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irst i said that the rate is per hour at that temp. no car is going to idle at that temp for but a few minutes.



No, you said that a motor will wear at 0.002 per hour at idle even once its' reached optimal temperature. Assuming that's millimeters (because it can't be inches, a cylinder wall would be gone in a matter of weeks) you'd still wear several mm per year off a cylinder wall -- you'd lose compression within weeks at that rate.

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second, the reason you take off and drive is to help the engine warm up quicker. i never said anything about how you should drive it just that you should. you should drive it like an old lady.



Yes, but it doesn't make any sense.

When you're driving, even like an old lady, your pistons will still be moving at least 3-4 times faster than they ar eat idle -- therefore you're doing 3-4 times as much damage every second. Even if you could warm the car up 3-4 times faster by driving it, which you can't, the net wear will be exactly the same.

Coupled with the fact that you're doing 2-4 times as much damage (using your numbers) every second when the engine is first started than you are after warm-up, it makes no sense at all to drive it before it's warmed up.

You're advocating doing 3-4 times more damage (engine is revving 3-4 times faster while driving than at idle) while the engine itself (because it's cold) is already doing 2-4 times as much damage to itself as it would be once it was lubed and warmer. The net effect (you're talking 0.008*3*3 for at least a few moments is a HUGE increase in wear compared to the 'extra' damage does while letting the car warm at idle.

Yes, sitting at idle does more instantaneous damage for a slightly longer period of time, but 1> you avoid the added wear from higher engine revs, and 2> you avoid multiplying the wear from that high initial wear due to taking off immediately. The cumulative effect is much lower.

The most efficient combination of speed and wear on the motor is to start it, wait until the revs settle, then drive. Once the revs have settled, you've already bypassed that high-wear period and are at a level that's above, but not significantly above normal operating wear. That's when you drive. Driving immediately puts significantly higher engine revolutions in the time period when you don't want it, and you can't alter the time it takes to warm up significantly enough (or even close) to offset the exponentially higher wear on the cylinders by driving in that time period.

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