zx9rmal
Novice Class
Posts: 75
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posted May 25, 2006 06:50 PM
Question for ridgeracer re: ZX-14 speed limiter
I did a top end run after I changed to a 16T front sprocket. The bike accelerated hard in 6th gear right up to 10,500 rpm, then just stopped. It felt like the motor would have easily pulled the redline if it weren't restricted. I assume the ECU is getting the speed limiting signal from the sensor at the front sprocket cover.
So here's my idea: suppose I disconnect that sensor, measure the resistance of the sensor, and then insert a resistor with the same resistance in the connector to the sensor.
If the ECU is getting the same resistance, but no rpm signal, might that disable the limiter??
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Mal Glanz
Ft. Lauderdale, FL
'12 ZX-14R
  
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ZXLNT
Needs a job
Kawpuke Extraordinare
Posts: 2853
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posted May 25, 2006 08:26 PM
The speed sensor doesn't operate on resistance. It uses a "hall effect sensor" to send pulses to the ecu. The more pulses per second that faster the speed the ecu registers... It operates basically the same way a camshaft sensor or crankshaft sensor operates.
I wonder if the ECU limits speed simply by a speed sensor reading or a possibly an RPM and Gear position reading. Meaning at a set RPM in top gear it will no longer accellerate..
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dubious
Needs a life
Needs more time to ride!
Posts: 8442
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posted May 25, 2006 09:43 PM
We need to remove the restiction to bottom power in lower gears too!
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natural selection.....
destiny will overcome intervention.
Some are not worthy of the effort.
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ridgeracer
Pro
Posts: 1309
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posted May 26, 2006 05:02 AM
 Edited By: ridgeracer on 26 May 2006 06:53
EDIT: Sorry wrong bike I thought he was talking about the 12
The speed restriction was added in 2001. If you compare the schematics for the 2000 A1 to the 2001 A2 the only difference is the speedo wire now goes to the ecu as well as instrument cluster.
See my article on i-hacked for all the particulars and how to build a bypass out of a few dollars of radioshack parts
http://www.i-hacked.com/content/view/178/45/
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ridgeracer
Pro
Posts: 1309
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posted May 26, 2006 05:29 AM
Edited By: ridgeracer on 26 May 2006 06:57
EDIT: You should be able to modifiy this spreadsheet for the zx-14. You will need to know the tire circumfrence, front sprocket, rear sprocket, redline rpm, primary ratio (crank to transmission) and 6th gear ratio.
Or post the numbers and I'll plug them in
I have a Excel spreadsheet for calculating the top speed of a zx12r given rpm, gear ratios, tire size
http://www.olympus.net/personal/mbially/zx12spdcalc.xls Its not very user friendly but if you know excel you shouldn't have any problems
It shows that with a 16 front 46 rear your actual speed at redline will be 177.5 mph
However the change in sprockets causes a speedo error of 112% meaning your indicated speed will be 12% greater than your actual speed. Put another way the bike will think its going 186, the restriction limit, when its actual speed is 186 / 1.12 or 166mph
My spreed sheets indicates you would hit that wall at 10,750 rpm.
Removing the speed restriction would get you another 11mph
BTW my spreadsheet also shows that with no restriction and standard gearing the bike should do 199.69 mph at 11,500 rpm
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ridgeracer
Pro
Posts: 1309
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posted May 26, 2006 05:51 AM
Actually I just realized you were talking about the ZX-14 not the 12
My bad.....never mind
I wondered why we were rehashing old ground
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zx9rmal
Novice Class
Posts: 75
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posted May 26, 2006 06:43 AM
quote:
EDIT: Sorry wrong bike I thought he was talking about the 12
The speed restriction was added in 2001. If you compare the schematics for the 2000 A1 to the 2001 A2 the only difference is the speedo wire now goes to the ecu as well as instrument cluster.
See my article on i-hacked for all the particulars and how to build a bypass out of a few dollars of radioshack parts
http://www.i-hacked.com/content/view/178/45/
Great article. Thanks. Do you know if the 14 speed limiter operates on the same principle??
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Mal Glanz
Ft. Lauderdale, FL
'12 ZX-14R
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ridgeracer
Pro
Posts: 1309
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posted May 26, 2006 07:13 AM
Yes and no. Yes, I'm sure it uses the same technology, No I don't think it can be hacked in the same way.
For one thing Muzzy doesn't sell a Bonneville box for the 14 and only for the 2001-2003 zx-12s. 2004 was the year Kawi upgraded the 12 ECU (see the speculation about ecus thread)
http://www.muzzys.com/MZPM-K12/index.html
BTW some have remarked on how the Muzzy box uses the same number and color of wires as my device in the i-hack article.
One way to findout would be to look in the shop manual and see if the speedo line still goes to the ECU
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zx9rmal
Novice Class
Posts: 75
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posted May 26, 2006 09:58 AM
Well, continuing on, I disconnected the front sprocket sensor. It's a 3 wire connector. On the sensor side, I measured resistance at about 17k ohms between 2 of the 3 contacts. The other 2 combinations had no resistance. On the hot side, with the key on, I measured 12v between 2 contacts, and about 5v between 2 other contacts. The 3rd combination had no voltage.
If I were to leave the connector disconnected and put in a 17k ohm resistor connecting the 2 appropriate contacts, you don't think this would eliminate the limiter, since the ECU is not getting the signal but IS getting a complete circuit??
Also, how about just leaving the sensor connected, but removing it from the sprocket cover, so as to eliminate the signal?? I don't really care about the speedo operation.
Last, how about somehow isolating 2 of the 4 corners of the countershaft nut, so as to reduce the signal by 1/2??
I'm sure I'm a bit over my head here, but I just thought I'd check out these ideas I have.
Thanks.
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Mal Glanz
Ft. Lauderdale, FL
'12 ZX-14R
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ridgeracer
Pro
Posts: 1309
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posted May 26, 2006 10:13 AM
This device is a 'smart' sensor.
On of the leads is 12v power, the other ground, and the third will switch back and forth from power to ground if you wave any kind of iron or steel, like a screwdriver in front of it.
This is a digital sensor. The faster you go, the more pulses per second come out of the sensor.
Im not familiar with the ZX-14 but on the 12 its not reading the nut but the gear teeth.
An interesting test would be to unplug it and drive it around the block a couple times. Your speedo won't work but the question is will the ECU turn on the red FI light to indicate there is an error with the speedo. This would indicate whether or not the ECU was monitoring the speedo line.
Putting a resistor in there is going to do anything for you.
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zx9rmal
Novice Class
Posts: 75
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posted May 26, 2006 10:18 AM
<>
I believe MCN in England did this and it worked ONE TIME before throwing a fault.
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Mal Glanz
Ft. Lauderdale, FL
'12 ZX-14R
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ridgeracer
Pro
Posts: 1309
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posted May 26, 2006 10:55 AM
Well if thats the case then the ECU is monitoring the speedo signal, most likley for speed restriction. This means we could fake it out. Not exactly like I did on the 12 but in similar fashion.
On the 12 the speedo signal splits into to wires, one going to the speedo, one to the ECU. We can cut the wire going to the ecu and put a black box in the middle that provides a false signal that never exceeds 186 mph.
OR, If you have some cash burning a hole in your pocket you could by a Yellow Box
http://www.blackrobotics.com/
This device would correct the 12% speedo error because of your sprocket change and kick your ECU limit back up to 186. With out the ratio info for my spreadsheet I can't tell for sure, but will a ZX-14 even go 186 at redline with a 16 sprocket?
If we use the 12 example above the bike would only go 177 with that sprocket so the 186 limit would not be an issue once the speedo was corrected for actuall speed.
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zx9rmal
Novice Class
Posts: 75
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posted May 26, 2006 11:10 AM
I 'm expecting a Speedohealer to be delivered soon. If that's how it works, then great. My best guess is that the 14 should go around 186-188 with the 16T, based on a 6-7% speedo error and a 6% reduction in final drive gearing. I'm gonna check the 16T gearing with my GPS tomorrow. I'll let you know.
Thanks for all the help.
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Mal Glanz
Ft. Lauderdale, FL
'12 ZX-14R
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