you found out you can have fun and it doesn't really cost you much ewxtra gas. I'd call that an unqualified success :thumbsup:

 

Thank you, I will be showing your data to my wife.:yes:

 

As usual, Andy is.... oh, nevermind. l

But yeah, I agree w/ Andy.

 

As usual, Andy is right.



Rob

 

cmon, you guys are going to give me a big head

cmon, you guys are going to give me a big head

 

you can't base this on one tank of gas- keep a notebook in the car and track it over time. i do that with all of my vehicles.
if you lugged the motor a lot in your efforts to get max mpg, you might have hurt your final mpg. BMW (or one of those German car companies) did some tests that showed that accelerating up to your final speed quicker actually helped mpg- which makes sense, as long as you don't go WFO and leave a pair of 50 foot black stripes from every stop sign... driving around town with a lot of idle time will also kill mpg. i've gotten into the habit of shutting the car off if im going to be sitting in one spot for more than a minute or so- places like drive up windows and drive up atms and what not.

 

Ya one tank for an experiment on fuel mileage=inconclusive.My 64 with a fuel injected 406 a turbo 350 and 3.08 gears was getting 17 maybe 18 mpg on the highway cruising at 70-75 mph.Around town didn't check because didn't care was driving 100 miles round trip to work every day.I wouldn't expect the big difference you are seeing if the carb it tuned properly which I would suspect its not.My s10 with FI would get about the same highway or around town and the same with both my grand am's.You need a o2 tuner for the carb to get the best mileage tuning because a 10mpg difference is way off.Even with the 700r4 now installed I don't expect to see more than a few mpg's but every little bit counts.Also my 65 elcamino had almost the same exact setup as you but a 700r4 and the difference from highway to around town wasn't a whole lot but I tuned it with a 02 tuner.

 

I hear ya on the one tank thing, but man it is hard to keep my foot out of it for that long, plus it was only a gee whiz experiment... as far as tuning, I think it is pretty well dead on. idles clean even with the big cam snappy throttle response right off idle and strong through redline. have not had it to the track to jet for max performance, but runs really well and always has, so I doubt there is much there as far as mpg goes. I am running a 750hp carb, so if I really wanna get crazy, i can change air bleeds etc.

ps. Andy, I agree with you, that's why I said not really a fail.

 

Wow I been driving my chevelle now for 9 years and I never caculated my MPG. I do on all my other vehicles but I just never really cared what my MPG is on the hotrod. I run at least a tank a month and have fun doing it. I try to smoke the tires at least once every time I take it out to you know, blow the soot out.

 

if you ck it, does it get better milage than if you dont ck it, lol

 

Weather has just a big of impact as accelleration. If it's colder out side, you'll waste more fuel as it takes longer to heat up and get to peak efficiency. I usually take the average of 3 tanks done at similar weather conditions and over the same commute route. Will give the best overall fuel econ idea.

 

My driver is a 4400 Lb. 70 Chevelle Sta. Wgn. with a 468, Q-Jet,Very Mild cam, 700R4 & a 3:07- 12 bolt. I drive it everywhere. I am near Pittsburgh, Pa. and it has been driven to Fla, Canada,Ill, East coast.
At 73 MPH it is turning 1950 RPMs and around 19.7 MPG. If I keep it around 65 MPH. it will hit the LOW 20s. NEVER check it around town, Just toooooo much fun mashin on the gas.
All interstate miles are in cruise ( Electronic Servo ).
Bob

 

I've found the slightest change in your idle adjustments makes a very large difference in mpg. The leaner your idle is, the better your mpg will be - most of the time you are coasting, braking, at stop lights, etc - in the idle circuit.

 

I did a trip in the elCamino last year to a car show a couple states away, I used exactly 1 full tank of gas to get there, and the same to get home. At the time I had a 2004r and 3.08 gears behind my 454. Over the winter I swapped in a M21 and 3.73s, went to the same car show using the same route, I used just under 3/4 of a tank this year, nothing was done to the engine and I was running the same wheels and tires as last year. near as I can figure the increase in mileage is due to the engine running in its sweet spot, closer to where the cam is designed to make power, last year it must have been lugging the engine. all I know for sure is it's way more fun to drive now!

 

yeah, mine is definitely a hotrod, and I drive it everyday for the most part... and I stand on the loud pedal some most times. I am not wide open most of the time because Tucson is a small town, and the cops will get to know me soon enough as it is. I like having a driver's license, but don't take that t mean I drive like an old lady. it is just that full throttle blasts to redline put me WAY over the speed limit in a hurry.

I was not too concerned about mileage, more curious really what effect aggessive driving compared to "old lady driving" had on gas mileage. Might have to try the same experiment with one of the other vehicles to see if there is the same result. only snafu with that is none of the others are equiped with overdrive transmissions of any sort. I am convinced that plays into the results I saw with this one.

 

You are shifting too high

So it took me 80k miles in my DD 2001 Mustang Bullitt to figure this out.

Normally I get around 16 MPG around town. But if I really short shift it and cruise in 5th gear at anything 45 MPH and over I can get it up to 18 MPG. I try and keep it under 2000 RPM as much as possible.

I do not manage to do this very often because it just isn't that much fun. :beers:

 

Lugging the motor typically only works for a Fuel Injection combinations, with a carb it typically hurts mileage as it hurts fuel flow from the boosters (lack of vacuum) and makes you use more squirter to cover the lean spot.

I have also found at times getting to your speed quick will not hurt mileage, but the current bone stock 99' Blazer I drive currently likes to be lazy to get good around town mileage.