How long to warm up a 10 year old Boxster?

[JFP in PA]

Mike-

All EPA CAFE ratings include cold starts, and according to the CAFE rules, the OEM has to outline the methodology used to obtain the claimed mileage for the owner in the manual. Starting the car and letting it warm up obviously produces zero miles of travel for several min. of engine running time, which over the life of the car will lower its actual achieved miles per gallon of fuel consumed. Simple arithmetic.

Over the life of my business, I have had multiple opportunities to rebuild engines for customers that I subsequently had to look into years later. Interestingly, engines that are always warmed before driving showed less bearing scuffing and tended to have better looking cylinder walls after nearly equivalent miles.

As you know, I have also both owned and crewed on various race cars over the years, and we never allowed the engines to be pushed without a full warm up. Several cars, in fact, used outside systems to circulate warmed coolant before the engines were even fired to reduce cylinder wall and bearing scuffing. Many years ago, a then prominent engine builder (now deceased) ran cell dyno runs on engines that were always kept warm vs. units that were cold started and then warmed up before making power runs. The engines that were perpetually kept warm consistently produced more power for longer periods than the ones that were cold started and warmed. When torn down, the always warm engines again showed less component wear as well. He attributed the differences to the dimensional stability of the engine's that were kept warm, and the additional wear on the cold start engines to dimensional shift processes that take place during the warm up cycles.

[Giller]

Maybe it's just me, but I never let my car warm up for longer than it takes to set the radio and buckle up and for one simple reason - idling a vehicle is horribly bad for the environment. No scientific proof exists that it hurts the vehicle to just go - as per the 1000's of articles written about this. So why not protect the environment?

[Sisu guy]

As someone who has spent the last 40 years designing and developing both air cooled and liquid cooled engines I can tell you without reservation that it is ALWAYS better to allow engines to warm up with light load before going to high speed or load.

Consider that the thermal expansion rate of aluminum is twice that of steel and consider what that means to various tolerances and oil film thicknesses when cold parts are suddenly exposed to the temperatures of combustion!

[JFP in PA]

Originally Posted by Giller

Maybe it's just me, but I never let my car warm up for longer than it takes to set the radio and buckle up and for one simple reason - idling a vehicle is horribly bad for the environment. No scientific proof exists that it hurts the vehicle to just go - as per the 1000's of articles written about this. So why not protect the environment?

Easy and in two words: Dimensional stability. Alloy engine cases move around quite a bit while warming up. It is not at all unusual for an M96 to have its cylinder bore dimensions move more than a couple of thousandths from stone cold to fully warm. Other parts of the cases move even further. And if the engine is "loaded" (read moving the car) during this period, you are subjecting it to unnecessary wear due to the alloy shifting. So you can protect the environment, or your engine; choice is yours............

[BIGJake111]

Originally Posted by Giller

Maybe it's just me, but I never let my car warm up for longer than it takes to set the radio and buckle up and for one simple reason - idling a vehicle is horribly bad for the environment. No scientific proof exists that it hurts the vehicle to just go - as per the 1000's of articles written about this. So why not protect the environment?

Why don't you get one these you hippie

Joking aside to my knowledge porsche is a fairly enviro friendly company even back with the 9X6 cars.

[Giller]

Originally Posted by BIGJake111

Why don't you get one these you hippie

Joking aside to my knowledge porsche is a fairly enviro friendly company even back with the 9X6 cars.

Hey, I'll be a hippie any day if I get to drive this beauty!!

[kk2002s]

I remember a similar tread when I first got my box a couple years back. I was letting it warm up until the temp needle began to start rising. There was, in that discussion, the fear that that kind of idle time allowed more moisture and gas into the oil and that was certainly not a good thing. Now of course if you drive 30+ mins at temp those extra ingredients should burn off.

Next time I start i'll time how long it takes for warm air to start blowing
All JFP's explanations about mechanical readiness is what initially prompted me warm up longer.
Might be coming full circle on this subject
Time to break out the Bell bottom pants

[99 Boxcutter]

Originally Posted by JFP in PA

Mike-

All EPA CAFE ratings include cold starts, and according to the CAFE rules, the OEM has to outline the methodology used to obtain the claimed mileage for the owner in the manual. Starting the car and letting it warm up obviously produces zero miles of travel for several min. of engine running time, which over the life of the car will lower its actual achieved miles per gallon of fuel consumed. Simple arithmetic.

Over the life of my business, I have had multiple opportunities to rebuild engines for customers that I subsequently had to look into years later. Interestingly, engines that are always warmed before driving showed less bearing scuffing and tended to have better looking cylinder walls after nearly equivalent miles.

As you know, I have also both owned and crewed on various race cars over the years, and we never allowed the engines to be pushed without a full warm up. Several cars, in fact, used outside systems to circulate warmed coolant before the engines were even fired to reduce cylinder wall and bearing scuffing. Many years ago, a then prominent engine builder (now deceased) ran cell dyno runs on engines that were always kept warm vs. units that were cold started and then warmed up before making power runs. The engines that were perpetually kept warm consistently produced more power for longer periods than the ones that were cold started and warmed. When torn down, the always warm engines again showed less component wear as well. He attributed the differences to the dimensional stability of the engine's that were kept warm, and the additional wear on the cold start engines to dimensional shift processes that take place during the warm up cycles.

Thanks for the thorough explanation.
I actually asked this question on Yahoo of all places and got laughed at by KungFooMaster69 who said "how old r u 85? star it and drove of"

Interestingly, my mom taught me to warm up the car when I was 8 years old and I have been doing it ever since out of habit. Last week I decided to put the "start and drive" method to the test and my Boxster got mad at me and started revving like a little hamster was pressing the gas pedal so that was the last time I do that.