Re: "Surge Free" spark plugs

["Steve Makohin" <wateredg@xxxxxxxxxxxx>]

Hello Ben,

Ben Barkow <dr.ben@xxxxxxxxx> wrote:

> What Parker did, I'd guess, was set your TPS richer - maybe back to spec 
> or maybe richer than spec. By twisting the TPS a hair clockwise, you fool 
> the ECU into thinking the butterfly is more open than it really is.... and 
> so needs more gas.

I've done the TPS (Throttle Position Sensor) adjustment to deliberately 
richen the mix, and it eliminated the surging and rough running. But as you 
would guess, when you are telling the engine management system that your 
throttle is open a bit more than it truly is, the system is delivering more 
fuel to the engine, from idle all the way up. I experienced a significant 
(to me) decline in fuel economy. Considering the R1100S's skimpy range, I 
decided against this option.

John Parker (my tech at Budds BMW, and a professional engine tuner) takes 
the approach of calibrating the TPS to spec in order to allow the engine to 
run as fuel efficiently as the factory intended, and to alleviate the 
surging and rough running through other means. His approach worked well for 
me.



[...]
> But the Oilheads do seem to have chamber deficiencies, odd in such an 
> otherwise evolved bike, as evidenced by the value of dual-plugging, a fix 
> traditional in two-valve Airheads. This is exacerbated by the silly choice 
> of 3-electrode plugs initially made by The Factory, later moved to 
> 2-electrode... and that is Parker's secret plug, the NGK equivalent to 
> present factory recommendation!!!

"Chamber deficiencies" may be cited, but the issue is an common engineering 
one: How do you have efficient and consistent combustion in a large 
cylinder. The key word is "large." Other big bore motorcycle manufacturers 
have gone to dual plugging for the same reasons -- two ignition sources 
result in more thorough and consistent combustion (bigger bangs, and more 
controllably consistent bangs). You can easily see the effect of dual 
plugging on a piston aircraft where you can turn off one bank of spark plugs 
and instantly see and hear the engine RPM drop. When you have a 13 liter 6 
cylinger engine (more than 2 liters per cylinder), the effect is emphasized.

As for John Parker's new plugs on my R1100S being "the NGK equivalent to 
present factory recommendation", I cannot confirm if BMW is indeed shipping 
dual-plug boxers with those exact same plugs (I am not knowledgeable in that 
area). The pertint piece of infirmation here is that BMW did not ship my 
R1100S with those plugs, nor do Parker's recommended plugs match the 
physical form (tip projection) or heat range of the spec plugs for my 
R1100S. The non-spec plugs made a significant improvement in ridability, and 
they were a cheap way to get that improvement.



[...]
> The straightforward appropriate fix for surging in a mostly stock bike is 
> a Techlusion 259 or, if you have mods, a Techlusion 1031. This gives you a 
> little box with four adjustments which add enrichment to the mixture as 
> much or as little as you like and if you set it to their recommendation, 
> you'll be happy.

I can confirm that the vast majority of Techlusion owners are happy with the 
result. They report no surging, a bit more power, snappier throttle 
response, and smooth, linear power throughout the throttle range (i.e., no 
lags or flat spots as may be experienced when under light load with gentle 
roll-on). On the down-side, they also experienced lower fuel economy, though 
most felt it was "worth it." A small minority of Techlusion boxer users 
removed the unit because they felt the increased fuel consumption was 
unacceptable.

For the ultimate in fixes with respect to smooth engine running, no surging, 
linear throttle response (etc.), and *without* the penalty of increased fuel 
consumption, there is the San Jose BMW dual-plugging upgrade. It is also the 
most expensive by far, at around CAD$1,800 for parts and labor. You can get 
your current heads machined for the second set of plugs and get the dual 
plugging kit, and do the work yourself for a lot less. Details on 
www.sjbmw.com. My research into this area has produced extremely positive 
responses from people who had the upgrade done to their mono-plug Oilheads.

- -Steve Makohin
 '01 R1100S/ABS
 Oakville, Ontario, Canada 

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End of oilheads-digest V2 #169
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