My 02 F150 is drawing most of its air from the engine compartment instead of the panel. How big of a problem is it?

 

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Here is an opinion based on science and fact.
The intake air is monitored by the IAT sensor.
As the temp changes, this sensor's input results in timing and fuel changes to match the air temp, rpm, gear, loading and motor design plus other considerations all as you drive.
The science of it never changes. The hotter the intake air, the less dense the air and the less power produced.
This leads to other operational facts.
As the intake air cools, the fuel added increases to match the density such that fuel ecomony tends to suffer.
The oppisite is true also. Hotter air can improve fuel economy but results in less power. The fuel is reduced and the ignition timing can go in the retard direction if the PCM dictates.
All the while the OX sensors are in the middle of these actions and modify them per engineering design of the software actions in the PCM.
While the question is in simple form, the answer is not so simple when all the effects of temp change are considered.
In gereral we like to have the air as cool as possible but within stop and go driving, the intake air is subject to heat gains thru the walls of the intake system and don't lower to outside temps (at the measurement point) until there is sufficient drive time to cool the ducting down and overcome the heat gains.This is based on an inlet from the outside.
An inlet from inside seldom ever gets down to outside ambient temps.
I run a monitor and have watched these items in action for temp vs conditions, ignition timing, injector operation etc so this is the basis of the 'fact' parts of it.
Hope this help you.

 

Bluegrass,

Thank you very much for a very informative answer. It's great that you explained it as opposed to just giving an answer for me to blindly follow. It's exciting to learn about my [12MPG BS POS] truck and I like learning about its inner workings. Thank you once again.

FG18

 

I put the AF1 intake on my 03 Expedition - does not come with a heat shield so the filter is open to the engine compartment. I datalogged the inlet air temp on several occaisions and found that the inlet air temp was 12-15 degrees warmer than ambient. So it is not exactly pulling completely hot air from the engine bay, but it wasn't as effective as it could be. So i made a heat sheild from a plastic trashcan from Home Depot and $5 worth of trunk liner weatherstripping.

I found that with the heat shield the inlet air temp went from whatever it was under the hood to the same as ambient air temp outside the truck in less than a minute of driving.

For the time, effort and cost, I'm happy However, AirForce One should make a shield for this application. If I can figure it out (based on someone else who figured it out), then a professional fabrication company should be able to figure it out.

 

c'mon lets see a pic of your creation

 

Second that. My AF1 came with a "heat-shield", but I'd be interested to what you fabbed yourself.

 

I just got off the phone with K&N and they will not sell the "heat shield" seperatly unless you can provide them with proof of purchase ie.. reciept or photo of K&N intake on vehicle "otherwise people could buy cheap intakes off of ebay and then buy the K&N heat shield and save money"

wow that speaks alot for the K&N products right there

 

Here is a link to my previous post. I need to give credit to another forum member who came up with the trash can idea. The other stuff is my own thinkin'.

https://www.f150online.com/forums/sh...ht=heat+shield

 

waterman308, thanks... your info and photo's helps me out alot, thanks for the R&D time to show that it is worth the time and effort.




*edit* ALSO a big thanks to BMWBig6 for pioneering the system

 

Hehe, I like your setup! Good to hear you're seeing positive results too.

 

here is the link to the original post that I found which give great information about making the sheild:

https://www.f150online.com/forums/sh...d.php?t=105800


One thing I found with mine - I have a "wing which folds out from the right side of the sheild (as if you are standing behind it) and ties into the cover over the radiator. It acts to keep hot air from flowing around the shield and entering the filter. Well, bending the plastic and stressing it against the MAF mounting bolts behind the filter cause a small crack in the plastic. Not enough to affect performance, but I certainly lost 10 points for appearance!

Version two may be make from sheet metal using V.1.0 as a model. Someday

 

Waterman 308,your heat shield is to cool! You really thought it out.You could have said it came w/ the kit and I would have believed you,it looks that good.I love how you used the nails to measure the contour of the hood to match the shield,plus you can't beat the price!Excellent!

 

the nail trick was ok, but I found that the insulation compressed more easily than the nails so the countour of the hood didn't exactly come out with the pattern of nails - but it gave me a place to start. When I raise my hood now, I can see a good impression of the outline of the shield in the insulation so I know It is making good contact. Just remember to get some trunk edge weather stripping to go around the shield. $5 at a junk yard from an old Crown Vic or whatever - got like 15 feet of it

I love junk yards

 

Wow Waterman - Awesome job !!! Pure Genius ..