Building a "Fuel Saver" Engine

[Anonymous]

OK, I've built my "go fast, who cares about gas mileage" engine, that sadly lost it's life to an overheat (moment of silence, please ), but now I want to build a mpg friendly car.

The car now has a internally stock engine in it now with my performance exhaust (Cliffy single out header, hi flow cat, and a generic turbo muffler with 2 1/4 pipe) on it and my full MSD Duraspark igntion setup (coil, 6A, Taylor wires, adjustable timing Duraspark module, beefier ignition wiring harness, stock Autolite Platinums) and it's getting about 20-24 mpg.

What other modifications can I do to get better gas mileage?

!. What would be a good fuel saver cam? I still have my Cliffy 264 cam from the old engine, but don't think it's a good choice for my plans.

2. Should I stick with the little air sucker 1946 Holley? Or should I swap my Holley 2300 equipped head on?

3. I have 3.73s in the 7.5 now and know that dropping to a lower gear would raise the mileage. I don't want to drop below 3.00, but I'm not sure which gears would be best with my stock C4.

Keep in mind that I'm not going for performance this time, this car is a daily driver and I never did drive it like it was anything else. Even with all the go fast parts it never got driven with a lead foot all the time.

Ok, Ok, I lead footed it home sometimes but that was a rare occurrence!

 

[Anlushac11]

8)

I would go with a stock or 252 deg cam.

I would mill the head to raise the compression a bit

I would also keep the stock 1 bbl carb.

A K&N airfilter

Synthetic lube in engine, trans, and rear end. 3.08 rears should be plentiful. My 80 came with a 2.73 and it has a 200 and C4.

When I first bought it and tuned it up and ran synth lube and new airfilter I was getting close to 28-30mpg. I also was only guy driving 60mph on the interstate. I also ran tires about 5 lbs over inflated.

Changing timing can also affect fuel economy but I cant recommend any settings.

My '80 Stang also has P215/60HR-14's and they grip really well. Running a bigger tire is not always best and especially not for mileage. Big tires can create more drag and rolling resistance.

Dropping the height of the car by an 1" and washing and waxing it to reduce drag will also improve fuel economy.

And remove as much weight out of car as possible without affecting comfort or safety, As in clean out the trash and out from under the seats.

 

[xctasy]

Do all the above. But read David Vizards article in this book on fuel economy, if you can get it. http://www.dukevideo.com/Products/H620.htm

The batty English-man took a little Mini with a 78 cube engine, shoved in a 270 degree cam, a full race exhast valves, the best intake manifold money could buy, and one single carb and a great intake air cleaner set-up. The ignition was electronic and optimised, the exhast was a very big race item, the diff ratio was sky -high, and the tires were 165/65.12's of a very low rolling resistance. The intake ports were left as cast (but the head wasn't plagued with an integral intake...but it was siamesed at the ports. The rockers were a higher ratio, the compression was way high, and it ran water injection. 53 US mpg at 65 mph with a vehicle with the areodynamics of a brick. It did a tour of the USA in the mid 1980's.

In my opinion, the Weber ADM 34 2-barrel is the most economical carb, and it was used on Aussie Falcons. Some were of a feedback kind, so it wouldn't invalidate your inspection if you had it...its got no CARB sticker or EO number, though. If it were my US car, I'd look at doing a carb swap too.

The transmission could be replaced with a T-bird C5, with some advantage to economy. In Australia, auto 3.3 Falcons ran 2.92:1 diffs with 185R14 tires. So, a 3.00:1 diff would be perfect.

In NZ and Australia, Total Economy Run Falcons tripped the US 29 mpg mark at an average of 55 mph in a heavy 3000 pound 79-80 Falcon with 1-bbl carb. The later 2-barrel was even more economical.

 

[Anonymous]

I remember reading an old article that was on the web about hot roding the little six. One part of the article discribed using 2 SU 1.5 inch carbs, they said it made power and greatly increased mileage.

I remember it was in black and white and I think it was Art Carr that did the work. 1963ish

John

 

[xctasy]

Yeh, that was the first incarnation. Clive Tricy did an early Mini book in the 1970's. Then DV did one, and then it got revamped as a version 2, and now 3.

The guy is a typical theoretical British engineer...but one who got his hands dirty, and discovered V8 engines. If you go over his books, he has an airflow management focus which has allowed me to predict horsepower and torque realtionships of any engine combination. His Car Craft articles have the same maths base, but if you are interested, the math is not hard.

He initialy found the Twin Carbs of a 4-cyl Mini were a good idea, then found they were not as good as one big carb, and then designed his own intake which out performed twin Weber/Dell'Orto set ups. All because of his testing and data collection. The porting and chambers of the first editions were totally different to the later versions.

If you got the time to read his books, do so. They are significant not because hes always right, its because he knows what makes power, and how to cut to the chase, so your not barking up the wrong tree with your modifications.

 

[x21]

Key to fuel efficiency-> Do NOT drive like me, hahaha
(punching the gas from a stop can't be good :roll: )

 

[Anonymous]

The car now has a internally stock engine in it now with my performance exhaust (Cliffy single out header, hi flow cat, and a generic turbo muffler with 2 1/4 pipe) on it and my full MSD Duraspark igntion setup (coil, 6A, Taylor wires, adjustable timing Duraspark module, beefier ignition wiring harness, stock Autolite Platinums) and it's getting about 20-24 mpg.

That mileage was with the old engine. I'm actually getting 27-29 city, don't drive on the freeway much.

As for the tires I'm rolling with 185/75R14s on a heavy stock steel wheel, so I'm going to put on my 17x8 Pony R's (that weigh about 25lbs less each) with 245/45R17 tires. I'm going to be using a bigger tire/rim combo without it being much bigger than stock. Plus it will weigh a lot less.

Timing, I'm just going to leave it at stock. I've never messed with it on my high power engines, I've always like that I could pull alot of power and have no driveability issues.

Weight is not a problem since I kicked my brother out and fixed his car. I've removed the cushions from the back seat (around 60lbs. right there!) and now just have the metal panel. Battery has been moved to the hatch, I reccomend this for everyone. Spare tire is now under the passenger side of the metal panel where the seats were, my CD changer and my emergency supply/toolkit is on the drivers side.

The front of the car is going to be dropped an inch, I've always loved the hot rod stance on these cars! 8) I'm also going to put an another air dam on it, I noticed an increase in my mileage when I had my Xenon one on.

I'll think I'll stay with the Holley that's on it now, and swap it later after my car's last emission test next year. No more emissions testing for me! I am going to fab up an airbox since my scoop is functional, it's also going to have two intake tubes that drop down low to pick up cooler air. A K&N X-Stream flow 11" filter top will be used.

Xecute: I actually have that book, because my father and I rebuilt a Mini engine for a friend who wanted to race his Mini. That little SOB could fly and it routinely stomped imports and domestics alike. Too bad it got stolen before it could be modded further. Future plans for it included nitrous and a turbo.

 

[Anonymous]

I've also had good luck with raising MPG by using a liitle water injection. It increases the effective compression ratio. I get about 1.5 MPG improvement until the bottle runs dry.

The EGR on the late-70s 3.3L has gotten a bad rap, too. It INCREASES MPG under gentle-foot driving conditions by leaning out the air-fuel mixture after the Holley 1946 mixes it up. When you stomp on it, the EGR goes away to give back the full 15:1 mix, but otherwise it runs around 16.5:1 while the EGR is open. This can be adjusted, too, by modifying the size of the washer in the throat of the EGR valve (NAPA sells these adjustable types).

Advancing the CAM timing with help, too - about 2-4 degrees is enough. Add an equal number of degrees to the spark advance if you do this.

Look for a 'yellow grommet' Duraspark in a junkyard (351W late-70s full-sized Fords). Get the little vacuum diaphragm that is connected to it, too. Hook it up the same way in your 3.3L to improve mileage with an electronically-controlled 'floating' 4 degree spark advance. It adds 4 degrees under light-foot conditions, like the EGR, to improve MPG.

 

[goinbroke2]

MarkP...I don't want to sound rude...but;
1)water inj does not raise effective comp ratio period. a)It only allows the combustion process to be unencumbered by detonation.b)It cools the intake charge which will make it denser and able to more fully fill the chamber.
2) The egr does not lean out the mixture. It is re-introducing a previously burnt mixture back into the intake which dilutes the fresh air/fuel mixture.This lowers the temp of combustion, high temp combustion is a big NOX producer.(NOX is bad for smog etc) If you have gained mpg by using it, bravo, but a fresh mixture properly atomized and cooled will always out torque/power/lower bsfc/etc one that is diluted with anything, exh gas or other.
3)Advancing cam timing is great for bottom end and in itself in theory could improve milage by having higher cyl pressure by closing the intake sooner. However, moving the ign timing would be a trial and error process because you don't know what your new cyl pressure is, and, every engine likes it's own amount of timing based on carbon build up/flow bias/chamber design/valve shrouding/etc.
Yes you can generically say a couple degree's, but for best performance you would have to find how fast you can bring in the timing curve,what would be the best initial, and best total.

If the engine is already built and the short block won't be tore down for light tension rings,roller cam,windage tray,crank scraper,return oil redirection, then at least do the head. Clean up porting and 5 angle valve job with stock dia valves on intake.Same on exh accept put as big a valve in the exh as possible to reduce pumping losses. Add small primary headers 1 1/2" about 42 inches long(4000rpm max,200 cubes, find more eng math at prestage.com) going into dual 2" pipes and high flow mufflers.
Go with a milage cam which would have wide lobe centres for less overlap and more cyl press, high lift,short duration.
Sythetic oil everywhere.

There's much more,I just realized how late it is and I got to go!

 

[Anonymous]

I know some people don't like JC Whitney, but as I am rebuilding my engine I noticed they offer a fuel saver cam. It comes with lifters and is only like 90 dollars. It said it would make the engine "super resposive" at low speeds.

Thought I'd let ya know

 

[LaGrasta]

I'm trying to set my 6 up this way as well. I drive 300 miles a week just getting to work and back. I haven't installed my Pertronix system yet, although it's sitting on my shelf waiting. I think that combined with taller wheels and lightened load will probaly be the best things I can do to increase mpg.

As far as JCWhitney, I'm a fan. They are less expensive on many parts, although you should still price compare. In the last two years though, they have dropped a lot of what we use. Almost all thir chrome accent pieces are gone and can't be ordered as I just tried in the last two months to do so.

Dragula, "BURN RUBBER NOT YOUR SOUL", That is a great sig, by the way.

 

[Anonymous]

Do you have an electric fan ?? The mechanical ones suck a lot of power from a little engine like the ford six. Of course, once the engine's hot, the electric ones turn on and suck power from the alternator...

 

[LaGrasta]

I don't have one yet, but it's on the list. I want to run a/c ( I know, I know) so I almost have to have an electric fan. As far as the alternator goes, I'll get one big enough to handle it all.

I followed a few fans this past week on ebay but all were too much $$$ except for a pair of Hyundai. I didn't think they'd fit plus they only pull. I want to mount it in front of the radiator with a push blade configuration. Anyone know if this is a mistake? Mounting it in front of the radiator that is.
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[CZLN6]

Howdy St80sixer and All:

I'd like to add a couple of items, not yet mentioned, in your quest for high mileage.

Whatever carb you use, make sure that the choke is set as lean as possible, that the float is as low as possible, that the idle mixture and Air/Fuel mixture are as lean as possible. And make sure that the accelerator pump is set so that it gives no more shot then is needed to make the transition from idle to accelerate to cruise. And get all the heat to the carb you possibly can; preheated air to the air cleaner, hot water heater under the carb.

All things being equal and driven right, a Holley/Weber 5200 progressive two barrel will get better gas mileage than a Holley #1946 one barrel.

Retain heat. If you're using a 180 degree thermostat, change it for a 195 stat. Higher heat promotes better atomization of fuel and a more complete burn. But, you must make sure that your cooling system can support and control the higher heat level.

Use as much initial timing advance as you can without getting any knock.

Finally, drive as if you had a raw egg between your foot and the accelerator pedal. No idleing, no warm up, no exurberant acceleration, lots of coasting, avoid stop and go traffic- plan your route accordingly, avoid cold starts.

Adios, David

 

[goinbroke2]

CZLN6, good points! To expand on that, how about a manual choke so you know it's off for sure and remove the accelerator lever and/or pump from the system? Slow tip in rates of the throttle won't require the extra fuel of the pump. Or use an over sized rad and then block off part of the grill for better aerodynamic's, the rad will make up for less air flow.

 

[Anonymous]

This is my goal too- increased performance and mileage. My first step is the 3.0 geared 8 inch, my next will be puting the one barrel back on. I checked my mileage recently- 14.6 mpg, same on freeway and in city (two differant tests). My speedo/odometer are right on. Besides having a tired engine, my rear grears are 3.2's (2950 rpm at 60ph is not good for mileage!) and the motorcraft 2bbl carb. The carb cut down my mileage by about 3mpg- I used to get 17 with the c-4 and one barrel, and 21 with the old 3spd (freeway)

I'm curious about carb choices. Over the few years I"ve been on this forum, I've heard a lot of folks here talk about webbers- some like them, but most complain about reliability and hassles trying to get them tuned right. I remember "inliner" played with his for several months before giving up.

The only thing I"ve heard good about webbers is the replacement for our stock one barrels- much more efficient, runs better, and cheaper than a rebuild at pony carbs, but not much of a performance increase. There was a discussion ahwile back about using the stock carb from a 250 on a mild 200. I'm wondering if webber makes a new one barrel for the 250 that could be used on a 200 for a slight performance increase? That way I wouldn't have to deal with the hassles of the linkage hookup I've heard are associated with the 5200, and probably have better mileage as well. I'm convinced from all the thread's I've read here that a one barrel is better for a mild engine than a 2bbl.

Thor

 

[Anonymous]

St80sixer,

I just noticed you are in Lynwood- not far from me at all! Cool, another local sixer! I hope to get all the local six cyl guys together (about 6 of us) this summer- sometime after I move in June. P.M. me so I have your e-mail address and I'll be in contact.

Thor