radness 0 Posted February 1, 2009 Hey, When i start my car up and it's cold , i notice a significant performance difference (obviously i dont floor it but even gentle pressure on the pedal gives a lot more response., why is this? Is it because; a. the engine block/bay is cold and so much more cold air is getting in it? b. The cold start is giving the engine more fueling c. the cat is not warmed up yet and so isn't so restrictive (i read that your Cat needs to be at working tempature before it can start removing the pollutants. Is this true? Sorry if this is a bit of a dumb question ! Quote Share this post Link to post Share on other sites
davidwort 0 Posted February 1, 2009 You don't say which engine? But it's down to how rich the engine is running, fuel doesn't vapourise and so mix with air as well at cold temps, so the engine runs richer to compensate, often over-doing it a bit. Quote Share this post Link to post Share on other sites
PROVR6 0 Posted February 1, 2009 I find the opposite. My car is more lively once the engine is upto temp. Quote Share this post Link to post Share on other sites
oldskoolkool 0 Posted February 1, 2009 The fuel atomises alot better in cold/damp consitions ! Quote Share this post Link to post Share on other sites
davidwort 0 Posted February 1, 2009 The fuel atomises alot better in cold/damp consitions ! I think you mean air is more dense at cold temps (more dense = more power potential), VW's are designed to run pretty hot as that makes the engine run more efficiently, fuel definitely doesn't atomise better when and engine is cold, why do you think carb engines have a choke? Quote Share this post Link to post Share on other sites
oldskoolkool 0 Posted February 1, 2009 The fuel atomises alot better in cold/damp consitions ! I think you mean air is more dense at cold temps (more dense = more power potential), VW's are designed to run pretty hot as that makes the engine run more efficiently, fuel definitely doesn't atomise better when and engine is cold, why do you think carb engines have a choke? yeh sorry the air is more dense sorry ! :bonk: Quote Share this post Link to post Share on other sites
radness 0 Posted February 1, 2009 You don't say which engine? But it's down to how rich the engine is running, fuel doesn't vapourise and so mix with air as well at cold temps, so the engine runs richer to compensate, often over-doing it a bit. Sorry, it's the 9a. Always thought it was a bit weird as soon as it reaches tempature it seems not to rev as well. (about 10-20% difference - i suspect) :( Quote Share this post Link to post Share on other sites
