Hotrodding the GS

Those sure came in handy during the last dozen Giants games...

Unfortunately I got it the first time... I was TRYING to not visualize but its too late... I already pictured you riding with a perplexed look around... then happy surprise when you remember your secret... then satisfied relief as you ride on...

So it looks like BMW has made some changes to throttle response on the new 2013. Anyone heard any details on what precisely they are doing yet? I wonder if they made changes that would require more engineering chllenges from Poolside or circumvent the feasibility of the Ice Air altogether heaven forbid?

  

Were you one of the half-million on the BART trains Wednesday night?

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Legal in all 50 states, and Canada.&#8194;

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I feel the same way regarding the desire to understand things ahead of time.

Regarding your air-cooled comment: Typically as both the motor and the ambient air temp increase a fuel injected motor is operated with a leaner mixture. Air-cooled motors even more so.

A hot motor, with warm intake air, will continue to run on very lean mixtures. The motor doesn't make the same power as it does with a richer mixture, but it runs cooler and emissions are lower.

The IICE Air puts a 'lower intake air temperature offset' into that lean mixture trend. The ECU responds to that 'temperature offset' with a richer mixture, and the motor makes better power at all ambient temps.

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Well, one thing I can tell you that if the factory changes the connector on the Intake Air Temp sensor, the IICE Air will not fit.&#8194;&#8194;Other than that it will work just fine.


Some technical notes about the new 1200 Wethead:

I haven't read any factory confirmation, but it appears to me the new 1200 will have throttle-by-wire. A throttle-by-wire system improves the throttle response of an emissions-regulated motor by not allowing the rider to control throttle movements.

The most accurate way to describe the system is that throttle-by-wire masks the rider inputs that would exhibit poor throttle response by simply not letting them happen.

Of course all of that is very different from good throttle response.


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"WeatHead"...did we already have a contest to name the new engine? I must have missed it:huh

Gotcha! Thanks! So then my assumption of all the other sensors remaining in play is correct (ambient/ intake pressure, etc). No worries about riding from Death Valley to Mt. Evans and the pressure changes
Not that it is in my near future

I thought it was a Wasser Kopf.

Well, since it's only partially wet... it will still rely on air cooling... perhaps it's kinda pretending to be wet... and not really a sign of true excitement that truely wet would indicate... Let's call it "Jelly Head" (as in personal lubricant squirted around the edges variety of wet)

Ah, no... while folks were crammed into BART like sardines in a Crown Prince can, I was outside enjoying the fresh ICEE-AIR

Saw the parade up-close last time, it was big fun.

Being an escapee from Kalifornia many years ago...nothing happening in Bagdad-By-The-Sea or across the bay in Berserkly would surprise me...but can you decode the billboard message? Thanks...

Ps...Not Crazy Horse, I got that.....

Maybe "Depends Head"...again only slightly wet

PM wrote in #3146: "A hot motor, with warm intake air, will continue to run on very lean mixtures. The motor doesn't make the same power as it does with a richer mixture, but it runs cooler and emissions are lower."


I may be misreading this...lean = cooler = lower emissions? I get the emissions part but thought lean mixture increases cylinder temps. Hence if the input temp from sensor indicated a lower ambient temp, the mixture would go richer for the denser air and engine would run cooler due to presence of more fuel. But, hey, I could be wrong.

I had the same thought until PS corrected me. I started thinking about it in the sense of thermodynamics. To put it simply, if the cylinder temperatures got hotter as the mixture was leaned out then the absence of any fuel would result in infinite heat Now we know that won't work. Unfortunately.
Thinking of small aircraft, as you ascend you would lean the mixture to account for less dense air. As you do so the exhaust gas temp increases, yes. Not because lean= hotter, but because the excess fuel acts as a coolant. It absorbs the heat. As the mix is leaned out there is less "coolant" (vaporizing fuel) and the EGT goes up. However, only so far. If the mix is leaned further then it starts dropping (less fuel, less work, less heat) until combustion can no longer be supported.

Two ways of stating same thing...lean mixture = less fuel = less "coolant"....therefore, lean mixture does result in increases of EGT or in my case the cylinder/engine temp on my boxer. More fuel in response to an ambient temp sensor that registers lower than actual ambient temps [hence air density is less than temp sensor would indicate] results in the fuel management putting more fuel [more coolant] into the cylinders resulting in a richer mixture. Sorry I know this not complicated, but I will be damned if I can see it...thanks for patience.

Kinda ...less fuel more temp [lean] : more fuel less temp [richer]

okay... after that discussion I take it back... lets go back to talking about magic pee packs.

There are three different temperatures of interest: intake air, cylinderhead and exhaust temperatures.

Intake Air: For any desired air/fuel ratio (AFR) colder air, because it packs more oxygen, needs a little more fuel. Hotter air needs a little less fuel. For instance, if it takes a 2 millisecond injector pulse at 68 degrees Fahrenheit to reach an AFR of 14.7:1, then at 32F it takes a pulse of 2.12 milliseconds. At 104F it requires a pulse of only 1.88 milliseconds to achieve that same 14.7:1 AFR.

Cylinderhead: This reaches its peak temperature when the mixture is at its Best Power ratio. If normal cruising is at 14.7:1, the Best Power AFR is roughly 12.5:1. The cylinder head gets hottest because the combustion is making most power. Richer or leaner than Best Power and the CHT goes down.

Exhaust Gas: This reaches its peak at roughly the ideal combustion mixture (stoichiometric) of 14.7:1 for gasoline. (E10 reaches a peak at about 14.1:1 but you don't have to think about it because your O2 sensor makes this adjustment automatically.) richer or leaner than Stoic and the EGT goes down.

So as you can see CHT and EGT reach a peak at different mixtures. Richer isn't always cooler, and leaner isn't always hotter. But leaner than Stoic is always cooler for both CHT and EGT; the leaner you get above Stoic, the cooler that CYT and EGT get.

RB

As a disclaimer, I (and probably "we") am talking about 10ths of AFR when talking about lean/ rich,
To add, as seen in the chart, depending on where you start with an engine, you could very well say that as you enrich the mixture the EGT temp goes up. So point of view has something to do with it Overly lean mix will not be any hotter than a overly rich mix.You can have too little or too much fuel to support strong combustion.Lean is typically fine at cruising/ low load situations. The AFR purpose is not necessarily to control temperatures on vehicles. Regardless, excess heat is wasted energy no matter if it is the exhaust or the cylinder head.
I will only agree with the above chart to an extent, though. It looks as if it is depicting temps for a moderately loaded engine. Under high loads, adding fuel (to an extent) will reduce temperatures in "best power" mode. IE, for gaining altitude in an aircraft. I whole heartedly agree with the relationship between cooler air being more dense and containing more O2 per unit volume. With piston engines, rich or lean/ CHT and EGT and what is an ideal ratio has much to do with loading.
Regardless, the vast majority of engines are lean running out of the gate.

Thanks for the comments and information. My experience has only been with carbureted motors [small block Chevy], old ones at that! If we ran lean on the track/course we would run the risk of burning valves and see engine oil temps skyrocket. The rule was when in doubt go rich. We indeed paid close attention to the AFR for endurance racing.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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But this is strictly empirical and anecdotal; so I appreciate the education. Even at this "late date"! <o></o>