Colder weather and detonation?

Since the weather has been getting colder these past few weeks I have noticed very noticible detonation from 6K onwards to redline. Do any of you experience detonation when the weather turns cool???

I'm going to experiment by setting my timing back 1 degree, then take the car out to see if there is any detonation.

here's a freaky rumor I heard, take it as you will.

In the winter months, oil companies add less than normal amounts of octane, and replace it with an anti-freezing additive. Personally I've noticed the power in my WRX has increased, but for some reason the GSR power had decreased, until I added 104 octane boost.

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I have noticed more detonation too. My theroy was that with the denser air came more power and a more complete burn which = more heat thus detonation but hey it could be just crapy winter blend fuel eithier way I keep turning up the fuel pressure vice backing off timing because I am a power freak. Or go to the paint store get a 5 gal can of zylene or toulene throw a gallon in each tank.

You might want to try Hotter(Warmer)spark plugs
If your Running colder plugs in cold environement will make ya detonate!!!!!!! [img]tongue.gif[/img] [img]wink.gif[/img]

Strange. If I'm going to detonate, it's going to be in HOT weather, not cold weather. The honda ECUs, albeit backwards IMHO, add fuel when it's cold, and I'm not talking just at startup. In certain states, Colorado being one, they add an oxidizer to the fuel (Ethanol I think) to help emissions. It sucks! MPG goes down, power goes down, and although I've not experienced it, I'd assume that the detonation threshold of the mixture goes down as well. Next time you drop by the pump, look the thing over pretty well. They are supposed to put stickers about additives on the pumps in plain sight.

You may be running lean. The ECU will let in more fuel to mix with the colder, denser air. If you're on the limits of your fuel system, like I was with my stock pump, you'll not have enough gas pressure/volume for the demand when the weather gets cold.