational conditions so the factory can pass it's environmental targets. However, to users, these items introduce jerky throttles and popping and banging on over-run and not much else.

 

Hi Dave, yes understood the general principles of the ECU system, it was just the fact that it seems counter intuitive that you can balance the three throttle bodies from a single manifold pressure sensor continuously connected to all three (i.e. there's not a MAP sensor for each throttle body). That means the reading from the MAP sensor (which looks very mass produced & low tech) must sync with the crank sensor and have a fast enough response to differentiate between the three bodies.
Not disputing the facts, I've balanced the throttles numerous times using TuneECU and you can see the effect, it works.....
Just blows the mind what is happening for it to do so.

 

i asked Scorpion what map they recommend when I bought my Serket Taper, they said the standard map as its a slip on and doesn't change the headers etc. When Triumph serviced my bike with the Serket on they mapped it to the low boy can without telling me ...bad move as it ran very rich with loads of popping & sooty deposits. I took it to Clive Woods for the next service as he is now local to me and I'd heard very good things about him, he balanced the throttle bodies and he checked the map and put the one for the twin Arrows in and it runs much better, he also said if I want to try any other maps he would change it foc - btw i've never had the baffle in -

 

As a heads up , triumph seem to flash the map at services as a matter of course, so if you have a map that's not triumph original you have to tell them to leave it alone, I got done at my last service so my next one in giving them a written list of donts

 

Good point Crispey, must remember that when I take mine in (although I also want to check with them that the map on TuneECU site is the most up to date for my setup).
I got out on the Speedy this weekend for first run of the year, Saturday ran with the standard exhaust just to make sure all was ok before I started messing and also to refresh my brain so I could do a straight comparison.
Got back mid afternoon and put the twin Arrows on having removed the db-killers (dead easy - no probs) and then re-mapped the ECU. I've had confirmation from Alain at TuneECU that it's still ok to use it on 2015 bikes (mine's a 94R), he said if you can connect and read then writing will be ok, he also inferred that on later models that are blocked you would be unable to connect anyway.
Original map was 20656 and I've now loaded 20521, went out for another run on Sunday, seems to run as sweet as before, just sounds better, deeper and a bit louder but not by too much and now get a nice burble on the over-run. Haven't heard any full on pops and bangs so far and exhaust not sooty yet, but early days.
I think unless you're thrashing it everywhere a bit of soot is inevitable, the wife's 675Daytona has a TOR can and the correct map on for years, runs spot on but tailpipe has got a light coating inside over the years.
While I had TuneECU connected I noticed one of the throttle bodies was a bit out of sync but not by much and didn't have time to lift the tank....so a job for next weekend.

 

Good catch that the arrow-low mapping is intended for the full arrow exhaust setup. Everybody on the internet advises this mapping after installing a low-mounted slip-on, but indeed it is not the right one if you keep the cats in and use the standard headers!

I have SC projects slip-on (low) and the arrow low mapping, and the popping is driving me crazy. Besides, fuel consumption is quite high.
So was planning to block the SAI, but after reading the above I will also load the arrow twin-mapping as that was intended for slip-on solely.
Thanks experts!