heat sheild experiment for AF1 on my Expy
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Joined: Jun 2006
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From: NJ
heat sheild experiment for AF1 on my Expy
I've been doing some data logging looking at my O2's (another post coming about that saga). But whilest I was at it, I have been comparing ambient air temp w/ the air temp coming into the engine via the unsheilded AF1 intake. I was told originally that it did not have a sheild or box because the "fresh air" from the left front of the vehicle floods the compartment once you are moving and basically blows the hot engine air away, giving you "cold air". This design is for the 03 Exp w/ the 4.6l engine.
What I observed however, was that no matter what the ambient air temp was, the inlet air temp was always 10-15 degrees warmer than ambient (according to my in-dash exterior temp gage anyway). That just didn't sound right to me for a "cold air intake", ya know?
I have been looking for a solution to this problem by fabricating my own air box/sheild. I found an excellent post on this forum using a Rubbermaid trash can! (https://www.f150online.com/forums/sh...hlight=bmwbig6)
I followed those instructions, plus a few changes to suit my needs and came up with a shield that is only open directly in front of the filter - it is sealed to the fender well, on the bottom and along the top via some junk yard weather stripping.
So I took it for a test drive today - outside temp ranging from 38 to 41. Sitting idle, the intake air temp was 6 - 10 degrees above ambient. However, almost as soon as I started driving, the intake air temp dropped exactly to ambient temperature! In fact, the intake air temp reacted almost immediately and was sensitive to 1 degree.
In truth, I'm not sure that a 10 degree temp difference makes that much difference in power (I mean that litterally; I really don't know). But If these things are being sold as "cold air intakes" and are not shielded from the engine compartment, then they in fact really are not getting the optimun quantity or quality of air that they could.
I'll post a pic of the finished product shortly w/ some info on what I did.
Hope this experiment will be helpful to someone else with an open element "cold air intake"!!!
What I observed however, was that no matter what the ambient air temp was, the inlet air temp was always 10-15 degrees warmer than ambient (according to my in-dash exterior temp gage anyway). That just didn't sound right to me for a "cold air intake", ya know?
I have been looking for a solution to this problem by fabricating my own air box/sheild. I found an excellent post on this forum using a Rubbermaid trash can! (https://www.f150online.com/forums/sh...hlight=bmwbig6)
I followed those instructions, plus a few changes to suit my needs and came up with a shield that is only open directly in front of the filter - it is sealed to the fender well, on the bottom and along the top via some junk yard weather stripping.
So I took it for a test drive today - outside temp ranging from 38 to 41. Sitting idle, the intake air temp was 6 - 10 degrees above ambient. However, almost as soon as I started driving, the intake air temp dropped exactly to ambient temperature! In fact, the intake air temp reacted almost immediately and was sensitive to 1 degree.
In truth, I'm not sure that a 10 degree temp difference makes that much difference in power (I mean that litterally; I really don't know). But If these things are being sold as "cold air intakes" and are not shielded from the engine compartment, then they in fact really are not getting the optimun quantity or quality of air that they could.
I'll post a pic of the finished product shortly w/ some info on what I did.
Hope this experiment will be helpful to someone else with an open element "cold air intake"!!!