What sort of MPG should I be getting?
10-17-2011, 01:18 PM
#1
2nd Gear Member
Thread Starter
Join Date: May 2011
Location: NY
Posts: 183
What sort of MPG should I be getting?
Here is my setup and I was wondering if I should expect more?
- original 302 iron top and bottom
- c4 trans
- aluminum intake manifold off an 80s Stang
- pertronix 2 with pertronix 2 coil (now with resistor wire bypassed) w/ hip wires
- new plugs, autolites left at .35 gap
- holley street avenger 570 carb (mechanic tuned along with timing)
- mild cam
- single exhaust with original exhaust manifold (slight leak)
- have an A/C system hooked up but not using now
I am getting about 13mpg with mild driving with occasional spirited moments.
Will I get an improvement if I gap my plugs to .40?
Should I try to tune my carb a little leaner?
I do smell gas now and then so I wonder if I am still running rich.
- original 302 iron top and bottom
- c4 trans
- aluminum intake manifold off an 80s Stang
- pertronix 2 with pertronix 2 coil (now with resistor wire bypassed) w/ hip wires
- new plugs, autolites left at .35 gap
- holley street avenger 570 carb (mechanic tuned along with timing)
- mild cam
- single exhaust with original exhaust manifold (slight leak)
- have an A/C system hooked up but not using now
I am getting about 13mpg with mild driving with occasional spirited moments.
Will I get an improvement if I gap my plugs to .40?
Should I try to tune my carb a little leaner?
I do smell gas now and then so I wonder if I am still running rich.
10-17-2011, 02:16 PM
#3
2nd Gear Member
Join Date: Sep 2008
Location: The garage (near SF bay- Calif)
Posts: 469
Timing and carb tune will affect your mileage the most.
The more advanced the timing the better the mileage. But if you go too far it will ping
on accelleration (bad for the engine). You'll get better MPGs and less pinging if you run premium gas.
But you'll have to advance the timing to compensate for premium.
13 around town is about right, but on the highway it should get closer to 18-20.
Have your mechanic look at why it's making the gas smell, it shouldn't do that. Maybe it
is running very rich or worse has a gas leak (which could result in a fire). Look for gas on the intake manifold around the carb first (most likely), then check the hose connections.
The more advanced the timing the better the mileage. But if you go too far it will ping
on accelleration (bad for the engine). You'll get better MPGs and less pinging if you run premium gas.
But you'll have to advance the timing to compensate for premium.
13 around town is about right, but on the highway it should get closer to 18-20.
Have your mechanic look at why it's making the gas smell, it shouldn't do that. Maybe it
is running very rich or worse has a gas leak (which could result in a fire). Look for gas on the intake manifold around the carb first (most likely), then check the hose connections.
Last edited by 1971mach1; 10-17-2011 at 02:26 PM.
10-17-2011, 04:29 PM
#4
2nd Gear Member
Thread Starter
Join Date: May 2011
Location: NY
Posts: 183
Timing and carb tune will affect your mileage the most.
The more advanced the timing the better the mileage. But if you go too far it will ping
on accelleration (bad for the engine). You'll get better MPGs and less pinging if you run premium gas.
But you'll have to advance the timing to compensate for premium.
13 around town is about right, but on the highway it should get closer to 18-20.
Have your mechanic look at why it's making the gas smell, it shouldn't do that. Maybe it
is running very rich or worse has a gas leak (which could result in a fire). Look for gas on the intake manifold around the carb first (most likely), then check the hose connections.
The more advanced the timing the better the mileage. But if you go too far it will ping
on accelleration (bad for the engine). You'll get better MPGs and less pinging if you run premium gas.
But you'll have to advance the timing to compensate for premium.
13 around town is about right, but on the highway it should get closer to 18-20.
Have your mechanic look at why it's making the gas smell, it shouldn't do that. Maybe it
is running very rich or worse has a gas leak (which could result in a fire). Look for gas on the intake manifold around the carb first (most likely), then check the hose connections.
Ive heard 18-20 is what I should get if I had a t-5 manual as opposed to a 3 speed auto with a 2.79 in the back. I had hoped to get to 16-18 and I already use premium but I had to add lead subsitute for my original valves. Probably should check my tires pressure and specs as well.
If everything is running great I am guessing it might not be worth it to try to squeak a few mpg out of it. But every time I look under the hood those Holley screws stare at me and beg to be fiddled with.
