Mileage Quest 2011!

[cdeal28078]

That is pretty decent gas mileage wyowill.
I've often thought about this.
Back then gas was still gas. You know what I mean? It smelled like gas and it burnt like gas. It actually didn't smell as bad as it does now. In 74 they were just going over to that nasty smelling unleaded mess we call gas today. Back then you couldn't throw a cigarette into a can of gas without it going up. I can't say I have tried it but I bet you can today. I remember when gas had a red tint too it and Premium actually had a pretty good smell to it. Ya'll remember that? I just wonder if gas was more flammable back then giving us more mpg than the so called gas we have today.
Today the gas just plain stinks. Only the gas with up to 10% alcohol in it smells a little less bad but it still stinks to me also. I hate filling the tank with gas these days. It smells worse than rotten eggs and sticks to your hands even after you wash them.
Clint

[fomocoguy]

Way back when we were all a bunch younger( 1974) I ordered a new F 100 SWB 4x4. It had a 360 , NP 435, 7.00-15 tires and whatever ratio was standard. Drove 122 miles round trip to job at mine. If we kept under 65 Hi-way patrol wouldn't bother us. Seems like New'blue averaged 14-15 MPG. (Ol'blue was a 1968 4x2 SWB) Co worker sez to me "what you need is headers and a 4 barrel" So, next days off we installed a set of headers (Doug Thorley it seems like) and Corvair Turbo mufflers. He had a Ford cast iron 4 barrel manofold and carb setting in his garage. That was the next step, Piece of Chocolate cake! YEA RIGHT.... Newblue would start but didn't have enough oomph to move. Lets see here 4:00 PM, my day to drive tonight....... off to shop for a carb kit.....no such luck. AHH A new carb...... Only 4 barrel in town was a TINY Holly for a PINTO!!!!!! Seems like it was a 360 CFM. NAPA guy ( Girlfriends little bro) sez "Try it ,If it wont work bring it back" So.... We try it . Newblue ran like a r@ped ape, and averaged under 6 gallons round trip ( big chief tablet and red crayon sez 20+ MPG) Ran steady average for next 3 years til I had a brain phart and sold Newblue for a Peterbilt. Will

I've heard that a 4 barrel will help from a lot of people now. It could turn into one of the mods I do; I just like the way she runs with the two barrel. Sounds like you probably got ahold of a 390 cfm carb. Holley has been making them for decades. Seems how the factory carb is around 320 cfm (I think) I can see how it could work ok. I had been thinking about a 500cfm edelbrock, but nothing serious yet. I've got a rebuilt 600 Holley and a 600 Edelbrock that might fund something else if I put them both on ebay.


EDIT: I just ran my engine through a few carb cfm calculators and they all say I need about 390 cfm. You may have something here. How did your truck do pulling a trailer or loaded down? I just don't want to lose any low rpm torque.

[woods]

A 390cfm carb will run VERY well on a lower rpm engine when tuned right. Your bottom end will increase. The 390 is kind of an expensive carb new though. You can make a universal Holley 1850 600cfm work pretty darn good on your engine. One thing about a vacuum secondary carb like the 600...the secondaires don't open all the way unless you have a very light spring in the seconday diaphragm, so they are actually less than 600cfm for the most part. The 1850 is a bare bones carb, but works very good when matched to your engine. Something to consider if you want to save a couple bucks.

[fomocoguy]

Another thing is that if I were going to switch carbs to a 390 I would just find one on ebay and rebuild it. I've always had pretty good luck rebuilding Holleys.

[1971ford]

Best thread ever. Once you are near the end of all the upgrading I plan on starting from page 1 and copying everything you did, I have a little advantage as well being i don't have a crewcab. Otherwise, we will be almost identical.


How do you drive? Super slow? or pretty normal? I drive my highboy incredibly slow (Take my sweet time getting from 0 to speed limit), plan out how the lights are cycling from a mile away so i can let off, etc... It's pretty much an art. Anyways, Since driving is the biggest affect on mileage it would be interesting if you could try to describe how you drive. Do you have a tach? when do you shift?

Oh, and the best part about me driving really slow, is in the end, I am very often "faster" than the ones mashing the pedal. They'll be at the red light they rushed to and I'll have it planned out a ways back, so as soon as the light goes green I blow by mr. speedy, as they lose mileage by accelerating. I think about mileage too much...

[fomocoguy]

Best thread ever. Once you are near the end of all the upgrading I plan on starting from page 1 and copying everything you did, I have a little advantage as well being i don't have a crewcab. Otherwise, we will be almost identical.


How do you drive? Super slow? or pretty normal? I drive my highboy incredibly slow (Take my sweet time getting from 0 to speed limit), plan out how the lights are cycling from a mile away so i can let off, etc... It's pretty much an art. Anyways, Since driving is the biggest affect on mileage it would be interesting if you could try to describe how you drive. Do you have a tach? when do you shift?

Oh, and the best part about me driving really slow, is in the end, I am very often "faster" than the ones mashing the pedal. They'll be at the red light they rushed to and I'll have it planned out a ways back, so as soon as the light goes green I blow by mr. speedy, as they lose mileage by accelerating. I think about mileage too much...

I would say I drive pretty normal for what I'm driving. There are plenty of cars passing me from a light, but not all of them. I just basically drive in a way that feels right for my engine and truck. I rarely rev it over 3k rpms unless I'm on a long on ramp and I'm going to merge onto the interstate. That's just by feel since my tach went south and I haven't replaced it yet. Either way, I don't really drive her hard.

[cdeal28078]

I think driving it smooth is important also. Every time you push the throttle 2 streams of raw gas shoot down the throat from the pump. That can add up to a little gas over a 100 miles if you are always on and off the gas.
clint

[wildcard]

A buddy of mine that drives a fuel tanker says the gas all comes from the same tanks at the refinery. And the only difference at his customers is the name on the sign out front.

[TX69F100]

I've heard the same thing from the guys in my area. I've also heard that the only differences at the pump are the additives (cleaners, etc.) that are added by the individual stations.

[cdeal28078]

I know a couple guys in the business and around here in NC the fuel is the same in the main tanks for during the process of filling the tankers the individual companies additives are added.
Finally got a short trip in on the interstate since going from the 3.25 Lock Rite rear gear back to the open 3.0 in my 71 F100.
Feels much better. I cruise at 65 and the RPM's re right around 2300. Perfect for a carbed engine from what I read. Bump it up to 70 and it is right around 2400 plus or minus 50 rpms or so.
Didn't hurt he bottom end a bit with this low compression 460. Feels like I don't have to mash the gas near as much to get up to speed.
clint

[woods]

I know a couple guys in the business and around here in NC the fuel is the same in the main tanks for during the process of filling the tankers the individual companies additives are added.
Finally got a short trip in on the interstate since going from the 3.25 Lock Rite rear gear back to the open 3.0 in my 71 F100.
Feels much better. I cruise at 65 and the RPM's re right around 2300. Perfect for a carbed engine from what I read. Bump it up to 70 and it is right around 2400 plus or minus 50 rpms or so.
Didn't hurt he bottom end a bit with this low compression 460. Feels like I don't have to mash the gas near as much to get up to speed.
clint

I have been considering going to a higher gear myself. I have 411's and even with a 35 inch tire, I am turning 3000 rpm at 70mph. The old 428 has enough grunt to pull a higher gear. Was thinking aout giving a 350(ish) a shot.

[flyboy2610]

I've never noticed much difference in the mileage their gas gets...but I can tell you that my deisel drops a little over 3 mpg with Chevron over just about any old truck stop, which is weird.

Not really. You use more, they sell more. They know what they're doing.

[woods]

I've never noticed much difference in the mileage their gas gets...but I can tell you that my deisel drops a little over 3 mpg with Chevron over just about any old truck stop, which is weird.

Not really. You use more, they sell more. They know what they're doing.

I always try to pretend that's not the case to keep me from going on some massive conspiracy rant, but I think it's a pretty safe bet to assume we are getting scammed. Not all sneaky like either...just a "pay this or don't drive" kinda deal, or "we know we are ripping you off, whatcha gonna do about it." Well, I'll whine about it to everyone, but other than that, not much.

[QC]

Well, I finally got a good run in this morning. Since the last run I've installed the electric fan and 195* thermostat, pertronix kit I had on the shelf, plus a new timing chain and high flow water pump. Todays numbers came in at 13.2 mpg. I finally busted out of the twelves! I was starting to wonder if that was ever going to happen. So, here is a break down from day one.

Running strong but worn distributor- 6 mpg

New distributor, finely tuned, and 12* BTDC- 12.6 mpg

3g alternator install- 11.4 mpg

Electric fan and 195 stat- 13.2 mpg


Unfortunately I don't like the way the engine runs at 200 degrees, so I think I'm going to put the 180 back in it. During the summer on a hot day and a long drive it would tick as if a lifter is bleeding down at idle when it had the 180 in it; now it does it after 30 min of driving on a 60 degree day. Hopefully it won't hurt the mpgs too much. I can say that I'll put the 195 back in for the winter months. My heat is awesome right now!

My next move will be the 180 stat and then some timing play. A friendly member here peaked my interest in switching my vacuum advance over to full manifold vacuum and increasing the timing some more if I can get away with it. It won't cost me anything, so I'm going to try it. Last time I messed with the timing I gained 6mpg, so it would make sense that it could help more. If some is good and more is better, then too much is just enough, right?

Manifold vacuum is backwards for the vacuum advance. Manifold vacuum vacuum is highest at an idle and drops when the throttle plates open. Ported vacuum (where the vacuum advance connects) is very low at idle and increases when the throttle plates open. If you hook the vacuum advance to manifold vacuum you will get full vacuum advance when the engine is idling.

[woods]

Well, I finally got a good run in this morning. Since the last run I've installed the electric fan and 195* thermostat, pertronix kit I had on the shelf, plus a new timing chain and high flow water pump. Todays numbers came in at 13.2 mpg. I finally busted out of the twelves! I was starting to wonder if that was ever going to happen. So, here is a break down from day one.

Running strong but worn distributor- 6 mpg

New distributor, finely tuned, and 12* BTDC- 12.6 mpg

3g alternator install- 11.4 mpg

Electric fan and 195 stat- 13.2 mpg


Unfortunately I don't like the way the engine runs at 200 degrees, so I think I'm going to put the 180 back in it. During the summer on a hot day and a long drive it would tick as if a lifter is bleeding down at idle when it had the 180 in it; now it does it after 30 min of driving on a 60 degree day. Hopefully it won't hurt the mpgs too much. I can say that I'll put the 195 back in for the winter months. My heat is awesome right now!

My next move will be the 180 stat and then some timing play. A friendly member here peaked my interest in switching my vacuum advance over to full manifold vacuum and increasing the timing some more if I can get away with it. It won't cost me anything, so I'm going to try it. Last time I messed with the timing I gained 6mpg, so it would make sense that it could help more. If some is good and more is better, then too much is just enough, right?

Manifold vacuum is backwards for the vacuum advance. Manifold vacuum vacuum is highest at an idle and drops when the throttle plates open. Ported vacuum (where the vacuum advance connects) is very low at idle and increases when the throttle plates open. If you hook the vacuum advance to manifold vacuum you will get full vacuum advance when the engine is idling.

Yes and no. You want your truck to have a lot of advance and idle, it makes it run smoother and the throttle much more crisp. The only difference between hooking it to manifold vac vs. ported vac is the right off throttle action. The vacuum drops as you give your engine throttle under load no matter where it is hooked. This drop of vacuum pulls some timing out of it, When under load, the vac advance has no bearing on timing. which is what you need when under load so it won't get pre-ignition clatter. The ported vacuum was really nothing more than a very early attempt at smog control. A rig idles cleaner when the timing is retarded.