Fuel Economy and $4 gas...

[SBTork]

when you get out of the shop, start posting pics and more info , can't wait

[D-Day]

I just got back from St. Louis (470 miles), and driving home I got 16.4 mpg on one tank, which included a lot of heavy driving over 75mph; sometimes to 90+. Average mileage for highway driving at 80mph+ is 15mpg.

1973 Chevrolet C2500 crew cab

Engine: 400 V8
Trans: 700R4
Gears: 3.73
Drivetrain: 2wd
Fuel delivery: Edelbrock carburetor

[8T3GMC]

Na thats about the normal running on 350's I got the new GM Goodwrence moter and that is what i am getting but I also got a lead foot. But something that might help you is that holley 650cfm Spread Bore. Yea I know your thinking I don't want to buy a carburater. But that carb is made for the economic aspect. Me and my brother were going to make mine and tone it out the butt for performance. But Its not made for performance. without the lead foot, I would maybe get 11 or 14 miles a gal. Someting that will help to if your not doing thia already is the 93 grade gas. If you go with it, it makes your run a little bit better and helps gas milege too.

[piecesparts]

Originally Posted by D-Day

I just got back from St. Louis (470 miles), and driving home I got 16.4 mpg on one tank, which included a lot of heavy driving over 75mph; sometimes to 90+. Average mileage for highway driving at 80mph+ is 15mpg.

1973 Chevrolet C2500 crew cab

Engine: 400 V8
Trans: 700R4
Gears: 3.73
Drivetrain: 2wd
Fuel delivery: Edelbrock carburetor

You are gonna upset those guys that say the Edlbrock carbs are not for the street. Good job, especially running greater than the speed limit.

[Kixwy2]

Originally Posted by 8T3GMC

Na thats about the normal running on 350's I got the new GM Goodwrence moter and that is what i am getting but I also got a lead foot. But something that might help you is that holley 650cfm Spread Bore. Yea I know your thinking I don't want to buy a carburater. But that carb is made for the economic aspect. Me and my brother were going to make mine and tone it out the butt for performance. But Its not made for performance. without the lead foot, I would maybe get 11 or 14 miles a gal. Someting that will help to if your not doing thia already is the 93 grade gas. If you go with it, it makes your run a little bit better and helps gas milege too.

Not a lead foot driver (until someone's creative driving pisses me off - ) but I'm all about efficiency. Now, I thought the q-jet was made for fuel economy and performance and was best-in-class? At least a bunch of car guys tell me so... since this is my first carbed vehicle, I've got nothing to compare to. I didn't find the rebuild all that hard even though everyone else gripes about the Rochester, so who knows...

Do you think I could do an octane boost over the 93 grade gas? I oughta smack my head for not remembering that regular used to be 91 octane!

[8T3GMC]

Well part of the promblem with the Q-jets is that they were made and toned to one truck or car, once they go bad they normally stay bad. If you boult the rebuilt one at autozone or advance auto parts or anywhere else like that you would have to buy three or four or even more Q-jets to work right. I bought one and then said forget it. Thats when I went to the holley Q-jet replacement.

It will help to move up to 93. Its more on the price but you get a extra mile or so.

[Thumpin455]

Qjets common malady is worn throttle shaft bores that allow air to leak past. Its relatively easy to fix with brass bushings and enlarging the holes a bit for them. Another thing is main well plugs leaking, some will some dont, and they are easy to fix by tapping the hole and installing a plug made from ready rod with a slot cut in the end for a screwdriver.

Next on the list is people tearing them apart and forgetting things/leaving parts off, or putting things in that shouldnt be, and using cheap parts, like the needle and seat.

If the float level isnt right, it wont work right because the calibration is set up for a particular fuel level. Too low and the fuel takes longer to reach the venturi, to high and it will pull fuel at idle and too much all around. People will try to compensate for it by moving jets and metering rods around when its something as simple as float level. Its the base setting on the carb and all others are dependent upon the float setting.

Buying a reman isnt wise because they just slap stuff together and use the cheapest parts they can find. You will find cross threaded screws and fuel inlets, cheap needle and seat assemblies, and metering rods of differing sizes. All the parts go in a big pile, and they just grab some and stuff them back in. It costs more to put them back the right way than it does to rebuild the one you have, including buying the bushings and throttle plate screws.

Qjets are a great carb, and they will make power with economy. If you dont know anything about carbs, or very little, or simply dont understand how they work, you will probably have a tough time with one. Some people really screw up Holleys and they are brain dead simple, but you still need to know how they work to be effective at tuning or rebuilding them. If you really want to know how to rebuild them correctly, and how to tune them, pick up the book by Cliff Ruggles.

If you have a low compression engine, under 9:1 static, then running premium fuel is a waste of money for you. It wont help you make more power, or get better mileage unless your engine requires it, and that is mainly dictated by compression ratio. A few other factors come into play, but CR is the main one. If you have 8:1 or lower you can run any camel whiz gas out there, and most 73-87 engines have compression that low, or lower. You get a better return from making the vehicle roll easier than you will from running premium 91-93 octane gas. Up here its $.40 more for 92 and it stinks having a vehicle that requires it.

The rain has let up here, so I can get the truck in without flooding the shop.. Right after I get this transmission rebuilt for one of the Fords..

[884x4Sub]

very interesting thread.......!

[1BadSS]

MPG definately shouldn't be a concern if you're driving a truck this old. Luckily for me, my 07 SWB with a 5.3, gets 24mpg down the highway with the AC on running on E85 @ 2.49/gal.

[884x4Sub]

Originally Posted by 1BadSS

MPG definately shouldn't be a concern if you're driving a truck this old. Luckily for me, my 07 SWB with a 5.3, gets 24mpg down the highway with the AC on running on E85 @ 2.49/gal.

Im old enough to remember my buddy getting 18 to 20 on a regular basis in a 71 Olds Delta 88 with a 455 and a Q Jet......and if you could find a stretch long enough it would wrap the 120 mph speedo back to 0......just trying to figure out how that worked.

[884x4Sub]

Originally Posted by 8T3GMC

Well part of the promblem with the Q-jets is that they were made and toned to one truck or car, once they go bad they normally stay bad. If you boult the rebuilt one at autozone or advance auto parts or anywhere else like that you would have to buy three or four or even more Q-jets to work right. I bought one and then said forget it. Thats when I went to the holley Q-jet replacement.

It will help to move up to 93. Its more on the price but you get a extra mile or so.

how do you like your Holley Q Jet replacement??

[Pyrotechnic]

I think a 700R4 and appropriate rear end gears are one of the biggest factors in fuel mileage. If you have a stock to mildly built motor, a stock rebuild with the usual fixes done by a competent builder will prove strong and not break the bank. For the typical street driven truck with around 28" tires, 3.42 to 3.73 are a good place to start.

I ran a Holley Reman Q-Jet on a stock 350 rebuild, cheap long tube headers and turbo mufflers, Turbo 350, and 3.42 gears. Got 14-15 MPG city and highway. I did a cam swap and it started to lean miss like crazy with the same carb. This should give you an idea how of close that carb was tuned.

The numbers for that Crew Cab are impressive. New crew cabs don't even do that good.

[D-Day]

I've thought about upgrading to an Edelbrock fuel injection conversion.

The 700R4 upgrade was the biggest thing I could do to improve fuel mileage at the time, and since I already have 3:73 gears, I'm thinking about fuel injection. Not sure if it's worth it or not.

I know the transmission has been worth it. It's saved me a lot of time and gas on long trips, compared to the old TH350. Doing 2700-2800 RPM at 65mph for 9-10 hours to get to St. Louis was not fun.

[James McClure]

D Day: Wheather or not it's worth the expense all depends upon what your actual savings over time will be. If your doing a lot of driving the payback or break even point will be sooner, but at that point I might be asking myself about using a computer controled diesel with mileage approaching 30 MPG. When I was working I drove 500 miles a week and thought about a different vehicle for transportation. Now that I am disabled and don't work it doesen't matter because I don't drive 50 miles a week. Each of us has different circumstances, different driving styles and different expectations of what good mileage is, so all of us are going to look at this issue in a different light.
One thing is sure, no one likes it. Reasons for the high prices run the gamet from Gov't conspiricy to mid east countries jacking us up & oil company price gouging. The trurh is, it's probably all 3. A fellow named Oldsmobile built the first car in 1898 and a couple of bicycle mechanics named Wright built the first airplane, who knows what some backyard mechanic will come up with where fuel is concerned. There are lots of schemes out there, but none are viable in the long term or are economically practicle at this point at our present level of knowlege. Hydrogen holds the greatest promise for cheap, plentiful, non poluting and renewable. Comments welcome, e-mail me. jmcclur2@nycap.rr.com. jim

[Thumpin455]

Hydrogen looks like the best solution, getting people to use it will be akin to getting them to appreciate nuclear power plants. Hydrogen is easy to produce, burns clean, makes plenty of power, and can be made relatively cheaply, but people still think Hindenburg when they hear it, as if gasoline isnt explosive.

I know a city engineer from Milwaukee, he tells me the city is switching to hydrogen for power. It actually isnt long before it starts reaching into other areas.

As a retrofit to vehicles it would be similar to running propane on a gas engine, so it isnt difficult or beyond reason that we could power our old trucks with hydrogen. I am all for it, but in the meantime I am exploring what I can do on my own.

Just like Jim I am disabled and dont have to commute, so its different for us. That makes it possible for those like us, who cant work but can still use our minds, and do some of the work needed, to figure out some new solutions. That doesnt stop those of you who still work 40+ a week from doing things to help yourselves, but not everyone knows where to look, or what will produce a decent result.

My point is, doing it yourself rather than paying someone to do it for you, should be part of your thinking. Change your lifestyle a bit, do some research, learn something new, and take the time you spend watching TV and apply it towards making your life better. Fix your truck yourself rather than taking it to a shop. There are a ton of things you can do to improve your vehicles efficiency. Each vehicle has some that are the same, and some that are specific, and making a 1% improvement on 100 things is easier than making a 100% improvement on any single thing. The smallest details will have an effect on the overall picture. Get enough improvement from the small ones and you will see a larger improvement overall. Doing the work yourself will take some of your time, but it should be enjoyable to achieve an improvement with your own hands.

If you already do the work yourself, then concentrate on minimizing friction and rolling resistance. Even people in emission nazi states can do that. If you can make changes to your engine and drivetrain, getting your engine to make more torque between idle and 3000 rpm will get you better mileage. The bonus of making more torque down low, is it is also more fun to drive, pulls easier when you tow, and you dont have to plan out passing the geriatric couple who are tooling along at 40mph.

Even if we can switch to hydrogen, unless you can produce it yourself you will have to pay someone for it. The days of cheap fuel are pretty much over, so making the vehicles we have now more efficient is in our best interests, no matter what they run on. DIY is the way of the near future, and there will be homework involved. You are going to have to learn some new things, or you will be riding the bus or taking the shoe leather express. I can help you learn, and I will help out if you ask, but you will have to put forth some effort too.

[Thumpin455]

Decided to break up my thoughts so the posts arent so epic.

I wish I could show some progress on my 76, but funds have kept me from doing anything substantial. Keeping the daily drivers running has been fun and expensive too. Unlimited time seems to mean limited funds. The weather is getting better so more can get done that doesnt require money, but it costs money to improve vehicles. I still need to get it registered again, but once I do I can show the improvement each change makes, and of course share that with you guys. Still working on this stuff, it just takes me a while to get things done.

[James McClure]

Thumpin: Contrary to common belief, hydrogen isn't yet cost effective. Hydrogen production requires electricity, lots of it. The amount of power (electrical) required to break water down into H and O2 excedes the energy produced when the H and O2 are recombined into water. The result is a net loss of energy. As it stands now, hydrogen production will only increase CO2 emissions from power plants producing electricity. The towns that are using hydrogen don't tell you the hydrogen they are using is really a derivitive of hydrogen, Methane. Methane is a gas produced during decomposition of bio-mass and is collected from sewer systems and dumps. The stuff is akin to propane, and it works quite well. There is a chicken farmer up here that produces his own for heating and cooking from chicken crap. Out at sea there are HUGE deposits of Methane Hydrate just waiting to be harvested. The question is how and at what cost. Estemates are there is enough energy in this hydrate to fill ALL the worlds energy needs for over 200 years. Problem is, it's still a focile fuel and produces CO2. Hydrogen on the othe hand produces no byproducts other than pure water and some NOX. Hydrogen answers so many questions, or will answer them as soon as technology shows us how to make it cheaply and cleanly. jim

[D-Day]

Originally Posted by James McClure

D Day: Wheather or not it's worth the expense all depends upon what your actual savings over time will be. If your doing a lot of driving the payback or break even point will be sooner, but at that point I might be asking myself about using a computer controled diesel with mileage approaching 30 MPG. When I was working I drove 500 miles a week and thought about a different vehicle for transportation. Now that I am disabled and don't work it doesen't matter because I don't drive 50 miles a week. Each of us has different circumstances, different driving styles and different expectations of what good mileage is, so all of us are going to look at this issue in a different light.
One thing is sure, no one likes it. Reasons for the high prices run the gamet from Gov't conspiricy to mid east countries jacking us up & oil company price gouging. The trurh is, it's probably all 3. A fellow named Oldsmobile built the first car in 1898 and a couple of bicycle mechanics named Wright built the first airplane, who knows what some backyard mechanic will come up with where fuel is concerned. There are lots of schemes out there, but none are viable in the long term or are economically practicle at this point at our present level of knowlege. Hydrogen holds the greatest promise for cheap, plentiful, non poluting and renewable. Comments welcome, e-mail me. jmcclur2@nycap.rr.com. jim

I've thought about a modern full diesel conversion. But that, would take probably $7,000+. As for fuel injection, if it just bumped my mpg up to 17-18mpg, that'd be worth it to me. It doesn't "have" to pay itself off immediately, because I just like improving my truck and changing things in general. So getting a few more mpg would be a huge bonus.

[Pyrotechnic]

The problem is....hydrogen is a by-product of the refining process. So instead of oil companies selling oil, they can sell you hydrogen instead, for the same energy content per volume price as gasoline or more. 3rd world countries or the other petroleum hog we know as China, aren't going to be converting to hydrogen any time soon so it's very win-win for the oil companies. Sell them petroleum, sell us hydrogen.

Better for the environment yes, but it's still going to be the same situation for your wallet.

[Ivan D.]

For those using their trucks as daily drivers, have you considered a diesel engine? I used to drive an 11:1 CR 429 big block in a jacked up truck with 35s, that thin required premium gas and best I saw from it was 10-11mpg at 55mph, around town it was right about 5mpg all the time - needless to say it got real expensive real fast, so I traded it for a 7.3 diesel dually - now this beast gets 10-12mpg city if I floor it, freeway tis 18-20mpg depending on head wind. Sure diesel fuel is more expensive that gas, but at the current prices it compares to 10mpg city and 17mpg city on regular 87, and keep in mind that my overall weight and rolling resistane are comparable to the crewcab mentioned above. You guys can easily find a 6.2 in good condition and run that, when properly tuned you should have no problems reaching 20mpg freeway as well, likely more if your truck is a regular cab with single rear wheels and no fat tires. As a matter of fact when money allows it my daily driver would be a late-'70s shortbed stepside (like I used to have) with a '92-'93 diesel (factory turbo, mechanical injection), 5-spd bolt-action, 1-ton SRW running gear with 3.55 or so gears, and stock-sized tires - that oughta be good for some mid-teens city and mid-20s on the freeway

[Thumpin455]

Originally Posted by James McClure

Thumpin: Contrary to common belief, hydrogen isn't yet cost effective. Hydrogen production requires electricity, lots of it. The amount of power (electrical) required to break water down into H and O2 excedes the energy produced when the H and O2 are recombined into water. The result is a net loss of energy. As it stands now, hydrogen production will only increase CO2 emissions from power plants producing electricity. The towns that are using hydrogen don't tell you the hydrogen they are using is really a derivitive of hydrogen, Methane. Methane is a gas produced during decomposition of bio-mass and is collected from sewer systems and dumps. The stuff is akin to propane, and it works quite well. There is a chicken farmer up here that produces his own for heating and cooking from chicken crap. Out at sea there are HUGE deposits of Methane Hydrate just waiting to be harvested. The question is how and at what cost. Estemates are there is enough energy in this hydrate to fill ALL the worlds energy needs for over 200 years. Problem is, it's still a focile fuel and produces CO2. Hydrogen on the othe hand produces no byproducts other than pure water and some NOX. Hydrogen answers so many questions, or will answer them as soon as technology shows us how to make it cheaply and cleanly. jim

That is the big drawback right now.. Relatively cheap is kinda misleading, sorry about that. If only there was a way to make electricity without burning fossil fuels... yeah I am being sarcastic there.. I am a fan of nuclear, wind, solar, geothermal, and pretty much any other passive source of electricity. Not that Nuke plants are passive, but getting power from nature is a good idea.

I have been working on a design for a wind generator built out of parts I have left over, I plan to use it to heat my shop in winter, and hopefully heat the still in summer. If it works, I can build a larger one to power my shop, and possibly parts of my house. Once I get the bugs worked out I would be more than happy to help others with it.

Imagine the fuel we could be getting from feedlots and hog confinement, in addition to chickens, turkeys, and any other animal that is penned up and raised for food. Growing up on a farm you learn about those things, but while gas was cheap, it wasnt worth the time to do it. Now its getting to the point of being worth it. The problem is most farmers I know dont have livestock anymore, things are changing for them.

Weather is nicer here this week, should be in the 50s. Once I get the paint fixed on the 67 Cougar, the truck is going in the shop. I need a parts runner that can pull a trailer. So it will get finished and legal. Once that is done I can start collecting all the parts I have been scrounging for the still. Hopefully in June I can afford to do some engine work on the 76, a cam and intake swap. For a 454 it sure has low torque, I plan to remedy that. The cam going in has 226/234 duration @ .050 and is quite similar to the cams I run in my big inch Pontiacs. Plenty of grunt available with them, and I can use a stock converter. It should wake the truck up plenty, increase torque across the entire RPM range, and that will make the truck easier to move. This works with my old 7.4L cars, why not a truck?

Well whenever I get started on it, I will make a thread about it. Plenty of pics with a paragraph on the back of each one explaining what each one is. I figure I can set up a rig where I can put half a gallon of gas in a can, and feed the carb with that. Then its a matter of counting miles until it runs out, hook up the regular tank and make it back home.. That way its close to scientific and I can get some decent numbers to show the improvements. Wont be able to vouch for emissions though, we dont have sniffers up here.

I have been waiting to do things like the brakes and alignment until I can show how much difference it can make. That will be included at some point. James why dont you make some changes and see what you can get out of them? I am sure you can find ways to improve the truck? You have pretty much the same background I do, mechanically anyway.. I would say we could see who can get the biggest gain, but my truck is currently a pig, so it wouldnt be fair.

[884x4Sub]

Originally Posted by Ivan D.

For those using their trucks as daily drivers, have you considered a diesel engine?

been there.....everything is fine with a modern diesel until something goes wrong.......then LOOK OUT!!!......did you know the price of ONE fuel injector for a dmax is like $385!!!!....the Ford is right there too.......for one! and that does not include installation.......injection pumps....another thing again......the 7.3 is probably not bad as its an older design but you cant buy them new.......youd be insane to own any modern diesel truck off warranty .......that and the considerably higher initial cost coupled with the price difference between diesel and gas alot of guys are going with gas unless they are pulling over 12,000 lbs......my next door nieghbour has an 04 6.0 Ford in a F250......it has had $35,000 woth of warranty repairs......imagine if that had to come out of your pocket!

which brings me to the reason "why am I here?"......got sick of my diesel and its repairs especially since my truck is not a daily driver I use it for towing.......bought my 87 for 3Gs off ebay......I'll paint it up in black and get a 400 sb built for it and keep it forever......fix it myself for dirt cheap in parts

btw 1994 GMC Suburban 2500 SLE Diesel 4x4 for sale......black on grey
leather, 4" exhaust, pillar gauges $7500

[Ivan D.]

Oh, modern diesel suck big time, sure they make gobs of torque, but they have to comply with some nasty emissions standards, as a result of which their fuel economy goes right down the porcelain throne - last time I was filling up there was a lady with an '08 F250 at the other pump, she complained she only gets like 16mpg with her truck, 18 at best, and that's actually typical for most modern diesels, whereas I can easily hit 20mpg and still have place for improvement. What I was talking about when I mentioned diesel was the older IDI diesels, the ones with teh Stanadyne DB2 mechanical injection pump - that one only costs like $300-400, injectors are fairly cheap as well and can actually be serviced at home. Sure an IDI diesel won't be a power monster, but even if you only get 300 lb-ft you got that from 1500 all the way up to wherever your IP governor kicks in, with my dually I'm cruising at max torque pretty much all the time. Added benefit is that very few of these trucks got catalytic converters, so you're pretty much free to do whatever mods you feel like without fear of the emissions nazis - big exhaust, turbos, water/methanol/propane injection, whatever, as long as your opacity checks out you're all set.

Edit: and yes, the 6.0 is a nasty engine, in the sense it sucks for repairs and reliability.

[chevyfan87]

now, i dont have the patience to read all of this but....im looking at buying an 81 with a 305 2bbl bone stock just has headers and dual exhaust, what should i expect for mileage? after i drop on a performer manifold and performer 600 carb? just looking for ideas

[Ivan D.]

I'd throw in 15mpg at best on the freeway, cause that seems like a common number for these trucks.