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.

I found everything except the black PVC pipe. I will check Home Depot later, when I can go across town.

They got my Keyless Entry to working, that I installed. There was a missing ground wire in the Body Control Box. They retrieved the factory code for me. So it all works now. Happy for that!

I would think it would be beneficial to them in many ways if they did.

Have fun doing your project today.

GREAT!!!! :thumbsup:

He should know me since I have the sticker with my s/n underneath.

Funny thing he (service guy at Bankston Ford) and his wife bought/live in the house my best friend's parents used to own/live in (They've both passed away, RIP). My best friend grew up in that house. Small world.

I did the Gotts intake mod on my truck which is basically identical to this and everyone at F150.net bashed me and said I was going to burn up my engine because it will be running lean. Even if it does run lean it would only be at WOT which I seldom go anyway. I'm glad someone actually had dynoed one and has firsthand experience and not just a bunch of dumbasses repeating what they've read.

Ever since I came up with this intake mod (Sept. 2005) I have not ever heard of anyone having any kind of trouble related to it. I have run it on both my 04 F150 and it is currently on my 06 F150.

Just did it, took longer to buy the stuff then doing it.

I think this part got left out: you must remove the positive battery cable for roughly 30 minutes after doing this mod. I didn't notice any difference after the mod was made. I then remembered to reset the computer it made a hell of a difference!

Removing the battery cable is optional. It is not required but it will speed up the adaptive process of the PCM. The PCM will make the adjustment on its own over a period of time.

Neither Home Depot nor Lowes had black PVC.

I used the regular white schedule 40 PVC but had to shave it down a little with a grinder.

Wow, thanks for the great write-up. I did this last night and it was REALLY easy. Got a K&N drop in and I think it took me longer to get to my saw in the garage (HoDepot only had 2 foot length of PVC) and cut the pipe then to actually assemble and put in the mod. Definitely go to Lowe's for the downspout connector. Home Depot had one of a different brand, but it was not the right fit. Went to Lowe's and they had the exact part you specified in stock. Seems to give me a little more on the top end, but that could be just wishful thinking. Now I can save that CAI money for something else! Thanks.

I'm going to do this...can't wait to check out the results driving around town. Too easy not to give this a try!

I've done it. Very easy, inexpensive and works great.

Thanks for all the feedback that everyone has posted. I appreciate it. I'm glad RockPick decided to let me post this back up for everyone's benefit. Thanks Brad! :beers:

If this is done before your mass air meter there is no way it can mess up your engine.The job of the mass air is to tell the computer how much air is injested so it can make the injectors work at what ever rate it takes to keep you in the right a/f ratio.I think alot of people got gun shy when doing cold air kits on the 05 plus mustang because it would run lean if the computer was not reflashed.On that system you replaced the tubing the mass air sensor was attached to.

Not completely true for the 5.4 3v. The 2004s and early 2005s were known to come from the factory in a near lean condition. Any increase at all was enough to lean them out further. Troyer did some dynoing a long time ago and posted the results. Any additional air on these should be done with care and preferrably with custom tunes.

Hey I to did this its so easy.Has a litte more kick to it.Got all the parts at lowes for 10.00 and some change.On the 3in pvc they had it 2ft piece but white just painted it black.

just finished putting it all together.... i have it downstairs drying right now... I will install and test drive in about 30 minutes....

just got back from my test runs... Did a couple WOT pulls. Seems to have picked up SLIGHTLY in the top end and slightly in throttle response.

I did seem to have picked up a slight whistle with it as well... might have to figure out how to solve that...

Will my 2005 with a December 2004 build date get leaned out worse from this?

There is no way of knowing for sure without dynoing it. If it were mine, I wouldnot take the chance. Mine was built 11/17/04 and I never messed with the intake until I had custom tunes. I may be overly caustious, but that is me.

I might have to try this mod seems easy and quick and cheap. I'll give it a shot this weekend

Filled up last night and got about .4 of a mile better on that tank. About half the tank was with the intake mod. I ran it hard a few times testing it and expected a decrease in mpg rather than an improvement. May have been weather or whatever, so will have to see if it continues. It is definitely more responsive.

I just got a few min to do this, and for the cost, the SOTP feel is more then worth the parts.

Easier pull in OD when accelerating, and at WOT it does have a bit more growl.

I could only find White PVC in the Metro area, just followed Jack's recommendation and painted it flat black.