Crank trigger setup
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Joined: Mar 2001
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From: Floyds Knobs. IN
Crank trigger setup
Here's a little something I put together for a customer. Thought it might interest someone. 
With the stock CAS we measured drive lash slop at 2.5* of crank rotation. That's not as much as I has suspected but it's still slop. With the crank trigger you run 0* slop.
First thing I did was build a jig to drill the pulley for the magnet seats. This allowed me to properly indicate the pulley and ensure that the two magnets that are needed on the pulley are seated exactly 180* apart. The jig is built with the end of an eshaft which allows any pulley to be bolted up tight and indexed with the stock keyway. This ensures proper timing.
Next step was to drill the two dimples in the pulley to set the magnets. I used a flat faced mill instead of a regular drill bit. This allows for a flat bottom hole where the magnet can sit true to the face of the pulley. The magnets are about .090" thick and .185" in diameter. I used a .200" mill and bored the hole to a depth of .100". This allows just enough room to set the magnet into the pulley with the epoxy that's used to hold it.
Last was the task of building a holder for the mag sensor. I used 1/4" aluminum and set it up to bolt to the now unused AC system mount on the front cover. You can't see it in the photo but the bracket is triangulated along the bottom for added stiffness. Simple enough but this was the most time consuming piece. The bracket needs to be STIFF...you don't want the sensor vibrating about.
All in all it probably took me 3 hours to put it all together. Once we got a good sensor mounted up the car fired right up. The setup has worked like a charm so far. If you're using the VR setup in the stock CAS for your Haltech, Megasquirt, etc. and want to improve on timing accuracy you might consider going a similar route.
With the stock CAS we measured drive lash slop at 2.5* of crank rotation. That's not as much as I has suspected but it's still slop. With the crank trigger you run 0* slop.
First thing I did was build a jig to drill the pulley for the magnet seats. This allowed me to properly indicate the pulley and ensure that the two magnets that are needed on the pulley are seated exactly 180* apart. The jig is built with the end of an eshaft which allows any pulley to be bolted up tight and indexed with the stock keyway. This ensures proper timing.
Next step was to drill the two dimples in the pulley to set the magnets. I used a flat faced mill instead of a regular drill bit. This allows for a flat bottom hole where the magnet can sit true to the face of the pulley. The magnets are about .090" thick and .185" in diameter. I used a .200" mill and bored the hole to a depth of .100". This allows just enough room to set the magnet into the pulley with the epoxy that's used to hold it.
Last was the task of building a holder for the mag sensor. I used 1/4" aluminum and set it up to bolt to the now unused AC system mount on the front cover. You can't see it in the photo but the bracket is triangulated along the bottom for added stiffness. Simple enough but this was the most time consuming piece. The bracket needs to be STIFF...you don't want the sensor vibrating about.
All in all it probably took me 3 hours to put it all together. Once we got a good sensor mounted up the car fired right up. The setup has worked like a charm so far. If you're using the VR setup in the stock CAS for your Haltech, Megasquirt, etc. and want to improve on timing accuracy you might consider going a similar route.
Looks great Chris,
What type of magnets did you use? where could they be bought?
And the sensor is just hte Haltech hall effect sensor?
Also, is it conicidence that there's a rare earth magnet ad at the bottom of this thread while I read it?? haha
What type of magnets did you use? where could they be bought?
And the sensor is just hte Haltech hall effect sensor?
Also, is it conicidence that there's a rare earth magnet ad at the bottom of this thread while I read it?? haha
Joined: Feb 2006
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From: Renton/Bellevue/Seattle WA
wowowowow I REALLY like this. I have always been scared of the CAS's slop. I did not know it was this easy to have done! I guess with this exact setup you would not be able to keep power steering. Do you have any ideas on a different way to mount the hall effect sensor to be able to keep PS?
THANK YOU very much for sharing this!
THANK YOU very much for sharing this!
Buy everything from Chris!
www.ludwigmotorsports.com
wowowowow I REALLY like this. I have always been scared of the CAS's slop. I did not know it was this easy to have done! I guess with this exact setup you would not be able to keep power steering. Do you have any ideas on a different way to mount the hall effect sensor to be able to keep PS?
THANK YOU very much for sharing this!
THANK YOU very much for sharing this!
An idea for that would be to come up with a way to mount both the AC/PS bracket and the Hall Sensor bracket in the same place....
Thread Starter
Joined: Mar 2001
Posts: 5,265
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From: Floyds Knobs. IN
wowowowow I REALLY like this. I have always been scared of the CAS's slop. I did not know it was this easy to have done! I guess with this exact setup you would not be able to keep power steering. Do you have any ideas on a different way to mount the hall effect sensor to be able to keep PS?
THANK YOU very much for sharing this!
THANK YOU very much for sharing this!
It would be easy enough to use some of the front cover bolts to mount a holder for the sensor. The sensor can go anywhere on the front cover. You're not limited to any one area. So you could theoretically make a sensor holder that bolts to the front cover where the OMP used to be if you were running without one. Just think outside the box if you have to.
Joined: Feb 2006
Posts: 2,897
Likes: 2
From: Renton/Bellevue/Seattle WA
It would be easy enough to use some of the front cover bolts to mount a holder for the sensor. The sensor can go anywhere on the front cover. You're not limited to any one area. So you could theoretically make a sensor holder that bolts to the front cover where the OMP used to be if you were running without one. Just think outside the box if you have to.
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Thread Starter
Joined: Mar 2001
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From: Floyds Knobs. IN
With the Haltech E8 we were using a stock 2nd gen CAS. So we went from:
type: multitooth rotary
trigger mode: reluctor
home mode: reluctor
trigger edge: falling
home edge: falling
to:
type: 2 or 3 pulse trig rotary
trigger mode: hall effect
home mode: hall effect
trigger edge: falling
home edge: rising
No idea what the MS setting would be.
Thread Starter
Joined: Mar 2001
Posts: 5,265
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From: Floyds Knobs. IN
Not really. We looked at adapting the FD system to an FC front cover and it's quite a bit of work. And the new hall sensor eliminates a lot of the variable in the stock VR sensors which is half the upside to this system.
Thread Starter
Joined: Mar 2001
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From: Floyds Knobs. IN
Of the two magnets one of the poles faces North the other faces South. The sensors will react differently when they encounter one face or another. The S3 sensor will go to a low state on the trigger channel when it passes a North facing magnet and it will go low on both the home and trigger channel when it passes a South facing magnet. So, with just two magnets you get two trigger events and one home event and sequential operation on a rotary. The S4 sensor pulls low on the trigger channel when it sees a North face and pulls low on the home only when it sees a South face.
That explanation should really be part of the haltech website for the sensors.
Of the two magnets one of the poles faces North the other faces South. The sensors will react differently when they encounter one face or another. The S3 sensor will go to a low state on the trigger channel when it passes a North facing magnet and it will go low on both the home and trigger channel when it passes a South facing magnet. So, with just two magnets you get two trigger events and one home event and sequential operation on a rotary. The S4 sensor pulls low on the trigger channel when it sees a North face and pulls low on the home only when it sees a South face.
Ok a few more questions/comments:
Do you think that it would be significantly more accurate with more magnets, 1 per rotor is the minimum, clearly having more would make it more accurate, but would it make a "real world" difference for any specific setup or type of driving?
Do the magnets require a specific alignment, (as in the home set at 0deg) would it make things more accurate or does this not matter at all?
How would you go about adapting this to an REW?
Can the magnets be attached to a magnetic metal surface, the documentation says they can't, but what about adding magnets for example to the existing REW crank wheel, it seems like it should work in this case because the surface they would be attaching to would not be solid, there wouldn't be much (or any) surface for the magnets to magnetize.
What I would like to do is set this up using the S3 sensor, in the stock REW home reluctor position, what I haven't figured out is how to attach the magnets, and too what. Possibly make or use a different wheel, or modify the stock trigger wheel to accept the magnets.
Do you think that it would be significantly more accurate with more magnets, 1 per rotor is the minimum, clearly having more would make it more accurate, but would it make a "real world" difference for any specific setup or type of driving?
Do the magnets require a specific alignment, (as in the home set at 0deg) would it make things more accurate or does this not matter at all?
How would you go about adapting this to an REW?
Can the magnets be attached to a magnetic metal surface, the documentation says they can't, but what about adding magnets for example to the existing REW crank wheel, it seems like it should work in this case because the surface they would be attaching to would not be solid, there wouldn't be much (or any) surface for the magnets to magnetize.
What I would like to do is set this up using the S3 sensor, in the stock REW home reluctor position, what I haven't figured out is how to attach the magnets, and too what. Possibly make or use a different wheel, or modify the stock trigger wheel to accept the magnets.
Last edited by slo; Aug 25, 2008 at 12:43 PM.
Thread Starter
Joined: Mar 2001
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From: Floyds Knobs. IN
Haltech has a LOT of documentation that they don't make available unless you ask for it. And how do you know to ask for it if you don't know it exists? Something I've complained about in the past.
More magnets will not make the system more accurate. There is kind of a dividing line between systems in this regard. Those systems that see every trigger event and use that information and systems that simply count the events. A very smart system can take a 60-2 trigger for example and see how fast the engine is accelerating between trigger events by how quickly the tooth count is changing between these events. This is how many OEM ECUs know there has been a misfire event. If the next tooth between trigger events suddenly doesn't appear when it's expected then it's assumed there has been a misfire. Haltech, and many other ECUs, simply don't do anything with these teeth (or magnets in the case of the trigger wheel we built). The processor counts them and that's it. This is what the tooth offset number represents in the setup. With an FD trigger and a tooth offset of 3 the ECU sees the home signal then counts three teeth before the trigger tooth. The event timing is only taken from the trigger tooth. The ECU computes when to initiate an event based on the calculated RPM, and the programmed offset from the trigger tooth or magnet. The offset is calculated in time based on the RPM. So at 6000 rpm 30* would equal X seconds and that's how long after the trigger event the coil is fired. Extra magnets or teeth simply doesn't make the system smarter.
The magnets must be mounted in a non-ferrous material. Aluminum is the obvious choice. It is possible to embed the magnet in the head of an aluminum bolt that's bolted into a steel flywheel for example. For the REW I would turn an aluminum wheel to mount the magnets in. That wheel could be attached to the stock trigger wheel. The magnets can be mounted to the outside radius of the wheel instead of the face as we did with the pulley above. The caveat there is that centrifugal force is then working against the epoxy which is now the only thing holding the magnet in. But a lot of systems are built like that.
The magnets can go anywhere on the pulley and the sensor can go anywhere. Basically, start by finding where you want to mount the sensor. Next align the crank so that it's at 70-75* BTDC #1. At that point the #1 or South facing magnet should be placed under the sensor. The #2 or North facing magnet would be located exactly 180* opposite the #1 magnet.
More magnets will not make the system more accurate. There is kind of a dividing line between systems in this regard. Those systems that see every trigger event and use that information and systems that simply count the events. A very smart system can take a 60-2 trigger for example and see how fast the engine is accelerating between trigger events by how quickly the tooth count is changing between these events. This is how many OEM ECUs know there has been a misfire event. If the next tooth between trigger events suddenly doesn't appear when it's expected then it's assumed there has been a misfire. Haltech, and many other ECUs, simply don't do anything with these teeth (or magnets in the case of the trigger wheel we built). The processor counts them and that's it. This is what the tooth offset number represents in the setup. With an FD trigger and a tooth offset of 3 the ECU sees the home signal then counts three teeth before the trigger tooth. The event timing is only taken from the trigger tooth. The ECU computes when to initiate an event based on the calculated RPM, and the programmed offset from the trigger tooth or magnet. The offset is calculated in time based on the RPM. So at 6000 rpm 30* would equal X seconds and that's how long after the trigger event the coil is fired. Extra magnets or teeth simply doesn't make the system smarter.
The magnets must be mounted in a non-ferrous material. Aluminum is the obvious choice. It is possible to embed the magnet in the head of an aluminum bolt that's bolted into a steel flywheel for example. For the REW I would turn an aluminum wheel to mount the magnets in. That wheel could be attached to the stock trigger wheel. The magnets can be mounted to the outside radius of the wheel instead of the face as we did with the pulley above. The caveat there is that centrifugal force is then working against the epoxy which is now the only thing holding the magnet in. But a lot of systems are built like that.
The magnets can go anywhere on the pulley and the sensor can go anywhere. Basically, start by finding where you want to mount the sensor. Next align the crank so that it's at 70-75* BTDC #1. At that point the #1 or South facing magnet should be placed under the sensor. The #2 or North facing magnet would be located exactly 180* opposite the #1 magnet.
Thread Starter
Joined: Mar 2001
Posts: 5,265
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From: Floyds Knobs. IN
The doc below explains the sensors. They refer to S1 and S2 sensors. These have been supplanted by the S3 and S4 sensor respectively. They operate the same.
http://www.ludwigmotorsports.com/hal...allsensors.pdf
Here is the Haltech doc on setting up the various crank triggers.
http://www.ludwigmotorsports.com/hal...ectSensors.PDF
http://www.ludwigmotorsports.com/hal...allsensors.pdf
Here is the Haltech doc on setting up the various crank triggers.
http://www.ludwigmotorsports.com/hal...ectSensors.PDF
I am missing something here, thanks for the post this is certainly a very helpful discussion.
I had assumed that unit would re calculate the crank position based on each tooth or magnet that passed.
So your saying that its only calculating crank position for all rotors based upon a single tooth regardless of the trigger mode.
That seems to contradict with this statement from the new E11 manual:
"When using a custom trigger of any sort the sensor must produce at least one trigger event for each ignition event and each trigger must occur a constant angle BTDC (in other words the teeth must all be evenly spaced and the number of teeth an even multiple of the number of cylinders the engine has). "
based upon the above statement it would seem that the ECU is correlating each firing event with a specific and different trigger event, which doesn't seem to fit with your description.
More magnets will not make the system more accurate.
Haltech, and many other ECUs, simply don't do anything with these teeth (or magnets in the case of the trigger wheel we built). The processor counts them and that's it. This is what the tooth offset number represents in the setup. With an FD trigger and a tooth offset of 3 the ECU sees the home signal then counts three teeth before the trigger tooth. The event timing is only taken from the trigger tooth. The ECU computes when to initiate an event based on the calculated RPM, and the programmed offset from the trigger tooth or magnet. The offset is calculated in time based on the RPM. So at 6000 rpm 30* would equal X seconds and that's how long after the trigger event the coil is fired. Extra magnets or teeth simply doesn't make the system smarter.
The magnets must be mounted in a non-ferrous material. Aluminum is the obvious choice. It is possible to embed the magnet in the head of an aluminum bolt that's bolted into a steel flywheel for example. For the REW I would turn an aluminum wheel to mount the magnets in. That wheel could be attached to the stock trigger wheel. The magnets can be mounted to the outside radius of the wheel instead of the face as we did with the pulley above. The caveat there is that centrifugal force is then working against the epoxy which is now the only thing holding the magnet in. But a lot of systems are built like that.
The magnets can go anywhere on the pulley and the sensor can go anywhere. Basically, start by finding where you want to mount the sensor. Next align the crank so that it's at 70-75* BTDC #1. At that point the #1 or South facing magnet should be placed under the sensor. The #2 or North facing magnet would be located exactly 180* opposite the #1 magnet.
I had assumed that unit would re calculate the crank position based on each tooth or magnet that passed.
So your saying that its only calculating crank position for all rotors based upon a single tooth regardless of the trigger mode.
That seems to contradict with this statement from the new E11 manual:
"When using a custom trigger of any sort the sensor must produce at least one trigger event for each ignition event and each trigger must occur a constant angle BTDC (in other words the teeth must all be evenly spaced and the number of teeth an even multiple of the number of cylinders the engine has). "
based upon the above statement it would seem that the ECU is correlating each firing event with a specific and different trigger event, which doesn't seem to fit with your description.
More magnets will not make the system more accurate.
Haltech, and many other ECUs, simply don't do anything with these teeth (or magnets in the case of the trigger wheel we built). The processor counts them and that's it. This is what the tooth offset number represents in the setup. With an FD trigger and a tooth offset of 3 the ECU sees the home signal then counts three teeth before the trigger tooth. The event timing is only taken from the trigger tooth. The ECU computes when to initiate an event based on the calculated RPM, and the programmed offset from the trigger tooth or magnet. The offset is calculated in time based on the RPM. So at 6000 rpm 30* would equal X seconds and that's how long after the trigger event the coil is fired. Extra magnets or teeth simply doesn't make the system smarter.
The magnets must be mounted in a non-ferrous material. Aluminum is the obvious choice. It is possible to embed the magnet in the head of an aluminum bolt that's bolted into a steel flywheel for example. For the REW I would turn an aluminum wheel to mount the magnets in. That wheel could be attached to the stock trigger wheel. The magnets can be mounted to the outside radius of the wheel instead of the face as we did with the pulley above. The caveat there is that centrifugal force is then working against the epoxy which is now the only thing holding the magnet in. But a lot of systems are built like that.
The magnets can go anywhere on the pulley and the sensor can go anywhere. Basically, start by finding where you want to mount the sensor. Next align the crank so that it's at 70-75* BTDC #1. At that point the #1 or South facing magnet should be placed under the sensor. The #2 or North facing magnet would be located exactly 180* opposite the #1 magnet.
Last edited by slo; Aug 25, 2008 at 05:37 PM.
Thread Starter
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From: Floyds Knobs. IN
It's not a contradiction at all. What that statement says is that you need a trigger tooth (magnet) for each event. And those events need to be established at a consistent number of degrees BTDC. One trigger tooth per rotor spaced exactly 180* apart on the wheel in this case is all that is saying. In the case of a V8 engine you would need a minimum of 4 teeth since that's how many ignition events there would be on a given crank revolution. If the wheel happened to have more teeth it would need to be an even multiple. You could not build a trigger wheel with 7 teeth for example for the V8 engine.
The ability of the ECU to establish an ignition event is centered completely around the trigger tooth for each cylinder. So it does have the ability to sort out cylinders one by one in as much as it can do with the tooth that corresponds to that cylinder. It just would not do anything with more teeth on the wheel if they were added short of counting them as they went by looking for the next trigger tooth.
The ability of the ECU to establish an ignition event is centered completely around the trigger tooth for each cylinder. So it does have the ability to sort out cylinders one by one in as much as it can do with the tooth that corresponds to that cylinder. It just would not do anything with more teeth on the wheel if they were added short of counting them as they went by looking for the next trigger tooth.
What you have said below makes sense, this is what I assumed coming into the discussion.
It seemed that you where saying that the ECU's crankshaft position calculation was based not on one trigger event per ignition event, but rather on one trigger event per home.
I asked the initial question because I had only ever seen a dual channel hall effect sensor work like the haltech S4, and didn't realize that a home and trigger event could be combined like you have done.
I am still not entirely convinced that there would be no benefit in accuracy (at least a theoretical benefit) in having more magnets or teeth etc. And we didn't discuss how the unit times injection events for sequential injection.
It seemed that you where saying that the ECU's crankshaft position calculation was based not on one trigger event per ignition event, but rather on one trigger event per home.
I asked the initial question because I had only ever seen a dual channel hall effect sensor work like the haltech S4, and didn't realize that a home and trigger event could be combined like you have done.
I am still not entirely convinced that there would be no benefit in accuracy (at least a theoretical benefit) in having more magnets or teeth etc. And we didn't discuss how the unit times injection events for sequential injection.
It's not a contradiction at all. What that statement says is that you need a trigger tooth (magnet) for each event. And those events need to be established at a consistent number of degrees BTDC. One trigger tooth per rotor spaced exactly 180* apart on the wheel in this case is all that is saying. In the case of a V8 engine you would need a minimum of 4 teeth since that's how many ignition events there would be on a given crank revolution. If the wheel happened to have more teeth it would need to be an even multiple. You could not build a trigger wheel with 7 teeth for example for the V8 engine.
The ability of the ECU to establish an ignition event is centered completely around the trigger tooth for each cylinder. So it does have the ability to sort out cylinders one by one in as much as it can do with the tooth that corresponds to that cylinder. It just would not do anything with more teeth on the wheel if they were added short of counting them as they went by looking for the next trigger tooth.
The ability of the ECU to establish an ignition event is centered completely around the trigger tooth for each cylinder. So it does have the ability to sort out cylinders one by one in as much as it can do with the tooth that corresponds to that cylinder. It just would not do anything with more teeth on the wheel if they were added short of counting them as they went by looking for the next trigger tooth.
