2009 F-150 5.4L Preliminary Dyno Results!

[Jackpine]

At cruise, there's very little load on the engine. I imagine that's how you get away with a lean A/F setting.

- Jack

[Power Hungry]

Originally Posted by JackandJanet

At cruise, there's very little load on the engine. I imagine that's how you get away with a lean A/F setting.

- Jack

Exactly. Running a tad lean (lean being a relative term here) during light cruise (minimum load) is not uncommon for most auto manufacturers. In fact, I've seen as high as 15.8:1 under light cruise. Under acceleration or load, fuel curves will richen up as necessary to keep things safe.

[secondarychaos]

Ok, so it's Lean + Load conditions that can cause issues.
thanks for the clarification!

[Power Hungry]

Originally Posted by secondarychaos

Ok, so it's Lean + Load conditions that can cause issues.
thanks for the clarification!

Couldn't have said it better myself!

[AgentOrange]

Bill,
I do not have a Gryphon yet, hopefully soon...that being said, because of the air intake mod I have, do you think it would be detrimental to my engine (stock 5.4 3v with stock air filter) to make WOT runs? Should I cap off the ram air section and just let it breathe through the fenderwell until I get a Gryphon?
I haven't made any WOT runs yet, and based upon your explanation of A/F ratios it's probably a good thing I haven't.
Thanks for any guidance.

[Jackpine]

Originally Posted by AgentOrange

Bill,
I do not have a Gryphon yet, hopefully soon...that being said, because of the air intake mod I have, do you think it would be detrimental to my engine (stock 5.4 3v with stock air filter) to make WOT runs? Should I cap off the ram air section and just let it breathe through the fenderwell until I get a Gryphon?
I haven't made any WOT runs yet, and based upon your explanation of A/F ratios it's probably a good thing I haven't.
Thanks for any guidance.

Let's see if I can get this right before Bill chimes in:

I think, because you've done no modifications to the intake system past the intake tube (the filter box and filter are all stock), you're not going to fool the MAF sensor into thinking there's less airflow than there really is. So, I don't think you have to worry about running lean.

But - and here I don't really have a clue how to proceed - at high speeds, your "ram" air intake is going to have a little bit of the effect of a blower (although I doubt it will be TOO significant). That COULD upset things a bit.

(BTW - the only reason I jumped in here was to test my understanding of this concern).

- Jack

[Power Hungry]

Correct, Jack.

As long as the relationship between the MAF sensor and the intake tube is not disturbed, the MAF sensor *should* correctly calculate the amount of air entering the engine. Of course, this is under N/A draw-thru conditions. The ram-air effect of the snorkel on AO's truck may have a slight effect on AFR, but based on other ram-air kits I've seen in the past, the effect is not enough to be concerned about.

This coincides with what we've seen on the dyno with a 60 MPH fan blowing directly into the engine compartment. There is occasionally a slight AFR shift (.1 - .2) with air blowing into the intake tube (with snorkel and bellows removed) but think that this may be more related to the turbulent conditions cause by the high speed fan and not necessarily because of the removal of the snorkel itself.

Hope this helps.