What is better when you`r gettin you`r car smog tested hot air from by the exhaust manifold or cooler air from by the grill ? thanks.
As I understand it, the car should be at operating temp to get a more accurate reading. Whether it is drawing cold or warm air shouldn't have a big difference in the reading. Usually the car is in a bay when they take the readings anyway.
it depends. The hotter the car is the less hydrocarbons you will have. The problem with it being hot is you raise your knox reading. Best thing to do is just take it in and see what it does. if it doesn't pass at least you'll have a printout of the readings and you can make adjustments from there.
