Originally Posted by TXCarGeek
I'm unsure what prompted me to do this, but do any of y'all wait for the RPMs to settle after a cold start before shifting into gear?
What's the precise reason for the higher revs to begin with? And is it at all beneficial to allow the engine to settle down like I have a tendency of doing?
You can decide which is best by your situation as I have done. Outside air temps? or in the garage as cold start ? Auto or manual trans etc....
Here's what I mean;
With the cars we have now, I don't really make a conscious decision to wait. My Madza CX-9 is garaged and I honestly don't look at the tach to see what it's cold start behavior is. By default though, I can tell you it does not jolt or slam into gear because I'd know it and would most definitively make a conscious decision to wait. That kind of drama on an automatic trans and drivetrain isn't ideal.
On my VW that sits out all winter, the cold starts are the same, no jolt as I put the car in gear to drive away. I mention the garage only because it might make a difference on some cars or older one's with carburetors. A garage temp of 40 f and an outside overnight temp in the mid 20's could make a difference in how high the revs are at the time you cold start it.
My Infinity was a 6MT and as others mentioned, with a manual transmission, you can engage the drivetrain without the slam of an automatic because you are manually searching the grab threshold and won't cause an abrupt friction point. The G35 I had would cold start outside in winter and rest at 1100 - 1200 rpms for a minute or so, drop to about 850 then drop to 650 or 700 or the normal rpms when warmed up. Carbureted motors had a mechanical means of dropping to normal from the 'fast idle' and these newer designs are electronic monitored and controlled.
With the older set up, I believe the fast idle speed was a means to warm up the car a bit faster and the fuel/air mix was a bit more finicky with mechanical controls and adjustments.
With newer cars an regulations, it's all done by computer and emission regulations (apparently) have proven faster warm-up is better for meeting standards.