DWV Intake Mod for 2004-2008 F150 with 5.4L Engine
 

*** This mod has been revised with improved materials and instructions. ***
Please read post # 74 in this thread for the latest version of this mod.

https://www.f150online.com/forums/3818781-post74.html

Original instructions below:

These are the instructions for the DWV intake mod that I designed in Sept. 2005 and tested in my 04 F150. I used it the entire time I had my 04 F150 and currently use it on my 06 F150. This mod removes the restriction at the end of the snorkel inside the fender hole of the stock intake. Bill Cohron (ASEMechanic) has dynoed this mod and it produced a 7-8 RWHP gain in the upper RPMs. It does not adversely affect the air/fuel ratios since it makes no changes to the air filter box or MAF sensor location. The main advantages of this modification are: small power increase, no increased engine noise (no drone!), similar to stock appearance, very easy assembly and installation.


DWV intake mod for the 2004-2008 F150 with 5.4L engine



Materials:

1. 7.5 inch length of 3 inch inside diameter black ABS DWV pipe.

2. One female-to-female 3 inch black ABS coupler.

3. One rubber downspout connector from the plumbing section of Lowe's or Home Depot. (Lowe's item number 23455.)

4. One 4 inch stainless steel worm clamp.

5. Small container of ABS pipe glue.



Assembly:

1. Cut black ABS pipe to length and remove any burrs from the ends.

2. Apply a light coat of ABS pipe glue to the end of the black ABS DWV pipe in a one inch wide strip. Apply a light coat of ABS glue to the inside of one end of the female coupler and immediately press the coupler into the black ABS DWV pipe with a twisting motion to fully seat the pipe in the coupler. Allow to dry 30 minutes.

3. Attach rubber downspout connector over end of female coupler and seat fully.



Installation:

1. Remove stock intake tube by removing 10mm bolt holding it in place.

2. Using a large flat blade screwdriver, insert it in the joint at the end of the flex section on the bottom where the notch is in order to remove the snorkel. Spraying silicone lubricant or WD-40 in the joint will help it come out easily. Be careful not to damage the flex section or snorkel in case you need to return to stock.

3. Loosen the 4 inch stainless steel worm clamp and slip over end of flex section. Tighten the worm clamp enough that it will not fall off.

4. Insert the end of the 3 inch black ABS DWV pipe into the flex section of the intake and slide it into the flex section as far as it will go.

5. Reinstall stock intake tube and replace 10mm bolt.

6. Slide the 3 inch black ABS DWV pipe out of the flex section and seat the downspout connector in the fender hole while compressing the flex section.

7. While holding the flex section compressed, tighten the stainless steel worm clamp to hold the black ABS DWV pipe in place.

IMPORTANT: If the flex section is not compressed the DWV intake mod may vibrate or rattle.

Pictures:

All the components laid out:
https://www.f150online.com/forums/me...components.jpg

Everything Assembled and ready to go in:
https://www.f150online.com/forums/me...-assembled.jpg

A full 3 inch inlet. No restriction here.
https://www.f150online.com/forums/me...tions-here.jpg

Here is what it looks like installed:
https://www.f150online.com/forums/me...-installed.jpg

Here is a what it looks like installed (closeup):
https://www.f150online.com/forums/me...-installed.jpg

does this work as good or better than a cai?

Thats pretty much the Gotts intake.

The original Gotts mod is for 97-03 F150s and those that have the conical air filter in the large round housing. This is the same concept applied to the intake of the 04-08 F150 with the 5.4L engine. JackandJanet also adapted a variation of the Gotts mod to the 04-08 F150 with the 5.4L engine. The DWV intake mod is not intended to work as good or better than an aftermarket CAI. It was intended to improve the intake air flow by removing the restriction at the end while preserving the factory noise reduction built into the stock intake. I have tried several other aftermarket CAIs and they all created horrible drone while towing our travel trailer. This mod does not create any drone whatsoever.

im going to do this tomorrow!

I can't tomorrow, but I see it in my future!

No, it's not. kd4crs did this mod about 3 and a half years ago, long before gotts even thought about it.

Back then it was called the DWV intake. The original thread was deleted long ago by the mods. IIRC it was because to many internet engineers were bickering about it's merits and so forth.

It's been proven many times by dyno tuners that any mod done to the stock intake that is upstream of the MAF sensor will have no ill effects on your engine at all. Thats all this mod does.

The DWV intake basically removes the inlet resriction and improves the throttle response. It will show the most improvement on a totally stock truck.

how did you get the 4x3 adapter into the fender hole?or do you just leave it flush?

It is flexible PVC and the 4 inch end goes over the female coupler, the 3 inch end goes in the fender.

i have it setup just like yours. i got a 4x3 rubber pvc adapter and i cant get the 3 " side to go in the fender hole,maybe i need to pry on it some more?

I think you may have purchased the wrong type of 4 inch to 3 inch connector. This is the link to the one that I used for this mod: http://www.lowes.com/lowes/lkn?actio...DSC&lpage=none

Lowe's item number: 23455.
https://www.f150online.com/forums/me...-connector.jpg
This is not the same type of adapter that is used to transition from 4 inch pipe to 3 inch pipe. Those type of adapters are made from much thicker PVC and will not fit the fender hole properly.

yep you are right,i did some cutting and trimming and made it work temporarily

I ran into Bluejay getting my oil changed at the dealership ($19.95 coupon), he was getting his keypad handle reprogrammed, he had the Lowe's list all made up to do this mod.

Can't wait to see the mod in person. :)

Is your dealership familiar with f150online and know who you guys are? I would imagine they do but just curious.

The service guy knows about the site and I suspect he knows who I am on here, but has never said so. He has a black 2007 Screw he is modding.