Axle Swap - Fuel Econ Woes

[Nalanthi]

Am I missing something?
I went from a 3.55 ratio to 4.10 to run 33" or 35" in the future. I'm running the same 31" tires and my econ seems to be cut almost in half - from 12-13MPG down to 6-6.5MPG.

I was under the impression that the change in fuel econ would for this setup would be quite decent.

...unless I'm misfiring again, which shouldn't be the case with a new dist, plugs, and wires. I'll have to check into that anyway. This all seems to have started after I swapped the axles. Hubs are unlocked, and everything spins quite freely.

 

[MadOgre]

What tranny do you have ?

The problem is the tiny tires. If you have an overdrive you should be ok even with the tiny tires. But I suppose you have a 3spd automatic or a 4 spd manual ? which wouldn't make for great economy with 4.10s and tiny 31 inch tires.

Put on the 35s and you will be happy again

 

[Nalanthi]

Ogre - long time, man.

I'm sitting on the 465.
Most of my driving is 13 miles each way daily - under 45MPH, half of which is in a 35MPH zone.

6.5MPG just doesn't seem right...

 

[MadOgre]

Ya ok that is pretty atrocious fuel economy.

Quadjet right?

What have you checked so far ?

So long I almost don't remember lol

 

[Nalanthi]

After I played with the Qjet for awhile, I flipped it on Craigslist, but I'll probably snag another later down the road for S&G.

I re-jetted a 1406 and have been using that since.

It's probably a dead plug in one of my no-fire spots when I had a trash distributor. Never changed the plugs there, so this thread is a kneejerk reaction. I'll yank plug tomorrow when I get home from work. I tried to light 'em up just an hour ago like I did when I first slapped the rear axle in and no dice - so this tells me everything I need to know.

Funny, however, that this just happened right as I swapped axles.

 

[Nalanthi]

...all worth it for the sake of "I drive an old steel carbed truck. **** you, sir."