how bad would a chipped ECU (p28,mugen).. affect the mileage of a car? i have heard as much as 20-40% overall.

any comments?

 

Shouldn't do much, but since you will be running more fuel it will go down some.

 

I plan to do a tuned Ecu by Katman from JDMhondaparts. (Mugen/skunk2 program) In a b17a w/ ctr pistons and cams, I was wondering what aproximate MPG...could I hope to have? in the city 20-24? or 18-20?
highway: 24-28?
All I have heard was that chipped p28's usually give "crappy, bad, horible" gas mileage.

 

yes it affects gas milleage i used 2 spend $10 every three days now i spend $5 a day

 

A 50% increase is unusually high, but it will hurt your milage. That's a major selling point for something like the Hondata system. It'll pay for itself within a few months if you drive allot, just in lower prices at the pump.