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MPG experiment...1976 Dart Lite...Sept 26...Up to 20.19!
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Author:  Backtobasics [ Fri Jun 27, 2008 8:01 am ]
Post subject:  MPG experiment...1976 Dart Lite...Sept 26...Up to 20.19!
I have an almost stock Dart Lite. 225 /6 with 3 SPEED and 7.25 rear end.
The car is manual steering, manual 4 wheel drum brakes, and very little options (3 speed wiper and 3 speed transmission were only primary options) Only "upgrades" so far are the modern radial tires, and a "dual" exhaust that splits into a Y where the stock converter would have been, through glasspacks out the rear. Exhaust is in line after carb, and distributor modifications, with a GOOD dual or bigger single system with better mufflers.

Since this was Dodge's MPG car, that is what I am going to start to do...Tune it for better mileage.

As run, it has 15" ralleye wheels, small bolt pattern. The drum brakes have been gone through COMPLETELY, and now stop EXCELLENT.

Dart has received a basic tune up consisting of:
  • plugs
    wires
    cap
    rotor
    fuel filter
    air filter
    oil change
I adjusted the valves to quiet it down, i still have one or 2 that are clacking, so I need to go back with the feeler gauge, and get them adjusted properly.
I also had to run the idle a little higher then I would like to make driving easier, as it would not leave a stop at low idle. Investigation led me to no accelerator pump function.
First full tank, of 35% in-town driving, and 65% highway, (with stop and go, but most highway is 35-55 consistantly) MPG was 13.5

Long Terms goals:
I am going to swap the 4Speed OD that I bought with the car, once I have maximized MPG in the current configuration. I also bought 8 3/4 rear with 3.55 (3.23 also available) rear end that I want to go in later. Eventual plans are Turbo stock /6, and 8.75 may wait until then, or in sooner if the 7.25 gives up sooner.
Author:  Backtobasics [ Fri Jun 27, 2008 8:28 am ]
Post subject: 
Next phase, next tank:

I am going to start with Carb. Mileage on odometer says 41K, so presume is 141K.

I started with carb teardown. There is extra "Stuff" on it. I will post pictures later. During teardown, I noticed coat hanger material wrapped around the choke shaft, and throttle shaft, several times. WTF. :?:

As I tore into it, I found 2 of the 3 bolts that hold the carb base to the carb main body were stripped. :roll:

So I took off the extra "stuff" and separated main body / upper body / base, and set them into the carb soaker cans. Main and upper look AWESOME
I am going to tap out the main body, to a larger size for new fasteners, and rebuild carb, then run for next MPG update.

Next up is to start with some of the distributor and ignition modifications.
I think the HEI will be next.

Ideas are welcome, some might be tried some might not.
Author:  sl6farmtruck [ Fri Jun 27, 2008 8:43 am ]
Post subject: 
I can come up with a whole host of crazy ideas, but I'd suggest you take a look at the following forums first, lots of great info on making mods for efficiency:

http://ecomodder.com/
http://www.gassavers.org/

I'll send you a PM later today. . .
Author:  Aggressive Ted [ Fri Jun 27, 2008 9:27 am ]
Post subject: 
Backtobasics,

I am not so fond of the Holley 1945 carb. I took mine apart so many times I stripped a hole too. Eventually I emailed Doc and asked if it was worth the effort to keep tuning the 1945. He encouraged me to switch to a 1920 Holley since jet changes can be done in about 1.5 minutes verses 15 tp 20 on the 1945. My first 1920 I found was covered with pine needles and all white with oxidation. I cleaned it up and it got me 20 mpg right after rebuild. I thought man, Doc really knows his stuff!
So I started studying the various incarnations o 1920's over the years. I have finally settled on the Economaster version 1968-72, which has netted some descent mileage for having a automatic and my aggressive driving habits.

You might want to skip through the grief and get one of SL6 Dan's. He has several available that are new old stock. You could hit 25 mpg pretty easy with your current transmission and rear end. Then tune engine from there.
It would be worth the money. Give Dan a PM.
Author:  Doc [ Fri Jun 27, 2008 9:31 am ]
Post subject: 
Keep the valve lash loose to help maximise MPG.
From what you describe... start looking for a different carburetor, yours sounds like it is worn-out. (used-up)
Once I have the basic engine running well, the best mpg comes from careful distributor advance and carb. tuning work.
DD
Author:  Backtobasics [ Fri Jun 27, 2008 10:31 am ]
Post subject: 
Quote:
Keep the valves loose to help maximise MPG.
From what you describe... start looking for a different carburetor, yours sounds like it is worn-out. (used-up)
Once I have the basic engine running well, the best mpg comes from careful distributor advance and carb. tuning work.
DD
The carb cleaned up really, really well. No other bolts are a problem, I am guessing someone thought it needed a herculean effort to tighten the base to main body.

For now, my brother and his machine facilties are going to tap out to a good size, and we will rebuild. If it shows signs of being dead, we will re-consider.

The projected plan is carb, valve adjustment, HEI mod, fuel line mod, exhaust system. After that, jetting on carb, and distributor modification recommended by you guys.
Author:  Backtobasics [ Fri Jun 27, 2008 12:14 pm ]
Post subject: 
Quote:
Backtobasics,

I am not so fond of the Holley 1945 carb. I took mine apart so many times I stripped a hole too. Eventually I emailed Doc and asked if it was worth the effort to keep tuning the 1945. He encouraged me to switch to a 1920 Holley since jet changes can be done in about 1.5 minutes verses 15 tp 20 on the 1945. My first 1920 I found was covered with pine needles and all white with oxidation. I cleaned it up and it got me 20 mpg right after rebuild. I thought man, Doc really knows his stuff!
So I started studying the various incarnations o 1920's over the years. I have finally settled on the Economaster version 1968-72, which has netted some descent mileage for having a automatic and my aggressive driving habits.

You might want to skip through the grief and get one of SL6 Dan's. He has several available that are new old stock. You could hit 25 mpg pretty easy with your current transmission and rear end. Then tune engine from there.
It would be worth the money. Give Dan a PM.
I am going to throw the 1945 back together to get the vehicle running, for the time being.
I will investigate one of the 1920 units.

Now where did I see that post.....
:)
Author:  slantvaliant [ Fri Jun 27, 2008 12:34 pm ]
Post subject: 
Quote:
For now, my brother and his machine facilties are going to tap out to a good size, and we will rebuild.
How about Helicoil, or a similar rethreading system to keep the original fastener size?
Quote:
The projected plan is carb, valve adjustment, HEI mod, fuel line mod, exhaust system. After that, jetting on carb, and distributor modification recommended by you guys.
Sounds like a plan! I keep a simple spreadsheet plan for my Valiant, with phases, for every area of the car. It links to a BOLO List (Be On the LookOut) for junkyarding.

For maximum mileage, make sure you adjust the nut behind the wheel. :D
Author:  Backtobasics [ Fri Jun 27, 2008 12:46 pm ]
Post subject: 
Quote:
For maximum mileage, make sure you adjust the nut behind the wheel. :D
Now that is IMPRESSIVE. How did you know it was loose?
:lol:
Author:  Aggressive Ted [ Fri Jun 27, 2008 4:23 pm ]
Post subject: 
BacktoBasics,

If you don't have one now you might consider this,

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0125292459

I got one of these off eBay earlier this year and love it. It saves a bunch of weight and is a great casting. There are many subtle improvements running one of these, such as quicker warm ups, less heat soak, better atomization of the fuel and better mileage. On cold winter days warm ups are quick and power is great just in a few blocks of driving. No more 2 mpg drop in the winter months. :D
Author:  SlantSixDan [ Fri Jun 27, 2008 6:20 pm ]
Post subject: 
Ted, could I get you to please read & use the eBay link posting guidelines contained in this post? It'll make your links easier to follow. I've gone ahead and fixed your link here.

Note that the Feather Duster / Dart Lite cars came from the factory with a good-quality sandcast aluminum intake. Aluminum intakes save weight and offer a moderately slight improvement in cold-engine driveability. They do not materially reduce heat soak, they do not significantly reduce the mileage reduction caused by winter driving conditions with a carbureted vehicle, and they do not make your coffee taste better in the morning. I know you like your aluminum intake a lot, Ted, but it is not the magical piece you seem to believe it to be. Your improvements are mostly down to the vacuum leaks you happened to fix with the intake swap.
Author:  DusterIdiot [ Fri Jun 27, 2008 6:28 pm ]
Post subject:  Er.. ok...
Quote:
During teardown, I noticed coat hanger material wrapped around the choke shaft, and throttle shaft, several times. WTF.

The return spring on the throttle shaft looks like that... the added items to your carb are probably a vaccuum pod for adjusting the throttle position, and or a dash pot to keep the carb plates open enough that during high vacc., high rev, idle throttle plate position- it doesn't lean out so bad it torches something....(manual trannies only have this problem)...

I wouldn't deep six the 1945 since this is a one year special mileage carb, you might get disappointed with the 1920 since it was not calibrated to 'work' with your models components...there are other proceedures in additional TSB's for this model that are not in the standard Service Manual...

If going for mileage, do as doc asks, make sure the cat convertor is gone since it's so old it's 'dead', make sure your distributor and vacc. advance pod are working correctly (special for your car also), check to make sure the EGR is working properly and not plugged and the vacc. lines are all in good order with no leaks (part of the mileage programming for that model only)...

you may see a bit less as the car came stock with skinny 195R75/14's...
than the 15's on there now.


Good luck on the experiment, a guy I met last year bought one from Wildcat Auto Wrecking in all stock condition with the A-833 OD and all the OEM parts were there... 30-32 mpg.. avg on the 'flats'....


-D.Idiot
Author:  runvs_826 [ Fri Jun 27, 2008 7:50 pm ]
Post subject: 
I read the whole thing from the beginning so I might be catching something that you wrote earlier and changed your mind on. First off, my opinion is that the 2.76 aren't spectacular for the slant and gas mileage. I believe that the 3.23 would be a better fit. I think those high high gears are for big blocks and non OD.
Second the A-833OD will help signifanctly, your on the right path on getting the carb setup first. If the 1920 doesn't fit your needs than the Super Six might be the way to go. However, if you can get the aluminum intake and carb tuned that would be fine. Weight savings is what those Lite's and Feather's were based on aluminum cases trannys, lighter hoods ect. So keep flowing with that river.
One thing I would recomend that many people may not think of is if you can take apart you head and clean it is to gasket match it. Yeah, it's suppose to be for performance, but the less your engine has to work or the more efficent you can make your engine per a gulp of fuel the better correct?
Author:  Backtobasics [ Fri Jun 27, 2008 8:03 pm ]
Post subject: 
Quote:
BacktoBasics,

If you don't have one now you might consider this,

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0125292459

I got one of these off eBay earlier this year and love it. It saves a bunch of weight and is a great casting. There are many subtle improvements running one of these, such as quicker warm ups, less heat soak, better atomization of the fuel and better mileage. On cold winter days warm ups are quick and power is great just in a few blocks of driving. No more 2 mpg drop in the winter months. :D
Ted
Thanks for the input. This vehicle had the aluminum intake already. I wonder if the benefits of this intake might be a detriment in the summer? Perhaps a phenolic spacer would help insulate the carb from the heat of the intake, AND add a little plenum volume?
:idea:
Author:  Backtobasics [ Fri Jun 27, 2008 8:12 pm ]
Post subject: 
Quote:
First off, my opinion is that the 2.76 aren't spectacular for the slant and gas mileage. I believe that the 3.23 would be a better fit. I think those high high gears are for big blocks and non OD.
Second the A-833OD will help signifanctly, your on the right path on getting the carb setup first. If the 1920 doesn't fit your needs than the Super Six might be the way to go. However, if you can get the aluminum intake and carb tuned that would be fine. Weight savings is what those Lite's and Feather's were based on aluminum cases trannys, lighter hoods ect. So keep flowing with that river.
One thing I would recomend that many people may not think of is if you can take apart you head and clean it is to gasket match it. Yeah, it's suppose to be for performance, but the less your engine has to work or the more efficent you can make your engine per a gulp of fuel the better correct?
I have to determine the gear set. It is on the list, shortly after the carb install. I have yet to be able to change the fluid in either differential or transmission, so that will likely be right after the carb. I am very interested in what happens with the rebuilt carb, and then we are off to the races. I do not want to do anything Frankensteinish with the car for weight savings, or aerodynamics, but a few small tricks might be in order.
As for internal, I agree. For the time being I want to throw the external tuning tips. I have highly considered finding a spare 225 and starting a porformance build with ported head, gasket match, etc.
Quote:
I wouldn't deep six the 1945 since this is a one year special mileage carb, you might get disappointed with the 1920 since it was not calibrated to 'work' with your models components...there are other proceedures in additional TSB's for this model that are not in the standard Service Manual...

If going for mileage, do as doc asks, make sure the cat convertor is gone since it's so old it's 'dead', make sure your distributor and vacc. advance pod are working correctly (special for your car also), check to make sure the EGR is working properly and not plugged and the vacc. lines are all in good order with no leaks (part of the mileage programming for that model only)...
I have the current carb, I have to confirm that it is the 1945. I am going to run it for now.
Converter is gone, replaced with a Y that converts exhaust from single to dual.

Thanks for input guys, I will have more questions as I go along.
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