Hotrodding the GS

[Poolside]

Originally Posted by supershaft

...I do think tweaking the injection and calling it "hot rodding" is a bit misleading.

The results of fine tuning the mapping are going to be a smoother engine and maybe a bit more power via a better mixture.

IMO, hot rodding is about increasing the engine's volumetric efficiency through weight reduction...

No way, SS. A misleading title would be, "Making Your Crank Bigger" or "Stroking Your Crank" or something like that.  Anyway, I came up with the title because that's what a performance mod is, hodrodding. It isn't difficult to imagine that Volumetric Efficiency (VE) is of no, or even negative consequence, without matched fueling. For example, filling in the gaps in fueling precision on a stock motor represents a greater performance increase than a header and silencer say. The total improvement to performance across the operating range of the motor (throttle angle and RPM), and over the operating states of the motor, exceeds the improvement of a header and silencer by several times. p.s.: Regarding your other comment, I don't have any reference for VE improvements through weight reduction.

[supershaft]

Well, I agree with you to some degree that tweaking the injection mapping could change the performance as much as a GOOD header and silencer combo on an otherwise stock motor. By several times? That all depends on the exhaust system. I think that might be a pretty good comparison. The differences are pretty subtle.

I also agree with you that some people call putting a louder can on their bike hot rodding their bike but then a lot of us don't.

But hey! If you can get the surging to go away on surgers without running the things overly rich and get a tad more performance out of them, GREAT! If I buy the stuff to put on peoples bikes, I am going to call it fine tuning their GS. That way they won't come back and say that it is running smoother but other than that they can't tell any difference and they want their money back. It's kind of like when I install an exhaust system that costs a fortune. I warn the customer that despite all the HP claims and whatnot, the biggest noticeable difference is going to be the noise level.

[grpweld]

Hotrod,

A hotrod is anything that is other than stock, I.E........ CUSTOMIZED!!!!!
you guys are spliting hairs here, let him do his thing

P.S. I am a long time drag racer & I like what you guys are doing!

[Billy Pilgrim]

This all sounds very interesting. And very timely.
I have taken my 07 1200GS to 2 shops already to try to fix the 'lumpiness', most noticeable when the enging is warm and in the lower end of the rpm range and at idle. Feels as if the motor is being strangled somehow.

To date they have tried 3 solutions:
swapping out the oxygen sensors for known good ones - didn't work;
cleaning the 'gum' out of the throttle bodies - no difference;
installing a new version of the ECU 'firmware' - some improvement but still not as smooth and free running as I'd like.

My next step was going to be to buy a PC. My local dyno guy says he can do a map for each cylinder, which sounds like what is needed if the hex head motor is, in fact, fuelled and sparked like 2 engines.

Poolside, you mention that the CAN BUS version of your 'solutions' are further down the track. Like how far?

More power to you and keep up the good work.

[johnjen]

Originally Posted by tagesk

I find that adjusting the valves to any given clearance isn't that hard.
Getting those pesky wires to pull equally, also as they are pulled upon, is not at all easy. If possible at all.

How will misalignment here influence the end result?
I guess the question is: More or less than today.

[TaSK]

There is a technique I use when fussing with throttle cables that minimizes this variability.

When you adjust the throttle cable barrel adjusters make sure that the cable itself doesn't rotate, at all. Then run the bike for at least one thermal cycle. Then re-check the setting. As you repeat this, the amount of adjustment will diminish each time you make an adjustment.

And yes this technique almost seems like you need 3 arms, or at least 3 hands, but it is possible with just 2
You're sorta using a iterative loop approach to finding the sweet spot each time an adjustment is made.

Now what is happening is the outer jacket of the cable is re-orienting itself to it's neutral position, which in turn changes its effective length and thus the setting you're seeking. AND as the cable barrel adjuster lock nut is tightened, the barrel adjuster changes it's effective length. This can be partially compensated by keeping the lock nut partially tight during checking of the setting, BUT NOT WHEN THE CABLE BARREL IS ADJUSTED. If you adjust the barrel adjuster with the lock nut tightened down to tight it will add additional wear and add even more change to its length between the loose and tightened conditions.

And if this doesn't work then your cables are WAY worn out, and most probably the inner teflon jacket has shifted position. The labor intensive but low $$ solution is to check both ends of each cable in the whole cable assembly to see if the teflon jacket has shifted and is poking out at one end. If so then carefully cutting off the excess jacket is a quick solution.

The other solution is to replace the entire throttle cable assembly with an all new assembly. Which BMW suggests because the throttle cable is a wear item and should be serviced (replaced) regularly.

JJ

[supershaft]

I use all those tricks except that I don't adjust the barrels with the lock nuts snug, I just don't check the sync until they are tight. Not right? I loosen them, move the barrel, and tighten them down again and THEN check the sync again. Another trick I use is to occasionally shut the engine off and snap the throttle wide open six or seven times. That helps the cables settle into where they want to be.

[Poolside]

Originally Posted by Billy Pilgrim

This all sounds very interesting. And very timely.
I have taken my 07 1200GS to 2 shops already to try to fix the 'lumpiness', most noticeable when the engine is warm and in the lower end of the rpm range and at idle. Feels as if the motor is being strangled somehow.

To date they have tried 3 solutions:
swapping out the oxygen sensors for known good ones - didn't work;
cleaning the 'gum' out of the throttle bodies - no difference;
installing a new version of the ECU 'firmware' - some improvement but still not as smooth and free running as I'd like.

My next step was going to be to buy a PC. My local dyno guy says he can do a map for each cylinder, which sounds like what is needed if the hex head motor is, in fact, fuelled and sparked like 2 engines.
That's what the ECU does, but it isn't how it should be. If you get a PC, tune both cylinders the same.

Poolside, you mention that the CAN BUS version of your 'solutions' are further down the track. Like how far?

We're developing the device for the 1200 CANbus over the winter, and it should be ready for spring. Maybe sooner. The first product, the one we're working on now, is designed to improve the low RPM symptoms you described, on the 1100/1150/1200. It will be finished in about three weeks. When that happens we'll put up a thread in the Vendors forum. You're having problems with a lumpy idle too? A device for that is also scheduled. It may get slotted in over the winter. The development work for all the devices will be posted here. In a few days I should have a production example of the first product in hand. At that time I'll post up a description of the products, and a timeline for development.

[Poolside]

The chart above is how the EFI on the 1100/1150 and 1200 operates. Most EFI systems operate very similar to this. Start at the top of the blue column and work your way down. The blue column lists a common sequence of rider inputs. Traveling at a constant speed, rolling on the gas, speed increase, rolling off the gas, speed decrease. The green boxes are the ECU subroutines, or algorithms if you like, that 'execute' based on what the rider is doing with the throttle. The subroutines are a set of instructions and procedures to carry out a particular task. The white boxes are what the subroutines do. As you can imagine, the chart somewhat generalized, but all the significant functions are there. The parts relevant to the BMW ECU are included. (That is, except for 'Start' and 'Idle'. I'll fill them in later.) JJ and I will go into more detail about the chart, and explain more about the rider inputs and ECU subroutines. [Edit] Regarding the empty boxes on the table. The boxes aren't empty per se. Rather, it's simple how EFI works. For example, Tip-in doesn't trigger the Overrun Fuel Cutoff subroutine, so that box is 'ghosted'.

[def]

Hmmmmm.....couldn't we just bolt on a couple of these things

http://www.dellorto.co.uk/

or a couple of these

http://www.amalcarb.co.uk/buildCarb_Monobloc.aspx (these worked very well on my TR6C Triumph),

along with some of these http://www.motorcycleinfo.co.uk/inde...&pageId=326734

and call it a day?

[Poolside]

Originally Posted by def

Hmmmmm.....couldn't we just bolt on a couple of these things and call it a day?

Can't argue with a well-adjusted carburetor. And, no doubt carburetors work better than the stock Motronic.

But, a well-tuned EFI system always works better than a carburetor.

The significant difference between the carb and the stock EFI is how they meter transient fuel. That is, the additional fuel that's added while the throttle is opening.

The second product we're working on performs that function, and then some. Remember on a carburetted car, you could blip the throttle enough times while at idle that you could stall the motor? This device can be adjusted to manipulate the Motronic's transient fuel function to such an extent.

The production model isn't gonna go that far of course, but the prototype I have here can.

[def]

Originally Posted by Poolside

Remember on a carburetted car, you could blip the throttle enough times while at idle that you could stall the motor?

Throttle bliping...I'll leave that for H-D riders...

The savvy rider or racer (car or auto) knows that throttle bliping does nothing but make noise and wash down cylinder walls.

I was musing about camshafts recently...I miss those old 413 CI max wedge engines with their killer torque, able to slowly spin the rear slicks through their auto transmissions at the drags strip....with the air cleaner off, their carbs sprayed fuel all over at idle...cam overlap was to blame...my TR6C with T&M #6/#9 grind cam combo would wet my legs with gasoline at an idle...same culprit...cam overlap...both valves open at the same time.

Those who fit pipes/mufflers to boxers in the hope of getting some exciting sounds are barking up the wrong pipe...install cams with some overlap and you'll get that nasty sound you seek....

....and, now back to your regularly scheduled boxer FI map..

I await yours and JJ's latest details regarding the boxer EFI changes.

[GS Addict]

Originally Posted by def

Throttle bliping...I'll leave that for H-D riders...

The savvy rider or racer (car or auto) knows that throttle bliping does nothing but make noise and wash down cylinder walls.

Except when downshifting..........

[johnjen]

Originally Posted by def

Hmmmmm.....couldn't we just bolt on a couple of these things

http://www.dellorto.co.uk/

or a couple of these

http://www.amalcarb.co.uk/buildCarb_Monobloc.aspx (these worked very well on my TR6C Triumph),

along with some of these http://www.motorcycleinfo.co.uk/inde...&pageId=326734

and call it a day?

Well after you bolt them on then you get to dial them in. Which takes time and access to the necessary brass.

In one sense it's a trade off of time spent fussing and the $$ spent on hardware
vs
fussing with the FI map, either directly or indirectly.

And then there is the added factors of carbs don't automatically adjust for altitude nor the change of seasons really all that well. And having spent the time and effort to retrofit a set of round slide carbs on my R65 and then live with them, I know that dialing in the EFI using the targeted modifications we are working on will be WAY easier on every level, and will be less costly and easy enough that anyone who can perform routine maintenance can make it happen.

And did you notice that those cams are horsepower cams, not mid range torque cams? So while this may provide a top end speed boost you will loose low end and some mid range power. Which some may desire but it wouldn't be the best choice for going slow in the dirt.

At one point I did consider yanking the EFI on my 1150 and installing some decent slide carbs, even though it is a PIA to get them dialed in and then have to fuss with them as the seasons change. But with these mods I don't have to deal with all of that fussing. Its much more of a set and forget and enjoy the ride instead of noticing engine responses that shouldn't be there in the first place.

Like Poolside sez, a properly dialed in EFI is invisible, you don't even know it's there.

JJ

[johnjen]

Originally Posted by def

Throttle bliping...I'll leave that for H-D riders...

The savvy rider or racer (car or auto) knows that throttle bliping does nothing but make noise and wash down cylinder walls.

I was musing about camshafts recently...I miss those old 413 CI max wedge engines with their killer torque, able to slowly spin the rear slicks through their auto transmissions at the drags strip....with the air cleaner off, their carbs sprayed fuel all over at idle...cam overlap was to blame...my TR6C with T&M #6/#9 grind cam combo would wet my legs with gasoline at an idle...same culprit...cam overlap...both valves open at the same time.

Those who fit pipes/mufflers to boxers in the hope of getting some exciting sounds are barking up the wrong pipe...install cams with some overlap and you'll get that nasty sound you seek....

....and, now back to your regularly scheduled boxer FI map..

I await yours and JJ's latest details regarding the boxer EFI changes.

Another factor that many forget is that adding an aftermarket pipe or other plumbing apparatai can make a small difference but then so can dialing in the adjustments already there. Such as valve gap matching, TB matching, engine timing, tweaking the electrical connections into and out of the EFI, etc. But in the end it's the EFI that controls making power, where, how, and when. Improve the EFI and any subsequent plumbing changes will have the best chance of adding what improvements they are capable of.

And if I were to push this even further, whether any aftermarket aparatai would even be wanted.

JJ

[johnjen]

Fuel injection engineers and s/w guys need a specific set of terms that match up with the functions (sub-routines) that they code. So some of the terms are not in common usage.

Tip in and tip out are 2 such terms.

They refer to
increasing the throttle angle (tip in)
and decreasing the throttle angle (tip out)
or
makes the butterfly more open (tip in)
and makes the butterfly less open (tip out)

We will go into more of the inner functioning of our EFI systems in due course. So forgive us for not answering your question straight away.
The answer is involved and in order to answer it fully we need to setup some baseline terms and functionality first.
And we'd rather do it correctly once rather than piecemeal a bunch of times.

JJ