Is My Mileage Normal?

[cervinigt]

Hey all, I'm new to this forum and to Mustangs in general. I picked up a 2006 GT Automatic with 67k miles on it in November. I just started driving it this week, as I did a lot of work on it during the winter. I'm only getting 13 MPG right now. I do a mix of highway and city driving, and I drive conservatively 90% of the time. The mods I have are a JLT CAI, BBK longtube headers, off road x-pipe, cervini side exhaust, and a custom dyno tune. The car is making 425 crank HP if that matters at all.

 

[Bullitt95]

Hey all, I'm new to this forum and to Mustangs in general. I picked up a 2006 GT Automatic with 67k miles on it in November. I just started driving it this week, as I did a lot of work on it during the winter. I'm only getting 13 MPG right now. I do a mix of highway and city driving, and I drive conservatively 90% of the time. The mods I have are a JLT CAI, BBK longtube headers, off road x-pipe, cervini side exhaust, and a custom dyno tune. The car is making 425 crank HP if that matters at all.

With those mods you won't be anywhere near 425 crank HP. More like 345 crank HP.
If the engine runs well but gas mileage is poor, I suspect you might have bad upstream O2 sensors. Since you have BBK LT headers, the O2 sensors will be further away from the engine so I'd assume you added sensor harness extenders. If so, make sure the electrical connections are good.
Have you scanned the ECU for codes?

 

[cervinigt]

With those mods you won't be anywhere near 425 crank HP. More like 345 crank HP.
If the engine runs well but gas mileage is poor, I suspect you might have bad upstream O2 sensors. Since you have BBK LT headers, the O2 sensors will be further away from the engine so I'd assume you added sensor harness extenders. If so, make sure the electrical connections are good.
Have you scanned the ECU for codes?

Dyno says 315 wheel horsepower and the people who tuned it said its at 425. It was a custom Dyno tune and they did something to the trans too. I'll check out those O2 sensors though.

 

[Bullitt95]

Your tuner is bullting you. There's no way you have a 26% drivetrain loss and 425 crank HP.

 

[cervinigt]

Your tuner is bull****ting you. There's no way you have a 26% drivetrain loss and 425 crank HP.

Dang that sucks. Oh well, whatever I got is still enough to beat Challengers and Camaros. Just need to get a supercharger I guess.