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[beardyweirdy@me.com_imp]

Hey All,

I've been tinkering and refitted the OEM Muffler to my bike.

I've been running with my lovely Over end can but but as I'm planning a trip or two soon, with a pillion, decided that a bit of peace and quiet might be nice ;-)

I'm actually loving the original can again! It's so smooth and it just purrs along. I'm running it on the end of my Arrow Cat Free 4-1, which was already fitted to the bike.

I've got a PCv and Auto Tune fitted, so I'm not too concerned about the fuelling, but wondered which way, if any, I should expect to see the fuelling go?

The flow of exhaust gas, I'm assuming, must be restricted with the Stock Muffler. Should this make the bike run lean or rich?

I ask as last time I went to the Dyno, after fitting air box mods and a cat free header with the Over muffler, I expected to see the bike running lean and was told that it was the opposite. The person at the tuners said that opening up the air box and exhaust would make the bike run rich and they'd had to lean it off. Not what I expected to hear.

So, that said, should I be expecting to richen it up after fitting the restricted, stock muffler?

What do you reckon?

[Bheezy27403_imp]

Hmmm, that's odd. I'm no expert but opening up a motor to breathe better should lean it out. Add more air, need to add more fuel.

[beardyweirdy@me.com_imp]

That's what I would have thought....

I'm giving it a few miles and then I'll look at the Auto Tume trim tables, to see what it wants.

[dbarkdoll_imp]

What exactly does the Auto Tune do? Just reads and logs air/fuel mixture for you to later download on a computer?

[beardyweirdy@me.com_imp]

What exactly does the Auto Tune do? Just reads and logs air/fuel mixture for you to later download on a computer?

It measures the Air/Fuel mixture via a Wideband O2 sensor in the exhaust pipe and adjusts the mixture, via a Power Commander to achieve the Air Fuel Ratio you have specified. You set up your Target AFR's via software on a computer that you connect to the Power Commander.

It's a nifty system.
On another note, I took it for another spin last night and checked the Trims it had suggested for the fuel and it was asking for the fuel to be reduced and the mixture leaned off. Makes sense.
I'm loving the 'New' quiet pipe, by the way.... Noisy exhausts are so last year ;-)

That said, and I might just be being paranoid, but I'm sure I've had more people step out in front of me since I quieted her down.

[PowerDubs_imp]

What exactly does the Auto Tune do? Just reads and logs air/fuel mixture for you to later download on a computer?

The power commander box allows you to adjust fuel +/- at the different rpm and throttle positions. This graph of data points is commonly referred to as the 'map'. The bike ecu has a map for the fuel, and also one for the ignition although this only adjusts the fuel map.

So the 'PC' allows you to change the map, but has no way of knowing what to do and where unless you put the bike on a dyno and are able to read it's air/fuel ratio at the various rpm and load.

The auto tune module plugs into the power commander on your bike, and you also install a wide band o2 sensor in your pipe. While you ride it looks at your a/f ratio from the wbo2 sensor and creates a modified map for you based on your 'target' a/f ratio you are requesting. Note- it just creates the map, it does not adjust the ecu file / parameters being used on the fly.

Once you return home, you can plug in your laptop and view the new suggested map the auto tune created. If you like it- you can then apply it (overwriting the existing map being ran). You then go ride again, repeat the process and see what the auto tune thinks the next time.

Given that you will always have differences in the rpm you ride at, and the throttle position for each rpm - it can take several rides to get a well adjusted map file dialed in.

Hope that helps. And yea- it doesn't 'auto' tune per say, at least not 100% on it's own. Still a fair amount of involvement- but way better than rejetting carbs, and looking at spark plug color.

[dbarkdoll_imp]

That is very cool. Thanks for the responses guys, very good job of explaining it. Any idea how much the auto tune module and o2 sensor cost?

[PowerDubs_imp]

Not cheap. Off the top my head if you shop around for both pieces you’re still looking at somewhere between 550 and $600. And you still need to have the O2 bung welded into the exhaust.

Basically both of these parts only exist for people that are making major modifications. If you are only putting on a different muffler than the bike will run fine as is.

If you want to change to a header to get rid of the cat, then you can buy just the power commander by itself or send your EC you for a reflash for somewhere around $300 if I remember correctly.


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[beardyweirdy@me.com_imp]

" Note- it just creates the map, it does not adjust the ecu file / parameters being used on the fly."

Is that right? I've always wondered and I've heard both that it does and that it doesn't....

I know the fuelling feels better with the Auto Tune on.

Acc. It might adjust on the fly. I was looking at putting Target AFR's in the 0% throttle line earlier, but Dynojet advise against it as it can upset the idle/over run and cause surging I think. They advise only adjusting the Fuel manually in the Fuel map. If the Auto Tune wasn't adjusting the AFR on the fly, then this wouldn't matter. I'm not 100% sure either way tho and just trying to work out if it does adjust as you ride...

[dbarkdoll_imp]

Not cheap. Off the top my head if you shop around for both pieces you’re still looking at somewhere between 550 and $600. And you still need to have the O2 bung welded into the exhaust.

Basically both of these parts only exist for people that are making major modifications. If you are only putting on a different muffler than the bike will run fine as is.

If you want to change to a header to get rid of the cat, then you can buy just the power commander by itself or send your EC you for a reflash for somewhere around $300 if I remember correctly.


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Noted. Thanks. I’m not planning on doing any of this at the moment btw, but it’s good info to know. I’m happy with my Arrow slip-on and stock everything else at the moment, as is my wallet. One day maybe! Prob just pick up a MT09 or Street Triple if the need for speed gets any worse tho.