What sort of fuel mileage should I expect?

[redster]

I think my tank is a bit bigger? I put about 62 litres in it before when it was damn near empty, i usually hit 310 kilometers at the halfway mark. I dunked the carb in carb medic last week and i just recently replaced the shot muffler with a new one. Before i did those 2 things i'd normally get 350-400 kilometers per full tank. It's a mystery to me how those 2 things made it THAT much better.

 

[Lorenzo]

I think my tank is a bit bigger? I put about 62 litres in it before when it was damn near empty, i usually hit 310 kilometers at the halfway mark. I dunked the carb in carb medic last week and i just recently replaced the shot muffler with a new one. Before i did those 2 things i'd normally get 350-400 kilometers per full tank. It's a mystery to me how those 2 things made it THAT much better.

Well it cant be the Carb because its a fresh brand new rebuilt Quadrajet. I think are tanks are the same, when i filled up from going 378km i put in 51.5 L which came to $65 It cant be that the dual exhaust is making this sh*t mileage! I dont know if exhaust leaks cause crap mileage because i know i have some of those...

 

[pencero]

if you've never seen 'mileage wars' or w/e its called on tv where the guys try to get the best mpg check it out. You guys don't seem to understand that there isnt any one factor to change and get better mileage magically. When it comes to mpg, everything is a factor! Even just having cheap tires can cost you big mpg over time! Running a 2nd battery can even improve your mileage a little too, by taking stress off of your old electrical system. Having crappy battery terminal wires can even cost you mileage bc the computer is lagging in your CCC car !

From having owned so much GM now, I'm aware that intake manifold gasket and head gasket are critical to getting good mpg. If either one/ or both of yours is shot then you can get oil changes and flush your coolant and replace your hoses and shocks all day but you'll never get over 15-17mpg. Your gaskets have to seal correctly in order to close in on 20 mpg territory


Since the G is based on stock cars driving w the windows open should increase your mileage if your rear shocks are recent. The wind catches the flat-back window like a sail and redistributes stress from up front throughout the back of the car. Obviously in a rusty car this would cause some irritating noises to happen and wouldn't be worth doing though.

Another huge factor is today's gas. Obviously if you can get 'pure gas' w/o any ethanol your G should run much better because thats the type of gas it was supposed to be running on, not this e-10 and e-15 / this 'blend' crap we have in chicago. Knowing how much ethanol/ CRAP is in the gas is important if you're concerned w mileage. Buying 'BP with invigorate' and 'shell with detergent' isnt saving you gas or money, that sh*t is for newer cars not your g-body. In a G the ethanol doesnt burn right and just ****s up your valves!

 

[Crapple21]

In my el camino with a 305 with a Holley 600 and 17inch wheels and everything else stock I drive an average of 55 miles a day and get 14mpg. And by no means am I babying it lol I like to get on it when I can. Mainly I like to take off real fast sometime.(well as fast as I can with a 305) I'm sure I could get better mpg if I kept my foot out of it. Oh and my main driving is on the freeway it's around 47 miles on the freeway.

 

[Clone TIE Pilot]

I think my tank is a bit bigger? I put about 62 litres in it before when it was damn near empty, i usually hit 310 kilometers at the halfway mark. I dunked the carb in carb medic last week and i just recently replaced the shot muffler with a new one. Before i did those 2 things i'd normally get 350-400 kilometers per full tank. It's a mystery to me how those 2 things made it THAT much better.

Well it cant be the Carb because its a fresh brand new rebuilt Quadrajet. I think are tanks are the same, when i filled up from going 378km i put in 51.5 L which came to $65 It cant be that the dual exhaust is making this sh*t mileage! I dont know if exhaust leaks cause crap mileage because i know i have some of those...

Yes it could be, depending on the quality of the rebuild, parts, core, and skill of the rebuilder. Very few shops do a good job rebuilding Carbs anymore. Even if it is a good rebuild, you still need to tune it with a dwell meter.

 

[Mike P]

“.....there isnt any one factor to change and get better mileage magically. When it comes to mpg, everything is a factor!....”

Pencero hit it on the head, and the only way you are going to realistically find out what your average is based on your combination and driving habits is going to be actually driving the car and tracking your fuel mileage.

 

[Intragration]

Very few shops do a good job rebuilding Carbs anymore. Even if it is a good rebuild, you still need to tune it with a dwell meter.

:?: Unless you're running points, I can't imagine what you'd use a dwell meter for.

 

[ERIC87442]

Never did it before, i have heard you need a dwell meter to mess with the mc solenoid

 

[Clone TIE Pilot]

Very few shops do a good job rebuilding Carbs anymore. Even if it is a good rebuild, you still need to tune it with a dwell meter.

:?: Unless you're running points, I can't imagine what you'd use a dwell meter for.

You set the idle mixture control dwell on a CCC car using a dwell meter and adjusting the idle air bleed valve. Not the idle mixture screws. You connect the dwell meter lead to the green diagnostics plug. This is something every gbody owner should know how to do. Anytime a CCC Quadrajet is rebuilt, the idle mixture dwell should be checked and adjusted along with the TPS.

A Haynes manual for your car will explain what you need to do. My SMI rebuilt carburetor didn't idle "well until I hooked up my dwell meter and adjusted the IAB valve, smoothed right out.

 

[Intragration]

This is something every gbody owner should know how to do. Anytime a CCC Quadrajet is rebuilt, the idle mixture dwell should be checked and adjusted along with the TPS.

Interesting, I didn't know this. Maybe it's something that every *CCC* G-body owner should know how to do... 😉