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-   -   Who here waits for 750rpm? (https://mbworld.org/forums/c-class-w204/270167-who-here-waits-750rpm.html)

dalazernet 11-17-2008 08:20 AM

Who here waits for 750rpm?
 
So, I'm not sure if anyone even noticed, but when the car first starts the engine RPMs are higher than normal with this car (they were with my W203 as well).. somewhere in the 1250rpm range... within a few minutes it settles down to 750, and then I get going. Does anyone else do the "waiting game" to make sure the car is happy before driving off, or do you just step on the peddle and go :zoom: ?

Just curious who here does what when starting their car...

Moto_Guzzi 11-17-2008 09:04 AM

Me
 
Me waits, usually take a min, just make sence to me for oil to load properly, my temps usually between 16 to 25c. After 5000Km my car sound exactly as the 1st day, maybe a bit softer.

webada 11-17-2008 10:30 AM

All the cars I've owned does this, at various RPM. I usually wait or if time allowed, stroll slowly for about 5-10mins. Gives the chance for the oils to breakdown and lube all around, especially during new york winters.

mac911 11-17-2008 10:32 AM

I wait a couple seconds just out of getting myself together, but I don't wait. To me, it's a waste of gasoline.

e1000 11-17-2008 10:39 AM

As I understand it, extended periods of idle warm up isn't necessary with newer cars unless you live in an overly cold climate. The higher idle when you start the car is to bring up the catalytic converters to operating temperatures. Best to let the engine start, idle for a few seconds, and then drive easy for the first couple miles.

jstaneff 11-17-2008 10:58 AM

I was going to blow this topic off but remembered it when I backed the car out of the garage this morning. My typical approach is to start the engine, check the mirrors, and start moving. This time I watched the tach too.

4, maybe 5 seconds at the high rpm, put it in Reverse, backed out the 20 ft, and it was idling at normal speeds (below 750). Very short high-speed idle. Then I shut off the engine. It will sit for a few hours before the commute this morning. (Why back it out ... garbage day, gotta get at the cans. Ugh.)

mb_horseshoe 11-17-2008 11:09 AM

I usually wait a full minute or two for the engine to warm up.

Sanjuro Makabe 11-17-2008 02:37 PM

same here, wait about a minute before driving, and I always start and cruise in C mode until the temp hits ~80, then I change to S mode and drive normally. No problems for me...

wblynch 11-17-2008 04:04 PM

Having owned air-cooled Harley Davidsons for many years I got used to warming them up before taking off. It is required if you want them to last reliably.

On my cars, I do wait 30 seconds or so before taking off even though most Southern California mornings are rather mild. If I lived in a freezing climate I would wait until the heater starts working.

I feel it's important to allow the metal components to realize some lubrication and warming before stressing the drivetrain. I typically keep my purchased cars for 15 years and 150,000 to 200,000 miles.

micropower99 11-17-2008 04:07 PM

Ah with newer cars it's not necessary to wait for it to warm up. But I do drive it easy for the first couple minutes.

webada 11-17-2008 04:51 PM


Originally Posted by micropower99 (Post 3173241)
Ah with newer cars it's not necessary to wait for it to warm up. But I do drive it easy for the first couple minutes.

I've heard that before but have not see any evidence of that claim. What makes cars today better at start-n-go? are we talking about vs cars 30 yrs ago before fuel injection time?

Excess idling is not good because it generates build ups from unburned fuel.
But with a cold start, you will typically see a late shift (1st to 2nd) and jerkiness. Getting the lubes warmed up is important, especially in cold climate. The viscosity of the motor oil today is design to have less warmup time. However, these properties deteriorates over time and usage. This is one of the benefits claimed by synthetic oils.

micropower99 11-17-2008 06:06 PM


Originally Posted by webada (Post 3173321)
I've heard that before but have not see any evidence of that claim. What makes cars today better at start-n-go? are we talking about vs cars 30 yrs ago before fuel injection time?

Excess idling is not good because it generates build ups from unburned fuel.
But with a cold start, you will typically see a late shift (1st to 2nd) and jerkiness. Getting the lubes warmed up is important, especially in cold climate. The viscosity of the motor oil today is design to have less warmup time. However, these properties deteriorates over time and usage. This is one of the benefits claimed by synthetic oils.

Honestly just from experience. I have never had any problems with my past cars doing it this way. Maybe if you intend to keep the car past 100K miles then it'd probably be something to consider.

C300Sport 11-17-2008 06:37 PM

I always get in and start the car immediately. Then I adjust the climate control, radio, seat belt, phone, etc, etc. Maybe 30 seconds and the engine is below 1000RPM but not quite 750, then I ease away for the first mile or two. All this excessive idling is actually pretty bad for your car. All the car needs is a few seconds to build oil pressure. Once started, easy driving for the first few miles is the least destructive way to warm a car up...much better than idling...simply Google the facts on this for some interesting reading.

Saks_C350_Sport 11-17-2008 06:58 PM

I just start and go.

CarGuru 11-17-2008 08:28 PM

I wait for 750 just because I feel better about it. My main reason though isn't the motor so much as I feel it easier on the A/T and less harsh shifting into reverse or drive at 750 than say the thunk you feel if you do it at 1200 or 900 etc...

-Ryan

peabers 11-17-2008 10:38 PM

I usually run the car for about 15 seconds during the summer and 30-60 seconds in the winter. About enough time to get my seatbelt on, radio/navi loaded, and check mirrors.

drevil2k2 11-17-2008 10:52 PM

Heading in the morning - start and go from the garage. If the car is outside for a while in the winter, I like to wait about 45-60 seconds.

Les-10 11-17-2008 11:44 PM


Originally Posted by CarGuru (Post 3173702)
I wait for 750 just because I feel better about it. My main reason though isn't the motor so much as I feel it easier on the A/T and less harsh shifting into reverse or drive at 750 than say the thunk you feel if you do it at 1200 or 900 etc...

-Ryan

Me too. I agree!

jstaneff 11-18-2008 09:36 AM

Where are your rpms at idle after 1/2 hour or so of driving? Mine settles to about 500. Yours?


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