Post your tricks for fuel mileage on a V8

Just picked up a early 70`s car with a big V8 in it and got to thinking about its gas mileage.What tricks are out there for improving fuel mileage on a V8 engine?? I know of a few I will be doing, one is replacing the stock fan with a clutch fan. What tricks have you done over the years to improve your mileage.

 

Tape a raw egg to the gas pedal.

 

It's always going to be a dog compared that modern 5speed overdrive with a lock up torque converter etc... May as well boot it and enjoy it.

 

Just try to keep your foot outta it. HUGE difference in gas mileage between traveling 65 or 80....seriously, huge difference. This is coming from someone who's been driving a 1970 Olds 455 for the last 104,000 miles.

 

lean them down, really hot ign spark, big gap spark plugs to fire the mixture and keep the flame going throughout the whole chamber

if the fire goes out in the chamber you will have unburned fuel and get high HC so set up your engine with a 2 gas analyzer

set the idel air screw jets to get good readings

THIS WORKS
but things like this take a lot of tinkering and time to get it right
its not for the faint hearted to keep something running when close to the edge

once you learn carb and ign set ups it can be used on all engines
sometimes when you have a big killer cam is another experience to get working good for driveability
it takes a lot of time to make this stuff to work , read books on carbs, set them up to fit your engine vacume gage which is another gauge to have in your car or truck
it took me a coupe years to get good at doing this and most of it was self inflected, and a little was from a high priced specitalty tune up guy{ thanks for sending me to school Mom, yes it was at about age 41}

 

Did you ever figure out what kind of mileage your getting?? I have a 71 Caddy now with a 472 in it and plan on using it for a few longer road trips. The car is not old enough for me but the price was right and it should be more comfortable then the T bucket!!

 

Most of the best tips have already been mentioned. Keep your tune-up razor sharp. Watch your tire pressures. Keep the air filter clean. Make sure the choke works properly for quick cold starts and that it opens fully when the engine warms up.

If the air cleaner has a heat stove tube running to the exhaust manifold, make sure the thermal switch is working properly so it's not pulling heated air thru the carb after the engine's warmed up. Make sure the distributor mechanical and vacuum advances are working. If for some reason you've removed the thermostat, put one back in and fix whatever overheating problem you might have had.

And as mentioned above install a vacuum gauge inside the car connected to a manifold, not ported, vacuum source. When driving try to maintain the highest manifold vacuum possible. That's the "egg on the accelerator pedal" tip that was also mentioned.

 

You don't have a hot rod to save money Fuck it ,stomp the pedal and have fun!!!
Find a way to save money in other aspects of your life

 

Years ago I had an 85 Ramcharger 4x4 with an auto and a 318 V-8. My friend who had it before me complained about the lousy gas mileage (less than 12 most of the time). I got it and drove it like a grandma and shoved in this device called the Tornado into the air cleaner. It actually did make a noticeable seat of the pants difference. Anyway the truck consistently got 20 mpg or better driving on a wide set of 31 inch BF Mud Terrains although in town fuel mileage was still horrible (less than 11 mpg). In addition to the weird Tornado thing (I took it off a car I sold) the truck had headers and dual exhaust, the rest of the motor was stock.

 

There are a bunch of things you can do to get good mileage, I can get around 25 with a TBI V8 on highway miles. First, flat top pistons help some with mileage. I run stock manifolds and 3" outlet stock y-pipe, with 3" out to the back and a 2.5" flow through design muffler, but headers can also boost mileage (so long as you keep your foot out of it!), also NO CAT! Or run a high flow one if you absolutely have to. Remove any type of restrictions in the air intake, or run an open side type filter (K&N, Edelbrock). Make sure your ignition system is in good shape and dont use cheap parts! They build up resistance and deteriorate quickly. Get a good brand of wires, and a quality cap and rotor. I prefer Autolite Copper plugs myself but this could be left to personal preference. I also run larger gaps then stock (around 040-045, IIRC)

Other areas are quality brands of fluids, not only in your engine, but in your transmission and axles. Also make sure tire pressures are good. An Overdrive transmission sure helps too though!

 

X2. Life's too short to drive the speed limit.

 

Quadrajet-just keep the tiny primaries open, save the huge secondaries for Saturday night!

 

I just picked up an old Offy dual-port for my 455 Olds. They are designed to improve gas mileage at the expense of top end pwr. The price was right, so I went for it. Looks a little rough right now, but it's getting refinished.

Dual port side

 

There was some discussion on building a miser motor with cheap vintage two barrel heads here:
http://www.jalopyjournal.com/forum/showthread.php?t=268086

 

I like to disconnect the wire from my sending unit, that way it looks like you're not using any fuel at all, until you run out......


That's the best I could do, all the good advice was already given out. ^^^^^

 

307 chevy =)

 

I run a 460 in my 57 , use to know every petrol garage owner by first name , took it to a good mate ,he ask what do you want 'Power or economy' I said both .
........and he did , it was a totally different car , with the fuel economy of a smallblock, most of the work was in the dizzy , modified the weights, changed the springs etc .This guy is old school and knows the tricks that many dont.
It worked for me big time. @ another 150kms per tank !

 

When I had my 75 Cad. I picked up 2 MPG just by re-routing the vacume hoses on the engine and setting the timing. Basically you want the vacume advance coming off its own port close to the center of the manifold and separate from the accessories, that way your timing goes to full advance quicker.

 

The big ones.

1. Take all the extra crap out of your car. Extra weight means extra fuel to move it.
2. Super tune your engine. Lean out as much as effectively possible while still having good throttle response and no overheating issues. Make sure you're timing is set right and is working as efficiently as possible. Send the distributor out for a rebuild if necessary.
3. Fully inflate tires.
4. Delicate and careful use of the go pedal.

There are some extreme fuel savers out there that do things I don't consider safe. These include shutting off the engine while approaching an intersection, shutting off the engine at a stop light. Shutting off the engine in stop and go traffic. Yes, they do save fuel. No, I don't think it's worth it to go to that extreme. I might as well just ride my crotch rocket everywhere I go (I pretty much do anyway!) and get 45 mpg.

 

The best for me so far is 100% synthetic gear lube in the diff and tranny. I picked up a 100 kilometers per tank on my 05 ranger, but most two wheel drives i know about are getting between 10 and 30 kilometers per tank.

 

Stretch a Prius chassis and drop the body on it.

 

A V-8 engine, even a performance engine, does NOT automatically translate into poor mileage!

Shop F-100 (390 2x4 4/speed) gets 22 MPG at 70 MPH. Of course, it gets less in city driving.

Here are some hints:

http://www.thecarburetorshop.com/Troubleshooting.htm#Fueleconomy

Jon.

 

i always would put a 4 b.holley on it.the factory ones or the two bar.suck for gas mileage.from what i have seen my old ford truck {75f250 4x4}gets about 10-14mpg.but what i think is funny is the 09f250 deisal was only getting 4mpg.holly shit now that sucks!!!!

 

Well a few years back I seen a motor home that had copper tubing coiled around the fuel line feeding the carb. I asked the owner about it and here is the deal. He said he was getting about 9 to 10 MPG until he coiled copper tubing connected to the heater hose inlet and outlet. By preheating the fuel before the carb he was now getting 15 to 18 mpg. I never tried it but I asked him if he had any vapor lock problems and he said none.

 

No one has mentioned internal mods except for the article RichardD posted. Smaller ports mean higher velocity and better suspension of fuel, tight quench for more turbulence during the ignition event, and a properly designed exhaust for good scavenging of the chamber. These things combined with a fairly high compression ratio and extremely good tuning will get the most out of every drop of the precious!!

 

Interesting!

Conventional wisdom is that by COOLING the fuel one will MARGINALLY improve the engine efficiency, thus both power and fuel economy.

The accepted (and tested) figure is roughly 1 percent for each 10 degrees F you can cool the fuel.

Jon.

 

cow magnets....put em on the metal fuel line, after the pump ...an old farmer told me that one...lol

 

My daily driver is an 84 El Camino/ 305 used to get 10-11 mpg. 390 holley,headers,
79 dist. 700 r4, disconnected smog pump, no cat convertor. now gets 17 in town
21-22 hwy. still has plenty of power.

 

You FORGOT to tell him to put the bloody ariel down ..............

 

Tall skinny tires, and keep 'em hard. The Caddy has lots of torque to haul the tallest you can find.
I had a Dual-Port on a 360 Dodge, gutless and lousy mileage, the stocker was better.
A good electronic ignition conversion will make some difference over points, especially if you don't keep the points in good tune. EI will go many times farther than points with zero maintenance.
An electric fan will do more than a viscous drive if you are really serious about getting better mileage. Personally, I leave the direct drive fan alone, simple and trouble-free.
Drop that sucker in the weeds, keep the air away from all that ugly stuff underneath. Air dams work, too. Seems to be at odds with the taller tires, but what can you do?
A cold air induction pipe sometimes helps, depends on the carb jetting, among other things.
Run the spark advance a bit ahead of specs.Just remember not to floor it when its over-advanced, it'll rattle like crazy and melt pistons. The 472 is probably pretty high CR so this might not be a good idea.
Hope some of these ideas work for you. If not, just drive that beast like you married an Arab!