Has anyone heard of simply drilling holes in the airbox for increased flow? The location of the holes could be placed so they aren't visible (back and under). I'm sure it would help, the question is how much and is it worth drilling into the airbox.

I've also seen people just remove the airbox...any words on this mod? Performance improvements? Sound change?

 

If you drill the holes in the back of the airbox then all the extra air you pull in the engine will be the hot air off of the engine. Someone cut their airbox in a way that the back of the box was left in place and sort of acted like a heat shield. I don't know if it helps. The only way to find out is to get a thermometer and measure the actual temperature of the air entering the TB.

DF

 

You know, I was thinking the same thing. Back when I was a teenager and raced motocross, we used to drill or cut holes in our airbox to increase flow. You just needed to position them so you got airflow without mud or water. They even used to sell replacement airboxes for bikes with really restrictive airboxes like my 82 Suzuki RM125 and 83 RM250. These aftermarket airboxes remind me of the FIPK's for trucks and cars today. I would think you could do the same thing with a truck. You just need to position the holes so you aren't picking up hot air directly off the engine.

 

yes, it makes a HUGE Difference in the pre97 trucks. You can use the MX round filter holes with the sponge in there to filter the air also.

The hot air cold air arguement, ignore it. You will gain power by doing this. I have done it in many pre95 rangers with a good 10hp gains

 

Matt,

You say it makes a huge diff in pre 97...
What about post 97?
Also, what are MX round filter holes?

The hot/cold air argument shouldn't necessarily be ignored...
The hotter the air temp, the less oxygen hence less possible power. I don't have the time/patience to put a thermometer in my
truck engine hot and cold, driving at different speeds etc.,
But I agree that you can assume the engine will benefit from any
increase in airflow...if you could place the airbox intake in a
more desirable location without the drawbacks of getting water
or more dirt in it...

Has anyone seen or done any mods for ram air? Like placing the
airbox inlet near the radiator or underneath the motor? I don't have a 4x4 so I'm not too concerned about water intake...although if its raining or you go through a puddle/small pond...

 

I agree that hot air DOES makes a difference! I bought a K&N Air system for about $200 about 2 months ago and noticed lack of power when the engine run for more that 40 minutes. I took it to two dealers and they both told me that they couldn't troubleshoot my problem with the K&N system on. So I put the stock air system back on and noticed that the power loss then was very slightly.

I believe I have faulty air sensor that it's sensitive to heat and I'll take the truck back the delaer for diagnostic. But one thing is sure, my 5.4L likes cold air!

 

Crash,

Where have you or do you suggest routing the dryer duct to?
If you're talking about standard dryer duct (ribbed), wouldn't that cause undue turbulence? I guess it wouldn't really matter since the filter "smooths" the flow out.
I researched the APC filter...could only find the vacfilter website.
Where can you get a "flow thru" filter? I assume it slips over
the K&N for additional filtering with little restriction?
I also found another "slipon" filter made by outwears racing.
Don't have much info on them...
Or maybe I'm not understanding your post:
Do you even have a K&N in that setup?
Pulling the restrictor: you mean the portion that goes into the fender well?

I just removed my airbox cover similar to the technical artical posted on this site:https://www.f150online.com/tech/airbox.html
I didn't notice too much noise increase...and only a minor
increase in power/torque. A guess: 5 hp...maybe more.
Just enough to notice you don't need quite as much throttle for the same acceleration.

I'll have to wait and see if there's a change when the motor is
hot.

I decide against drilling into the airbox since I might want to return to stock form...

Thanks for the inputs fellas.