Best engine modification.....To improve gas mileage???

[Snuffleupagus]

Our 86 wagoneer has a 4bbl Edelbrock......
Edelbrock Performer Series intake w/EGR.......
It's taken a lot to get her running nice, quiet and smooth. Still......The best mileage I can out of this engine is roughly 9-10 MPG highway.
I'm thinking the best way to get better mileage would be to switch back to a stock intake along with a 2bbl carb.
It'll be some time before being able to make any huge modifications.
Does anyone else have any ideas which would help improve the all around mileage without breaking the bank?

[Stuka]

Our 86 wagoneer has a 4bbl Edelbrock......
Edelbrock Performer Series intake w/EGR.......
It's taken a lot to get her running nice, quiet and smooth. Still......The best mileage I can out of this engine is roughly 9-10 MPG highway.
I'm thinking the best way to get better mileage would be to switch back to a stock intake along with a 2bbl carb.
It'll be some time before being able to make any huge modifications.
Does anyone else have any ideas which would help improve the all around mileage without breaking the bank?

The single best way to get better fuel economy is to change your driving style. If you are always using the secondaries, you are going to get horrible fuel economy. If you drive it nicely, accelerate slowly, try to carry momentum, etc, you can get much better economy. I used to be able to get close to 14 out of my old cherokee, and that was with a 6" lift 33's, bumpers, safari rack, etc. But then if I drove it to "have fun" I would get 10 or so.

Same goes for my J10. When it was bone stock, I could get 17 out of (its a i6 with a 4sp though).

Now obviously there can be mechanical limitations. I certainly would not remove the performer intake. The better flow that it provides increases efficiency which in turn leads to more power, which can lead to better fuel economy if driven properly.

I think the second biggest hit to fuel economy is tires. On most of my Jeeps, I take a 1-2mpg hit with mud tires compared to street tires.

[Grand_Wag_85]

When is the last time you did a tune up? What are you running for an ignition? An ignition upgrade won't make a huge improvement but it will help a little. As Stuka said driving style is one of the biggest factors concerning MPG's.

[carnuck]

More info needed. Driving style, tire size, where you drive (city/hwy/mountains), gearing

I have an '81 C20 with 454 and TH400 that gets 10 mpg in town but drops to 8 freeway cruising due to 4.10 gears.

[GeologyJeep]

The idea that a 2bbl carb is more efficient seems to be a persistant urban myth. If you keep your toes out of the back two barrels and let the two barrels that were designed for economy do their job they will usually make a big difference. I've got a Q-jet on a Buick engine in my '69 and can really notice two things when I step on the gas. The speedometer goes up and the gas gauge goes down. Mr. Ed

[War Wagon]

I have the same carb/intake combo as you. I have 33" tires (pizza cutters though) and 3:08 gears. We tuned the carb with a air/fuel meter reading a 02 sensor in the exhaust. The biggest improvement in MPG was recurving the advance and moving the vacuum advance to manifold vacuum instead of ported vacuum off the carb. This took a lot of trial and error but was well worth it. I had to weld up the mechanical advance slot to limit mechanical advance and install lighter mechanical advance springs to bring in the mechanical advance quicker. I set initial advance higher than stock, around 12 degrees. You may also have to limit vacuum, mine has an adjustable vacuum advance canister. We could get 17 MPG on the highway in The War Wagon with this setup, 360/T400/QT. I found all this info on a Mustang site as we use motorcraft distributors. I will look for the links.

http://www.reincarnation-automotive.com ... index.html

[lindel]

Basically, anything that makes the engine breathe more efficiently will make a difference. Better intake, cam, carb with smaller primaries and annular boosters, better scavaging exhaust with less back pressure. If you can get the air in and out quicker, it'll be more efficient.

[LMJ20]

I agree with Lindel
Anythign that you can do to improve the breathign of the engine and reduce internal friction will improve the eficiency of the engine.
Also not driving it like a totla maniac helps too.
One thing that has been proven to help is Port and Polishing the heads. I know it seems like dabling in the dark arts to some but it is really pretty simple.
There are tons of write ups on line and videos on youtube. Just take your time and pay attention to what your doing.
And the best part, Its probably the cheapest moddification you can do yourself.
Another easy moddification would be headders. You can get some in the $150-$200 range. although i cant speak for thier quality, im sure they will be less restrictive than stock.

A relativly easy way to reduce internal friction(or in this case drag) is to install a crank scraper.
I have read numerous articles talking about the benifits of these devices and will deffinetly be getting one soon for my 401.

There are a lot more products out there that help your engine breath and reduce friction. Just make sure you do your reasearch before hand so you dont end up buying somehting that is equivelent to an can of dehydrated water.

[ClovisMan]

Stick a 2x4 block of wood under the gas pedal. Other than that, just a good tune-up/carb rebuild/free flowing exhaust, everything that has already been said I'm sure.

[stumblinman]

http://www.oreillyauto.com/site/c/detai ... ord=121gmf

That should do it...

[cliff54]

War Wagon hit on something that is commonly ignored - the ignition curve. If you don't have a TFI setup, get one (HEI, DUI all great too). Take the dizzy to an old time mechanic or race shop with a distributor machine. It's cheap and it yields results.

I run a STOCK Motorcraft TFI setup with MSD6 in my AMC Spirit drag car. The TFI is THAT good after professional tuning on a distributor machine.