crank sensor setup. Help!

[bigbuck1449]

I am working on my pickup for crank position and have some questions. The engine is a 2 cylinder motorcycle engine and I have removed the old stator and mag pickup and machined a new hub for the crank shaft. I am using a mag timing sensor with one magnet on the hub. I have read that if you use one pickup that the computer has to predict tdc. If I place the magnet say 20 or 30 degrees before tdc and program for an off set pickup will the computer know more about were tdc will be before its to late. I believe when I was trying to figure this out it was because I needed the computer to change timing for boost and running a missing tooth tone wheel was the only way to accomplish this. I could be wrong but I will get back in the manual and make for sure that's what the problem was for I just wanted to throw it out there while it was on my mind.

[bigbuck1449]

I did some rechecking and my question was on the right track. The computer has to predict when the next tdc will occur. I guess more specificly my question is will the timing be more accurate if the trigger is offset just before maximum ignition advance. I am running two the ls1 coils with turbo charging and using the Megasquirt v3.0 to control timing.

[mxrob]

From what I understand MS is behind on the tach signal it's acting upon by one cycle. Tach actually should come in just at or slightly after TDC so the processor has a full cycle to deal with injection and ignition timing. That's how mine is set up and it works great on ignition... working on fuel now.
http://www.msruns.com/viewtopic.php?f=93&t=23004

[bigbuck1449]

Thanks for the input mxrob. From what I have read what you are saying is what I got out of it to. I was thinking that the only reason behind that was because most triggers are setup right at or very close to tdc and ignition occurs before the trigger is ever seen. But if you have the trigger set right before the ignition event would ms use the most recent trigger or two trigger events back. I like your setup with the cam sensor and the 36-1 crank. I wanted to use a setup like that on my engine but didn't spend the time trying to figure out how to setup the cam sensor. My engine is a Honda cm400 but is installed in a buggy. The over head cam setup is pretty close to what you have. If putting the trigger 30 degrees btdc compared to tdc makes no improvement on accuracy should I try placeing two triggers on my flywheel or just redesign for a 36-1 setup with or without the cam sensor. Mxrob what type of sensor are you using for you cam.