VR or Hall effect sensor for Crank position?

[lycominghunter]

Hello All,
I'm converting a YFZ450 engine (4 stroke single cylinder) to EFI and my current problem is choosing a VR or Hall effect sensor for the crank sensor. The plan is to use a 36-1 tooth wheel. I was planning to use a VR sensor, however after looking at this website (http://www.aitekinstruments.com/pdf/cat08_sensors.pdf), and doing a simple calculation to find the speed of the tooth wheel at 10,000 rpm, I find that the teeth will be traveling at 2094 inches/sec for a 4 inch diameter tooth wheel. For these VR sensors, it says that 500 inches/second is the recommended or ideal speed of the tooth wheel, and that 1000 inches/sec is the max limit. Both of which are far less than the tooth wheel speed that we will be spinning...
So my question is, is there a VR sensor that can distinguish each tooth at this speed? Am i missing something because I know that ford uses a VR sensor on their crank tooth wheel. Also, are VR sensors typically limited to what they can pick up during cranking speed for start up?
If this is the case then I guess a Hall effect sensor is the way to go.
Thank you very much for your time and help. It is greatly appreciated.

[myk777]

Take a look at this thread:

http://www.microsquirt.com/viewtopic.php?f=38&t=23570

I much prefer gear tooth hall sensors myself, you can see my YFZ450 installation on the second page of that thread.

Mike

[lycominghunter]

Thanks Mike. I have your threads copied into microsoft word and have been going over them and all of the manuals for microsquirt. I think that I am going to go with a hall sensor too, but I figure I'll test a VR too just to see if itll work.

And I have a quick question for you. Did you have to have to use a cam sensor and why? Couldn't you just use the missing tooth to trigger injection and ignition? (see option 3. M-N crank wheel w/no cam synch http://www.microsquirt.info/dualspark.htm)

Thanks for your help. I really appreciate it.

Jason

[myk777]

I wanted to try sequential fueling and also the speed density algorith and at the time needed sequential to properly time the map sample in the cycle, the latest MS2extra codes have a way around this however. If your doing alpha-N and wasted spark and dont care about the injection timing then yes, you can run without the cam sensor.

Mike