For any add-on boards such as VR conditioners, optos and OEM interface boards
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By PSIG
#54914
The "smart" VR chips such as the MAX99xx series work well with specific wheel and tooth designs. Not so well with others, but there is no clear guidance for what will and won't work. Some designs have a high VR voltage after missing teeth, and the automatic threshold feature causes teeth to be missed and sync lost, for example. Less-smart conditioners don't have this issue, or other issuess that trick the smart ones.

That doesn't mean the smart ones don't work well, because they certainly can, and for some situations the simple ones can't, such as damaged teeth or wobbly wheels. The point is, no one type works for everything, but either type works for most. Unfortunately, the factors of why one would work better is not a simple issue. Try either one, and if it doesn't work try the other, or check your system for why it wouldn't work, e.g., electrical noise will cripple any type.

Timing drift is an issue with Speeduino only if the VR is wired backwards, or if a Rising output is used, with almost all conditioner designs that I know of. This is because of backwards wiring reading off of the less stable rising signal edge, or the signal distortion caused by the board input circuit that affects a Rising output much more than a Falling output. That is an ECM circuit design issue, not a VR module issue.

While the MAX series has zero-crossing detection capability, it isn't actually used for signal switching. :shock: Yeah, weird. You can use it for that, but only in Mode B, which I've never seen used in available modules because it disables the smart features. Instead the MAX uses zero-crossing as a signal filter and noise blocker as a bias to the input. TLDR; Due to these factors, simple conditioner designs can be just as accurate and drift no more than smart designs.

While I'm running my mouth (fingers?) I may as well repeat a common misconception about VR versus Hall/digital in DIY systems. VR sensors are simpler, more robust and often cheaper than Hall, but the signals they produce require rather tricky, higher-cost and less-robust conditioner circuits to make usable for the ECM. Hall and other digital types do not. Now which is "better"? ;) Either type can work very well, but you can see on these forums that the vast majority of trigger signal issues we see are with VR, due to that tricky circuit, and possibility of reversed wiring. Always make your own choices, but my general preferences for the shortest path to success are to use Hall for custom projects (if I have a choice), and start with simple-circuit VR conditioners if I don't, and go from there. They are your choices. Do your thing! 8-)
User avatar
By DStage
#54935
NickZ wrote: Thu Jan 27, 2022 1:02 am I was more thinking you may have designed something that might work better for Honda or Toyota.
I am always interested in new designs, but I also like to stick with what i know works.

If you get the chance to test it on a Honda or Toyota type VR please keep us updated
Heh I did not mention that but it did cross my mind that this one might at least have a chance in Honda/Toyota applications. Maybe not straight out of the box but there's some room to play. At this point I do not have anything of those brands at hand ;-)

And I agree with PSIG that there's no one design to rule them all here. As for Hall I also think it's easier in a way, at least it's cleaner. Other than price I think VR is simply more robust, there really nothing to be broken there while Halls do fail sometimes like for example those in ABS (I'll have to replace mine cause now I don't have speedometer working :p). It's quite interesting what you said about MAX principle of operation, somewhat strange choices they had :)

As an example in at least two of my cars there's a VR on crank but on cam Fiat used Hall, go figure.
User avatar
By PSIG
#54940
DStage wrote: Fri Jan 28, 2022 1:16 amHeh I did not mention that but it did cross my mind that this one might at least have a chance in Honda/Toyota applications.
One of the design goals of the DSC conditioner (sold by several suppliers), was to "tame" the systems with paired VR grounds, such as Subaru, Toyota and some Hondas, etc. Due to the wide variety of paired-ground systems, even that doesn't work every time, but in specific field testing and for years now on thousands of engines, it gets the job done almost every time. ;) It's even used by a couple Fortune 500 companies for research projects, and is generally my first choice unless for very specific reasons.

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