Hi WT,

OK, I guess that's one way to tell me to keep it short & sweet. I'm not very good at that, unfortunately.

There is the *potential* for improving gas mileage a little bit from reducing restriction on both the intake and the exhaust side; moreso on the intake side, as there is substantial restriction in the air intake tract (airbox & filter assembly).

Some people have seen gains of as much as 2 mpg just from installing a good airbox elimination kit. For those who stay on top of their mileage results accurately & consistently, sure, it's possible to see small improvements in mileage from airflow mods like those, again, in these vehicles, moreso on the intake side than the exhaust.

This potential for improving mileage via airflow mods is all based on reducing *restriction*, meaning, the engine doesn't have to overcome quite as much load (restriction) to pull in it's required air, or to expell the spent exhaust gases.

This *potential* is indeed real, but whether someone realizes true increases in gas mileage in everyday driving will depend primarily on how the vehicle is actually operated, and the quality of the fuel being burned. We all know the very natural tendency to drive our vehicles harder after installing power-producing parts, and that will of course negate any potential mileage gains. Once the novelty of new go-fast parts wears off, you may realize that potential, I think is about the most accurate way to state this, perhaps.

When you make changes that actually lean out the A/F mixture, sure, when in closed loop (part-throttle operation when the engine is up to normal operating termperature) the ECU does "listen" to the feedback from the O2 sensors, and adjust the mixture accordingly, up to it's ability to do so, but here is the key point that must be remembered: that only happens when it's *needed*, and even then it's done simply to *restore* proper A/F ratios that have been altered via a mod that affects them, so it's *restoring* proper A/F, not always making the A/F richer than it used to be.

------------------
Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer

[This message has been edited by Superchips_Distributor (edited 06-07-2001).]

 

No, actually I WAS trying to help save you
some time. But I really appreciate you taking as much time as you did .
I understand all the facets of your explanation,though I think i need to expand my "shade tree" knowledge of how the IC engine works.You said
"the ECU does "listen" to the feedback from the O2 sensors, and adjust the mixture accordingly -- TO *restore* proper A/F ratios that have been altered via a mod that affects them, so it's *restoring* proper A/F, not always making the A/F richer than it used to be."

So doesn't stand to reason that if a greater volume of air is present than, more fuel is needed to maintain the "correct" ratio?? Or is there not more air , it's just that the motor doesn't have to expend as much energy to get what it needs?

Many Thanks,
Glenn

 

Mike,
I think I get it ...I posted in the engine forum before I bothered you here and
didn't wait long enough. A couple of guys laid it out for me, and together with your help I think I can make a good ejimicated decision.....
thanks again ,
WT

 

I'm wonderin if i go for an air filter and a nice clean flowing exhaust doesn't the computer look to optimize the mix thereby adding more fuel??
And if it does that, then how might i expect to get more gas mileage as most people attest to??
And where would the extra horse power come from since the air is still filling the cylinder @ atmospheric pressure??
More responsive yes, hp AND mpg I dunno.
I can certainly see HP gains with the chip
& higher octane, though.
Jus wunderin....
P.S
Please don't feel obligated to go into a lengthy answer as i know your'e busy and prone to being too generous wih your time sometimes.But any info would be appreciated.
WT


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Ordered on 11/2/00:
VIN'd on 11/13
Built on 12/4
ETA week of 12/25
Merry Christmas to me !
Picked up 12/28/00
drove 100 miles in Snowstorm on sh!&&y roads on 12/30/00 -- SWEET !!
4X4 Lariat
SCrew, Arizona
Beige, 5.4 Liter, Offroad
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slider, Capt's seats,
Side steps, Bed xtndr,6
CD, L S D 3.55

******* X2K Lid, Line-X Spray-in liner, Eventualy: Intake/Exhaust mods.

 

Hi WT,

OK good, I'm glad you've got a handle on it. Yes, if more air is introduced into the motor, it needs more fuel added, you bet. However, doing things like an airbox kit & exhaust don't cause really *significant* increases in the amount of air being used by the engine, and on these particular vehicles, that is well within the systems ability to compensate. That does not in any way negate the potential for improvements in fuel mileage, as that comes from being able to use less throttle opening than previously to achieve the same velocity, thanks to the added power. Hence, the motor doesn't have to work quite as hard, so when driven conservately, you can potentially pick up a little bit better mileage.

Good luck!

------------------
Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer