Miata CAS and Crank Sensor?

[networkingdude]

i will ask and post my results back here in case someone else wants to go the same route

[ftjandra]

I am pretty sure that the Haltech can use a 4-1 cam trigger for sequential inj/ign, but as Alex already said, the timing resolution at fast rpm changes would be horrible.

--Ferdi

[networkingdude]

I am pretty sure that the Haltech can use a 4-1 cam trigger for sequential inj/ign, but as Alex already said, the timing resolution at fast rpm changes would be horrible.

--Ferdi

you guys say the resolution will be poor? I thought that the resolution would be good as long as the ecu was fast enough. Now comparing the resolution you would get using the 4-1 on a megasquirt IF it could do sequential would probably be poor... I get that... BUT since the haltech is quite a bit faster would is still pose a problem?

[networkingdude]

and are there any books or websites that go in to ridiculous detail on crank triggers/cam triggers that tell you everything about this stuff?

[ftjandra]

I don't think the MS is slow and I don't particularly think my E6X is fast.

Basically, the ecu can't detect fast rpm changes because there are only 4 teeth that are spaced very wide apart - equal to 2 teeth on the crank. The ecu measures the time between each tooth to figure out the rpm. So, obviously the more teeth you have (spaced closer together), the faster the ecu will be able to figure out that the rpm is changing. Whether this has a real affect I can't say.

You see how it has nothing to do with processing speed of the ecu, but more with that it doesn't get enough info?

Btw, I fitted a 60 tooth wheel onto the crank and used the cas sensor for the sync event. I am running sequential injection and waste spark ignition because that's all my E6X can do.

--Ferdi

[networkingdude]

the e6x compared to the ms would be similar however the platinum 1000/200 are much faster

but i get your point and understand what you are saying

I am just confused as to what negatives poor resolution would have?

and if i need to end up fitting a trigger wheel who makes a kit? Do you have pics of your setup Ferdi?

[ftjandra]

Well, if the ecu doesn't know what the exact rpm is in 'real-time' how will it know when to send the spark (timing) or how much fuel to inject? If the rpm is changing fast, like on the drag strip, the ecu would always be lagging behind just a few milliseconds. Like, I said, I have no idea how much of a difference it really makes.

I am using an aftermarket crank pulley (ATI) that I fitted a 60-2 trigger wheel onto.


Btw, how do you know the processing speed of the Haltech ecus? Do they list what processors they use inside?

--Ferdi

[networkingdude]

wow... I was thinking of using the ati damper as well. Did you make that trigger wheel? And how do you have the sensor mounted? Is that custom as well?

As for the Haltech you have is 16bit and 16mhz, the newer ones are 32 bit and 56mhz Motorola processors i believe

[networkingdude]

I also dont see the ati FIX on you pulley, did you omit this in your install?

[Lex]

What I was getting at with poor timing resolution was that if I were to improve my ignition system, I wouldn't consider anything more than wasted spark until I was able to detect changes in RPM faster than what a cam wheel on a belt could.

That being said, the higher resolution of modern cars greatly helps in terms of emissions improvements during engine transients and fault detection (misfires, etc)

[ftjandra]

The trigger wheel is one from electromotive. I bored out the center and drilled the mounting holes. The sensor mount I made myself. You are right, those pics don't show the 'fix' because I was one of the first guys to get one. I later added the fix, which required the center of the trigger wheel to be machined down. This post on miata.net has pics with the fix isntalled (you must be a member there to have known about the fix?).

Ah, interesting about the processor speeds. I wish that the communication between the E6X and the laptop would be faster, but that's the only time I feel that it is slow. I think a lot has to do with the Halwin software, which from my experience with it does not seem very well written.

--Ferdi

[networkingdude]

well... you guys have me convinced! I'll see about getting a trigger wheel made up.

If i can't find a shop or sutable trigger that i can fit to the ati do any of you provide such a service?

Now to clarify why i want to go through all this trouble when i know wasted spark or a dizzy would work is because I love to tinker, i need to learn, and it just seems to be a better way to do things. I still may even end up with a MS depending on my budget.

Haltech has new software for their newer units and they use usb so it will be much faster

EDIT: which part number or what specs are for that trigger wheel? And how much did you have to machine it?

[ftjandra]

I used the 6" diameter 60-2 trigger wheel (electromotive part# 230-72660). I don't have the specs of how much I machined off, but once you have the ATI pulley you should be able to easily measure it. Another option I have seen is to mount the trigger wheel on the front of the stock crank pulley. It's not as exact, though, because the front of the pulley can move in relation to the back...it is a damper afterall.

Yes, I wish Haltech would come out with updated software for the E6X as I hear that the software for the newer units is much better. But, I doubt that will ever happen.

Now to clarify why i want to go through all this trouble when i know wasted spark or a dizzy would work is because I love to tinker, i need to learn, and it just seems to be a better way to do things.

Same here.

--Ferdi

[networkingdude]

do you have pics of the crank sensor mount?

[ftjandra]

do you have pics of the crank sensor mount?

No, unfortunately I do not (I usually have pics of everything...). Make sure to make the mount out of non-magnetic material, like aluminum, otherwise it'll mess up the sensor.

--Ferdi