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Trigger Wheel Guide


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18 hours ago, Gixer1460 said:

 Re : physically moving the timing wheel position - can this not be achieved in software? ie. set cranking rpm (sub 400 rpm) timing down around 0 degrees or even ATDC?

Yep, of course it can, and thats how it works with the 36-1 wheel. And it works fine as you have a gap every 10* for reference leading up to each TDC point

But, the problem is, the teeth are at the TDC's for each pair of cylinders but we never want to spark at TDC. We want BTDC timings which means we need a spark during the 90* gap in between teeth for cylinder 1 and 4, and in a 180* gap leading up to cylinders 2 and 3.

So if we leave it all as standard but grind the long tooth off, the ecu gets the TDC timing reference from the teeth but the spark event has to be calculated to occur during the gap.

The only way the ECU can do this is by timing the gaps and then predicting how long after the last tooth reference it needs to wait before creating the next spark event to try and get it 8* before the next TDC. But because the cranking revolution is quite erratic as it goes through the compression strokes, this timed spark event might actually happen at 15*BTDC, then TDC, then 5*BTDC, then 20*BTDC etc etc. All of this is a problem while cranking and trying to start. Running is different as each revalution is very even in its rotation thus easily timed.

So my idea was to mechanically put in 8* (or what ever cranking timing suits your engine), by either moving the sensor or moving the wheel so the spark events happens on the tooth, so the spark event is no longer a calcualated guess but an event that happens on each tooth trigger, thus being far more reliable and repeatable for starting. So by setting the cranking timing in TS at 0.0, we are telling it to spark at TDC which is the tooth. But we will actually be getting a spark event at 8*BTDC or whatever we set the VR sensor to. This can then be trimmed out in TS or we just build an ignition table with all values minus 8*. So if we wanted 15* at Idle we would put 7* in the table as we already have 8* static timing.

This is what i did when i tried it, i just highlighted all cells in my ignition table and reduced all the values by 8* to compensate for moving the wheel. Thats why in the video of it running with the 4-1 wheel, when you watch the Advance gauge, they go up to about 28* rather than the 36* it would normally show. But the actuall timing should have been close to 36* still. Then when i changed back to the 36-1 i just highlighted all cells in the table and added the 8* back in to all values to get me back where i started. Took Seconds

Edited by slingy1157
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Thanks for experimenting and reporting results! It seems that MS wheel decoder has progressed quite a lot from MS1. Back in days I tried several trigger combinations and 12-1 was lowest missing tooth wheel that was giving somewhat reliable starting. But it's good to keep in mind that results may vary a lot depending engine compression ratio, crank/flywheel weight and many other details. So if possible I would recommend to play safe and use a bit more teeth on trigger.

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2 hours ago, Arttu said:

Thanks for experimenting and reporting results! It seems that MS wheel decoder has progressed quite a lot from MS1. Back in days I tried several trigger combinations and 12-1 was lowest missing tooth wheel that was giving somewhat reliable starting. But it's good to keep in mind that results may vary a lot depending engine compression ratio, crank/flywheel weight and many other details. So if possible I would recommend to play safe and use a bit more teeth on trigger.

No worries, it was a bit of fun for an hour. As the engine warmed up a bit the first time i tried the 4-1 wheel, it was starting just like the 36-1 wheel, hardly touching the starter had it jump straight to life. Had me shaking my head thinking why are we all messing with multi-tooth wheels when a hacksaw and file will create a working set up lol.

But then when i did the video, i purposely wanted to show a "first start of the day" worst case scenario. Maybe i should have let it warm up a bit more to show see if would get better and better like the previous day.

My Tune isn't great either as i have a rough tune from a knackered 1052cc motor on 550cc injectors running a good 1157cc motor on 330cc injectors so even though everything has been scaled to suit i think the cold start and everything will be a bit off as well.

So i think the 4-1 wheel, properly set up as stated before, plus tuned a bit better would be an adequate performer for VERY minimal effort.

But i absolutely agree that the 36-1 wheel or similar is still an easy option to get very good repeatable results.

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Ok, so a few days ago i got a fancy timing light where you can set advance values etc and did i bit of a check on both wheels with timing fixed for testing. I  used an old ignition and cut a 25mm hole through it, centered on where the VR sensor and wheel align so i could strobe the wheel without having too much oil leakage lol

The 36-1 wheel was absolutely spot on, and brilliantly stable, never even looking like wondering in any way. When i dialed in 10 BTDC on the timing light it showed TDC perfectly aligned which was exactly as Tunerstudio showed which is great so the values in the timing table should also be spot on when in use, so that is reassuring.

It also verifies that the settings in TS are correct for this set up as well. This is something i have been meaning to do for years.

The 4-1 wheel though, was very erratic on the other hand, each time the light fired the tooth was in a different position, and not just by a little either. I reckon there was maybe a 20 deg variation in where the tooth was which was a big surprise be honest. I didn't have time to go into any settings change or experimenting with setup but thought i would share this finding. There was still a fare bit of oil spitting out so i couldn't get my camera close enough to take any useful pictures.

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I guess with such large gaps between teeth corresponding with piston accelerations / decelerations through the cycle and there being little 'count down' potential, timing variation is reasonable - Good research though. I remember my install was somewhat 'lumpy' until some revs were gained.

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7 minutes ago, Gixer1460 said:

I guess with such large gaps between teeth corresponding with piston accelerations / decelerations through the cycle and there being little 'count down' potential, timing variation is reasonable - Good research though. I remember my install was somewhat 'lumpy' until some revs were gained.

Yep, that's about it.

I tried giving it a few revs to see if it steadied but couldnt tell as the second it came off idle, too much oil was spitting out to even get the timing light nere it lol

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  • 4 weeks later...

Just had one last idea for an improvement with using the cut down oem 4-1 wheel though i havnt tested it but think it would help.

So basically rather than using the 3rd tooth after the gap which is tdc for No1 cylinder for the reference for the first ignition event, use the 1st tooth after the gap. This means in Tunerstudio, the setting for "Tooth #1Angle (deg BTDC)", which was 180 deg in the video can now be 0.0 . This combined with slotting the vr backing plate to put 8 deg of stattic timing in for starting so our cranking timing in TS can also be set at 0.0 means that there should be minimal timing errors as we are now telling the ecu to fire on the first tooth after the gap.

But we are now also telling the ecu to fire its first ignition output "ign1" on the first tooth which would normally be for cylinders 1-4, but this will now be for cylinders 2-3 as we are using the tooth exactly opposite the oem tdc for cylinder 1 markings know for our timing.

So list this set up;

1. Remove oem wheel and cut off long tooth

2. Remove oem crank pickup backplate and mark and slot holes for 8 deg static advance.

3. Re install backplate and wheel.

4. Connect "ign1" output to driver for coils  2-3, and "ign2" output to driver for coils 1-4

5. Set Tunerstudio up as 

Missing tooth wheel

No of teeth = 4

Missing teeth= 1

Tooth #1 angle =0.0

Cranking advance =0.0

6. Create an ignition table but minus your permanent advance from it. ie if you want 15* at idle put 7* in the table as you have 8* static dialled in on the back plate.

 

So i think the above will be as accurate as the oem wheel can get, and would sure be an easy install. Would love to here from someone if they do try the above out.

 

Edited by slingy1157
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I had a standalone on my old car called SDS which just has two magnets for the pickup, a high and low signal about 10 degrees before TDC seaparted 180* on the wheel.  Two magnets was enough for batch firing.  I assume with such low resolution you'd have to use hysteresis to calculate things...

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10 hours ago, slingy1157 said:

Thinking about it my plug leads are long enough that i could just swap 1-4 and 2-3 around and try the 4-1 wheel one last time on the above settings and see if there are any differences maybe. Will see if i get time.

Or just swop the signal wires on the coils?

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  • 9 months later...
13 hours ago, Scara said:

Cheers for the reply Arttu - how did the installation go ? Were there any inherent issues doing it this way ? were you satisfied with the outcome ?

Installation was really straightforward. I used tach signal from Dyna as trigger for the Megasquirt. Worked fine without any hiccups. The setup was working just fine in general as well. Although this was my friend's bike so I can't tell much how it performs in everyday use. But at least he has been happy and I didn't notice anything strange during dyno tuning.

Obvious drawback with this arrangement is that ignition mapping will be limited to what the Dyna can offer. On positive side installation and tuning is somewhat simpler since you don't need to care about triggering and ignition settings. Especially if there isn't ready trigger solution available for your engine and ECU.

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2 hours ago, Arttu said:

Installation was really straightforward. I used tach signal from Dyna as trigger for the Megasquirt. Worked fine without any hiccups. The setup was working just fine in general as well. Although this was my friend's bike so I can't tell much how it performs in everyday use. But at least he has been happy and I didn't notice anything strange during dyno tuning.

Obvious drawback with this arrangement is that ignition mapping will be limited to what the Dyna can offer. On positive side installation and tuning is somewhat simpler since you don't need to care about triggering and ignition settings. Especially if there isn't ready trigger solution available for your engine and ECU.

Your comments are of great help Arttu. Perhaps you would be able to educate me on exactly the set up you used either through this forum or direct. You might call me a real dinosaur. I am not smart enough to figure out ECU's although many find them easy as 123....

What I have been trying to avoid is going balls out ECU , Injection, Trigger Wheel, as their is insufficient practices and intelligence in Australia, present company excluded, who are and have been trying to achieve similar results within this forum collectively.

I have the Dyna 2000 installed; a set of TB's ready to go, although a thorough clarification on which Mega-squirt ECU was employed to achieve the task would be outstanding. The confusion for me like many I suspect is the separation between an all encompassing ECU and a ECU Fuel Only Controller, and what its desired attachments and upgrades should be for our specific use.

I shot several emails across the globe over the weekend and prior, which included Dyna themselves. Of the 15 sent out, only 2 have responded thus far, but Dyna did recommend the Mega-squirt as it happens in exactly the same method as you have stated, Tacho connection output.

I have begun reading up on their systems and to be honest, its a foreign to me as learning Japanese. Any input you can offer to help simplify it, will always be well received by this budding builder. As stated by Gixer1460 somewhere in the forum, Consider me the ultimate "ECU for Dummies" student if you would, that way we get it straight from the get go..

 

regards Scara...............

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7 hours ago, Scara said:

Your comments are of great help Arttu. Perhaps you would be able to educate me on exactly the set up you used either through this forum or direct. You might call me a real dinosaur. I am not smart enough to figure out ECU's although many find them easy as 123....

What I have been trying to avoid is going balls out ECU , Injection, Trigger Wheel, as their is insufficient practices and intelligence in Australia, present company excluded, who are and have been trying to achieve similar results within this forum collectively.

I have the Dyna 2000 installed; a set of TB's ready to go, although a thorough clarification on which Mega-squirt ECU was employed to achieve the task would be outstanding. The confusion for me like many I suspect is the separation between an all encompassing ECU and a ECU Fuel Only Controller, and what its desired attachments and upgrades should be for our specific use.

I shot several emails across the globe over the weekend and prior, which included Dyna themselves. Of the 15 sent out, only 2 have responded thus far, but Dyna did recommend the Mega-squirt as it happens in exactly the same method as you have stated, Tacho connection output.

I have begun reading up on their systems and to be honest, its a foreign to me as learning Japanese. Any input you can offer to help simplify it, will always be well received by this budding builder. As stated by Gixer1460 somewhere in the forum, Consider me the ultimate "ECU for Dummies" student if you would, that way we get it straight from the get go..

Well, full installation can be quite straightforward as well if there is some proven setup that you can copy. I can probably provide something like that for air cooled GS/GSX engines and oil cooled GSX-R/Bandit engines. If you like. But like you said, if you have to figure out everything by your self then using existing ignition system can simplify things a lot.

I can help you with your project if needed. Give some advice or provide pretty much full installation set or anything in between ;)  Just drop me a PM and tell a bit more about your plans. Let's see then how to proceed.

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1 hour ago, Fugly said:

Please excuse my ignorance, but doesn't MS 3 do fuel and spark? If this is the case why would you run a separate ecu for the spark when you can manage both from one ecu?

Because going full control really needs a crank trigger with more resolution than 4 odd teeth. The Dyna solution is a bit ghetto / simplistic but it works if you accept the limitations - I believe it group fires two cylinder injectors - like wasted spark but with fuel!

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Yes Microsquirt does fuel and spark after adding ignition drivers, a trigger wheel on the crank, and a camshaft sensor. In my case I already had a programable Dyna 2000, so I had nothing to lose about going fuel only. It is a race application so no low rpm stuff, who cares about emmisions, and batch fired injection works perfectly well at WOT. I have a crank sensor to adapt and could machine up the trigger wheel, but while I have a reliable stable system, why bother. I will try it one day and no doubt I will find absolutely no difference in on-track performance. Just like finding out that the speeds and lap times between the normally aspirated injected engine were no different to the engine with FCR carbs.

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16 hours ago, Arttu said:

Well, full installation can be quite straightforward as well if there is some proven setup that you can copy. I can probably provide something like that for air cooled GS/GSX engines and oil cooled GSX-R/Bandit engines. If you like. But like you said, if you have to figure out everything by your self then using existing ignition system can simplify things a lot.

I can help you with your project if needed. Give some advice or provide pretty much full installation set or anything in between ;)  Just drop me a PM and tell a bit more about your plans. Let's see then how to proceed.

Incoming pm your way.... ;)

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