Hotrodding the GS

Man, that was a lot of homework...good stuff tho.

We do, we do!

Well, I guess we have different definitions of "hot rodding". That's fine but 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, friction reduction, porting, cam timing, compression, combustion chamber shape and the like. Unless the injection mapping is WAY off (which I don't think it is), the increases in performance through changing the mapping won't be that great. Having said that, I CAN appreciate subtle improvements! They all add up! Personally, I don't see how some deal with how their bikes surge. Completely eleminating that is more than a subtle difference but I still don't call that "hot rodding".

Change my name to Smiling Bob!

IMO, your post contributes nothing whatsoever to this thread, and I, for one, would appreciate it if you would obsess about something else, somewhere else.

Just sayin'.

I think pointing out that the thread title is promising something that can't be delivered is very relevant. (That is, at least, the way some people define things.) Especially when it is for a price. I really do wish them all the luck in the world because even subtle improvements are improvements nonetheless but why do they need to call their future product something that it isn't? I would be afraid that it might set people up for disappointment. I might very well be preventing a heartache!

With all due respect and just saying, I am not obsessing at all. I am having fun bringing up what I think is a good point. IMO, your above post contributes nothing at all to this thread. Besides, THIS forum IS for obsessing about things Oilhead Boxer related.

We choose the words hot rodding because it kept the title short, was evocative of what we are doing and is intriguing. Not because it's an exact description. Sorry if that caused some confusion.

And those who do dive into this thread will realize in short order just what we are talking about sooner rather than later just by reading the thread.

And this is ADVrider.

We do things a little differently in this corner of the sandbox.
And exactitude in all things and all ways usually isn't one we rigorously strive to maintain. There is a fun factor involved that tends to lighten things up a tad.

So while we may not meet your expectations of what hot rodding means most will understand what the point of this thread is all about. Sorta along the lines of you can't please everybody all the time.

JJ

PM sent

I appreciate you guys digging into this.

Here's my definition of hot rodding.

Hot Rodding (pronounced hawt rah-ding) - To make modifications to an engine and supporting components with the sole purpose of making shit work the way it was meant to work before EPA, bean counters, and non-mechanically inclined people want things to be... (ant - vanilla, generic)

I'm a proponent of hot rodding. My '05 Harley runs as it should have from the factory, and yes it probably doesn't make the environazi's happy. It runs better than stock in all aspects, gets better mileage than stock, runs cooler, passes semi's like they're standing still. Double the stock horsepower and torque. I would LOVE it if my GS would run better. Mileage is about the same as my modded Harley yet it's a smaller engine in a lighter package. Clearly there is room for improvement.

My biggest gripe with EFI modifications is the harsher (gritty) quality that usually comes with it. I hope this is a consideration in your design.

bob

Standing by with interest. In my view, you're really talking about 'free' horsepower -- no engine disassembly, no lumpy cams, etc. My HP2, is stock save a full Akrapovic and new air filter and I must say, it runs wonderfully. I'm assuming dyno trials will back up the product and ridden normally, the milage will improve as the mixture is corrected for optimal rather than smog running.....and you likely have already guessed how green I am.....Bruce

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]

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<table border="0" cellpadding="5" width="650"><tr><td>No way, SS. A misleading title would be, "Making Your Crank Bigger" or "Stroking Your Crank" or something like that.&#8194;

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.</td></tr></table>
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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.

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!

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.

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

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.

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<table border="0" cellpadding="5" width="650"><tr><td>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.</td></tr></table>
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<table border="0" cellpadding="5" width="650"><tr><td>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'.
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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/index.cfm?fa=contentGeneric.sfjsxqzbkjrcgwel&pageId=326734

and call it a day?

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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.

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