Warm the engine driving or in the driveway?

[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.

[BYprodriver]

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]

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]

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]

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]

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]

Originally Posted by tranceatlantic

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

Which is exactly what Porsche suggests

[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.