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Sometimes when it's really cold and I'm just starting the car, I don't like going above 1.5k RPM. When making turns or if I hit traffic, I'll be in third gear going 8mph. Is that bad for the car?

Same goes for if I'm in 6th gear and some congestion caused me to slow down to 25 mph. I start accelerating again and notice I am in 6th gear, forgetting to downshift earlier. Just really low torque or is it bad for the car?
 

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The engine has to work harder in a higher gear at lower speeds than a lower gear at higher speeds. I'm not sure about the long term damages, but I try not to make that a habbit.
 

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I know that when the car is still warming up in cold weather you want to keep the RPMs down, but I think 1.5k is being overly cautious. I think as long as you keep it under 3k, the engine will be fine
 

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I've always heard lugging an engine is bad for it. I think this is especially bad in cold engine conditions because more exhaust will blow past the rings and get into your oil and making it acidic and it will also pick up moisture. You pistons and rings don't fit the cylinders perfectly until warm. The more torque you generate against cylinders that don't want to move (i.e. high gear) then the more exhuast that will blow by. When you're warming up an engine you're waiting on at least four things: metal expansion to operating dimensions, oil to optimal operating temperature, uniform distribution of temperature for good combustion, and catalyst light up. However, you want the engine to warm up as fast as you safely can to minimize blow by. So warming up your engine parked isn't a good thing.

All that said, I've noticed that the Z won't give you good timing and/or all the throttle until the engine warms up. Have you ever noticed that your Z is sluggish when cold and it will surge just as it begins to reach temp? I think that the ECU "holds back" until temperatures are safe. Similar features are in the S2000 and M3, except they also have rev limiters that raise once the engine is warm enough. So it might be reasonably safe to just start driving without any special adjustment to the temp.

However, my strategy is to let the engine run for 30 seconds before I start to move when it's cold. This lets the pistons and rings warm up a bit before I start moving. Next, I use very light throttle and I try to shift such that oil pressure never goes too high. Once the temp guage comes up about 5 minutes later I give it another minute or so and make sure the oil pressure has dropped to it's regular operating pressure. This is my way of estimating when the oil is warm. Your temp guage only tells you when the water core is at operating temp. I believe oil lags behind just slightly in warming up on the Z.

Be sure your tires warm up too before getting on the gas too much. ;)
--
Jeff
 

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It's definitely not good for the engine or economy. You want to be in a gear that is allows the engine to have some power and not struggle to move the car.
 

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I agree with Beer Goggles' post.

First off, you don't want to put any added stress on an engine in low rpms especially anything below 1100 rpm. Your better bet is to just downshift so you don't risk stalling the car and to keep the engine in running with higher rpms to better utilize its power curve.

Second, it is always good to let the car warm up before driving it, but if you are driving it and it is still warming up, then I would say to try and keep the rpms in the range of 1200 to 2000 rpm (I drive up to at least 3000 rpm). Driving around a cold engine with too low rpm and added stress on an engine is not good at all.
 
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