Gas Mileage ideas
06-18-2008, 08:19 AM
#1
3rd Gear
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Gas Mileage ideas
With gas prices going up, I decided to see what kind of mileage I was getting in my 78 Pace car. I am getting anywhere from 9 - 11 mpg (ouch). I have the L82 with 3 speed auto which explains some of it but I think I should get about 15 mpg. I have changed the obvious (plugs, filters, wires, cap n rotor) is there a way I can increase this?
06-18-2008, 09:21 AM
#3
Le Mans Master
Adjust the carb, be sure all hoses are connected and all emissions controls are in place (or completely removed and carb changed to compensate). Could be your catalytic converter is clogged. Could be you have a heavy foot......
06-18-2008, 09:28 AM
#4
Drifting
Yeah, but even those just take you from, what, 12mpg, to 15mpg? Unless you are driving cross country in the thing, I don't think that will make that much of a diff. Where as, people who have done the 5 or 6 speed conversion boast milleage of 21mpg and better, and that's with MORE horse power than stock, to boot.
06-18-2008, 09:46 AM
#5
Safety Car
Overdrive is about the only way for you to increase your mileage. Fuel injection will help a little too, and a goo wideband O2 sensor to verify you're not running rich would be wise. I get 23-25 with my 81' and it has a fuel injected 406. 
It's for sale too if you just want to add another car to the garage. 
-Justin
It's for sale too if you just want to add another car to the garage. -Justin
06-18-2008, 11:25 AM
#6
Drifting
I was able to get 21mpg on my 78 L-82 4 speed (before the 5 speed swap) on rare occasions when the stars aligned...always freeway mileage and always driven for greatest economy.
An automatic will almost always give less mileage (at least in these older cars where the convertor doesnt lock up).
But that same car would get at best 13 in the city, which by the way hasnt improved with the 5 speed.
Truthfully if you want mileage, you have to tune for it and it will always require more than just new plugs and filters, and even then the difference is only goping to be visible if you drive for mileage...which frankly I cant do in my car with much enthusiasm
An automatic will almost always give less mileage (at least in these older cars where the convertor doesnt lock up).
But that same car would get at best 13 in the city, which by the way hasnt improved with the 5 speed.
Truthfully if you want mileage, you have to tune for it and it will always require more than just new plugs and filters, and even then the difference is only goping to be visible if you drive for mileage...which frankly I cant do in my car with much enthusiasm
06-18-2008, 11:34 AM
#7
Le Mans Master
Yeah, but even those just take you from, what, 12mpg, to 15mpg? Unless you are driving cross country in the thing, I don't think that will make that much of a diff. Where as, people who have done the 5 or 6 speed conversion boast milleage of 21mpg and better, and that's with MORE horse power than stock, to boot.
06-18-2008, 03:35 PM
#9
Racer
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With gas prices going up, I decided to see what kind of mileage I was getting in my 78 Pace car. I am getting anywhere from 9 - 11 mpg (ouch). I have the L82 with 3 speed auto which explains some of it but I think I should get about 15 mpg. I have changed the obvious (plugs, filters, wires, cap n rotor) is there a way I can increase this?
06-18-2008, 06:49 PM
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Today's gas thread #1.
06-18-2008, 09:59 PM
#15
Instructor
My 75 L48 with Th400, headers with dual exhaust and high flow cats, edelbrock intake and 1406 carb, electric fans, a/c removed, no spare tire carrier, rebuilt distributor with timing set per Lars' papers...14-15 mpg around town. Upwards of 18 on the highway! I stay off the interstates on trips. Too likely to run at 75-80mph. Loses as much as 2 mpg. Dynoed 185 at the wheels.
Have an LT1 with 4L60e waiting in the wings. Looking for more Hp and 20 mpg. Have yet to look into what the rear is though.
Have an LT1 with 4L60e waiting in the wings. Looking for more Hp and 20 mpg. Have yet to look into what the rear is though.
06-19-2008, 12:04 AM
#16
Burning Brakes
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Make sure your tires are fully inflated for less rolling resistance- and longer wear. I run my Goodyear Eagle GTII's at 36-38lbs cold. Also, dispose of as much weight as possible- dump the spare, carrier and jack, and carry a AAA card. Go on a diet- Mark Martin was always faster than Jimmy Spencer...
06-20-2008, 11:25 AM
#17
3rd Gear
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I am not looking for exceptional mileage (although the horses were funny). I just thought if I could get close to 15 mpg I would be happy. I know my three speed auto isn't helping any and I do not intend to drive for mileage - but if I can increase the mileage a bit that means more gas which means more driving. The carb is running well, tires are new, emission controls have been removed and I do not believe I have a catalytic converter. Maybe pulling out the 3 speed tranny and putting in a 4 or 5 speed might be the option to go. I can always switch it back when I restore it to complete original.
06-20-2008, 12:33 PM
#20
Drifting
If you want mileage, trade it for a Japanese car.
Seriously though, you should be getting better from it.
I average about 16 with an L82 and 4speed with a 3:70 gear.
Seriously though, you should be getting better from it.
I average about 16 with an L82 and 4speed with a 3:70 gear.