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VSS with ABS (for TC)

 
Old 04-09-2019, 12:47 PM
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Default VSS with ABS (for TC)

When you steal the 4 VSS signals away from ABS you have to unplug the ABS connector to prevent the ABS circuit affecting the resulting variable reluctance voltage. So then you lose ABS.

Has anyone out there worked out a way to grab the VSS from the 4 corners (how convenient!) and yet still allow ABS to function? I want it all, traction control on acceleration as well as traction control on rapid deceleration events (ABS!).
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Old 04-23-2019, 05:35 PM
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You probably don't want to be doing both as it will effect the readings of each other.
Instead, just buy 4 of the abs vss sensors and mount them in slightly different spots on the same wheel.

Should work fine.
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Old 04-23-2019, 05:46 PM
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I've got a couple ideas kicking around for this. One, install a switch on the brake pedal, when braking i'll route the signal to the ABS module. When accelerating it'll send it to the VSS inputs on the MS3 (through a conditioner).

Another idea is some way to isolate the two from each other with some kind of high impedance amplifier. I'm working it soon and will get back if I find anything.

Thanks
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Old 04-23-2019, 05:50 PM
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the stock ABS sensors are like $75-$150, so I'm not a fan of that price (x4 for all corners). But I'm seeing a Dorman alternative from summit for like $27 bucks. Maybe I'll try this path if I can easily mount in next to the ABS sensor.
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Old 04-23-2019, 06:13 PM
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Originally Posted by Mudflap View Post
When you steal the 4 VSS signals away from ABS you have to unplug the ABS connector to prevent the ABS circuit affecting the resulting variable reluctance voltage. So then you lose ABS.
Are you certain they need to be unplugged? It's extremely common to share VR signals between different modules. I'm currently doing it with the VR crank signal on my F150.
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Old 04-23-2019, 06:22 PM
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This is a good point, in my mind they shouldn't need to be disconnected, but I was just trusting the initial post info.
Depends on how the ABS circuit works.
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Old 04-23-2019, 08:24 PM
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I ran a Racelogic box on Acamas teed into all four wheel speed sensors and ABS was fully functional. You absolutely do not need to unplug the ABS when doing this.
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Basically I've come over to the camp of "If something is a reliability problem on the track, just ask Andrew and do what he says".
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Old 04-23-2019, 10:31 PM
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OK - except that it doesn't work. I've got an o-scope that I'm going to try out soon. I believe the ABS is putting a voltage offset on the line when connected. I can the offset with my multimeter.

I'm using the VR Conditioner to bring in the VR signal. I believe it is high input impedance and so should not impact the ABS. And it doesn't. But the ABS affects the VR Conditioner and it doesn't work when ABS is connected.

Also, I'm not the first to point this out.
https://www.miataturbo.net/suspensio...sensors-90212/

Can anyone else verify (or dispute) this?
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Old 04-23-2019, 11:14 PM
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Originally Posted by Mudflap View Post
OK - except that it doesn't work. I've got an o-scope that I'm going to try out soon. I believe the ABS is putting a voltage offset on the line when connected. I can the offset with my multimeter.

I'm using the VR Conditioner to bring in the VR signal. I believe it is high input impedance and so should not impact the ABS. And it doesn't. But the ABS affects the VR Conditioner and it doesn't work when ABS is connected.

Also, I'm not the first to point this out.
https://www.miataturbo.net/suspensio...sensors-90212/

Can anyone else verify (or dispute) this?
What ABS are you using?

I also ran a RaceLogic TC system with my NB2 ABS and it worked fine. It would even log wheel speeds during ABS activation.

--Ian
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Old 04-23-2019, 11:19 PM
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I'm running a MS3PNP with an MSM 2004 (so NB2) and the stock ABS sensors. Let me try a few things to verify what is going on.
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Old 04-24-2019, 06:36 AM
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Did you use a VR-Conditioner? Pretty sure the MS3pro only has a conditioner for crank and cam sensors. The other inputs still need a separate conditioner.
Edit:
A nevermind saw that you did use a conditioner.

I use the two front ABS sensors and spliced them into a VR conditioner bord and into the MS3 pro module. my ABS is working fine. I have a 99 NB.

Did you try a different conditioner? I had a faulty one the first time I tried.
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