Car Model: 2005 Subaru Impreza WRX Manual w/ 18G turbo, 565cc injectors, walbro fuel pump, full 3" exhaust, Perrin CAI, STi Top Mount Intercooler.
Mileage: 69,000
Gallons: 11.2
Miles: 374
MPG: 28 mpg average based on Cobb AccessPort Reading
EPA est. MPG: 25mpg highway
% improved: 12%
Conclusion: On the trip I took to Orlando and back, this is the reading I got, plus a few miles around town here in New Port Richey. I think a 12% increase over stock is huge considering the car has an upgraded TD05H-18G turbo, 565cc injectors, walbro 255lph fuel pump, and running 300 AWHP, which is way more than the 187 AWHP stock, and having all-wheel drive. I personally would like to thank Cobb Tuning for making a great product with the AccessPort, and would tell anyone that fuel mileage and performance is all in the tuning.

 

With some quick math 374 miles on 11.2 gallons is 33.4 MPG, not 28.

 

Oh, no question at all that tuning has everything to do with both performance and economy. The two go hand in hand, and you can't have either without proper tuning!

I'm going to have to call your data questionable, however. First, we can't go by what your onboard computer says. They have to be calibrated correctly to get mileage correct. I could easily set mine to read higher or lower just by changing one setting. (when I set my 49.9 mpg record, the ScanGauge had me convinced I was at over 52 mpg... it was wrong)

And the mpg you're claiming doesn't jive with your numbers, which aren't accurate enough (see first post in thread). 374 miles using 11.2 gallons would be 33.39 mpg.

So, give it another shot. Take an accurate mileage reading and exact fuel fillup reading. Do the math. See what's really going on.

 

Ok, and those were the numbers that I got when I made my trip, whether it was higher or lower, I didnt do the math. I used what the Cobb AccessPort was giving me as the reading for average fuel mileage. But math cant lie, when my receipt says 11.2 gallons of fuel when I refueled, and I mark on the receipt the mileage I put on that tank so I can keep track of the mileage I put on my car from tank to tank or week to week (i reset my trip odometer every time i refuel). The math does read 33.39mpg, which could also be scewed by the fact I drove with the a/c off for a while, and I always drive 45mph in 5th gear cruising, which can skew the AccessPorts numbers. The 28 mpg was what it was reading when I was going 75mph 5th gear with CC on. I baby my car around town, and despite having 300 HP, I am almost never in boost, and most of the time a Prius will outrun me at the light. So a 35 MPG possibility on the open roads here in Pasco, at 45mph, 5th gear at 1900rshared_pm is attainable, and will skew the mathematics. I only wrote the AccessPort's number because that was a more realistic highway number, and not a fuel run on a tank of gas.

 

Drove back from the Shell station on the corner of Florida and Hillsborough to the shell station on ISB here in Daytona, cruise control at 70 from Tampa to Orlando, at 65 the rest of the way. Almost no traffic slow downs, AC on the whole way. Results were very surprising. Next time I go it'll be at 65 the whole way. Should be up in 6th place now

Car Type: 2001 Audi S4, Giac Stage II, 17psi, Borla 3", Bailey DVs, Darintake
Miles on Car: 155198.9
Gallons: 4.640
Miles: 135.1
MPG: 29.12
EPA: 22
% Improved:%32.36

 

And he jumps into the top 10 with a vengeance!

 

woo hoo!

Got a bit of a typo on the PDF though

 

Ah, forgot to re-sort the numbers. Fixed.

 

well the saturn is still going. that is still my best mpg but i stopped tring to drive with a feather foot. normal mpg with a/c, traffic, and a heavy foot is still running 32-33 mpg in the city. cant complain about my little old beater.

 

Car type: 2004 MINI Cooper s, panel filter, powerflex control arm bushings, m7 std's, h sport 25.5mm sway bar.
Miles on car: 56310
Gallons:8.2
Miles:291.1
MPG:35.5
EPA:34
% improved: 4.4% (if my math is right)

With the windows up, on the interstate, no cc. I been watching my mpg thus summer and I just can't get my mini up to 36 mpg. Oh well.