Maximum number of speedpulse

[sphilips]

I have a M800 with traction controle option and want to install 2 speed sensors on the wheel. I have acces to the original abs speed rings (We don't use the abs) and sensors. But these a about 40 impulse per rotation. I have seen on the motec datasheet that there has to be a large space between the teeth. Now I want to know if this is limited to the sensor or the m800.

I think 40 impulses is better than 20 impulses.

It is for a Honda cbr 1000rr 2010 model. If anyone has some experiance with this model and they want to help me. Please send contact data.

[stevieturbo]

I doubt what you suggest will pose a problem.

But you dont mention what diameter the wheel is. A 50mm wheel with 40 teeth will be different than a 500mm wheel with 40 teeth in terms of how the signal is seen.

Most modern cars have a large number of teeth on quite a small diameter shaft to monitor wheel speed for ABS, and they work fine.
Only way to find out is to try it.

[sphilips]

diameter is 17 inch wheels, circumference front 200 cm, rear 210 cm.

[stevieturbo]

diameter is 17 inch wheels, circumference front 200 cm, rear 210 cm.

Not the road wheels. The trigger wheels.

Or is the trigger wheel at the outer diameter of the road wheel ? if so, 40 teeth over that huge circumference will quite slow pulses as far as the ecu is concerned.

Especially as some crank sensors can have 60 teeth over a pretty small diameter and spin to several thousand rpm

[Holmz]

...
Or is the trigger wheel at the outer diameter of the road wheel ? if so, 40 teeth over that huge circumference will quite slow pulses as far as the ecu is concerned.
...

I think that the shaft speed is the same given the wheels/tyres are the same.
So the pulse repetition interval should not be affected.

The pulse depth/amplitude might change as the metal is going by at a faster rate though.

[IDP]

From M800 Help file:

Note : The time measurement resolution of the speed measurement
system is 1usec. This limits the resolution to which the
ECU can measure wheel speed at high speed. The more teeth
on the measuring wheel the less resolution at high speed
but the faster the update rate at low speed.

For example a 60 tooth wheel at 300km/hr would typically
have a resolution of about 1km/hr. If the number of teeth
were 12 then the resolution would be 0.2km/hr. At lower
speed the resolution is proportionally higher.

[MarkMc]

I do not think you will have a problem BUT the one thing to ALWAYS remember about trigger discs and sensors is that they need to be matched.

I have seen a lot of people over the years make their own trigger discs and not match the tooth profile to the sensor. Common hall sensors like a GT101 do not like very small tooth spacings but that really depends on speed. If you have a factory style ABS trigger disc then you should use the matching sensor, then you know it will work.

If it is a magnetic sensor then you will probably have to use a DMC (Dual Mag converter) so that the M800 can definitely read the wheel speed at very low speeds.....but again this is setup dependant, you would have to wire it up to see what output the sensor gives.

[FoxPerformance]

doesnt the cbr 1000 use rear speed off the transmission on the engine case? this has plenty of teeth for good resolution on the cbr 600's

chris brown of motec gave me a excel spreadsheet that works out the least amount of teeth to use that's desireble for TC, and it is 24 teeth. if you can get a signal off the transmission then this would be ideal. getting 24 teeth on a small diameter may be a challenge for whatever sensor you're using as stated above.

On my front wheel i am only using the 5 rotor bolts as pickups(must be steel) for front speed and this has been acceptable as front speed on a bike is constant (unless wheeling) but having more teeth on the rear is necessary for good tc actuation. you'll need to setup your config for two separate calibrations for front and rear if doing it this way.

I was using only as 4 pickup teeth on the rear sensor on a 4" diameter (this is the stock rear speed sensor configuration ducati uses), the tc worked decent but not as well as I think with 24 teeth.

[MarkMc]

I have 36 teeth on a 60mm diameter disc for my Ref....but I chose the right sensor.

[sphilips]

I'll give it a try and use the abs sensors.

I don't want to use the gearbox (as standard hrc) as evertime we change sprockets I need to adjust the ratio.