Booster Plug - The cure for surging?

[happy wanderer]

Maybe something of interest to those following this thread. Webbikeworld did a review of the booster plug.

http://www.webbikeworld.com/t2/booster-plug/

Thanks for the link to this article. Although he tested it on a F800 the results are quite convincing. I have found Webbikeworld reviews are pretty thorough and honest, especially for things like helmets, boots, bluetooth systems etc.

I've been sitting on the fence about the boosterplug for months now but this morning I went ahead and ordered one. This also gives me a great excuse for one more good long fall ride!

When it comes to surging, my bike has proved to be near impossible to cure so I'm skeptical but optomistic because as I said before, the difference between cold and warm is very dramatic on my particular bike. This guys' approach interests me for that reason plus the quality of the dongle he's made and the documentation of the issue leads me to believe he knows what he's on about.

I'll post the results back here once I receive it and get some testing time in the saddle.

 

[globalrider]

Calling Global Rider....

Sorry Rin, but my twin spark GS Adventure does not surge....that is why I held off buying an oilhead till then.

Bottom line is BMW should have addressed this ages ago...like the first year.

 

[j-budimlya]

For those with OLD single cable TB controls, if you have not, I suggest that you replace the throttle cable with a new one. Long before the cable breaks, it no longer slides reproductable in the sheath. And no matter how much you tinker with the TB sync, it is not stable. I found that when I replaced the cable, I was able to get a great sync, and the surging was eliminated. Upon further inspection, when I removed the sheath from the old cable, it was in bad shape, with lots of small burrs that kept it from sliding smoothly. Of course, when I di this, I also did a complete tuneup with new plugs, and valve adjustmennt....so I can't attribute the results to the cable only. But there is no doubt, a new cable is critical to a good balance that stays good for a while. Please note, if you do a new cable, that it is ncessary to resync the TB's after a short time, because the new cable has to "relax" to being under connstant tension.....

 

[happy wanderer]

Thanks Jim. I replaced my throttle cable last year as per BMW Service Bulletin 2748.

See http://nmpcs.com/r11r/surge.pdf

It did make adjusting them easier since the new cable is Teflon lined but it did not purge the surge.

 

[A4Skyhawk]

Cause of Pinging

Bikerfish1100,

Pinging is another word for pre-detonation, knocking or dieseling.

As the piston approaches top dead center, the plug fires and the fuel/air mixture begins to burn. The key word here is "burn." The heat of combustion expands the gases in the cylinder, both burned and unburned, pushing against the piston and propelling man and machine merrily down the road. However, if the piston cannot move fast enough, the temperature and pressure rise to the point where any remaining unburned fuel/air mixture explodes rather than burns. The resulting shock wave impinges on the piston face and cylinder wall, causing the ping. Very bad for engine life uness you have a diesel engine, which operates by compressing a low-octane fuel/air mixture until it does explode. Diesel engines are of very robust construction to withstand the shocks.

When the engine is being lugged, the mixture reaches explosive conditions because the piston cannot move fast enough to expand the space above the piston and keep the pressure down. Also, the chemical properties of the fuel/air mixture affect the point at which predetonation occurs. Higher octane fuels are actually less explosive than low octane fuels and tolerate higher pressures and temperatures. Rich mixtures are also less prone to pre-detonation than lean ones, as the "extra" fuel has a cooling effect. Hot engines also contribute to pinging.

The easiest ways to reduce pinging are to use higher octane fuel and to downshift to avoid lugging the engine.

Large displacement cylinders can be more prone to pinging because the large volume of the fuel/air mixture can cause the pressure and temperature to rise to the detonation point before all the mixture is burned. Having two or more spark plugs establishes multiple flame fronts to ensure that the entire charge is burned before the detonation point is reached. Remember the dual-plug fix for older airheads when high-octane leaded gas went away and was was replaced with lower-octane lead free?

Timing is also very important. If ignition is initiated too early as the piston is on the way "up," all the factors mentioned above are exacerbated. If one cannot obtain the required octane fuel for the engine, retarding the timing will reduce pinging (at the expense of power). One more thing - the compression ratio of the engine is another starting point for the whole problem. Higher compression = higher pressure = higher temperature = higher propensity to detonate.

As a pilot, when flying piston-powered aircraft, you have a control to adjust the mixture. When the demand for power is high (think takeoff or dogfighting), you richen the mixture. During cruise, you lean the mixture to get better fuel consumption, while monitoring the engine temperture to avoid pre-detonation. If the plane has a constant-speed propeller, one also selects an increased propeller RPM when high power levels are needed, which "flattens" the angle of the prop, essentially taking more but smaller bites of air - this is the equivalent of downshifting. High-performance prop-jobs used 115/145 octane "purple" gas, with 115 representing the lean octane rating and 145 the rich mixture rating. Loaded with lead, though.

Jets are easier! Not to mention more fun!

George T'man
Old Navy Jet Jock

 

[bikerfish1100]

George- Good explanation. i have known and understood pretty much all of what you talked about, minus a detail or 3. I asked rgilroy to explain his comments about causes of pinging as what he did say seemed pretty garbled (and he discounted everything that i've ever understood to be true about pre-detonation), and what he left unsaid could have been pretty funny, if not actually informative.

 

[globalrider]

(internal combustion engines require a richer mixture at colder air temps, as colder air holds more O2)

They need more fuel at colder temperatures, but the A/F mixture stays the same. You also produce more HP at that point, but nothing is free as consumption goes up as well. Just look up the performance tables in any aircraft operating handbook.

 

[globalrider]

Maybe something of interest to those following this thread. Webbikeworld did a review of the booster plug.

http://www.webbikeworld.com/t2/booster-plug/

Having just heard of this device from a local rider, I am trying to get some real technical info and not the usual "it works, its nice" type of reviews that Webbikeworkd puts out.

Info like before and after A/F mixtures, before and after cylinder head and exhaust gas temperatures under various engine loads (that all requires a dyno).

And I am not willing to give up fuel economy by more than say 2 or 3%.

 

[happy wanderer]

Having just heard of this device from a local rider, I am trying to get some real technical info and not the usual "it works, its nice" type of reviews that Webbikeworkd puts out.

Info like before and after A/F mixtures, before and after cylinder head and exhaust gas temperatures under various engine loads (that all requires a dyno).

And I am not willing to give up fuel economy by more than say 2 or 3%.

Not sure if you noticed but this thread died 6 years ago. The Booster Plug does work but only temporarily as the ECU "learns" and adapts AFR which makes the Booster Plug ineffective over the long term. Resetting the ECU starts the learning process all over again but it will not last.

You have previously said your oilhead GSA does not surge but if you want to enrich the mixture the way to go is either using the LC-2 wideband 02 sensor and controller or the AF-XIED product which was developed using this technology. It has been thoroughly tested and proven to solve surging and other fueling problems quite effectively.

When all this was going on several years ago I beta tested the AF-XIED on my R1100RT and eventually installed the LC-1 controller and wideband 02 sensor on it. I can now run with a rich mixture for slow speeds and low RPMs when surging reared it's ugly head and then run very lean at highway speeds to save on fuel using a secondary output. I can do this with the flick of a tiny switch on the go and it's a wonderful thing.

This is a very long and very educational thread on the subject.
http://forums.bmwmoa.org/showthread.php?56990-2004-R1150RT-Wideband-O2-Sensors&highlight=wideband+02

 

[globalrider]

This is for my new 2016 R1200 GS Adventure LC which like my 2003 R1150 GSA runs fine. BTW, my old R1150 GSA still does not surge and never did.

I only asked because I was put onto this product yesterday by a local rider that has it on his F700 and he said it transformed his motorcycle.

So I am curious how it transforms a motorcycle and what it actually does, both positive and negative.

 

[globalrider]

This is a very long and very educational thread on the subject.
http://forums.bmwmoa.org/showthread.php?56990-2004-R1150RT-Wideband-O2-Sensors&highlight=wideband+02

Not that I have running issues, but it is an interesting read just on the first page so far.

 

[happy wanderer]

The booster plug uses a thermistor with a temp curve different to the OEM air temp probe and using a resistor divider it changes the voltage such that the ECU thinks it is colder outside than it really is by about 20 degrees C. The ECU richens the mixture accordingly but fairly quickly (withing a tank or two) slowly adjusts the mixture back to 14.7. So over time, it is not effective. In the short term the difference is noticeable.

The AF-XIED intercepts the voltage signal from the O2 sensor and tricks the ECU into thinking the mix is too lean so it richens it up using the built in algorithms and fuel data table. Much more effective solution and it does not get "learned out" as the booster plug does. This is true for all the resistor type fixes to the air temp sensor and Roger collected a bunch of data to prove it.

 

[globalrider]

The booster plug uses a thermistor with a temp curve different to the OEM air temp probe and using a resistor divider it changes the voltage such that the ECU thinks it is colder outside than it really is by about 20 degrees C. The ECU richens the mixture accordingly but fairly quickly (withing a tank or two) slowly adjusts the mixture back to 14.7. So over time, it is not effective. In the short term the difference is noticeable.

What I thought and also posted in the Wetheads folder earlier.

In the case of my new R1200 GSA LC, I really see no point to changing things that work right from BMW. So I'll scrap that thought.

Thanks!

 

[nrpetersen]

My 2000 R1100RT has only one throttle position sensor (a potentiometer) but has two throttle bodies, each of which has a brass colored bypass screw (called BBS). The processor has some sort of algorithm that approximates the cylinder airflow from pot angle measurements on only one throttle body. I want to know how one oxygen sensor can properly modulate the otherwise-identical injector pulse lengths for discrepancies in the air vs opening of the opposite throttle bodies.

I contend that surging is actually caused by one cylinder (probably the right one) misfiring as the mixture goes outside of a combustible range which is A/F from 8:1 to about 18:1. The fuel admission to each cylinder may be identical, but the amount of air taken into each cylinder could be way off. It is a stretch to assume that the air vs butterfly angle remains identical enough for the two sides.

 

[BC1100S]

The fuel admission to each cylinder may be identical, but the amount of air taken into each cylinder could be way off. It is a stretch to assume that the air vs butterfly angle remains identical enough for the two sides.

This is why its important to balance one's throttle bodies with an accurate device such as the Harmonizer.

 

[nrpetersen]

This is why its important to balance one's throttle bodies with an accurate device such as the Harmonizer.

Good point, but what assures one that the two throttle bodies have the same opening vs flow characteristics given that a helluva lot happens at high manifold vacuum when the butterflies are just cracked. Those butterfly ports are really huge & i could easily imagine a major flow discrepancy (like 2:1) under overrun and near closed throttle - just where we get most surging.

A test would be to slightly offset the BBSs and the do-not-touch throttle stops in one direction and then again in another direction to see what the effect on surging is.

 

[roger 04 rt]

My 2000 R1100RT has only one throttle position sensor (a potentiometer) but has two throttle bodies, each of which has a brass colored bypass screw (called BBS). The processor has some sort of algorithm that approximates the cylinder airflow from pot angle measurements on only one throttle body. I want to know how one oxygen sensor can properly modulate the otherwise-identical injector pulse lengths for discrepancies in the air vs opening of the opposite throttle bodies.

I contend that surging is actually caused by one cylinder (probably the right one) misfiring as the mixture goes outside of a combustible range which is A/F from 8:1 to about 18:1. The fuel admission to each cylinder may be identical, but the amount of air taken into each cylinder could be way off. It is a stretch to assume that the air vs butterfly angle remains identical enough for the two sides.

Surging isn't caused by misfiring but is caused by unequal AFRs which lead to unequal HP right vs left cylinder. The phenomenon is well known to pilots who regularly lean to the point where engine roughness occurs (but no misfiring).

Since there is no O2 sensor on the right cylinder there is nothing the Motronic can do to equalize AFR. You balance air by TB sync but the injectors can't be equalized (they can be cleaned though and often the balance is improved).

However if you richen the mixture enough, both cylinders burn all the O2 and the power is about the same.

The LC-2 or AF-Xied can get the mixture rich enough to eliminate surging. As Happy Wanderer said, the BoosterPlug is learned away by the long term trims.

 

[roger 04 rt]

Having just heard of this device from a local rider, I am trying to get some real technical info and not the usual "it works, its nice" type of reviews that Webbikeworkd puts out.

Info like before and after A/F mixtures, before and after cylinder head and exhaust gas temperatures under various engine loads (that all requires a dyno).

And I am not willing to give up fuel economy by more than say 2 or 3%.

This is for my new 2016 R1200 GS Adventure LC which like my 2003 R1150 GSA runs fine. BTW, my old R1150 GSA still does not surge and never did.

I only asked because I was put onto this product yesterday by a local rider that has it on his F700 and he said it transformed his motorcycle.

So I am curious how it transforms a motorcycle and what it actually does, both positive and negative.

Alex,
The Boosterplug does nothing after an adaptation period.

Here is how adaptation works: http://advrider.com/index.php?threa...-af-xied-for-bmw.749080/page-40#post-23675190

Here is data showing its effect before and then after adaptation: http://advrider.com/index.php?threa...-af-xied-for-bmw.749080/page-27#post-23126838

And here: http://advrider.com/index.php?threa...-af-xied-for-bmw.749080/page-28#post-23158376


If you want smoother running and somewhat cooler EGTs try lambda-shifting with LC-2s or AF-XIEDs. Additional fuel consumption is within your 2-3% range.

 

[nrpetersen]

Surging isn't caused by misfiring but is caused by unequal AFRs which lead to unequal HP right vs left cylinder. The phenomenon is well known to pilots who regularly lean to the point where engine roughness occurs (but no misfiring).

Since there is no O2 sensor on the right cylinder there is nothing the Motronic can do to equalize AFR. You balance air by TB sync but the injectors

Agree this far, but my contention is that the area ratio of the butterfly opening to the BBS opening is so great that the throttle bodies don't maintain the equality for small openings after they have been in service for a while. As evidence, consider:

• How fine the setting screw pitch on the throttle stop screw is.
• And note how incredibly tiny the annulus opening of a throttle body butterfly is to maintain engine idle.
• And the many precautions to NEVER fiddle with the throttle stops,
• My own experience where offsetting the RH throttle stop very slightly and compensating with the BBS setting cleared my R1100 of surging.

I strongly suspect that the separate throttle bodies using just one butterfly position feedback and one oxygen sensor feedback transducer system is a technical approach that got these bikes through initial emission testing, but isn't good for the long haul.

 

[cycleman2]

Think of the throttle position sensor as the rough setting and the BBS as the fine tuning. You can turn the BBS screws a bit to compensate (increase or decrease) the vacuum to get a balanced reading in the area of 3000 rpm without moving the cables. This may give you a slight different vacuum reading at idle between the two sides, but that is less important than a equal vacuum higher up in the rpm range. The BBS and the throttle plate work together as both are affecting the amount of air getting into the intake tract to mix with the fuel. This method works well for very small differences in vacuum as the small cable adjusts are a pain.

Think of the left side as the reference point and you match the right to this reference point. in the stock exhaust the 02 sensor is located at the point where both headers intersect, so yes it might be a slightly different AFR for one side or the other, but the difference is not measureable and is balanced out by the throttle body sync.

No doubt would be better with 2 throttle body sensors and 2 02 sensors, but that came later. We work with what we got.

The cure for surging had lots written about it, could be allusive and certainly was more of a problem for some than others.