Warm the engine driving or in the driveway? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Topless · 08-09-2012, 02:11 PM

Quote:

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.

BYprodriver · 08-09-2012, 02:30 PM

Quote:

Originally Posted by Topless

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.

My warmup procedure varies depending on several variables, but when I rebuilt my engine, during the breakin period it idled a long time before it moved.

jaykay · 08-10-2012, 04:58 AM

From cold, I try a time my move off until after thewhine form the secondary air pump (I think) dies and seeing the temp needle move off...a little...this maybe a minute or so

My rationale is more gradual even warming of the aluminum heads. We all have heard of the cracking issue yes?

Mark_T · 08-10-2012, 06:07 AM

Quote:

Originally Posted by jaykay

My rationale is more gradual even warming of the aluminum heads. We all have heard of the cracking issue yes?

Yes, but this is generally a result of air or a blockage in the cooling system. Shouldn't be an issue on a properly maintained car.

pothole · 08-13-2012, 04:06 AM

Quote:

Originally Posted by jaykay

My rationale is more gradual even warming of the aluminum heads. We all have heard of the cracking issue yes?

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.

tranceatlantic · 08-10-2012, 05:04 AM

here's my 2 cents:

Idling may be less stressful for the engine but will require more time to to reach normal running temp. Driving is harsher but the engine will warm up faster. I would suggest driving gently until the engine has warmed up.

Mark_T · 08-10-2012, 06:09 AM

Quote:

Originally Posted by tranceatlantic

I would suggest driving gently until the engine has warmed up.

Which is exactly what Porsche suggests

ProjectM96 · 08-10-2012, 06:27 AM

I just start driving and keep it under 4500rpm for the first 10 minutes. It takes forever for the engine to warm up.

stephen wilson · 08-10-2012, 07:04 AM

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 ¢

Bruce Wayne · 08-11-2012, 05:02 AM

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.