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911 twin plug COP trigger offset


Endurance_Racer

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Hey guys,

 

Have a link G5 running a EFI conversion with a 60-2 crank trigger and the cam with a single window that is 120 out before TDC. I have a scope and am trying to sort out the offset for this thing. I always have a hard time sorting this window out. Here is the trigger scope.

I also am wondering if I can run 12cylinder and reallocate the ignition for the twin plug Audi coils as we have two coils per cylinder. Appreciate it.

Trigger Scope911-3.5 - 2024-06-20 5;52;14 pm.llg5

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9 hours ago, Endurance_Racer said:

I have a scope and am trying to sort out the offset for this thing. I always have a hard time sorting this window out. Here is the trigger scope.

Not sure what you are asking here?  You use a timing light to set the trigger offset, adjust the offset until the timing light/pulley marks show the same value that you have set as the reference in the set base timing screen.  

 

9 hours ago, Endurance_Racer said:

I also am wondering if I can run 12cylinder and reallocate the ignition for the twin plug Audi coils as we have two coils per cylinder. Appreciate it.

The engine will need to be set to 6 cyl for spark and injection to occur at the correct angle.  You will need to wire two coils to each ign drive.  

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Yes I appreciate that Adam. I thought this is how it should be wired. We did use a timing light. Seems to be off still. So that is why I posted the ignition offset. I will do the timing sweep again and see what we come up with. I believe the shop owner might have drilled the cam pickup reference incorrectly in the rear of the engine. This would have the offset all off.

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On 6/22/2024 at 12:50 AM, Endurance_Racer said:

I believe the shop owner might have drilled the cam pickup reference incorrectly in the rear of the engine. This would have the offset all off.

The cam sensor is only used for phase, it has no effect on timing or offset.  If the cam tooth is in the wrong place then the worst that would happen is the spark would be on the wrong phase, firing at TDC exhaust stroke instead of the compression stroke so the engine wouldnt start.  

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  • 3 weeks later...

Yeah, this is exactly what was going on. I had the calculation from where the offset should be and once, he drilled it in the right spot. It fired right up. 

I also want to ask if we can implement some things for this air-cooled engine. I will be doing a lot more of them on the Link. The Owner of the shop is really happy with the end result. But as a tuner I have some things I want to address.

1. I want to be able to have an air-cooled cylinder temperature calibration, so that we can adjust Hot start crank enrichment, post start, and so on. Because the Cylinder head temp. on these billet heads can get up to 330 degrees F. So being able to change all the axis for the Temperature would be great.

2. I want to see if you guys for the twin plug engines can tell the ECU to allocate injectors 7-12 for secondary coils to fire simultaneously as the primary for the matching cylinder. Just a thought.

The ECT lockout thing for the Closed loop needs to for sure be bumped for Air cooled stuff to at least 380 degrees. This is hurting us badly.

I am sure there will be a few other things I will ask to add later. Thanks for all your hard work.

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8 hours ago, Laminar said:

If you have a pair of smart coils firing at the same time, is there a reason you couldn't drive both coils from the same ignition channel as if you were doing waste spark?

You absolutely can. I just Like to keep things wired independently of each other. Also makes Diagnosing much easier. 

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