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I have noticed that every morning that I first start the car, it has a very noticable power increase from when it is warmed up. Especially in the low end. Can anybody explain why that is, and what I could do to keep that power even after the engine has warmed up? Thanks
 

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two reasons mainly... one the engine is cold and two the outside air temp is cooler that it would be in the afternoon...

i'm sure you know this, but don't go romping the car around until it's fully warmed up... running it hard when it's not in it's operationg temp range can cause problems overtime. basically the oil isn't thinned enough and isn't providing max protection where it should...


paul
 

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This is very typical behavior for a cold engine until the engine warms-up. A couple of things to note: first because the air is cooler it has more mass and therefore needs more fuel. Hence with all this extra mass and fuel the engine is rather peppy until it warms-up. After it warms-up it needs less fuel to run than when it was cold. Why? Well of course the engine is warmer and needs a leaner air/fuel mixture to burn.

Anyway that's it in a nutshell but there is a great deal of physics going here. If you can understand how air mass changes with temperature then you should be able to understand why less fuel is needed on a warm engine.

I could be wrong the air/fuel mixture ratios may look something like this:
Cold engine: 9:1 (running rich)
Warm engine: 14.7:1 (normal mixture)
 

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I thought it was running running in closed loop when cold and open loop when warm. I may have that backwards....When cold, it bypasses all the emissions controls until it gets warmed up.

I am not totally sure, someone back me up or discredit that.
Thanks
 
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