ans2k

so i know on the pre MY06 they had the air pump to help rev the car to 2K to warm up the cat on cold starts. i have heard it was for more of an emission thing. i also know that today's oils are fine driving around while the engine is cold and that it doesnt need to warm up first to begin driving. i was wondering if it was ok to lower the idle on cold starts. it's just that i hate to wake up the family in the mornings. i got the idea from people removing the air pump from their s2k.

Gernby

When an engine is cold, so much heat energy gets sucked out of the combustion by the cold pistons, cylinder walls, and head that there isn't as much energy left over to overcome the compression stroke of the next cylinder. This makes the idle rough if the idle speed is too low. However, it isn't going to cause any damage to reduce the idle speed to a point that you like. I lowered mine to 800 RPMs for the exact same reason as you, but later had to raise it when I got larger injectors.

BTW, the air pump has nothing to do with idle on older S2000's. It only injected fresh air into the exhaust to mix with unburned fuel so the catalytic converter would heat up quicker.

BTW #2, it's not good to warm up an engine at idle. There is so little cylinder pressure during idle that the rings don't seal, so you get a lot of blow by and oil contamination. Just start it and go.

ans2k

wait you moved the cold idle to 800!? im still on stock injectors.

i always thought the big tube going into the intakes of all pre MY06 came from the air pump. and that is what i always heard.

isn't that what i stated? but thats for the reply, gernby. always glad to have your input.