Will I get better gas mileage on the highway at speeds of 65-75 mph with my cutout open or closed? The obvious answer seems to be open, but I just wanted to make sure.

 

I don't really notice a difference between open and closed. Any difference would be negligible.

 

when i installed my catback and cutout, i picked up about 1-1.5mpg highway.

and i had it installed 200miles from my house, i was visiting a freind who sold the system to me. so i checked milage going to his place then coming home with the system installed. both trips had minimal traffic.

how much was the catback and how much was the cutout...hard to tell

 

I have a pretty free flowing cat-back, so difference between open and closed is pretty minimal to me. Personally I'd rather keep it closed and lose .5mpg and not run the risk of getting a ticket for loud exhaust... not that the chances of that are high or anything.

 

For me the benefits, if any at all, will be lost due to the obnoxious noise it makes when open at that speed.

Therefore I keep mine closed most of the time.

TS

 

versus the stock catback, youll prolly see a couple more highway miles, but will lose city mpg, b/c the cutout kills low end torque, hence the car has to rev higher to get going and maintain speeds.