Hey people what grade gas are you using and which is better for these old engines.......Also will dual exhaust help with the gas mileage?

 

dont know bout the gas, but duals will help with ur milage

 

The cheap stuff. Actually, mileage-wise it makes no difference a'tall, but cents per mile it does. Your engine isn' old enough at circa 1978 to have any "old engine issues" (ie, it was designed for unleaded gas - and engines designed for leaded gas (with soft valve seats) don't get any help from high-grade gas - they either need external gas additives or new, harder valve seats).

Aside from price, the difference in grades of gas is not "quality" or "energy", it's resistance to detonation (or knock). If you have a high-compression racer-boy setup (as opposed to a standard truck engine in stock truck setup), you might need a grade other than cheap to keep the engine from knocking. If the engine does not knock on the cheap stuff, you don't need anything more expensive, and you don't get any benefit from the more expensive gas.

...and that's internal combustion economics 101, demystification of stuff the gasoline companies try to confuse you with in their advertising.

Otherwise, check the basics - clean filters, plugs up to snuff, tire pressure correct, etc. Also driving style - accelerate slow, decelerate slow, don't stomp on the gas and stomp on the brake.

 

Well just got it a few weeks ago.... haven't put alot of miles on it...... Hasn' t been used mainly on 2 different farms in the area so low mileage...99704 right now....... just changed plugs and wires...... sounds alot better..... heard that the previous owner ran the high test in there..... I am almost done a tank of the regular stuff....... don't hear any knocking...... does dual exhaust help with the mileage...... haven't seen many different air intake for this year of truck...... are those K&N air filters worth the money for this year of a truck?


Thanks for the help......

 

Having dual exhaust won't really affect the gas milage, but the type of mufflers you are using might. If you are running straight pipes or glasspacks as opposed to regular mufflers it will hurt your gas milage. The little bit of backpressure from the mufflers helps the engine make low end torque so you can accelerate easier from a stop.

A drop in k&n filter is a waste for the money it costs, if you can buy or make a cold air intake it should help.

-Jon

 

if you can buy or make a cold air intake it should help???

I haven't heard of this...
so really does exhaust mod not give better mileage?

 

as for octane level go as low as you can with out your engine pinging hard enough that the knock sensor causing it to retart timing. the lower the octane the more power....octane rating is there to tell you resistance to detonation...hi octane..hi resistance...so ...go as cheap as you can....but do this after yo umake sure your injectors are clean. good luck!

 

Another thing is driving habits...I have a '96 F-150, 5.0 liter and I've found that my best gas mileage is right at 55 mph. Experiment with it and check your mileage to see where it gets the best mileage. Mine is at 55 mph, don't know if that's due to engine design or the way it was broke in. Try it....hope that helps
GradyJ

 

if you really wanted to go for MPG, put in a vaccuum gauge. Hook it up to the intake manifold and mount it in the cab. Watch the needle as you're driving and try to keep it as high as you can (within reason) at all times.

 

I've noticed the same thing, and I drove coast to coast this summer so gas was a big expense. The difference between 90kph and 100kph was huge, 900km on both tanks vs 750. I did one run at 120 (70-75mph) and had to fill up after only 500km. Keep the needle straight up and down and she drink a lot less.

I've got a '94 F-150, I6.

 

With stock timing and no mods there is no reason to use a higher grade gas, but if you push the limits of timing you may need to. On my '95 302 truck I actually coaxed slightly better mileage out of premium fuel and more advanced timing, but not enough extra to make it worth the price differential. At the time gas was cheaper, so it might pay off now. In my case I was looking for more performance over mileage, so set the timing back to a regular gas grade friendly setting.

I'll also agree that on the highway my mileage changes quickly as speed increases. In my case it seems to be at around 60-65, but I have a tall rear end ratio and also a bed cover. If I'm over 65 I may as well drive 75-80 because the mileage drops quickly.

 

[QUOTE=Ecnerwal]...and that's internal combustion economics 101, demystification of stuff the gasoline companies try to confuse you with in their advertising.QUOTE]

Yup!


The reason being is it is the most effiant RPM at that gear. Usally somewhere between 1300 and 1600 RPMs in top grear will net the highest MPG.

 

so adding a vacume gauge really works?

Are they easy to instal?

Where do you buy them?

 

i have a 93 long bed 5.0 and i am getting only 550 out of both tanks at 70-80 mph so it is what it is

 

Yes, Yes and Summit. (autometer).


they work because you can then monitor the load. More load on the motor less vacume. Less vacume means more fuel pressure which means crappy gas milage.