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Hey guys, I have this Mallory 685 ignition box that has an optional plug on it for a MAP sensor. I guess you connect a vacuum line to the MAP sensor to read boost and you can retard a selected amount per lb of boost.

Would this be a good way to control the timing?

Here are whats in the instructions:

Mode 8 - Boost timing retard degrees per PSI of boost. If you have an optional MAP sensor connected, the HYFIRE® 685 will retard the timing as the boost pressure increases. Mode 8 tells the system how many degrees to retard the timing for each pound of boost. The MAP sensor plugs into the 3 wire connector that comes out of the front panel.

Mode A - MAP sensor select. There are two MAP sensors available that are compatible with the HYFIRE® 685. One is a 2 Bar sensor (Accel P/N 74776), which is good for about 15 PSI of boost, and the other is a 3 Bar sensor (Accel P/N 74777), good for about 30 PSI of boost. Use mode A to tell the HYFIRE® 685 which sensor you are using. If you dont have a MAP sensor installed, this function has no effect.
 

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Discussion Starter #2
No body using anything like this?>


What are you guys doing with the timing?
 

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i have the msd version on my car. seems to be working well. for every pound of boost it reads, it pulls 1* of timing.
 

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They are good !!!... but are more of a band-aid for not having the car tuned. some can even adjust how much timing they pull per pound of boost.

I have one but have yet to use it. I only run 10-12 psi so I just use stock timing.
 

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im not running a lot of boost either, but just want to be safe. car is tuned too. im sure i wouldnt have any issues, but to be certain im good, its a cheap investment.
 
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