I'm getting 19.5 without a vacuum advance with my 289 with a 600cfm and Edelbrock Tarantula manifold in my Falcon. My Maverick is getting 23 with a 250 6 cyl.
I'm sorry, but there is just no way in hell. That would be around 40 mpg or better on the stock 14 gallon tank these cars have.. I've been driving these cars long enough to know that kind of mileage is pretty much impossible. I don't think they're even aerodynamically capable of it. I can BARELY stretch mine to around 420-430 on 13-13.5 gallons, and that's driving like a granny, downhill with a tail wind. And I've done about everything possible to my car to get the absolute most out of it, along with years of fine tuning. Your odometer has to be way off, or you got a bigger then stock tank. How many gallons does it take to fill up?
I'm with you on this. Breaking past 30mpg on a carburated motor is really difficult. Now I know he's got a 250 six based on other posts and I know those get worse than the 200 sixes, and my 72 comet with a 200 got 22mpg at best ever. I can't imagine what would be necessary to bring a 250 up to 40mpg or better. Maybe he's got a carb like the ones talked about here: http://fuel-efficient-vehicles.org/energy-news/?page_id=785
Uh, my '72 Comet was a 14 gallon and my '74 Comet is a 14 gallon. I remember reading somewhere that there was a larger tank somewhere.
Same way I got approx 50mpg out of a '93 V6 Ranger pickup with a 3.0, tow it half of the distance... Had a car and more parts than one truck could hold to pick up in Rockville MD, so we put the Ranger on the trailer, towed it up and then drove it back... No doubt careful tuning can make a noticeable difference, but it's hard to compete with modern stuff that has EFI, VVT, and overdrive, plus is more aerodynamic... If you want every bit of milage possible, one of the easiest tuning aids is a wideband A/F gauge... Once the carb is tuned for a 14.7:1 ratio you're going to be very close, just need to optimize timing for last bit of MPG... Of course the gauge is going to cost you $250 or more, so you're going too have to drive a lot to yield a savings(sorta like when the wife buys a $700 sofa on sale for $450 just to save you money)... Can also use them for performance gains as well, if the ratio doesn't drop to around 12.5:1 at WOT then there is some performance left on the table... Of course every engine and vehicle is a little different and still takes a bit of trial & error to come up with optimum ...
your original post isn't saying much at all. you're not listing the total miles per week and how many days you drive to work if that's what you're referring to.
I need to get a vacuum gauge and mess with my idle mixture screws.I also don't have my kick down rod hooked up to my tranny and maybe my timing might be slightly off. I always smells gas fumes when im driving down the road.I was going to take it to a local carb shop but the owner told me that he thinks 10 miles a gallon is the best I will be able to get with my setup.He wanted to charge me 80 bucks to throw it on the gas analyzer machine and he said he thought it was a waste of money cause I wouldn't note a difference
I'm about to order a wide-band AFR kit from Glow Shift Direct for $184, getting my new exhaust this weekend, and gonna install the wide-band sometime in the next month. I'm really excited to have that tool in my arsenal. I'm a bit of a cheapskate so I want my engine to be at it's most efficient while I'm thrashing it. You should be able to get better than 10mpg easily. There is a bit more than just the carb being dialed in to getting the best mileage. Ignition system plays a big role in it too. One of the reasons I'm so stoked about getting an AFR kit installed is that you really need to know what's coming out the tailpipe if you want to properly play with the interaction between your ignition system and your fuel delivery system.
No I'm not saying it's wrong, I'm saying the stated size of the tank is BS. They can call it a 16 gallon tank all they want, it barely holds 14.5 even after running it out of gas (which I did once sitting in line at a gas station because the attendant had a case of the runs that day). Now yea, theres always gonna be loss of tank size over time due to built up sludge and stuff on the bottom, but OTOH my 93 bronco had a stated tank size of 32, but filled 36. I've never thought of my tank as a 16 gallon tank I guess.
FWIW- Cheap low octane gas doesn't get the mileage as name brand high octane. It's possible to see 3 to 5 mpg difference using the same brand gasoline with different octane. Also the same amount of mpg by changing the quality of gasoline.
I could swear this is actually the third time I've read this same conversation. People pointing to the stated size of the tank and other people going... yea... right. I recall there is even a 22 gallon tank that drops right in with minor adjustment, its not a maverick tank of course. I just know that of the 2 comet's I've owned both could not have been filled to 16 gallons under any circumstances. I'd agree with that, with the caveat that higher octanes usually require a slight adjustment to your tune to see a gain, otherwise you typically lose efficiency and mpg.
Does it really matter? What size tank do you have Comet Fever? Here's the reasons I don't think it matters: 1) you can't ever use the whole 16 gallons, unless you like running out of gas. 2) if the listed tank size is 16 and every time someone fills up their tank it says 14 or less, whose going to remember its a 16 gallon tank? 3) its irrelevant how much the tank holds unless you are calculating how far you can go per fill-up for a long distance trip, in which case you would come up short using 16 gallons because of reason 1. In my experience when most people discuss their MPG in relation to their car, they refer to their average fill-up amount and not the listed tank size anyway. Who cares if your tank holds 20 gallons if you always fill up at a 1/4 tank and never fill more than 15 gallons? I fill every friday after work, between 13.5 and 13.9 gallons every time. The pointer is on or next to the E-line every time. The 2 times I have run my 71 or 74 out of fuel it took ~14.5 gallons to fill the tank. One time the gas attendant wasn't paying attention, and he pumped my gas until it overflowed, 14.2 gallons. I noted it in my fill-up log as it skewed my mileage. This was just a few months back. Edit - I took out the numbers because I had forgotten that both entries had also been skewed by a missed partial fill-up whcih I have noted on the entry prior to the overflow.
Also: A 16 gallon tank (or any tank for that matter), when ran "empty"....is not really empty. It still has gas in it that the pick-up tube can't reach.
