Y2KZX12R
Needs a job
CompetitionCNC.com
Posts: 3762
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posted January 11, 2004 05:39 AM
Motorcyclist, aug 2002...
I just got an email from a guy that fried his ohm meter setting his TPS using the Motorcyclist article...
So I dug up this old post where I noted a few issues so no one else makes this mistake.
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I was flying back from a Mitsubishi meeting in Vegas this past week and in the airport I was picking up some snacks for the "no meal flight" in the concession stand. My wife was in the book shop picking up some reading material for herself and thought nicely to get me some reading material for the flight. One of the things she grabbed was the August 2002 Motorcyclist. So after takeoff I started to read thru it and I came across the article about "Nine ways to better FI mapping". I had heard about the article on "another board" but hadn't seen it yet. I read the article and came to some conclusions.
There is several points of mis information in there.
I wouldn't jump to blame Cliff, it may be miss prints.
But the bottom line is that Motorcyclist didn't bother to take the time to read and check the contents of the article. That's sad.
However, I think Motorcyclist is starting to come around in its contents lately. They seem to be trying to publish more information that is use full for readers and less opinion based columns. I think its a great direction.
I was hesitant to comment on the article, not wanting to discredit Cliff. Cliff is an old board member and has contributed tons of great info for the board members.
I'm not trying to bash him and I don't know if Motorcyclist changed what he said or he simply mis spoke by accident.
And besides, as any old board members know, its not my style to discredit board members for the sake of argument.
1) The TPS is a basically potentiometer as are most of the sensors in a FI system. They have a reference voltage coming in, usually 5vdc, and the sensor manipulates the voltage and sends it back.
The proper way to set the TPS output voltage is with a VOLT meter. You could damage an ohm meter if you put voltage across it like this article says.
Shame on Motorcyclist.
2) The article states you set the % of advance you want. With the PC-III software is not set in percent. Its set in degrees offset of the reference signal from the crank sensor. Its not even an actual timing number in relation to crank angle. In fact with the PC-III software you have no idea what the ignition timing is in relation to crank angle. The factory parts (crank, rotor, pickup coil)are mass produced and have manufacturing tolerances. Therefore unless you dynamically set the ignition "offset" to x degrees before TDC then you do not know the actual ignition timing. This can be done with a degree wheel and fabricating some simple reference devices. And checked dynamically with the side cover off and a light.
Even the air gap between the ignition coil and rotor can effect the dynamic timing due to signal pulse triggering threshold. Something only seen with an oscilloscope.
You don't need to be concerned with it thou. Only the guys that modified the pickup coils early on needed to check the air gap.
On some racing computer control systems the ignition is set using a crank angle variable. Some use an actual number of degrees BTDC. But the PC-III simply changes the pulse offset in degrees from an unknown number in relation to crank angle.
3) Fuel doesn't "contain" pure octane anymore to control knock. Its a rating number that is derived about by a laboratory,(research rating) and an engine with a variable compression ratio, (motor rating). In the USA we use the R+M/2 formula to attach a number that you see on the pump. They can raise the "octane number" in many ways with different chemicals and proccesses besides octane.
It is true that fuel ages and becomes "bad" or less resistant to detonation with age. So the context of the statement is accurate. This is where a fuel Catalyst such as the Fitch helps. I'm not going to go into the Fitch now but it does modify the molecular chains. I've used a 4 gas analyzer and have seen huge reductions in unburned hydrocarbons.
But sadly, the adds are a huge exaggeration for marketing. But that's marketing.
4) The injectors shut off on the zx12r at 0% throttle above 6500 rpm. So changing the fuel numbers in this area will do nothing. I think Cliff was referring to the on off abruptness below 6000 rpm and they printed 60% throttle. ??
I don't think they understood the context of what Cliff was trying to say. Because at 60% throttle you are well into the meat of the map where mapping by A/F ratio is done.
5) When the idle is hunting on the zx12r the A/F ratio hunts in synchronization with it.
Flip flopping the numbers in the map in opposition to the hunt helps stabilize the hunt.
When you remove the perforated plate in the factory exhaust Can this hunt becomes magnified. Yet the noise level is unchanged. This leads me to believe that the perforated plate was a drive ability (idle) fix done after the pre production bikes were sent around. Removing this plate is also worth a few HP.
I agree that the reduction of back pressure destabilizes the i/e port cross flow in the head at an idle. The effect is more noticeable on the zx12r because of the big cams it has from the factory compared to the bussa or most other bikes.
But like I said before I'm glad to see articles like this.
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Y2KZX12R
CompetitionCNC.com
   
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beansbaxter
Needs a life
Posts: 5911
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posted January 13, 2004 11:23 AM
I just read that after doing six straight hours of statistics homework...my head is gonna burst!
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necro
Needs a job
My Grandma Is A Virgin
Posts: 2148
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posted January 13, 2004 04:19 PM
What are you studing?
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3829
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Megabyte
Pro
Posts: 1047
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posted January 13, 2004 10:49 PM
quote:
I just read that after doing six straight hours of statistics homework...my head is gonna burst!
I know the feeling. A number of years ago while working on my Math major, there were many times after hours of studying when my brain would enter another dimension; it was a mind altering experience....
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We First make our habits and then our habits make us.
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TurboBlew
Moderator
BUSY DOING THE SCHIAVO
Posts: 4590
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posted January 14, 2004 02:32 AM
Beans... 6hrs???
You need a tutor buddy. How many credit hours is the course worth?
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Also a BadAss Internet Forum Moderator 4 Hire!! Come at me brah!
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