Standard vs PCV vs AF-XIED

All this has started me thinking if it would be worth changing the exhaust headers. At the moment they are standard headers that I picked up cheaply on eBay as there is damage on the right front pipe. Have them de catted and the originals are sitting in the shed. I know I don't need to but I like fiddle around with it.
Any thoughts on whether the narrower collector and removal of the balance pipe would be a bonus to all round performance?
The original system is designed more with the catalytic converter in mind rather than gas extraction so I wondered if anyone had found it a benefit going for the aftermarket type?
Seem to have read somewhere that the O2 sensors should ideally be about 18" from the exhaust port and the standard system has them at 22". The aftermarket systems do seem to have them a bit closer than 22" so maybe there's something in it.
 
Having run the XIED`s for over 2 years - 20k + miles on an 2009 1200gs.
My recorded data shows AFR`s of setting 6 = 14.1 , setting 7 = 13.8 , setting 8 = 13.2,
I know stick with setting 7. The system seems to take 3 tanks of fuel to settle down.( adaptations )
I have now fitted them on a 2012 GS so will check these results on the twin cam when I get time to hook up the Innovate dual LM2 to the bike and log the data.

No problem, Keith. Might make you a bit unsettled when you get back on your own.

Interesting figures, Mistacat. I can understand number 6 being 14.1 but thought each 'click' was equivalent to 0.1. (They don't really click.) Which should give a maximum richness of around 13.7 to 1?
Be curious to see what effect it has on your TC, although I doubt that there's that much difference from the SC.
A variance in components or O2 sensors maybe?
Going to let mine be for a few hundred miles yet and let the adaption settle down before I start tweaking the knob. I'll maybe pull one of the O2 sensors to get an idea on the mixture after that. Roger had said that Mike at nightrider reckoned his bike took 1500 miles to fully adapt.
That'll be one for Roger to ponder over when he reads this thread.

John, You've done a great job of explaining the what's and why's of your decision. The candid descriptions of what is it like getting started are useful too.

As far as the settings go, you can trust Mistacat's information. By running duel LC-2's at the same time he runs the AF-XIEDs , he is giving pretty exact information. Each setting adds more than 0.1 AFR (maybe you're looking at settings 1-4 which don't add much fuel).

Going a little further on this explanation, the narrowband O2 sensors are sensitive to exhaust temperature. This means that the "exact" AFR for closed loop is dependent on several things: distance from cylinder to O2, engine load and engine model. Even though you don't know the AFR precisely, that's not important. By trying various settings, you find the one that adds the best amount of fuel for your bike and riding style. Said differently, it's not important if you're at 13.7:1 or 13.95:1, you just want to find the fuel addition that smoothes out the engine's performance.

The other variable is the condition of your O2 sensors. A few older 1150s have had O2 sensors that were damaged or worn out and didn't output enough signal to work effectively with the AF-XIED. On those bikes, O2 sensor replacement was needed. Yours should be fine.
 
All this has started me thinking if it would be worth changing the exhaust headers. At the moment they are standard headers that I picked up cheaply on eBay as there is damage on the right front pipe. Have them de catted and the originals are sitting in the shed. I know I don't need to but I like fiddle around with it.
Any thoughts on whether the narrower collector and removal of the balance pipe would be a bonus to all round performance?
The original system is designed more with the catalytic converter in mind rather than gas extraction so I wondered if anyone had found it a benefit going for the aftermarket type?
Seem to have read somewhere that the O2 sensors should ideally be about 18" from the exhaust port and the standard system has them at 22". The aftermarket systems do seem to have them a bit closer than 22" so maybe there's something in it.

As you move the O2 sensors closer to the exhaust valve, the temperature goes up. That flattens the transfer curve of the narrowband O2 sensor somewhat, leading to closed loop AFRs that get richer for the same AF-XIED setting.

The second thing that happens as you get the O2 sensor closer to the exhaust valve is that the closed loop period gets shorter. This can be seen especially on the R1150GS which has the O2 sensor inside the catalytic converter and a long way from the exhaust valve. At idle, the closed loop period is about 5 seconds (normal period is about one second).

All that said, 18-22" is fine and won't create much of a difference.
 
That's a relief!
Just bought a full system on eBay this morning that has the de cat headers, no balance pipe and the O2 bosses look closer to the exhaust port.
Full 'Bos' system including sports silencer in excellent condition for £100? I was the only person to bid. Surprised me.

I'll get a look at the O2 sensors when I change the exhaust to check to see if they're sooty. Maybe I'll need to back it down to 7.
Mistacat, what exhaust headers and silencer are you running?

Roger, can you explain a bit more about the closed loop period?
I assumed that 'closed loop' referred to a throttle % opening X rpm specific area of the fuel map. In other words, if you were cruising at 4000 rpm at 20% throttle, it would remain in the closed loop area indefinitely.
What does a 1 or 5 second closed loop period mean exactly?
I think it's good to have some understanding about the workings of your bike rather than go with the flow.
 
I am using a Remus system, No balance pipe. (had it on the 2009 now on the 2012).
The stock narrow band O2 sensors are approx 14 inches from the exhaust port and the wide band sampling ports approx 17 inches.
Remus oval silencer with the db killer removed, I have made a 7 inch extension with a 1 3/4 inch perforated core wrapped in sound absorbent material. This was done so that the gases exit behind the number plate and panniers. It turned out to be quieter than when the db killer was installed and stops the number plate melting.
 
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I'll get a look at the O2 sensors when I change the exhaust to check to see if they're sooty. Maybe I'll need to back it down to 7.

...

Roger, can you explain a bit more about the closed loop period?
I assumed that 'closed loop' referred to a throttle % opening X rpm specific area of the fuel map. In other words, if you were cruising at 4000 rpm at 20% throttle, it would remain in the closed loop area indefinitely.
What does a 1 or 5 second closed loop period mean exactly?
I think it's good to have some understanding about the workings of your bike rather than go with the flow.

John,
I've been running 13.5 or 13.8:1 for about 4 years. When I remove the O2 sensor, sometimes there is a light soot but it never is more than that. If you find a little soot, I don't think I'd worry. When you check your center plugs the might look slightly less white. Below is a photo of what mine now look like. Of interest, my header used to get a light rustiness after a month or two of riding. With the lower EGT due to 13.5:1, the headers have a dark, burnished look with no rust.

The term closed loop refers to that part of the fuel map (roughly it's less than half throttle, below 6500 RPM, engine warmed-up, throttle not moving too fast) where the Motronic or BMSK is executing a program that straddles the switching point of the O2 sensor. The switching point of a stock narrowband O2 is lambda=1, which is 14.7:1 for gasoline (14.1:1 for gasoline with 10% ethanol). By switching point, I mean that exhaust gas O2 concentration where the O2 sensor output voltage changes rapidly from 800 mV to 100 mV. Below is a chart of the closed loop area of the Motronic MA 2.4 from my bike. The R1200 bikes have a broader area and don't have the light load exclusion area that you can see on the R1150 chart. When you run an AF-XIED or LC-2, you alter the switching point to less exhaust O2 which means it is RICHER.

The closed loop program ramps the mixture a little richer until it sees 800 mV and then a little leaner until 100 mV, then a little richer, and on and on until you move the throttle a lot, or until you open the throttle very wide. The time it takes to ramp from lean to rich and back to lean is the closed loop period. That period includes the time it takes for a change in mixture to get through the combustion process and travel down the exhaust pipe and register at the O2 sensor and it also includes a bit of holding time in the richer and lean states before changing the mixture ramping direction. The R1150GS has a long period at idle because it takes a long time for the O2 concentration change to reach the sensor's location. It doesn't mean much to us as riders, just an interesting point of data.

By running this closed loop program the Motronic or BMSK is able to learn exactly where the switching point is located and then develop short term and long term trims (you might want to google those trim terms), thereby keeping fueling in an exact range.

13.8autolite.JPG


R1150ClosedLoop4.jpg
 
Thanks for clarifying that, Roger. As usual, completely overloaded with information. Ah well, give me something to read this evening.

Got another run out today. That's just under 300 miles now since I've installed the AF-XIED units and it's still getting better.
I know many people complain about a flat spot around 4-5k rpm on the standard engine. Well, 4k rpm is my new favorite number.
Open the taps at 4k rpm in top gear and the bike just surges forward. Hold on a bit too long and you could quickly find yourself into three figure speeds. So I'm told. :rolleyes:
I think I'm starting to notice the engine getting smoother across the rev band. The fueling is starting to feel a lot 'cleaner'.
Best way to describe it is that it feels more like a KTM 1190, only without the 150 bhp, of course. It just goes.
Looking quickly over Roger's figures, I'm guessing that my riding style is mainly in the closed loop. Suits me fine. I just love the surge of power in the middle of the rev range before I shift into a higher gear. Don't feel the need to redline it that much.

Fuel consumption is still about 3 mpg higher than before, but that might be down to me being a bit more enthusiastic with the throttle recently. May take a bit longer to get an accurate idea.

It did catch me out when moving off from traffic lights today. It stalled on me because I still haven't quite got used to the lower tickover. More a question of me adjusting rather than the bike.

Looking forward to trying the new exhaust system in a week or so to see if there's any changes.
 
Well, exhaust system arrived today and got it fitted tonight. Good condition and a bargain, too.
Noticed that the O2 sensors have no soot on them now when changing them over. Look a better colour too.
System sounds nice and deep but not too loud, baffle is still in place. Even the wife noticed that it sounded deeper!
Coming up on 500 miles on the AF XIED units now and very pleased with them. They're doing exactly what they're supposed to do.
Looking forward to getting a run out tomorrow to see how the different exhaust system feels.
 
How you getting on with the af xied. Mines just come to day will get it fitted next week
 
Was just about to round up when I spotted your post.
Now have a 1000 miles on them and very pleased with the result.
One thing I have done since my last post is to replace the standard exhaust system. Think I must be getting too old for these things, noise was driving me mad!
I found that it increased the vibration slightly and made me do silly things occasionally. Guess it's not 1973 with a Yoshimura pipe on my Honda 500 four. :blast
So, what improvements have I found with the AF-XiED units?
The engine is now sooo flexible. Tickover has dropped to around 1200rpm so have had to re learn moving off a bit so that I don't stall.
In around towns I'm short shifting up at only 3000rpm, the engine just pulls relatively smoothly from very low revs. Gear changes are much smoother, too, particularly in the higher gears where I rarely have to use the clutch.
It's the throttle roll ons that I really like. Sitting at around 60 mph in top and ready to overtake, opening the throttle and the bike just surges forward without having to drop a gear.
The mid range is really strong now.
Not sure if that was one of the things that I didn't like about the sports exhaust system. While it did seem to let the engine 'breathe' better at the upper end of the rev range, I felt that there was reduced back pressure which meant a loss in the mid range. To me, that's what the GS engine is all about. BTW silencer currently on eBay starting at 99p if you don't value your hearing.
Was out on it this fine afternoon and love the smooth, flexible pull of this engine. If only BMW had been allowed to put this engine out without the restrictions it would have been a peach!
Downsides?
Fuel consumption increase by maybe 2mpg but may be down to a more, um, enthusiastic throttle hand.
For the R1200 engine two units are required which works out a bit pricey, but comparable the the cost of a new PCV or a Hilltop remap.
Unfortunately, they are unlikely to appear on eBay or the 'Items for sale' on the forum for a while as they are still rare here.

So which one?

Of course, the Hilltop mafia are going to say their choice is the best and while I'm sure that it is a positive improvement over stock, I genuinely would doubt that it is any better than the gains made by using AF-XiED units. Until we have someone who has sampled both, that will have to remain a matter of personal opinion.
In terms of cost, it's around the same. Although, speaking as someone who has had their own business, you must factor in the cost of getting there as well as travel and tuning time on the dyno.
That's a big variable, I know. For me, living in N Ireland, too big.
You need to be sure that this bike is really, really, really, really a 'keeper'. An expression I've noticed used a lot on the forum. Because when the bike goes, so does your re-mapping. Wouldn't mention it to the prospective buyer as a selling plus either. Because unless he's an aficionado of the forum and knows what you're talking about, he'll run a mile! I would.
One forum member has spent a grand on remaps so far.

The PCV is a good job. Had one and was very impressed with it. Positives are it was cheap to buy second hand, relatively easy to install and made the bike run noticeably better.
Downsides are dubious waterproofing on some of the connectors. Far too many connectors needed anyway. Bit obvious that you have one if you 'forget' to tell your insurance company, too.
The mapping is 'fixed'. That is, the fuelling did not adapt to changes in temperature, exhaust/filter changes, engine wear, etc. unlike the benefits from the standard ECU.
You were either relying on getting it dyno'd or depending on the fuel map of a GS that was 'similar' to yours but currently riding around California.
So spend the money on a dyno run! Great! Except that there's still no adaptability and the new map is only valid for the conditions on the day that it's dyno'd.
Fit Autotune units! Add another couple of hundred quid and even more cables and connectors. Been there, done that. That's the point I began to look for an alternative.

So back to the AF-XiED units. Discrete, if you like them to be. No dyno required. The ECU 'learns' the new AFR setting and applies it as you ride. It adapts the AFR to your personal riding habits. I think one of the reasons that people are suspicious of these units is that no dyno time is required. Doesn't need dyno time so must be crap, right? Booster Plug mentality, I think.
If you want to know how they work, see Roger's thread if you have a spare week. It's all there.
Easily fitted in half an hour if you are taking your time to make a neat installation. You have a certain amount of adjustability with the AFR if don't want to use the recommended settings.
Selling that 'keeper' for a new LC?
Removed even more easily and has a resale value. Or else you can fit them to your next bike if you want to.

I would recommend any one of these options, having sampled two of them myself. As I say, I've no reason to doubt that a Hilltop is a valid choice.
You will have a bike that is much nicer to ride, keeper or not.
 
Two months later, are they still performing well? Have you played around with the settings or left them alone? Which setting did you settle with in the end? So many questions! ! Think this is the route I'd like to take for my single cam.
 
TBH I never really think about them now!
I have adapted to how the bike runs so well that I have just accepted that it's the way it runs now.
There are 11 graduations of adjustment on each unit, easily adjusted with a small screwdriver. Number 1 is standard and number 11 is reckoned to be an increase of around 8% in the air/fuel ratio in the closed loop of the fuel injection.
I started off at number 8, which seems to be the most popular and went to 9 when I fitted the sports exhaust. Didn't have the exhaust on long so just put it back to 8 and have left it there since.
So, how well does it run?
It's just sooo flexible and smooth now. Frequently, when in slower traffic, I unintentionally find myself letting the revs dip below 2k.
No dramas, no engine hunting. You feel the engine turning over but more of a low frequency throb than vibration.
The sweet spot is around 3.5-4.5k rpm which is where I probably spend most time. Need to overtake? Just open the taps in sixth and you're passing quickly without any drama. Drop a gear and I'm glad I have my top box where the passenger seat was!
I'm currently running de catted headers, the flappy valve and standard TC silencer.
The de catted headers certainly seem to let it rev a bit more cleanly near the red line, but I do feel that the standard headers make it a bit more punchy in the mid range, so the standard headers may go back on soon.
I just prefer the flappy valve to keep the exhaust quieter through towns and on longer runs. The TC pipe can be quite loud.
For real world driveabilty, I just love this bike now.
They are 'fit and forget' and I would still recommend them as the first modification I would make over silencers, etc.
 
Cheers for that. I don't think silencers alone make any real difference, in the past I had my old gsxr11 on a dyno and tried several different cans, horsepower exactly the same on all.

I have a set of decatted standard headers sitting in my garage and a gutted end can and would like to stick at least the headers on. Always worried about it running to lean as they tend to do in standard trim. These things seem to be able to address my concerns.
 
A German magazine did a review on about 20 different cans fitted to a TC, complete with dyno runs for each. Very enlightening.
Only two produced an increase in power by about two bhp but a massive increase in noise. Most, including the really expensive ones were lucky to produce the same as stock. You can save a couple of kilos weight but have you seen the size of the average tosser? :rolleyes:
You can view the video of the test if you look on you tube and virtually all suffered from that stutter when moving off.
Like most manufacturers these days, it's difficult to improve on the systems they've developed without a big increase in noise.
Performance increase is all in the mind.
You could go ahead and try your de catted headers without doing any harm. The ECU will adapt to them fairly quickly. You won't do any damage. You'll find an improvement higher up the rev range.
You may lose a bit of mid range depending how much you've gutted the silencer. I would try it with the standard first.
The guy who developed the AF XiED units has done a lot of measuring, not just his opinion, and has concluded that the ECU is a very clever piece of kit. When you make a modest change to the exhaust, it adjusts the fueling. Can take a tank or so of fuel to do it though.
So, do that and it'll be a bit quicker higher up the revs, it'll not do your engine any harm but it'll still be harsh with the flat spot and the surging. Simples!
The AF XiED units work in tandem with the ECU and with the de cat headers or similar, you bike will be a totally different beast.
Let us know how you get on.
 
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The guy who developed the AF XiED units has done a lot of measuring, not just his opinion, and has concluded that the ECU is a very clever piece of kit. When you make a modest change to the exhaust, it adjusts the fueling. Can take a tank or so of fuel to do it though.
...

You're right, it took a lot of measurements and research to work out just how sophisticated the Motronics and BMSKs are. They are able to compensate and correct (in other words adapt to) many engine, intake and exhaust changes. The bmsk is even clever enough to work pretty well with one of the O2 sensors disconnected. It uses what it learns on the good O2 and applies it to the other side--not perfectly of course.

In the most recent revisions of the GS-911 software, the engineers at hexcode have teased out the short term and long term trims for both cylinders. What that means is that we are no longer "guessing" from measurements, but can see the exact structure of the adaptation mechanisms.

Lambda control factors for each cylinder that keep the short-term, closed-loop fueling set at exactly the lambda setting of the O2 (or O2/AF-XIED if you have it).

From the short term trims it then develops a table of long term trims. Additive Trims for each cylinder fix problems at small angles, such as injector switch-on speed or vacuum leaks--to name a couple. Multiplicative Trims to take care of fuel pressure, air temp sensor errors (why BoosterPlugs don't work for long), fuel ethanol content and to carry any shifting of the O2 sensor to THE ENTIRE FUEL TABLE, which is why the af-xied works outside the closed loop area.

These ECUs are really very good stuff but a bit technical. Bottom line though is like comberjohn said, "a very clever piece of kit".
 
Just wanted to clarify a point that I made shortly after fitting the AF-XIED units. At that time, I thought that my tickover had dropped slightly, making the engine hesitate when moving off. Now I think it was probably imagination.
Now I believe what was actually happening was that my throttle bodies were slightly out of sync at the time causing the hesitation.
I had to sync them last week and realised that the symptoms were the same.
 


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