Do people really warm up cars anymore
Discussion
balls-out said:
there seems a lot of people confused about oil pressure. when the car is cold the oil pressure will be very high. cold oil is more viscous. Reasons for not caning a cold engine are not primarily to do with oil pressure - which will come up within a second or so (if not you have a problem). Not thrashing a cold engine is more about the expansion and contraction of the moving parts and cold oil may be too thick to fully reach and lubricate all the places it should.
Idling to warm the car up is said to be bad as it prolongs the warm-up period resulting in more nasty by-products to wear your bores and poision your cat. the combustion process is 'cleaner' when everything is hot.
An oil temperature gauge is usful because it not only tells you the oil temp, but is also a good measure of the internal temperature of many of the engines parts.
Oil temperature guages are fine, but not as good as oil pressure. In the Caterham I know exactly when the oil is warm from the pressure. Also idling to warm the engine will only wear your bores if you have high levels of contaminates in the oil. Carbons due to rich running will degrade the oil over a period of time and IMO frequent oil changes are the answer to engine life. Also production engines have very average tolerances and will take a fair amount of abuse without warming, from stone cold I have tested lots of hire cars to their limiters and apart from the cars with built in protection all of them without hesitation have bounced their limiters/valves happily. Oil temperature has little relevance to components as it is only a reflection of dissipated heat, bearing surface temps run differently as the loads are higher on the small surface areas. Low oil pressure will kill an engine very quickly at high loads, low temperature wont it just means the pump is working harder and the system will be under more pressure, compared to the pressure of combustion it is not worth worrying about. Modern oils are very trick and work from low temperatures unlike the old days of castor, if this wasn't the case half the cars on the road would sieze regularly. Low friction coatings and lighter materials also play a part, we are fairly idiot proof with the safety factors involved in most engines (most being the base for several higher output platforms).Idling to warm the car up is said to be bad as it prolongs the warm-up period resulting in more nasty by-products to wear your bores and poision your cat. the combustion process is 'cleaner' when everything is hot.
An oil temperature gauge is usful because it not only tells you the oil temp, but is also a good measure of the internal temperature of many of the engines parts.
Cliff notes. Change your oil regularly and dont rev the tits off the engine until you see 'normal' temperatures over a 5 min period and you will have half a chance of decent engine life
Whats with all this low oil pressure when starting from cold nonsense?
At Idle, oil pressure will be high until the engine comes up to temp, where it'll gradually drop down to normal operating range.
The oil pressure at idle on a warm engine has to go pretty bloody low before it becomes a problem. Low oil pressure with the engine under load is a different kettle of fish, however.
At Idle, oil pressure will be high until the engine comes up to temp, where it'll gradually drop down to normal operating range.
The oil pressure at idle on a warm engine has to go pretty bloody low before it becomes a problem. Low oil pressure with the engine under load is a different kettle of fish, however.
Edited by HAB on Thursday 26th June 22:23
HAB said:
Whats with all this low oil pressure when starting from cold nonsense?
At Idle, oil pressure will be high until the engine comes up to temp, where it'll gradually drop down to normal operating range.
The oil pressure at idle on a warm engine has to go pretty bloody low before it becomes a problem. Low oil pressure with the engine under load is a different kettle of fish, however.
True. Some bike engines in kit cars can get hot enough to have the low oil pressure light flicker at tick over. Not a problem as no load, so very little pressure is required at those times.At Idle, oil pressure will be high until the engine comes up to temp, where it'll gradually drop down to normal operating range.
The oil pressure at idle on a warm engine has to go pretty bloody low before it becomes a problem. Low oil pressure with the engine under load is a different kettle of fish, however.
Edited by HAB on Thursday 26th June 22:23
Not just bike engines, a lot of road cars after a few laps of a circuit will have the oil pressure light flickering on idle - as you say no big deal.
As long as the oil pressure needle climbs with the revs and maintainns high pressure at high rpm, everything is fine.
As long as the oil pressure needle climbs with the revs and maintainns high pressure at high rpm, everything is fine.
Edited by HAB on Thursday 26th June 22:48
Hmmm, With the daily drivers its normal to drive of more or less imediately after start up, but I (I cants speak for the missus) the revs lowish until its truelly warmed. But with the vette, it takes a full 2 minutes to get it firing on all 8, once again once that happens I drive off quite happily. A highlift cam etc. always takes a few more to get them running.
G
G
The manual for my Punto says that on coming back to idle after stressing the engine for prolonged periods that the oil pressure light may come on but will go out as soon as you pull away again. Didn't stop me bricking it the first time it happened and turning the engine off sharpish!
People worry far too much for no reason at all.
I start the car, do up my belt, pop on the lights, pop into drive and drive off.
Within a mile or so of normal driving the water temp is around 60°C to 70. Then i'll drive a bit harder, 2 miles down the road when the thermostat is open I'll take it to the redline if the need arises.
The oil temperature wont be fully up but it will be more than well circulated and will have some heat in it, also by this time the transmission etc will be warm too.
Dave!
I start the car, do up my belt, pop on the lights, pop into drive and drive off.
Within a mile or so of normal driving the water temp is around 60°C to 70. Then i'll drive a bit harder, 2 miles down the road when the thermostat is open I'll take it to the redline if the need arises.
The oil temperature wont be fully up but it will be more than well circulated and will have some heat in it, also by this time the transmission etc will be warm too.
Dave!
no beans until the oil has hit 90 degrees. Religiously.
And no labouring in high gear during the warm up period.
This is the first car i've had with water and oil temps and i know everyone says this but it is true, it always amazes me how much longer oil takes to reach operating temp than water. Makes we wonder how often i booted the old saxo too early for its own good!
Its true that most water temp gauges are little more than decoration, sticking to the middle at any normal operating temp and then only moving up when this is exceeded. The water temp on the rallye moves all the time and it took me a while to get used to this (2 visits to 2 different garages for re-assurance later!!!)
And no labouring in high gear during the warm up period.
This is the first car i've had with water and oil temps and i know everyone says this but it is true, it always amazes me how much longer oil takes to reach operating temp than water. Makes we wonder how often i booted the old saxo too early for its own good!
Its true that most water temp gauges are little more than decoration, sticking to the middle at any normal operating temp and then only moving up when this is exceeded. The water temp on the rallye moves all the time and it took me a while to get used to this (2 visits to 2 different garages for re-assurance later!!!)
In a turbo car the turbo is obviously lubricated and cooled (Along with some which have additional water cooling) by the oil.
By starting and then popping your belt on, the usual get in the car routine the turbo will have enough lubrication and cooling for it to work fine. The only reason not to thrash it is to let the parts of the turbo, impellar, shaft yada yada all warm up equally, this doesn't mean drive it off boost.
Also with turbos and the wonderous item that is the turbo timer, which unless you run on track and don't do a warm down lap is completely pointless. Turbos cool down quite quickly from incredibly hot temperatures and long periods at idle are not needed, unless you just braked hard from a top speed run directly onto your driveway.
Dave!
By starting and then popping your belt on, the usual get in the car routine the turbo will have enough lubrication and cooling for it to work fine. The only reason not to thrash it is to let the parts of the turbo, impellar, shaft yada yada all warm up equally, this doesn't mean drive it off boost.
Also with turbos and the wonderous item that is the turbo timer, which unless you run on track and don't do a warm down lap is completely pointless. Turbos cool down quite quickly from incredibly hot temperatures and long periods at idle are not needed, unless you just braked hard from a top speed run directly onto your driveway.
Dave!
there was a post some time ago (maybe a letter in autocar actualy)
I guy was asking if the best way to warm his car after start up was to blip the throttle taking it to 4k or so until warm, his reasoning was the fact that this is what F1 mechanics do & alot of other race car teams to get their cars warm.
The advice that came back was a resounding yes! to my horror, although it was said it may not be very neighbour friendly
this was a profesional giving advice by the way from what I remember, I dont do it myself but do let it idle, which seems to now be not the done thing 
Anyone know the reasoning for race teams warming their cars this way? thought i remembered him saying it was to get the oil distributed as fast as possible & that wear on the engine came from 'high loads' with cold/no oil, ie setting off in the morning & planting it, wether at high or low revs.
I guy was asking if the best way to warm his car after start up was to blip the throttle taking it to 4k or so until warm, his reasoning was the fact that this is what F1 mechanics do & alot of other race car teams to get their cars warm.
The advice that came back was a resounding yes! to my horror, although it was said it may not be very neighbour friendly
this was a profesional giving advice by the way from what I remember, I dont do it myself but do let it idle, which seems to now be not the done thing Anyone know the reasoning for race teams warming their cars this way? thought i remembered him saying it was to get the oil distributed as fast as possible & that wear on the engine came from 'high loads' with cold/no oil, ie setting off in the morning & planting it, wether at high or low revs.
the idle map on your car is not a nice place for the engine to be. the sooner you can get onto your normal map the better.
Modern oil is designed to work from. So not driving because of oil temp isn't really a good enough reason.
Just be gentle until the cars ready, if you cant tell when the cars ready they you shouldn't be driving. But once its all in shape then drive it like you stole it
Modern oil is designed to work from. So not driving because of oil temp isn't really a good enough reason.
Just be gentle until the cars ready, if you cant tell when the cars ready they you shouldn't be driving. But once its all in shape then drive it like you stole it
Mine always gets warmed up properly (even though I get some stick for it) because I know that if something goes bang it won't be cheap to fix.
Back in the days of proper Audis (;)) they used to fit oil temperature gauges so mine gets driven on light throttle and doesn't get revved over 3000 rpm until the oil is upto the correct temperature.
Depending on the weather it can take anything from 3 miles to 7 miles.
Back in the days of proper Audis (;)) they used to fit oil temperature gauges so mine gets driven on light throttle and doesn't get revved over 3000 rpm until the oil is upto the correct temperature.
Depending on the weather it can take anything from 3 miles to 7 miles.
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