I was re-reading up on some warm up and cool down techniques you guys use.. And then I read something about letting your car idle for too long is bad. I tried to do a search, but I came up with nothing.

So is idling your car for too long really bad? I mean for warming up the engine and all. Or is it just a myth? Someone please help, but also explain why. Thanks!

 

how on earth could it be bad??? its jus sitting there

 

If you let the car idle to warm up, only the engine oil and coolant is getting up to temp. The transmission, TC and rear diff will all be below operating temp when you take off to drive. This is a problem because the ECU only really monitors engine coolant temp for things like limiting the boost when the engine is cold.

Basically, if you floor it right after you leave your garage in the morning, you have a higher chance of damaging something if the fluids are all different temps. If you pull out with the engine oil and coolant cold, the car will hold back boost (and possibly timing ... that's being discussed currently) until everything is up to temp.

 

I see.. It makes sense. I let it idle until the coolant warms up, then I just drive around until my oil temp is up. What oil temperature is good to start boosting? And how do you guys warm up your oil? Just by driving it around? Just seeing how you guys do it.

 

hahahaha this reminds me of something that happened to me the other day

So its on my lunch and im going to run some errands. Its when I got to the hobby store to pick up some super glue that it all happened. I turned my evo off (hks turbo timer set to 1 min) and i start to walk away. This guy comes up to me and says this "Most people dont know this but it isnt good to let your car idle for to long."
"oh really why is that?" i replied kind of laughing to my self(im an ASE certifed tech for 2 years and work at a speed shop)
"Yea! it makes your oil not last as long!" he said
its about that time that my car actally shut off and thats when i said as i walked away.
"its ok it only runs for a minute after i turn it off to let the turbo cool down."

omg the look on his face was priceless, he was sooo confused hahaha.

 

It's not really bad, it's just not beneficial at all, plus you'd be wasting gas for no reason.

As other people have said, you can let your car warm up completely but your transmission and differential fluids will still be cold, so despite the temperature gauge on your instrument panel showing the typical operating temperatures, you won't be able to drive your car however you want without worrying about any damage down the line. Most people let the car warm up for 30-45 seconds so the fluids in the engine will have heated up a bit, then when you begin to drive away (conservatively, of course), the fluids will warm up simultaneously.