Hotrodding the GS

<BR><table border="0" cellpadding="5" width="650"><tr><td>Some parts arrived on Friday, so I can put together a production example. This assembly will be representative of the first product we're going to be selling. I'll be figuring out what the assembly process will be, and see what sort of fixtures will be needed.

I'll be sure to get some pictures up when it gets to the 'hello world' stage
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Sign me up for one!

You're going to be build these in your garage? That's the was Apple and HP started. Now we've got the iPone and Carly Fiorina. There's a bar to get over.

I'm hopeful here. All ears and waiting to see what is born/borne of this.

I know nothing about controls like the Motronic. But I'd be interested in hearing about how you're altering it's behaviour with out spoofing the inputs from the sensors. If you could put in in laymans terms.

I appreciate the answer, but what I was really hoping for was for ya'll
to fill in the blank blocks on the chart that was posted. Just
one of those "wanna know what makes it tick" things

The blank blocks will remain blank (well except for two of them) but a more in depth explanation is in the works even as I write this. But 1st up will be a definition of specific fuel injection terms just to help make things clear(er).

JJ

<table border="0" cellpadding="5" width="650"><tr><td>Here is a table summarizing the operation of Electronic Fuel Injection. After the chart is a Glossary of Terms.

I'm hoping to make the subject of fuel injection a little more understandable, or at least approachable. You may not believe it, but the fundamental operation of EFI, if not the electronics and software themselves, is fairly easy to grasp.

A lot of people who ride are interested in knowing what the ECU is doing, good and bad, to affect the pleasure of riding. If you're one of those people, I hope you find this useful.

How to read the chart:

Begin at the top left, and work your way down the blue column. The blue column lists a common sequence of rider inputs. For example, traveling at a constant speed, rolling on the gas, speed increase, rolling off the gas, speed decrease, etc.

The green boxes along the top are the ECU subroutines, or algorithms if you like. The subroutines are triggered to 'execute' based on what the rider is doing with the throttle. The subroutines are a set of instructions and procedures designed to carry out a particular task.


The IICE Air operates in the Blue range - Really ramps up open loop acceleration.
The IICE Cool operates in the Violet ranges - Puts the punch back into the throttle response.
The IICE Smooth operates in the Pink range - This one is the fix for Surging! But it also goes a long way to improving throttle response.

Following the chart is a definition of terms.</td></tr></table>


<table border="0" cellpadding="5" width="650"><tr><td>Steady State
Just like it sounds. Throttle is steady and the motor is turning at a constant RPM. Steady State includes a constant throttle and speed on uphill or downhill grade.

Tip-in
Refers to an opening throttle movement. An increase in throttle angle. Tip-in isn't the amount of throttle movement, it's the movement itself. Specifically refers to the duration of time when the throttle angle is actually increasing.

Tip-out
Refers to a closing throttle movement. A reduction in throttle angle. Tip-out isn't the amount of throttle movement, it's the movement itself. Specifically refers to the duration of time when the throttle angle is actually decreasing.

Overrun Fuel Cutoff (or OFC)
Starting from any steady state throttle position, if the throttle is tipped out 15% or more the ECU cuts off all the fuel flow. If the rider closes the throttle completely and allows the bike to slow, fuel cutoff continues. Fuel delivery resumes below 1700 RPM, and is felt as a distinct lurch.

Leading Throttle
Say you're traveling at 35 mph and you tip-in the throttle to 75% and hold it there. The bike is increasing speed but hasn't yet reached its final velocity for the new throttle setting. You can think about that condition in terms of the motor trying to 'catch up' to the throttle. The throttle is ahead of the motor, and is 'leading' it to a new RPM.

Trailing Throttle
Opposite polarity to Leading Throttle. You've backed out of the throttle some and bike is slowing but hasn't yet reached its final velocity for the new reduced throttle setting. The throttle is trailing the motor.

Closed Loop
Closed control loop operation is probably the most complex routine in EFI systems. But to explain it simply, Closed Loop is when the ECU is using O2 Sensor feedback to adjust its fuel calculations. When the ECU is running in Closed Loop, some sensors are ignored and are left out of the fuel delivery calculation.

Open Loop
During Open Loop operation the ECU does not use O2 Sensor feedback to adjust its fuel calculations. And similar to Closed Loop, when the ECU is running in Open Loop, some sensors are ignored and are left out of the fuel delivery calculation.

Transient Enrichment (aka: Accelerator Pump)
Whenever the throttle is opened, while you're twisting the grip I mean, additional fuel is momentarily required. Throttle movement is a transient event, and the additional fuel is called Transient Enrichment. Without Transient Enrichment, the motor would stall when the throttle is opened. With the right amount of transient enrichment, throttle response is crisp. It puts a smile on your face. With an insufficient amount, as typical for an emissions-based motor, the throttle feels soft.

Transient Enleanment
The opposite of Transient Enrichment. How's that for sidestepping the answer? Seriously though, the two terms are actually the same term, but different signs. You know, one is positive and the other is negative. One momentarily adds fuel and the other momentarily removes fuel. Generally the two terms, Transient Enrichment and Transient Enleanment, are collectively referred to as Transient Fuel.
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"With the right amount of enrichment, the throttle response is crisp. Puts a smile on your face. "

50 state legal?

<BR>Oh yea, of course.


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I just read this thread and I am all tingly thinking about when this product is released so I can get my hands on one. I just love my 1150gsa even though there is a little wierdness with the fueling. not enough bad habbits to make me want to get rid of it, but not as smooth as I think it could be. if this device does even half of what it is being predicted, I will be happy.

I changed the pipe to a Akra and got rid of the cat to make it sound better (to me). wasn't looking really to gain any performance but i would certainly like the EFI settings to be more in tune with the newer, freer flowing exhaust.

I will be checking back every day to see progress. cheers to you both for working on something that should benefit us all.
John

While I have few if any complaints regarding the Motronic 2.4 on my '01 GS, I believe there are ways to eliminate detonation which occurs frequently on boxers of this vintage.

If I'm not mistaken, H-D uses a Delphi ECU which employs spark ionization to determine when detonation is occurring. During detonation, the impedance across the spark plug gap increases dramatically providing immediate warning of detonation, thus allowing instantaneous adjustment of fuel and timing to eliminate the detonation. Is is seamless and eliminates any need for knock sensor hardware.

Also, how about throttle by wire....I am surprised that BMW has not done this already. With such a scheme, throttling the boxer could be tailored by adjusting slew rates, tip in and tip out rates, etc.

TB sync could be incorporated easily into such a scheme.

What say you Poolside, JJ?

Experts, correct me if I'm wrong but our boxer's ECU brains have only four inputs;

1: Throttle position.
2: Lambda signal
3: Ambient air temperature
4: Engine speed

I know that engine oil temperature is also measured but I am unaware if this parameter is used by the Motronic.

That's not much information to work with considering an automobile has MAP and other additional inputs to work with when determining engine fueling needs.

Don't forget air density.

Yeah, I don't know what it has and doesn't - eager to learn though.
But I'm shocked if it doesn't have any input for atmospheric pressure :huh
If no, from sea level to high mountain elevations the fuel would be
way off???

As I remember from older posts on this forum, you set your TPS one voltage at sea level and another voltage at mountain high. Because of air density.

Dan.

I realize this may be asking a lot, but could you provide the link to that post?

JJ

Sure.

There may be other posts but this is the one I found using Google.

Dan.

I guess I forgot. Where is the density sensor?

i believe it is located inside the ECU as in most other modern bikes and cars.

Can't this be picked up from the lambda sensor? If the air is thinner than expected and the stoichiometry is off as a result, then the lambda sensor should detect that the engine is running too rich and adjust accordingly. Or vice versa for "too thick" air.

That would only work during closed loop operation, though. I'm not sure how this works during non-steady-state conditions. I defer to the tuner gurus on this thread....