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.

Let me try again. I don't know where the 2500 number came from either, I always "hear" 3000. As far as "scientific evidence", you won't find ONE definitive answer. There is no one magic number, it varies for may reasons, and no obvious harm will be done within a wide range of operation.

I also agree that Manufacuter's recommendations are driven by many factors other than our best interest.

That Hot Rod article has nothing to do with engine warmup, the are referring to continuous low operating temperatures.

What racing teams do has no relation to street driving. Racers want everything at full operating temperature before going on track because "putting" around is hazardous, a waste of track time, and they want maximum H.P. right away.

IMO it works out like this: 2000 is about the lowest operating RPM where the engine pulls well without lugging, which is also hard on the engine (bearings). Staying above this RPM when upshifting, with an average RPM drop of 1000, puts you at around 3000. I agree that the object is to put minimal load on the engine during warmup, so I only use 1/4 throttle.

During cold winter days I will Idle longer than my normal 60 Seconds.

Just my ¢ :D

i think that's a valid point..

personally i keep mine at about 3k until the engine and gear box have warmed up. yes i may peak out at 3.5k when its warming up and dont want the revs too low and lugging the engine, but then neither do i want it too high putting wear, pressure and stresses on a cold engine and transmission.

500 rpm either way is not going to be a show stopper, but probably the guide is what both you and the car are comfortable with. if 3,000 or 4,000 feels better then so be it.

bear in mind also that the local environment will also play a part; if you are in Edmonton, Minnesota or up state New York in the winter or Texas, Florida or New Mexico in the summer, the oils, seals and metals will respond differently.

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.

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

Agreed, I think this is the most compelling argument for being really gentle (rather than just moderately gentle) when warming up the car. The mechanical side doesn't worry me too much, but cracking the heads definitely does.

That said, personally I think pulling away after about 30 secs is the best bet. It takes so much longer for the engine to reach temp idling that I think the load increase associated with very light driving is worth it compared to running the engine cold for long periods, which is effectively what you're doing when starting from cold and leaving it to idle.

I drive gently up to about 3k to 3.5k revs until the water hits temp, then slowly increase the available rev range over the next five to ten mins, depending on conditions. Even then, I probably won't allow extended excursions near the red line for another five to ten minutes. After that, I'll drive it like I stole it.

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.