[XThrax]

Can it result in more mileage? (thinking about upgrading my prelude Si to a Vtech) will I get more mileage if I upgrade my stock air intake to cold air?

[Lionel H]

No,usually it means less mileage.It takes more hay to feed the horse the bigger it gets.

[Featherman]

what mostly happens when increasing hp is that one enjoys the extra power and uses it, thereby increasing fuel consumption, especially if the weight/power ratio initially was not satisfactory .