Hotrodding the GS

<table border="0" cellpadding="5" width="650"><tr><td>Yes, that's right. The IICE Cool modifies how the ECU controls Transient Throttle fueling (aka: throttle tip-in). For that to work properly, the IICE Air must be set to -10°.
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<table border="0" cellpadding="5" width="650"><tr><td>Switching to a smaller front sprocket vs. fitting the IICE Air.

Regarding the improvement in abrupt or 'snatchy' throttle, there's a reason why fitting the smaller sprocket feels the same as fitting an IICE Air and keeping the larger sprocket.

The reason is, the issue that causes abrupt throttle response was never the sprocket in the first place. The abruptness is caused by problems in transient fueling. Changing to a smaller front sprocket does help mask the fueling problem though. I'll explain why that is a little later.

Here's the sequence of events that makes the throttle so abrupt. First the rider opens the throttle and immediately the motor goes lean for a moment. The lean condition causes a drop in power output. The drop in power output is due to insufficient transient fueling. The rider experiences the drop in power output as a momentary lurch.

The momentary lean condition, and corresponding drop in power output, lasts for approximately two to three combustion cycles. The motor doesn't stall during this power interruption, but you sure lurch forward in the saddle from the momentary decrease in power. The lurch is the first half of the abruptness. It occurs during the throttle tip-in.

Throttle tip-in is a transient event, it only lasts a moment. It comprises the period of time that the rider is actually moving the throttle, plus two or three combustion cycles. After that period, normal fueling resumes and normal power is restored.

When normal fueling resumes, the rider experiences the increase in power output as a momentary lunge. And it's the preceding drop in power that makes the normal power feel abrupt.

Did you get that last piece? The abrupt throttle is composed of two events, one after the other. The drop in power when the throttle is tipped in, followed by normal power a moment later. The lurch-followed-by-lunge is the abruptness the rider feels when the throttle is moved.

Why does the throttle abruptness improve a little when I fit a smaller front sprocket? The answer to that is simple. A smaller front sprocket is a lower drive ratio, which means it takes less power from the motor to move the bike forward. The lower drive ratio needs less power, so the reduction in power from the momentary lean condition during throttle tip in is less noticeable.

Fitting a smaller front sprocket only masks the transient fueling problem. And here's something... Fitting an IICE Air also only masks the transient fueling problem.

The IICE Air, and other competitive products, are designed to enrich acceleration, not throttle tip-in.

Now, if you dump enough fuel in during acceleration (setting the IICE Air to -30° for example), it will make a small improvement to the initial lean condition at throttle tip-in. But it will be overly rich during acceleration and will not feel as crisp.

So while there is a small improvement to one, it comes at the expense of the other. It's a blunt instrument approach that lacks refinement. To fix the lurch-followed-by-lunge at throttle tip-in, and really make the throttle responsive, you need an IICE Cool.
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Thanks for that explaination....

Said briefly (and I hope accurately), during leading-throttle the engine goes into open loop mode ignoring the O2 sensor, and fueling the engine based on a map using the relevant DME inputs -- one of them being air temp. With the IICE Air, the DME is fooled and made to think the incoming air is cooler/denser than it really is, and thus uses a slightly richer fueling than it otherwise would ... So far so good I hope....

Now ... the IICE-Cool will be messing with the coolant/oil temperature sensor. How is it that the DME uses this input during tip-in (and will be fooled by IICE-Cool) into giving us the digital equal to a bigger accelerator pump?

THANKS!

Very brief ride report:

Excellent!

It's everything they say. The GS has more grunt when I roll my right wrist, and feels about the same at steady throttle. Hooning around the neighborhood hills and streets, it's a refreshing change, and makes the bike more enjoyable to ride. I'm damn glad I got one.

That's it in a nutshell.

As chance would have it, I answered that the other day. http://www.advrider.com/forums/showthread.php?p=17413094#post17413094 Inside that post there's also a link to a paper on the topic of transient fueling.


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<table border="0" cellpadding="5" width="650"><tr><td>That's why we built the darn things, to make people happy!


NOTE: For anyone else who wants to be "damn glad you got one", you have about a week before IICE Air sales come to an end.
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thanks! Missed that somehow............

Sub 50 deg and falling temps yesterday afternoon in Pa. I needed to get my PA Airheads supertech check over to Sipps place, so its a good oppty to play with the new unit.
And Play we did .
I am running a Scorpion low exhaust on a 05 R12GS, primarily to use two full size HT panniers.Its also lighter as well.Thats just a data point ,as I have no real idea of the actual impact (if any) of using this exhaust on the bikes performance or its impact when using the new Ice chip.
Observations:
The throttle seems happier/crisper thru the rev range. almost like the Dellortos on the R90S.
Exhaust note seems louder ,but that doesnt make sense.
Speedo seems like I am going faster ,but that doesnt make sense either.

The HD ( low glide ?) that was behind me on the slab home (wanting to be in front of me) soon recognized that that wasnt going to happen ( hooligan in me). Although, I was suprized he was able to hang back there at WOT ! Couldnt have been a stocker. Anyway I backed off , friendly waves and acknowledgments of our shenaginagans and off on our seperate ways. He musta thought, what the hell was that thing ?...a BMW Humvee with hippo hands flopping in the breeze at triple digit speeds... out to play in the cold.

Anyway, I like my ice chip,thanks guys!
The drive train already gets a workout and this improvement will only increase the fun factor.
Im a happy camper - and it was worth the wait.
Regards
Bruce

Poolside, no more my checked the mail today and I got mail. I will be installing this weekend.

I got mine!

Installed last week- now it appears that front wheel has been on a diet because it is getting waaaay light. Thanks Poolside.

<table border="0" cellpadding="5" width="650"><tr><td>And hallelujah for that!


JJ and I are glad that you folks are happy with your new toys! Sorry to make you wait so long. Especially those who ordered much earlier in the year.
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Man, just got back from running some errands, and making sure I didn't wear out my front tire too quickly (I'm really lucky I don't own a sport bike).

Anyway, I have to register a serious complaint about my ICEAir. The damn bike runs into the rev-limiter way too soon now. Frickin' lame.



JC

Poolside - I just sent you a PM with a dumb question and an order via PayPal with $$.

There are no dumb questions Ken, only dumb answers.



Edit: Check your Inbox

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Got mine down here at the southernmost tip of Texas today!

How soon can I order the IICE Cool?

Hell, let him finish the last batch first. I'm still waiting on mine.

Got mine installed this weekend. Bit of a PITA with the SW Mototech bars. It took a couple minutes to wiggle the panels out. Pretty straight forward it feels a bit better. We shall see.

Got mine too. But I don't see where to connect it. This thread has become too big to navigate effectively.

Could someone please point my dumb ass to a post that describes the connection point with PICTURES?

I figured it out with this link.

http://www.powerfrkusa.net/setup/bmw-installation-guides/r-1200-gs/