View Single Post
Old 01-03-2008, 12:02 AM   #1
Scooby Guru
Member#: 71092
Join Date: Sep 2004
Chapter/Region: MWSOC
Location: Delaware County, Ohio
2005 2.5RS Wagon
Regal Blue Pearl

Default Why Is The Engine Knocking Like Mad During Cold Snap?

OK, so we got hit by a cold snap today, about 20F colder than I've ever logged the car. I actually recorded an IAT of 5F as I started up the car! For some reason, the car was knocking LIKE MAD today. Very, very frequent knock and HUGE corrections (like 5-7 degrees FLKC+FBKC). Once the car got hot enough than the under-hood temps pushed the IATs up into the 60s (about 30 minutes of driving), the knock dropped back down to about what I've been seeing lately.

What gives?

At first I thought maybe the colder air was dense enough to raise my load (increased load->increased knock), but once I looked at the data again, it's was having a fit even at part-throttle where the loads were no higher than I had been seeing (~0.6-0.8g/rev). What the heck was going on while it was so cold?
* Registered users of the site do not see these ads.
williaty is offline   Reply With Quote