Warm the engine driving or in the driveway?

[shadrach74]

Originally Posted by stephen wilson

The problem isn't about the load on the engine while idling. Engines don't run as efficiently or cleanly at idle, so it can lead to excessive combustion byproducts in the oil.

Shadrach, you answered your own question. The reason to limit RPM's while warming up is because all of the engine components haven't warmed up, so internal tolerances won't be correct. It's not just a question of having some oil flowing. As far as the 2500 RPM number ( I usually hear 3000 ), I think that's derived from experience and common sense. You can feel it, 4000 it getting to the area I would consider high RPM.

I did not say there was no reason to limit RPM, What I said was that I have scene "0" scientific evidence to support the 2500RPM number. You're right, it's not just question of having oil flowing. It's a questing of having oil pressure within the specified parameters. Too low and parts don't get adequate lubrication - too high and seals get blown. The latter is likely a bigger concern. Cold, viscous, oil + High RPM = High pressure. High pressure + cold seals = the propensity for a leak.
As far as tolerance and interference issues under normal conditions, my experience is that it's muchado about nothing with water cooled engines. Where oil temp is an issue is how it relates oil pressure. Many people have tried to pass off many old wives tails as coming from "experience and common sense."

I don't care if someone limits their RPM to 2500RPM until all the gauges are in the middle, it certainly is not going to hurt anything...what's mildly annoying is the people throwing out a hard number like there is some sort of science behind it. There's not as far as I can see, but I'm open to learning... I do believe that Porsche (imperfect as they've been through 986/996/987 lines knows something about engines and would not set a limit at 4K unless there was a reason to. BMW is the same, Some of the M cars had computer controlled red-lines depending on temp, but nothing as ridiculous as 2500.

[BYprodriver]

Originally Posted by particlewave

Ummm....because Porsche says so, and they made the car.
Do you not have an owners manual? I'll take their word for it.

I think the point is that idling the engine is doing exactly jack for the drivetrain and its fluids. Idling til warm may make one think that the car is ready for hard driving, when in truth this would be extremely rough on the drivetrain. Gentle driving until warm ensures that everything is ready for high rpm driving.
JM2C

Yes I do have a owners manual & I have read every word in it at least twice.
It also says to change oil every 15,000 miles with Mobil 1 0w-40. Ummmm..... I assume you follow this also.
Ever watch a professional race team warmup a car for hitting the track?
KN3D

[Overdrive]

Originally Posted by BYprodriver

Yes I do have a owners manual & I have read every word in it at least twice.

Sure you didn't miss the part where they say not to exceed 4000rpms, not to apply full throttle, not to apply more than 80% throttle, then? It's definitely there.

I really have no idea where the 2500rpm thing came from. I've heard the 3000 quite a bit, and I trust the experiences of folks in that respect. 2500 to me is too low, and i chastise myself when I catch myself letting the revs drop that low from time to time.

So I follow a combination of owner recommendation and owner's manual recommendation and my range until warming up is from 3000-4000 rpms, plenty to be had in there while being nice to the car, and it warms up within 5-10 minutes.

Originally Posted by BYprodriver

It also says to change oil every 15,000 miles with Mobil 1 0w-40. Ummmm..... I assume you follow this also.

No, but I know people who do and at least one member of this forum who does, and do so because they put enough miles on the vehicle to warrant an oil change at 15,000 miles in less than a year's time. They've had no problems that I've seen, but it's because they're extremely scheduled with their maintenance. So the manual information isn't totally incorrect, it's just not for everyone since a lot of people just don't drive their cars as much as they should. Porsche didn't advise that with the expectation that it'd take some people 15 years to rack up 15,000 miles.

[BYprodriver]

Originally Posted by Overdrive

Sure you didn't miss the part where they say not to exceed 4000rpms, not to apply full throttle, not to apply more than 80% throttle, then? It's definitely there.

I really have no idea where the 2500rpm thing came from. I've heard the 3000 quite a bit, and I trust the experiences of folks in that respect. 2500 to me is too low, and i chastise myself when I catch myself letting the revs drop that low from time to time.

So I follow a combination of owner recommendation and owner's manual recommendation and my range until warming up is from 3000-4000 rpms, plenty to be had in there while being nice to the car, and it warms up within 5-10 minutes.



No, but I know people who do and at least one member of this forum who does, and do so because they put enough miles on the vehicle to warrant an oil change at 15,000 miles in less than a year's time. They've had no problems that I've seen, but it's because they're extremely scheduled with their maintenance. So the manual information isn't totally incorrect, it's just not for everyone since a lot of people just don't drive their cars as much as they should. Porsche didn't advise that with the expectation that it'd take some people 15 years to rack up 15,000 miles.

I intentionally withheld any comments about RPM limits so none of your post makes any sense.

[Mark_T]

Yet Porsche, in the owner's manual, specifically states that you should not let the car sit and idle when you start it and that you should immediately drive off. There must be some reason for them to make a point of saying that.

[shadrach74]

Is there any scientific basis for the 2500rpm number that has been posted a number of times? Just to be clear we are running modern engines, with modern synthetic oils (hopefully)... I can see no logical or scientific reason to stay under 2500 RPM. If the system has oil pressure, then there should be no metal to metal contact. Certainly full throttle or Red line ops are a no-no until the fluids are warm, because that may generate oil pressures that are higher than factory parameters. Also, in extreme temps, dissimilar metals contract and expand at different rates. Metal to Metal interference form this phenomenon is highly unlikely, but is still something that we should keep in mind.

2500, 3000, Idle...whatever. The factory says 4K is the limit cold and there is likely some scientific reason for that...other than someone on an internet forum said it once and 25 people repeated it.

[tonycarreon]

Originally Posted by shadrach74

...

hah! you mean everything on the internet isn't true?

my procedure:
1. open garage door
2. insert key and turn to on, until oil check is done (or chime stops, whichever occurs first)
3. start engine
4. pull out of garage
5. drive away hoping the garage door closed
6. drive to the highway onramp, 1.2 miles from the house
7. resist the urge to have fun for another 4 or 5 miles
8. usually fail

[tony_fury]

Originally Posted by tonycarreon

hah! you mean everything on the internet isn't true?

my procedure:
1. open garage door
2. insert key and turn to on, until oil check is done (or chime stops, whichever occurs first)
3. start engine
4. pull out of garage
5. drive away hoping the garage door closed
6. drive to the highway onramp, 1.2 miles from the house
7. resist the urge to have fun for another 4 or 5 miles
8. usually fail

I think item #6 is the problem causing item #8 to fail..
You need to move, you live too close to the on ramp...lol

[stephen wilson]

#5 is funny! I would change that one. Once or twice I hit the remote twice, leaving the garage open all day, facing the street, inviting anyone to rob me. Now I wait until it's fully closed before pulling away. So I guess I do Idle for 1 Minute or so.

[BYprodriver]

Originally Posted by Mark_T

Yet Porsche, in the owner's manual, specifically states that you should not let the car sit and idle when you start it and that you should immediately drive off. There must be some reason for them to make a point of saying that.

I agree. The reason they say that is to minimize emissions by warming the catalytic converters as fast as possible, after all Porsche has to warranty emissions parts for 8 years. Also vehicles get very low MPG while motionless.

[Topless]

Originally Posted by BYprodriver

I agree. The reason they say that is to minimize emissions by warming the catalytic converters as fast as possible, after all Porsche has to warranty emissions parts for 8 years. Also vehicles get very low MPG while motionless.

Yep, also idling the car while stone cold tends to load up the cats with rich mixture carbon. Then the car runs lousy and the cats fail prematurely. Just get in and drive.

[BYprodriver]

Originally Posted by Topless

Yep, also idling the car while stone cold tends to load up the cats with rich mixture carbon. Then the car runs lousy and the cats fail prematurely. Just get in and drive.

Aced my smog test yesterday, 102,000 miles on my original cats.
I prefer replacing cats over engines.

[Topless]

Originally Posted by BYprodriver

Aced my smog test yesterday, 102,000 miles on my original cats.
I prefer replacing cats over engines.

I guess we have both seen good success using different warmup techniques (102K on original motor and cats) so it really doesn't matter much, at least in SoCal. Ultimately it is your car and your $$ so do what you feel is best.

[san rensho]

Originally Posted by BYprodriver

I agree. The reason they say that is to minimize emissions by warming the catalytic converters as fast as possible, after all Porsche has to warranty emissions parts for 8 years. Also vehicles get very low MPG while motionless.

Yep, the Porsche recommendation to drive immediately is based on emmision and MPG concerns, it has nothing to do with engine longevity.

Its indisputable that there is exponentially more wear on an engine at cold temperatures, and the more load you add at cold temperatures, the more wear.

See HOTRODSRJ’s COOLING TIPS Operating temperature vs power and longevity!

Now I don't recommend idling the car until it reaches operating temperature, although that would minimize engine wear, but idling the car for a minute or 2 or 3 is much better for the car than turning the key and driving off.

[particlewave]

Did I miss something? The only mention in this thread of 2500 was my post, and I just said that I rev it to 2500 for a few seconds before take off to smooth out throttle response. It's a little jerky on first take off if I don't. Probably should clean the maf and throttle body.

[shadrach74]

Originally Posted by particlewave

Did I miss something? The only mention in this thread of 2500 was my post, and I just said that I rev it to 2500 for a few seconds before take off to smooth out throttle response. It's a little jerky on first take off if I don't. Probably should clean the maf and throttle body.

Not directed specifically at you. It's been echoed as gospel both here and other places. I've also heard it stated in person. When I ask why or where the info came from, I've never gotten anything remotely close to a solid answer.

[Ghostrider 310]

One additional thought, if you leave your subdivision and hit a light you are sitting idling anyhow, which is going to happen during the course of any warm up period.

[Overdrive]

Originally Posted by BYprodriver

I intentionally withheld any comments about RPM limits so none of your post makes any sense.

I know you did that. All I was stating was that I really don't know where the 2500rpm thing came from, either. Maybe it seemed like I was directing my talk about 2500/3000 rpms at you, but that was not my intent. (oops)

My reason for bringing up the 4,000rpm limit is because that's what's written in the manual, which you said you read. I think stating something because it's in the very documentation we're talking about makes sense. Your comment about having read the manual seemed to indicate that, having done so, you did not see anything regarding a cold driving process to follow. That was what I took from it, and I could certainly be wrong. That, along with the mention of oil change intervals, was what I was commenting on when I quoted you regarding the manual. The stuff in between is talking more to the thread subject matter in general. That was not directed at you or anything you said.

I too read my manual cover-to-cover a few times the day I brought the car home, and specifically tracked down that section where this information is to find out how the car should be driven cold. I really haven't seen or heard from anyone that 2500rpms is the magic number. Be it 2500 or 3000, I am in total agreement with you that there is no concrete proof or any sort of test that I've seen to substantiate either one being ideal. Basically, I'm trusting the specialists who have stated that it is what's best for the car.