Fuel consumption?
Thread Starter
Race Director
Joined: Aug 2004
Posts: 14,639
Likes: 39
From: Winston-Salem North Carolina
St. Jude Donor '08-'09
Fuel consumption?
On our run up to Bear mountain this past weekend, I and a friend gassed up and left from the same town, did the same run, took the exact same route home. My car is an 02Z06 headers/ hi flow cats/ dynoe tune from ECS. His car is an 04Z06 stock maniflod/cats/vararam/ and a tune done by him with a preadator. I used a 1/4 tank of gas on the way up, he used 3/4 tank on the way up. I told him its his tune, running too rich, which he agreed, but he's now wondering if the vararam had something to do with it, because the filters weren't seated all the way. I'm far from an expert, so his question is, would the computer alter the car to run richer if the air flow isn't restricted by the filters? I don't think so, but i've been wrong before.
Melting Slicks
Joined: May 2003
Posts: 3,490
Likes: 68
From: Hewitt NJ
Well the computer wouldn't alter the A/F ratio to run richer. However, if there is less restriction to the air going (hence a greater amount of air gets into the engine) then the computer would add a little more fuel. I doubt this is the case as 1/2 of gas is a HUGE difference. It sounds like it's his tune and probably some discrepancy between your gas gages.
Thread Starter
Race Director
Joined: Aug 2004
Posts: 14,639
Likes: 39
From: Winston-Salem North Carolina
St. Jude Donor '08-'09
Originally Posted by MYCoupe
Well the computer wouldn't alter the A/F ratio to run richer. However, if there is less restriction to the air going (hence a greater amount of air gets into the engine) then the computer would add a little more fuel. I doubt this is the case as 1/2 of gas is a HUGE difference. It sounds like it's his tune and probably some discrepancy between your gas gages.
Thanks for the reply. BTW- I drive way more aggressivly than he does, so we've ruled that out.
Team Owner
Joined: Jul 2004
Posts: 124,167
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From: .... NJ
Cruise-In VII Veteran
St. Jude Donor '05 thru '19
If air gets by the mass air it would run leaner. With that much a difference in gas I would say he could have a leak. If he was running that fat he would be pushing out a lot of black smoke. Are his exhaust tips filthy with carbon?
Le Mans Master
Joined: Oct 2002
Posts: 6,799
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From: dudley MA
Originally Posted by StephenT
If air gets by the mass air it would run leaner. With that much a difference in gas I would say he could have a leak. If he was running that fat he would be pushing out a lot of black smoke. Are his exhaust tips filthy with carbon?
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Team Owner
Joined: Jul 2004
Posts: 24,652
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From: NJ
St. Jude Donor '05-'08
my first thought would be that either the gas gauge was wrong showing that he used 3/4 tank and/or his gas gauge is wrong and when he filled up the first time they really didn't fill it up.
I would add Techron to the gas tank first and see what happens.
I would add Techron to the gas tank first and see what happens.
Advanced
Joined: Jul 2005
Posts: 64
Likes: 1
Miliage
1st--- No matter how accurate You think the MPG are using Corvettes
dash readings ---- (its not accurate) The only way for the average person is to :
1-FILL the tank - & make note of ODOMETER,
2- Drive Your miles/trip & Then Fill the tank again -- noting how many miles You have driven !!!!!
3-Then Divide that # of miles by the gallons You put in on the second fill-up !!!!!!!
easy as 1-2-3 !!!!!!!!!!!!!!!!
dash readings ---- (its not accurate) The only way for the average person is to :
1-FILL the tank - & make note of ODOMETER,
2- Drive Your miles/trip & Then Fill the tank again -- noting how many miles You have driven !!!!!
3-Then Divide that # of miles by the gallons You put in on the second fill-up !!!!!!!
easy as 1-2-3 !!!!!!!!!!!!!!!!
Le Mans Master
Joined: Dec 2003
Posts: 7,506
Likes: 0
From: Hillsborough NJ
Originally Posted by stonecoldsaysto
1st--- No matter how accurate You think the MPG are using Corvettes
dash readings ---- (its not accurate) The only way for the average person is to :
1-FILL the tank - & make note of ODOMETER,
2- Drive Your miles/trip & Then Fill the tank again -- noting how many miles You have driven !!!!!
3-Then Divide that # of miles by the gallons You put in on the second fill-up !!!!!!!
easy as 1-2-3 !!!!!!!!!!!!!!!!
dash readings ---- (its not accurate) The only way for the average person is to :
1-FILL the tank - & make note of ODOMETER,
2- Drive Your miles/trip & Then Fill the tank again -- noting how many miles You have driven !!!!!
3-Then Divide that # of miles by the gallons You put in on the second fill-up !!!!!!!
easy as 1-2-3 !!!!!!!!!!!!!!!!
It was the way we did it before all this on-board computer gimmickty, and it is truly the only accurate determinat of fuel economy.
Drifting
Joined: Dec 2005
Posts: 1,720
Likes: 3
From: East Hampton CT
I have a vararam, LT's, and a custom tune done myself (not a canned tune) and my car recently got 28mpg (DIC) driving up I-91 to VT (some steep hills) at 75mph. The car then was driven by my father for another 500mi for an average (DIC reading) of 34mpg!
Predators are next to useless for any sort of tuning, sounds like your buddy is running pig rich...as well as a possibility of someone's fuel gauge or DIC being off. Have him get a REAL tune and he'll be good to go.
Predators are next to useless for any sort of tuning, sounds like your buddy is running pig rich...as well as a possibility of someone's fuel gauge or DIC being off. Have him get a REAL tune and he'll be good to go.
Safety Car
Joined: Jan 2005
Posts: 3,675
Likes: 58
From: Hayward (Bay Area) CA
Originally Posted by sxe60
C5's are notorious for gas gauge problems, so I wouldn't put much faith in them. As has been suggested, fill up and then divide the miles driven.
Mine used to get a decent milage before I stored it for 6 months, while I was out of the country. Since I came back and drive it, it seems to be using toooo much gas. Not sure if that a gas gauge problem or just using too much gas due to other reasons. Even the DIC and analog shows gas drops so fast now..
I put in half a tank and it disppears sooner than how it was before... Not sure why.. 
Thread Starter
Race Director
Joined: Aug 2004
Posts: 14,639
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From: Winston-Salem North Carolina
St. Jude Donor '08-'09
Originally Posted by Vette_Fan
Mine used to get a decent milage before I stored it for 6 months, while I was out of the country. Since I came back and drive it, it seems to be using toooo much gas. Not sure if that a gas gauge problem or just using too much gas due to other reasons. Even the DIC and analog shows gas drops so fast now.. I put in half a tank and it disppears sooner than how it was before... Not sure why.. 
Pro
Joined: Jul 2003
Posts: 688
Likes: 0
From: Dover AFB DE
Originally Posted by jjcslynn
I have the vararam and I just got 29 MPG on the highway from Delaware to Kentucky and back.
Probably the gauges...
Probably the gauges...
