No Emissions 258 MPG

[pyro]

Finally got all my emissions crap ripped out and capped off, tuned the carb and after my first fill-up I'm getting 14.5 mpg. Does this sound normal, or what else should I look to do to give it a boost if possible? Here's what I've done:
replaced spark plugs and wires
removed smog pump and lines
removed air cleaner valves and sensors (except rear pcv)
removed fuel vapor canister
replaced carb springs and tune
swapped in an msd coil
ran a bottle of seafoam through it for Great Googley MoogleyGreat Googley MoogleyGreat Googley MoogleyGreat Googley Moogleys

I'm by no means complaining, but if there's anything else I missed, every little bit helps on a DD.

[Tripwire]

Do you have bigger tires? That will be a factor in gas usage...also consider the speedometer correction????

carrying. And unnecessary dead weight like a 10000 piece tool set or a winch?

Since its carbed, those flappers and hot and fresh air hoses you removed aint helping either

Out of curiosity ......did ripping out all that stuff help any?

[itselliot]

Finally got all my emissions crap ripped out and capped off, tuned the carb and after my first fill-up I'm getting 14.5 mpg. Does this sound normal, or what else should I look to do to give it a boost if possible? Here's what I've done:
replaced spark plugs and wires
removed smog pump and lines
removed air cleaner valves and sensors (except rear pcv)
removed fuel vapor canister
replaced carb springs and tune
swapped in an msd coil
ran a bottle of seafoam through it for Great Googley MoogleyGreat Googley MoogleyGreat Googley MoogleyGreat Googley Moogleys

I'm by no means complaining, but if there's anything else I missed, every little bit helps on a DD.

Why? The vapor canister is also connected to the gas tank...........Do a little more research on it.

[jeepjerry]

I think you can pull better than that. Which carb do you have on it? Ive always had better luck getting fuel mileage out of an earlier non electronic carter bbd 2 barrel. I had an AMC eagle that i got 18 mpg with the electronic carter and then put one from a 70s gremlin onto it and got 22mpg. My dad daily drove a J10 for years with the same drivetrain as you and got 17-18 mpg with all the emissions and everything stock though.

[Tornado230]

I can achieve numbers like that with my J-10 in town driving.
258/auto/2:72 rear
All emission features intact, including converter.
Stock tires (235's).
On the road can get 17+, depending on speed.

[pyro]

I think you can pull better than that. Which carb do you have on it? Ive always had better luck getting fuel mileage out of an earlier non electronic carter bbd 2 barrel. I had an AMC eagle that i got 18 mpg with the electronic carter and then put one from a 70s gremlin onto it and got 22mpg. My dad daily drove a J10 for years with the same drivetrain as you and got 17-18 mpg with all the emissions and everything stock though.

iirc its the mastercraft carb. I believe that's what came stock on it. honestly I don't know much about the carb other than the adjustments. I have it pretty leaned out so it idles good.

as for the other stuff...it has 31x10.5 bfg at's, the speedo is correct and I don't have any dead weight on board. as it stands now I am getting the same mpg as before when everything was on it running correctly. still have some work to do.

I got rid of the canister and just left the line open to vent. they aren't really worth anything going by my research and insight from others.

for the record this is on a mixed tank...maybe 40% in town/60% cruising (60-70 mph)

[babywag]

Should be able to do better than that with a 258.

Emissions removal (if you didn't have a bunch of vacuum leaks) isn't going to change your mileage @ all.
Only thing that will do that is a good tune/driving habits.

[jeeper54]

What gear ratio? I had 3:31 and 31 inch tires and got about 15 in town. 81 cherokee larado w/t with 258/727

[Carnuck]

Probably the metering rods need adjusting or the inlet line is loose and twisting on the seat/needle and raising the float level.

[Locked and Loaded]

Do you want to sell the canister?

[pyro]

already threw it all out

[Locked and Loaded]

They are hard to find.

[pyro]

i posted over on fsjn but forgot to on here...its long gone by now unfortunately

for the record heres a pic of the carb:


anyone confirm which model it is?

[joe]

Carter BBD.

[Rich88]

...Since its carbed, those flappers and hot and fresh air hoses you removed aint helping either....

X2. If you had fresh air intake hose from the front to the air cleaner snorkel, put it back. That's a performance item that helps.

If you had hot air tube from the exhaust manifold, put that back too, as that permits a leaner idle mixture.

The air pump is really the only emissions thing you removed, and even so, you will not see any measurable increase in mpg.

As for PCV, that's not really emissions. It keeps your engine healthier longer by removing acidic-laden fumes and gunk from building up inside. If you ever took the valve covers off a pre-pcv engine with 100K miles on it, you'd find that a 2 lb valve cover weighs now weights about 5 lbs, being lined with 1/2" thick layer of goo and crud.

The myth keeps perpetuating that these engines are "robbed" of significant HP and mpg by all their "emissions crap", when really, that only applied to a handful of some engines in the early 70's before things got figured out.