Gas mileage 3.0 vs 3.1 pulley

[stang99]

I recently changed to a 3.0 press on instead of the 3.1 I was running since it uses the same belt and was inexpensive from AR. Nothing else on my car was touched. But, before I was getting 17-20 mpg and now I am getting 15-18. This last tank I was running really low on gas and I wanted to fill up near my house so I ran the last 70 miles on a 255 mile tank very easy. I used the a/c about 1/2 the time, max. When I filled up I put 15.1 gallons in the tank which came to 17 mpg.
I have decided that the extra pound of boost is most effective at low RPM's before the blower heat sinks or maxes out. So, I am using all that extra torque and liking it so much that it has killed my mileage. Still, you'd think that a change of just .1" in the pulley should not cost 2 mpg. And, when you stay out of boost, you should get about the same mileage.
Perhaps there are some considerations that I am missing? Any ideas?
BTW: The car doesn't seem to go any faster in the 1/4 but it sure breaks the tires loose on the street easier

 

[Poisonous Mods]

U might have a point P. but i em running a faster time with the 2.80 vs the 3.00. only 3tenths on the Kuhmos.

Remember im one of them that complained about how bad she is with gas so i went & bought the Focus for my self.

But to impact ur MPG by 2 not sure.... how much power did u get with the swap?

 

[03DOHC]

I filled up with 76 gas yesterday, and while it seems to give me better mpg so far it pings whereas the chevron gas didn't.

 

[jhwalker]

I like the sound of the engine between 3500 and 5000 rpm, not necessarily at WOT, but just cruising. Plus the engine is 'battle ready to repel hostile bowties'.
My mileage is very, very bad
I have quit computing mileage since it depresses me.
I may start running to work 3 days a week. It is only 6 miles.
:-D
JW

 

[stang99]

I filled up in Palmdale and ran down to the Trick Racing fuel station at really slow and sane speeds this morning and I only got 19.1 mpg, down the hill to the Valley. I guess that the 3.0 pulley is just making enough papasitic drag to kill the mileage. Crawling down hill in light traffic I should get about the max mileage that the car is capable of.

 

[BALDSNAKE]

Tetge I'm surprised that you are concerned about economy when you run the freakin life out of your car at LACR everytime someone from "down below" comes to town.
Hey did those Jack Rabbit turds dropped in the exchanger tank plug up that leak yet?
Yesterday went 420 miles to Pismo and back. 75-80 mph average and 20.5 mpg.
2.93 pully/ gator belt /100mm idler
Swanson chip/tune
JBA shorties/Bassani x w/cats/Flowmasters no baffles,etc.
Meziere H20 pump
C&L/K&N
Accufab
Densos
Whooops! I posted some "some" of my mods. Shhhhh!

 

[stang99]

I fixed the heat exchanger last night by taking it off the car and fabricating a plug that I epoxied into the hole in the exchanger. Unfortunately, I did not remove my sway bar and I was jumped at C-Bad by a crew of vermacious kurnids, you kicked my headlights in. My heat exchanger fix, on the other hand, which cost next to nothing, apparently was a good thing.
Also, my car returned to relatively good mileage after I filled the heat exchanger with distilled water (not gin). I got just over 18 mpg driving briskly including 6 runs at C-Bad. I am assuming that when there is no coolent in the intercooler, some sensors inform the ecu of this fact and it goes to reduced timing and a richer mixture, and if you push things at all, it removes all boost. So, my bad mileage was due to the leak in my heat exchanger. Ain't technology grand?

 

[stang99]

Last report: I flogged the car home from C-Bad and got 19.6 mpg on the tank. Clearly it was the empty intercooler that caused my mileage to take a dive. One more thing to pay attention to.