7427 timing idea

Anyone ever try using the p/s spark scalar and running the input to a toggle to have the ability to run adjusted timing for things like boost or n2o? Something like setting up your spark maps 10* off, and using that to add timing back in until you trigger the n2o or have a Hobbs switch activate for boost retard?

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Originally Posted by cgw

Anyone ever try using the p/s spark scalar and running the input to a toggle to have the ability to run adjusted timing for things like boost or n2o? Something like setting up your spark maps 10* off, and using that to add timing back in until you trigger the n2o or have a Hobbs switch activate for boost retard?

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I use the IAT myself. Add a relay with a resistor when the N20 activates and tell the PCM the IAT is super hot. Set that area of the IAT map to retard the timing by the amount you want. Works on Vortec Black box PCMs and 0411s too. My 1997 Express is on a 150 shot currently. Pull about 8° of timing for that shot.

So far this seems to be a pretty versatile pcm, I made the switch today from SD to MAF and I'm really liking it so far. I'd like to replace the 7747 in my 75 K5 with a 7427 as well eventually. The truck I'm playing with right now is stock other than the tbi swap, its a 250/th350/np203 1973 K5 that is my daily driver/work truck

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Originally Posted by Fast355

I use the IAT myself. Add a relay with a resistor when the N20 activates and tell the PCM the IAT is super hot. Set that area of the IAT map to retard the timing by the amount you want. Works on Vortec Black box PCMs and 0411s too. My 1997 Express is on a 150 shot currently. Pull about 8° of timing for that shot.

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Interesting idea, could work with many ECMs.