Does prolonged engine idle on a slope cause engine damage? (RX7, fuel)

[Nepenthe]

Originally Posted by usafracer

I dare you to go out at -20 start your car and after 30 seconds take off.

I'm not stepping foot outside if it's -20 Fahrenheit! 105 degrees is just fine, I go out and run around in that, but -20?? That's like 50 degrees colder than the point at which I get virtually paralyzed by the cold. Youch!

I guess you'd have to have a block heater to get it started. My old RX-7, awesome car that it was, refused to start if it was below about 40 degrees.

Anyway, isn't there a difference between warming up the engine and warming up the interior? I guess my impression from the first post was that the sister-in-law turns the car on with the heater on HI (which can slow down the rate at which the engine heats up) and leaves it for 20 mins so when she gets in it's toasty warm, not so she can get the engine and oil up to operating temps necessarily.

[Innovator831021]

Originally Posted by Nepenthe

Anyway, isn't there a difference between warming up the engine and warming up the interior? I guess my impression from the first post was that the sister-in-law turns the car on with the heater on HI (which can slow down the rate at which the engine heats up) and leaves it for 20 mins so when she gets in it's toasty warm, not so she can get the engine and oil up to operating temps necessarily.

Warming up the engine is priority, the interior is just a bonus. You are technically right about the slower rate of warming up with the heat on. Interior heat is produced by air being blown through a heater core, this heater core is nothing but a mini radiator (usually located in the dash) that is plumbed off the main coolant circuit. So if you have the blower pushing air through this heater core then you have a form of heat transfer in the coolant... so yes it is cooling the engine to a minor extent.

[Nepenthe]

Yah, even here in Texas I noticed a difference in heat up times if I ran the heater. My procedure is about 20-30 seconds of warm up time from a cold start if it's above 70 degrees. Below that I usually idle for about two minutes, but then I've only started my current car below 32 F maybe a couple of times. I drive it with a very light load and below 3000 RPMs (rev limit is 8600) until the water temp meter shows the normal number of bars.

Anyway, I stopped running the heater until I see all those bars, because there was a pretty noticeable slowness to the movement of the temp meter (plus it's shooting out cold air!). I didn't think prolonged cold running was very good for it.

[Innovator831021]

Originally Posted by Nepenthe

Yah, even here in Texas I noticed a difference in heat up times if I ran the heater. My procedure is about 20-30 seconds of warm up time from a cold start if it's above 70 degrees. Below that I usually idle for about two minutes, but then I've only started my current car below 32 F maybe a couple of times. I drive it with a very light load and below 3000 RPMs (rev limit is 8600) until the water temp meter shows the normal number of bars.

Anyway, I stopped running the heater until I see all those bars, because there was a pretty noticeable slowness to the movement of the temp meter (plus it's shooting out cold air!). I didn't think prolonged cold running was very good for it.

Good job on taking care of your engine. I laugh every time I see one of my idiot friends hop in their nice car on a snowy day, start a cold engine and just romp it from the get go.

[Steve-o]

Originally Posted by JTraik

Actually to let the engine warm from cold to operating temp is the most ideal, but time consuming. Engine clearances are all designed around operating temperature, you don't want full load on a cold engine. I wish I gave myself the time in the morning to let my engines warm up for at LEAST 10 minutes before driving.

What I do is let it warm up until I see the temp needle start moving up beyond the cold range. Ill start driving then, but shifting slow and going verrrrry easy on the gas until it reaches normal temp. I then watch the oil temp and once thats reached normal operating levels, only then do I drive her hard. I like the fact that on the BMW M3, you can only rev the engine to a certain RPM, as the ECU senses engine and oil temp and limits the available RPMs based on what the sensors tell it. Thats smart. I wish other car manufacturers would do that to prevent boneheads from firing up their cars on cold winter mornings and then taking off at full throttle. UGH!

[Innovator831021]

Originally Posted by Steve-o

I like the fact that on the BMW M3, you can only rev the engine to a certain RPM, as the ECU senses engine and oil temp and limits the available RPMs based on what the sensors tell it. Thats smart. I wish other car manufacturers would do that to prevent boneheads from firing up their cars on cold winter mornings and then taking off at full throttle. UGH!

I would really hate that feature. Hell I don't even like ABS. Its quite ironic since my field is semiconductors but I do not like the idea of computer controlled anything in my vehicles. I like to have complete mechanical control and full knowledge over every feature I possibly can so in the end if anything goes wrong I can blame myself and immediately know how to approach the problem. If a bonehead wants to ruin his M3 I say by all means let him, stupid people shouldn't be allowed to control such sophisticated machinery and there should be repercussions... plus it would give me a good laugh if a saw a M3 with 30k on the clock spewing blue smoke.

[wankel7]

Good lord just get a block heater and have her plug it in every night. 10-20 is just a waste of gas.

[usafracer]

Not everone has access to a place to plug there vehicle in.

[geos]

Originally Posted by martinezsa

My sister-in-law's driveway is a pretty rough incline, probably about a 23° decline from the road. She consistantly will leave her car parked at this incline with the engine idling for 10 or 20 minutes to warm it up.

10 or 20 minutes??? Where did she get this brilliant idea? Why bother turning it off at all? Subaru engines are 90° inclined. They seem to do ok.

[Ticky909]

I warm it for the amount of time it takes to scrape, the worse the weather the longer the warm up I guess. nothing like being on your hands and knees on the hood of a car completely coated in 2 mm of ice at 5:00 a.m. with a hand scraper trying to clear the windshield haha. good 'ol CO. That generally takes a varying amount of time between 1-4 minutes, then short shift, 2.7k or less with smoothness being the priority.