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Old 09-18-2019, 08:58 PM   #6 (permalink)
quagss
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Join Date: Jun 2015
Location: Syracuse, NY
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Subi - '15 Subaru Impreza Premium
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Quote:
Originally Posted by Ecky View Post
Most cars also retard ignition timing for a while to get the catalyst up to temperate. All this does is start the burn late, so that it's still burning when the exhaust valves open. Some of the combustion that would have pushed on the pistons goes out the exhaust and heats the catalyst.

Disabling cold ignition retard help cold start fuel economy but gets rid of acceleration of cat heat up.
Any way for the layperson to do this without a tuner? I own an NA Subaru Impreza, perhaps the least mod-able car currently out there.
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