Driving habits and shifting with cold engine/oil?

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So there are 2 trains of thought I have with this, but I'm not sure which is more accurate With a cold motor: Do I short shift a bit to keep the RPMs down / higher torque from motor since the oil is cold and thick - avoid sending the oil pump into bypass? Or do I shift at normal speed, but go easy on the gas - higher RPM and lower torque. Maybe lower torque because parts of the motor haven't expanded into tolerance? Yeah I'm probably overthinking this... But the general population would say we over think most things on here anyway smile
 
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I'm in the camp of slow, steady, and easy, steadily ramping up until warm But my cars are automatic, do I don't know what that decodes to you.
 
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BMW does the rising redline feature with increasing engine temps, so I suppose its not good to rev up a cold engine. An issue I ran into doing autocross on with cool oil, was pumping more oil up into the valve cover faster than it could drain down. Throw in a long hard corner at redline and so much built up that a bunch of oil went through the PCV system and put on a good smoke show... So, for my cars, I go with lower rpms with low throttle input for the first couple minutes.
 
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...and besides take it easy, get out of first gear and move easy. In first gear the torque multiplication may not be good for cold gear lube and cold transmission parts.
 
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Hyundai limits boost at oil temps under 150F. This is more important too with the oil controlled cam timing. The oil needs to be a consistent viscosity for that to work correctly. That is why you find the OEM oil temp sensors up by the cam oil control solenoids.
 
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My rule is no more than 50% throttle until the engine is fully warm, and I try to stay at least 2k RPM under whatever the redline is at the time (it moves from 5k to 7k to 9k as the engine warms up). I also make sure the heater is off until the engine is at operating temp. After the engine is at operating temp, I still go easy on it for another 5 minutes or so. Then, I open it up every chance I get and try to keep the revs above 4k.
 
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Originally Posted By: IndyIan
BMW does the rising redline feature with increasing engine temps, so I suppose its not good to rev up a cold engine.
Only on M cars, as far as I know. And most of them use a 10w-60 oil, so it's doubly important. But yes, it's definitely not good to rev too high on a cold engine.
 
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My neighbor drives a new Mustang GT. His rule is that once the starter is completely disengaged it's a signal that the engine is completely warmed up and full throttle is the order of the day. He claims that since he only keeps a car 2 years it makes no difference how he drives other than the rear tires don't last very long.
 
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The only thing I do different on my Camaro between a hot day and a cold day, is I'll rev the engine to ~1700 rpm instead of letting it sit at idle speed when the engine is cold to quiet the piston slap. Otherwise, in daily driver use in Detroit Metro traffic, my normal shift point is 2300 rpm, and my normal throttle setting for acceleration is ~1/8" of depression on the accelerator. And I still outrun traffic. The Camaro is so overpowered for normal use, I can go for weeks during the winter without getting WOT or revving over 3000 rpm. Then when spring comes, it's time to let the beast loose.
 
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Now that guy really beats a car worse than me - finally! As a note, I think a filter is more likely to go into bypass with very HOT oil, since with COLD oil the pump isn't pumping into open atmosphere - it's pumping into a mains gallery drill jammed up with viscous oil trying to eke its way out .001 radial clearanced bearings and other smallish orifaces, so the pressure differential would not be large. Recall its not bypassing into a "dump" its just bypassing the purported filter "restriction".
 
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My '89 S-15 Jimmy (automatic trans) didn't shift into overdrive until the engine was considered to be "warmed-up" and I was told that was done purposely to keep the revs a bit higher and help the engine to warm up. I take it easy in general on whatever I'm driving, trying not to abuse the car until it warms up.
 
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So your suggesting that the backpressure caused by cold oil in the rest of the system is limiting the flow THROUGH the filter and thus the pressure drop within it which would trigger the bypass?
 
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Originally Posted By: opus1
My '89 S-15 Jimmy (automatic trans) didn't shift into overdrive until the engine was considered to be "warmed-up" and I was told that was done purposely to keep the revs a bit higher and help the engine to warm up. I take it easy in general on whatever I'm driving, trying not to abuse the car until it warms up.
My Taurus SHO was like this. If the trans fluid did not warm up to at least 140F within a few miles it would not lock up the TC. If the ambient were below zero and I took off on the highway after starting it just never locked up. I took to driving a bit different route that included a couple stop signs before hitting the open road to fix this.
 
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There's a hill a couple 1/10s mile from my house and I take it in 4th instead of 5th at 45 MPH so as to not lug. IMO lugging's worse than revving. I run about 2600 RPM doing this. Neither is great.
 
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Originally Posted By: opus1
My '89 S-15 Jimmy (automatic trans) didn't shift into overdrive until the engine was considered to be "warmed-up" and I was told that was done purposely to keep the revs a bit higher and help the engine to warm up. I take it easy in general on whatever I'm driving, trying not to abuse the car until it warms up.
That strategy by the manufacturer was to heat up the cat more quickly.......Not save wear and tear on the other mechanical components.
 
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Originally Posted By: 4wheeldog
Originally Posted By: opus1
My '89 S-15 Jimmy (automatic trans) didn't shift into overdrive until the engine was considered to be "warmed-up" and I was told that was done purposely to keep the revs a bit higher and help the engine to warm up. I take it easy in general on whatever I'm driving, trying not to abuse the car until it warms up.
That strategy by the manufacturer was to heat up the cat more quickly.......Not save wear and tear on the other mechanical components.
Agree 100%. Many manufacturers do not want to go through the trouble and expense of including a secondary air pump to move a higher volume of oxygenated air through the cats to heat them up quicker after a cold start, so they use the engine to be the "air pump". By forcing the engine to rev higher than normal idle, much more air gets pushed through the system, thus warming up the cats much faster. However, with a secondary air pump, the engine can idle normally while the pump forces outside air directly into the exhaust system. My old 3.5L Altima would rev at 2,000+ RPM for several minutes in sub-freezing weather for this purpose. It did not have a secondary air pump. My Benz (like most German cars) has a secondary air pump, and almost never has a high idle. In sub-freezing weather, it may idle around 1,000 RPM for 10 - 15 seconds after start up, but that's it. Right back to 650 rpm immediately after the initial 10-15 seconds. The secondary air pump turns on for about 1-2 minutes (depending on outside temp) to warm up the cats.
 
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Oh, and to add to the actual topic of this thread (lol)... I generally do not let the car idle beyond 1-2 minutes at any outside temp. I drive gently until the coolant has reached thermostat opening temperature, and try to keep both RPM and load to a minimum. I then drive progressively more normal while still trying to remain somewhat gentle for a few extra minutes thereafter (to allow for oil to come up to temp as well). After that, it's normal driving. When driving gentle, I obviously want to avoid lugging the engine, but also want to avoid unnecessarily pushing it. I use judgement to determine how to do this. For example, if I'm on flat ground, and traffic is not a concern, I may shift at or below 2000 RPM. However, if there is a large hill in front of me or if I need to merge into traffic, then I might shift at a slightly higher RPM (2,500) to avoid lugging the engine. The warm-up period could last only 6-8 minutes in the hottest part of the summer, but could extend outwards to 15 minutes in the coldest part of the winter (-30 C)...
 
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Originally Posted By: il_signore97
Originally Posted By: 4wheeldog
Originally Posted By: opus1
My '89 S-15 Jimmy (automatic trans) didn't shift into overdrive until the engine was considered to be "warmed-up" and I was told that was done purposely to keep the revs a bit higher and help the engine to warm up. I take it easy in general on whatever I'm driving, trying not to abuse the car until it warms up.
That strategy by the manufacturer was to heat up the cat more quickly.......Not save wear and tear on the other mechanical components.
Agree 100%. Many manufacturers do not want to go through the trouble and expense of including a secondary air pump to move a higher volume of oxygenated air through the cats to heat them up quicker after a cold start, so they use the engine to be the "air pump". By forcing the engine to rev higher than normal idle, much more air gets pushed through the system, thus warming up the cats much faster. However, with a secondary air pump, the engine can idle normally while the pump forces outside air directly into the exhaust system. My old 3.5L Altima would rev at 2,000+ RPM for several minutes in sub-freezing weather for this purpose. It did not have a secondary air pump. My Benz (like most German cars) has a secondary air pump, and almost never has a high idle. In sub-freezing weather, it may idle around 1,000 RPM for 10 - 15 seconds after start up, but that's it. Right back to 650 rpm immediately after the initial 10-15 seconds. The secondary air pump turns on for about 1-2 minutes (depending on outside temp) to warm up the cats.
Now that's interesting. I didn't know that about a secondary air pump. Here in sask we get real cold for a couple months. I plug in my vehicles once ambient evening temps go lower than -10. Coolant blows warm air almost immediately,even when it's -30. I let my vehicles warm up when it's real cold. Once I get warm air from the vents I'll start driving.
 
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