DIC gas mileage average vs. reality
Thread Starter
Instructor
Joined: Oct 2005
Posts: 149
Likes: 1
From: MD
DIC gas mileage average vs. reality
Each time I fill up my 99FRC, I reset the trip odometer and the DIC fuel average. I've filled up 4 times since I own this car and the actual gas mileage has been 88% of the DIC average on each tank. It seems others have noticed the same thing. Is there a way to have the DIC reprogrammed so that it shows you the true (i.e. multiplied by 0.88) gas mileage? Maybe this has been discussed before but I couldn't find any trace of it in the forums.
I'm also puzzled that this gas mileage overestimation by the DIC is so systematic, almost as though GM had been trying to fool C5 owners. If the error was sometime up, sometime down, I wouldn't be so suspicious ... but given that true mileage is always within 87.5%-88.5% of estimated mileage, I can't help but wonder.
I'm also puzzled that this gas mileage overestimation by the DIC is so systematic, almost as though GM had been trying to fool C5 owners. If the error was sometime up, sometime down, I wouldn't be so suspicious ... but given that true mileage is always within 87.5%-88.5% of estimated mileage, I can't help but wonder.
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Most owners will notice a difference between hand calculated mileage and that shown on the DIC. Part of the reason could be the differences in how much gas is put back in the tank at time of fillup.
Burning Brakes
Joined: Jul 2004
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From: If your not the lead dog the view never changes Boise, Id
I think it estimates avg mpg by calculating the instant mpg wich is constantly changing not by memorizing how much fuel goes thrue the injectors during a tank of gas. 
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Michael S. Palmer
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Joined: Feb 2003
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From: Plainfield Illinois
Try this:
I have flown a lot... On our airplanes we DEPEND on fuel totalizers for range before we fall outa the sky. These totalizers are VERY expensive. The totalizers on our cars are the same except they don't have the AIRPLANE tax (which I assure you is far higher than the corvette tax).
The Vettes use a greater number of units each year than the airplanes. They are therefore cheaper. But they are made the same. The Vette totalizers are very accurate. They measure the amount of gas that has passed through the totalizer, not how much you filled the car with. I can always add a few quarts to the tank after the nozzle has shut off, when I fill up, after the gas pump has shut off. The totalizer just says you have filled up, it doesn't know (or care) how much is in the tank...
By the by, it seems to be pretty accurate... depending on how full you have filled the tank. Now, about the range figure... Don't count on it... The totalizer does NOT know just how much you CRAMMED (if any) in the tank.... THAT'S suspect........
ZOOOM
I have flown a lot... On our airplanes we DEPEND on fuel totalizers for range before we fall outa the sky. These totalizers are VERY expensive. The totalizers on our cars are the same except they don't have the AIRPLANE tax (which I assure you is far higher than the corvette tax).
The Vettes use a greater number of units each year than the airplanes. They are therefore cheaper. But they are made the same. The Vette totalizers are very accurate. They measure the amount of gas that has passed through the totalizer, not how much you filled the car with. I can always add a few quarts to the tank after the nozzle has shut off, when I fill up, after the gas pump has shut off. The totalizer just says you have filled up, it doesn't know (or care) how much is in the tank...
By the by, it seems to be pretty accurate... depending on how full you have filled the tank. Now, about the range figure... Don't count on it... The totalizer does NOT know just how much you CRAMMED (if any) in the tank.... THAT'S suspect........
ZOOOM
Safety Car
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From: Pleasanton CA
St. Jude Donor '10-'11-'12, '14-'17,'21, '25
I think it's the forum quotient. I hear about all these guys getting 28+mpg. I think I've seen as high as 32. I know that in my 04 vert, A4, 2.73, I get 18 to 20 mpg in mixed city/freeway driving with occasional blasts to triple digits. I have never had better than 25 mpg with mostly freeway driving. And yes, I don't trust the DIC I do the calculating by myself.
Team Owner
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From: Virginia
St. Jude Donor '11
Originally Posted by dyeggy
I think it's the forum quotient. I hear about all these guys getting 28+mpg. I think I've seen as high as 32. I know that in my 04 vert, A4, 2.73, I get 18 to 20 mpg in mixed city/freeway driving with occasional blasts to triple digits. I have never had better than 25 mpg with mostly freeway driving. And yes, I don't trust the DIC I do the calculating by myself.
dayem...same here
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From: NorCAL Live your passion--why wait, you ain't getting any younger
Originally Posted by CombatVette
I don't give a damn about my Corvette's gas mileage.
Its smiles-per-mile that count.
Smileage----can I copyright that? How do you spell it?
