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Discussion Starter #1
How does the ECU advance timing on turbo distributor if the pickup has no mechanical way of changing alignment from the camshaft!?

I cant find any informations anywhere because most information I find is about mechnical and vacuum advance methods.
 

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The ECU looks at the signal from the pick-up and calculates when to fire the coil. The rotor makes contact for a fairly wide crank angle (I haven't measured, but it's probably around 40 crank degrees or so), allowing the distributor to route the spark to the right tower through a wide range of crank angles.
 

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Discussion Starter #3
Thank you I just mesured the pickup contact area and its 30 degrees.

Now I always thought the distance between distributor cap contacts was where the coil took time to charge (like a capacitor).

If the engine is idling the ECU will trigger ignition events very late during contact in the pickup so this mean the coil cant be pre-charged? A ignition coil can receive a power surge and transform it to very high voltage instantly? So the MSD 6a for exemple is the one that will store power between ignitions ?
 

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The coil only sparks when the ECU cuts power to the coil. So the ECU calculates both when to start dwell and when to cut the dwell and make the spark.

The distributor contacts are just a rotary switch for the high voltage. They don't control what the coil does.
 

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Discussion Starter #5
Thank you very much for that information.

On another topic if you dont mind, I asked a local shop to weld a bung for the air intake temp sensor very close to the throttle body but they put it right at the air filter. I told them the air temp will rise a lot with the turbo and then lower some with the intercooler and they say it doesnt matter.

They are wrong are they? It HAS to be at the TB to get the final air temperature before it gets in the manifolds ?
 

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You need the IAT sensor to be after the turbo and after the intercooler if using an aftermarket ECU.

The stock ECU had it before these - apparently it used correction tables based on the behavior of the stock turbo and intercooler.
 
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