Hotrodding the GS

There are experts and I am not one BUT - I am pretty sure (anyone know for sure?) that most all current ECU's have a air density sensor within the ECU housing - that has been my experience and it is essential to have that to compare - air temp - air density - with the lambda which is post combustion. As air density is not completely corolated with air temp. ie. hot and high altitude. Moisture content... weather systems....

Never heard about air density meter but air pressure is measured in most of modern ECU's. It does the same in rough frame.

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<table border="0" cellpadding="5" width="650"><tr><td>Yea, built in my garage. You're right, there are some tough acts to follow.

To your question. Like I was saying in an earlier post, the 1st of these 4 upcoming devices does alter the air temperature sensor signal. In layman's terms, it is a spoof of the temperature signal.

But, two things are different about it. First, it's adjustable. Adjustability gives the rider a performance choice, and gives the device a wider operating range. Second, without that adjustability it will not work well with the 2nd, 3rd, and 4th, (so far) upcoming products.

The 1st device, the IICE Air, works on the air temperature. The air temperature controls the 'Open Loop' operating range of the ECU.
On the chart it's the BLUE box. (Link to Chart)
During open loop operation the altered temperature signal informs the ECU that the air is a little denser than it actually is, so it adjusts the mixture to match. The end result is the mixture is slightly rich relative to the actual air density.

The 2nd device, the IICE Cool, works on the oil/coolant temperature. The oil/coolant temperature controls the 'Transient Enrichment' feature, and also Overrun Fuel Cutoff.
On the chart it's the two VIOLET boxes. (Link to Chart)
Transient Enrichment is where throttle response comes into play. The hesitation while opening the throttle is gone. When someone says "I like how the motor feels" they are talking about off/on transition throttle response.

Besides off/on throttle transitions, the other big area where transient fuel makes all the difference is when pulling away from a stop. You know how it is, you let out the clutch and it almost feels like the motor is going to stall. It goes soft. You must open the throttle more, and fan the clutch to get rolling. Ridiculous.

With the right amount of transient enrichment the motor just torques away from a stop. It gives the feeling of having more power than it needs. Beautiful.

The Motronic does have some very nice operating states, trouble is they're never there when you need them. Well, we're fixing that.
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Interesting stuff, even to the owner of one of the lesser BMW's. I have one of the "fool the ECU air temps sensor devices". I have noticed if I chop the throttle suddenly followed with partial throttle, I get a noticeable stutter in my get along. I think you just explained it.

I've got an '05 12GS, and while I like the engine much more than the 1150 models I had (smoother and more powerful), there's a bunch I don't like about it.

When I give it gas to accelerate (normally from lower RPM's - say 3500), it sure seems to take a lot to really get going.

Yet when it's about 5000 rpm, now matter which gear it's in, the bike zooms.

I would like this dead spot in the middle of the RPM band to go away.



But, I'd also like to keep my good fuel economy.

These take a good-sized bite out of that dead spot. And of the improvements available from the first two products, 35% is provided by air temp and 65% by oil temp.

There's a difference in fuel use only during Tip-in and Leading Throttle. Steady State will have the same mileage.

Many people's mileage goes down when they get a new pipe, acourse that's attributable to racing around with their new toy. I'd imagine you'd have some of that with these products, especially since the go-pedal feels so much nicer.


p.s.: To flatten the power output across the powerband requires a new program in the ECU. And it's also possible to do it with high end external add-ons or ECUs, but not with something like a Power Commander.

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And you're not doing that?

I assumed from your posts that you were creating new control algorithms using, or re-using, sensor data (air temp, and oil temp) to reprogram the ECU.

Is this not correct?

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<table border="0" cellpadding="5" width="650"><tr><td>How can I say this? We are inputting externally-controlled changes to the ECU, to cause it to operate in different parts of it's internal algorithm. I hope that's not too ambiguous, cause I'm not trying to be.

JJ says something about it in the quote below. I'll explain more about it later if you like, or I can point you to reference material. I'll try and explain it briefly here.

The stock ECU has 'rules' that it follows. These rules go something like, find out where the throttle is at, and the motor RPM, and what the other inputs are, and determine the fuel and spark outputs. That is an algorithm, a set of rules.

Any external change to any input creates differences in the outputs. Some changes are small, others large. Some are desirable, some are not. Some happen when you want then to, others don't. I'm meaning desirable from a drivability point of view.

Replacing the ECU is only necessary if it is. That may sound vague, but causing the ECU to operate in different parts of its algorithm 'rule set' makes a huge difference. If it's done right, it makes all the difference that people want made, and sometimes it exceeds expectations. What I mean by that is, many people do not know what truly excellent throttle response is, so they literally don't know what to expect. They know how one bike compares to another one they've owned, but often they don't have an absolute frame of reference.

With every stock motor I've seen, the stock ECU is capable of proper fueling. Capable of making the motor run as good as it can. To achieve that performance requires the ECU to operate outside the margins say, of its 'rule set'. That is possible to do with outside modification.

Causing the ECU to operate in different parts of 'rule set' can sometimes be a fairly simple process, or it may need to be more complex to work well, or work at all. Our 1st device is fairly simple. The 2nd one is fairly complex with microprocessor control, and it also interacts with the 1st one. That's the way it needs to be given the 'algorithm' in the Motronic ECU. Nothing else would, or could, work.

What you want is the removal of the undesirable aspects. That generally doesn't mean a 'flat power output'. I don't think I can explain here all that's entailed in the phrase "flattening the power output". But I can say you probably wouldn't like it, most people don't.

That undesirable dip in the powerband, it takes a big bite out of that.</td></tr></table>

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Have you had the opportunity to ride the 2010s?

This behavior was what most impressed me about the new motor... a very linear and controllable move away from a stop.

It is also more manageable at the bottom when riding across rough ground than previous models.

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So, when do we bolt this box of magic onto the pfig and take it up the hill for a spin, jump and slide?

Good question.... Whenever all the 8 LB. brains get done working on the issue I guess. Folks went to the moon using a devise called an E6B not too long ago, not a challenge, just a comment. great work gentleman, a little friendly prodding.

But the dip in the powerband from 4000 to 5000 rpm is still there. According to the various motorcycle mags I've read.

I understand what you're saying. In essence you'll be selling some device that hooks up to the ECU that tricks it into performing better. Sorta like a Power Commander.

You're not selling an ECU reprogramming service (software only).

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&#8194;E6B!

I have to replace the drive belt in the dryer just now. So, right after that.

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<table border="0" cellpadding="5" width="650"><tr><td>That's it, no software. We're selling both passive and microprocessor-controlled hardware.

These devices hook up to the existing components on the bike, and in that regard it's similar to a Power Commander. But the similarities pretty much end there.

The PC sort of 'takes over' certain operations of the ECU. And it's got a fancy user interface, and programmable maps and such. There's a lot of fussing to get it right, enjoyable fussing I might add. And of course, when you're all done, bragging rights.

I understand that appeals to a lot of people, heck it appeals to me too! But would you believe me if said it wasn't strictly necessary?

The ECU already has the 'right maps' as it were. And what our products do is access them.
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Jim, I'm in town for part of the holiday break and a little after.
We can make an HD movie.

Of course this would be WUI*, I'm guessing.

I now have in-house counsel...




*Wrenching Under the Influence

- Thanks to Gaspipe, the Original for that one.

If I am correct (and I most always am), the actual processor in our Motronics is not addressable leaving you with either replacing the processor with one that is addressable (and authoring and installing maps, a daunting task) or, telling the existing Motronic processor lies in order to get improved performance (drivability) or messing with the FI pulse width signals coming from the Motronic.

It appears that you are going to lie to the Motronic, yes?

Very much looking forward to these products. My GS could use a smooth throttle response.

I don't doubt that the stock ECU isn't tuned to provide optimum performance. My question is why would BMW not install stock ECU's that tune the engines to perfection from the get-go? Is it laziness? Emissions laws? Cost-cutting? Lack of knowledgeable personnel?

Perhaps this has already been addressed, but I didn't see it after reading/skimming of this thread.

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I can see it now. "Hi sweetheart, can you come and get your dad and I out of jail?"


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It's probably a little of everything you mentioned. Poor drivability is usually driven by emissions regs. For good drivability to survive the design process costs money and requires qualified people and components. With a loyal customer base, and without any equivalent competition from the big 4, the factory may not have had much motivation.

The ECU already has the 'right maps' as it were. The ones we want are just in a different area. And what our products do is access them.

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