How to get better fuel economy out of CFI?

[friskyfrankie]

thats a pretty big difference just from switching gas. More than ethanol should explain

As I said, a difference but as you said, it is rather drastic so if the numbers are accurate, something else is going on.

[sly]

I know a lot of folks that have had issues with Walmart gas. It's discount tier gas. Shell is top tier. I use QuikTrip as it's another top tier provider and priced like the discount places.

[91merc]

Just out of curiosity, what were the mpg "ratings" when these cars were new?

[friskyfrankie]

Probably something in the neighborhood of 14 city and 22 highway with the average of about 17.

[Tiggie]

[91merc]

I wonder if 80s vehicles are getting much worse than the original advertised mpgs partly because the national speed limit was 55, and they didn't have ethanol blended gas back then

[Tiggie]

Those factors certainly don't hurt. Thirty plus years of use and unknown maintenance doesn't help.

The average highway I've gotten from any box (carb or SEFI in my case) is around 22 MPG given pretty ideal conditions.

[Brown_Muscle]

Those points and not to mention the 10% ethanol blend in modern gasoline hurts it as well

[DerekTheGreat]

I wonder if 80s vehicles are getting much worse than the original advertised mpgs partly because the national speed limit was 55, and they didn't have ethanol blended gas back then

Could be, but if I do 55 or 60 in my '88, I'll see numbers north of 24 mpg. If I run it around 70, I see about 22 - 24 depending on the grade of the road and all that.

[91merc]

Well yesterday I drove to another city to go get my glasses about an hour and a half away and I was getting about 15mpg on the way there and close to 20mpg on the way back, so I don't know if the long drive helped It or what. I usually have a 45 minute commute to work e ry morning

[kishy]

I don't have detailed stats at my fingertips, but I'm one of the "around 20" claims you've probably seen.

The best fuel economy I can recall getting out of a box Panther (between fuel-ups, not counting playing with the tripminder in the wagon where I've seen something like 160MPG) has been 21-22, and it was my CFI 84 Town Car, going rather fast on the highway. Logic would dictate that I should be able to do the mid-20s numbers that some other folks talk about if I slow down, but 55mph is slow enough to almost be physically painful, so...I pay a few extra bucks for fuel to make up for that.

I'd say you should expect about 14 in the city with a pretty aggressive right foot, and only a couple mpg better if you baby it. Considering your EGR is disabled, you're probably right where you should be.

Make sure the computer is happy, and part of that does mean functioning EGR. Make sure base timing is correct. Make sure tire pressures are a few psi above what the door sticker says - I typically run 36. Make sure your front brakes don't drag (stock box brakes love to drag). That's my priority list for keeping the fuel consumption within reasonable bounds.