Predict my fuel economy. 530 mile road trip coming up

[Three6Eight]

Hey folks I have a 530 mile or so road trip coming up. Im driving to Fairfield CA from San Diego CA

I've done this trip on my 2 other cars.

On my 1998 Buick Regal GS with a 3.8 Supercharged V6 and some mods I did a personal best of 31.85 MPG. The EPA rating for this car on the freeway is 25MPG.

On my 1999 Chevrolt C2500 Pickup with a 6.5 TurboDiesel bone stock I did a personal best of 21.36 MPG. The EPA rating for this truck is 17 MPG Highway


So now I'm going to try this out with my Corvette. My current stat is 16.68 MPG 18.6% below EPA combined rating. The EPA freeway rating for the C5 is 25 mpg,16 city and 20.5 combined Heres my current gaslog

http://www.gassavers.org/garage/viewgaslog/2555

My car has a 6 Speed with Shorty headers and an intake and dynoed at 331 horsepower to the wheels. I intend on going 69 MPH most of the trip. Im going to behave and resist the temptation of going WOT because Im a stat freak and I want to bring my stats up..

Its always fun seeing how high you can go over the EPA rating. So on my Regal I did 6 MPG better then the EPA rating and on my C2500 I did 4 MPG better then the EPA rating.

So predict my MPG for this trip . Like I said Im going to stay at 69 MPH and at that speed the engine is spinning around 1500 RPM or so

[qikslvr01]

I have a friend who busted 30mpg in a similar car. Good luck!

[theholycow]

Stock gearing? T56 tranny?

I predict 32mpg.

Prove me wrong. Get 35mpg.

[GasSavers_GasUser]

With that thing turning 1500 rpm at 69mph like you said you better get 36 or better mpg easy if you don't hit a traffic jam on those freeway parking lots.

The motor won't even break a sweat at 1500rpm and you have some of the best aerodynamics going for you.

I know you can do it.

Dave

[Three6Eight]

Some high expectations already and thats exactly why I make these topics before I do this road trip.

If I dont get at least 32 mpg Im going to be dissapointed

[Project84]

I have friends w/ LS1 Camaro/TA's getting in the 30's routinely with a much more extensive performance mod list than shorty headers/intake (do you mean CAI or intake manifold?)

The engine/tranny combo if perfectly capable of 35+ (you may be interested in finding a tuning shop to street tune your car.... more power and MPG are both hiding behind your factory ECU maps)

My LT1 w/ quite a bit of work, 6sp and 3.42 gears only managed 21.x on a 500 miles round trip. lol