I just got a 2001 F-150 with a 4.6L auto. I've heard these are the best you can get. I'm looking at them mainly for fuel economy. With their economy setting set for premium fuel only, or is it for regular 87 octane?

Thanks.

 

I am getting close to 19mpg 5.4 4x4 lariat 5.4 with 2.5% advance on 1kto2.5k leave others at original profermance settings in fuel lean 2.5% 1k to 2.5k tire size at 620 revs per mile and axle at 2.76 in CT 93octane avalible every where. back off if there is any pinging .his is where i am at with it your results may be different. make sure you have time to reprogram if needed i had a hill to test the pinging on to get to these settings
also have under drive pulleys and a k+n air filter and run 5w20 full synthetic

 

The original performance tune on the predator requires 93 octane, but the manual specifies a way to back off timing and fuel curve so it can run on 87

 

Actually the manual only tells you to adjust your timing curves for 87 octane use... it warns against adjusting the A/F ratio without the proper equipment to monitor the actual output.

-Kerry

 

With the gear/tire setting, your mileage is probably less than you think. I've never seen a 4x4 with less than a 3.55 gear.
My 5.4L 4x4 with 3.55 gears and 17" wheels gets about 14mpg around town and 16.5 on the highway.

 

for some reason the gear change from the predator doesnt change the speedo but does effect when the overdrive, shifts at 41 instaed of 45 .
I have check the miles driven and they are the same no mater where i set it at. 19 mile stretch on highway is the test area for distance.
also have tonnu cover and keeping it at 65 and revos

 

From reading this thread it sounds like the predator can modify the A/F ratio to something other than the 14.7:1 that the closed fuel loop will try to force (narrow band O2 sensor).

Is this true?

For example, best economy is typically around 16:1, but this ratio is not optimal from an emissions stand point.

Does anyone know how they do this?

Are they running open loop instead?

Or perhaps just tweaking the O2 thresholds a bit?

Thanks,
Tim