I get 40 to 45 mpg at 60mph average 28 to 30
Running 321hp with turbo kit.

this seems pointless, go to 55, reset your DIC, then check it out

The most i have seen on my car was 409 and that is only with a CAI!

mine is gettin really poor fuel mileage, im getting 28.9 on the highway at 70mph

im getting about 32 average

Checking different types of driving. Not drafting or other methods to increase mileage.
Running over 300 miles on 11 gallon fillups.
I do run 80% Freeway driving. Speedlimit 70 mph in my area so that drags it down as well. 70Mph I get on average 33mpg It is the in town that sucks the mileage down right now since I can't keep my foot out of it.

I have seen over 400 range if I can keep my starts slow.

same here but thats hard

glad you like the other bonus' of the turbo kit

Interesting topic. I just did the 2.4 supercharger install, with 42lb injectors, 2 weeks ago. On my 3 hour drive home through WVA, MD, and PA I got 41.1 mpg on the DIC for the trip home. The drive there with no supercharger netted 30.9 mpg on the DIC. I thought damn this is sweet...until I calculated mileage manually. Turns out my trip home got me just over 31 mpg in reality. At full tank, fuel range shows mid 450's though, which I know isnt true. Point of the story is, and I'm no expert but, I believe the DIC calculates mpg based on percentage of injector useage, and doesnt take into account the size of the injectors. So anyone that installs larger injectors could see a false reading for mpg on their DIC if the injector duty cycle is much different than stock. Mine being a daily driven, basically stock 2.4 w/ m62, 42lb'ers and a conservative tune gives me a pretty low IDC. The pcm sees just the percentage, not the actual amount of fuel passing through. This percentage, I'm sure, is just thrown into an algorithm based on the stock injector size. Thus the crazy mpg readings.

So if my theory is true, when installing larger injectors:
New IDC<stock IDC=High mpg reading on DIC
New IDC>stock IDC=Low mpg reading on DIC

The only way to really know mpg is the good old fashioned way of filling up your tank to the top, driving x amount of miles, then filling up your tank again to see how many gallons you used. Mileage/gal used=mpg

Anyone know if my theory is true???

I have been looking for just that information but could not find anybody that new how the mpg was actually being caluculated. I have ran full tanks through but never a 100% freeway run to see if I could get a real calculation for freeway MPG. I have gotton over 300 miles per tank when I have ran a larger percentage of Freeway.
Still getting great mileage either way but would like to know exactly how it is calculated.
I am running 60# injectors.

what can be the problem, i've got a 2007 cobalt ss/sc stock..i was getting 36mpg and 470ish on a tank of gas, now i'm down to like 32 mpg. thought the aif filter may be dirty, and it was so i got an OE K nd N and now it runs better but no improvement, the tires have the correct psi, but what elso could be causing a drop in mpg all of a sudden.

usually to work and back i drive 55 to 60 w/o using the AC. what else can i check to figure out my my gas mileage is sucking. work is a 115 mile round trip everyday.
thanks

I am on a freeway that is 70mph. What I noticed is that before the turbo I would get 36 mpg at 60 but as soon as I went to 70 plus it dropped to 32 or so. I would say check your mph verses mpg. If that doesn't make sense then will have to look else where.

I am on a freeway that is 70mph. What I noticed is that before the turbo I would get 36 mpg at 60 but as soon as I went to 70 plus it dropped to 32 or so. I would say check your mph verses mpg. If that doesn't make sense then will have to look else where.

i set the cruise at 55, which is what i was driving before, now at 55 it gets no better than 32 to 33. and i havn't changed anything except the oil, and the air filter

most i ever seen on my car was 666km (7.7L/100km)....after seeing that number after i left the gas station i had a bad feeling about driving home...lol

^^^lol, thats funny most i seen is 441 miles getting 33mpg

My best was on a on the way back from my girlfriends parents place. A full half hour stretch with the DIC reading 4.6L/100km (51 MPG). And I verified it with a fill up too!

my dic said 500 out of a tank getting 41mpg

The gauge is incorrect on mine all the time. It would be nice if a real chevy tech could give us exactly what is up with the calculation.

The gauge is incorrect on mine all the time. It would be nice if a real chevy tech could give us exactly what is up with the calculation.

Stock injectors, as well as 42's won't affect the DIC readout (usually).

60lb/hr injectors can, however, affect the DIC depending on how your car was tuned to use them.
Reason being that the flow rate modifier can affect how the DIC reads injector flow.

I get like 230-240 miles out of a tank. Mostly city driving. Makes me sad :(

wtf pure highway driving 70-80mph using cruise control best I ever got was 336 miles and lights were blinking all over it was low

Point of interest 60mph seemed to be the sweet spot for best mpg. That will alone increase the mpg by 3 to 5 mpg at least for me. Also if I go south it is more down hill which will also increase my mpg. Actual mpg is about 28 mpg in normal but can get 30mpg if I am really trying.

30 mpg here at 65 cruise control with 42 injectors 3.1 pulley, plugs, drop in oem k&n filter

Well up here in Canada in the summer i got about 600-650kms to a tank highway and 550-650 kms in city/town driving. winter it's more like 400-500kms because of all the idling and warming up i have to get it to do, less traction on the road, and harder to keep tires pressure at right pressures... :P

Well up here in Canada in the summer i got about 600-650kms to a tank highway and 550-650 kms in city/town driving. winter it's more like 400-500kms because of all the idling and warming up i have to get it to do, less traction on the road, and harder to keep tires pressure at right pressures... :P

are you serious! I'm out in merritt, barely ever doing more than 50km/h and I just filled up today and get 480kms? Is this right? My car has the Stage 2

Well my car is stock now when I drove my car from chicago to arizona I got 400miles to one gallon checked it as I filled up now this is going from 55 to 60 and from 60 to 70 as I drove thru the diffrent states but when I hit the 70mph I got 415 wich I was happy but this was from e85 that's all texas amarillo had it was either that or 83 octane at 4am all gas stations were close so I risked it to keep the octane up but engine was fine didn't knock or anything actually felt a bit faster lol but im not trying it again

I do alot of highway driving so my L/100km is around 7.2L and my fuel range hit 792km

Computer reset for mileage available 460miles We know this is incorrect since 60lb injectors Actual mpg was about 29mpg.

well 250motorsportz... i dunno. it's what i get. i really don't drive it hard at all. only stock at the moment... i usually have my tire from 35 to 40 psi... and ever so often i throw in an octane booster and/or injector cleaner... nothing really specail... use premium but i doubt that will make all that much of a difference.

are you serious! I'm out in merritt, barely ever doing more than 50km/h and I just filled up today and get 480kms? Is this right? My car has the Stage 2

Translation - short trips in town = poorer fuel economy.

Especially when you let that stage 2 strut it's stuff :)

Take her for a longish highway run, guessing you will see much better mileage :twothumbs

Use the instantaneous readout to find the sweetspot on the highway when you activate cruise control. That would be the absolute highest MPG you would get, which is unattainable since you will always have to stop somewhere and idle. The average calculation is useful for your fill ups but if you want to diagnose something or compare data, the instant readout is useful.

07 SS stage 2 STOCK=423mi Highway w one tank

Tires 35psi

cruise control set @ 59-60

A/C off

Driver plus 120Lbs cargo:twothumbs

http://i295.photobucket.com/albums/mm158/lzwiefelhofer/fuelrange.jpg

This is my best. It took a lot of drafting behind large vehicles and a tail wind.
2007 G5 GT, 5-speed, stock.

well ive seen some outrageous readings on my mpg gauge but i doubt they were true. Thats on MY case, YOU were drafting, quite possible with that drag shadow....

well doing the math, the tank is 13 gallons if you can manage an average of 35 mpg at whatever speed(s) you are going you can get to 455 miles before a fill up. Now I brim mine every time I fill up so if I try can get almost an extra gallon of fuel in my filler neck. Which means 500 miles on a tank is possible