The kd4crs/Power Hungry/Gotts Mod (revisited - and with pictures)

[Jackpine]

Bill - I think you're right on the tests needed with and without the resonators. And, don't feel bad about finding that article a difficult read - part of the reason you did is that the guy can't write! He uses words without regard to their meaning so that several sentences are nonsensical. However, I suspect his math is valid for the systems he's studied (which does not match our trucks).

As I said somewhere near the beginning of this thread, fluid flow (air in the duct acts like an fluid) is a very complex, and poorly understood process. I say it's poorly understood because the mathematical models make too many assumptions that allow it to be studied, but that do not allow a precise prediction of the outcome (there's always a bit of error between the predicted results and the actual observed results).

I was concerned about the possible bad effects of turbulence in the duct and it would be very easy I think to create a sort of "standing wave" that would interfere with movement of the air mass into the engine. I would still like to have a smoothly "curved" snorkel section that would turn to match the angle of the intake tube more smoothly than what I have right now. I think the sharp angle I have at the bellows can create problems.

The article seems to say that the resonators act to reduce the effects of turbulence and standing waves.

But, in our case, the resonators were designed for the original duct with the factory snorkel. I honestly have no idea if they are beneficial with the larger intake opening or are actually harmful. However, I felt leaving them on was more prudent than removing them. It also allowed me to return the setup to stock if I chose.

I can only report that the truck seems to run well at WOT and I've noticed no loss in power or adverse effects on gas mileage. Other people seem to say the same for their mods with the resonators removed.

So, the effects of the resonators are probably not enormously significant. (And, sorry if I got "geeky" too)! :o

- Jack

[Jackpine]

Originally Posted by jimmyv13

If they are so beneficial, why don't aftermarket CAI's have them?

Jimmy, your question is good too. My uneducated guess is that the aftermarket CAI manufacturers don't have the engineering brainpower or facilities that Ford has. They take a more "trial and error", "common sense" approach - similar to what we did when we "reasoned" that a wider snorkel would be good.

- Jack

[txarsoncop]

Jack,

Thanks, you confirmed what I thought I was reading.

Granted I understand fluid dynamics are tricky, tricky. So take my musings below with a grain of salt. But, I live next to a PERFECT example of fluid dynamics gone wrong. Plus being a firefighter and having a master plumber for a father I understand the "common sense" wet side pretty well.

The author of the article was referring to a single cylinder engine and, at first, I thought well that's totally wrong for our 8 cyl application. But then I thought I remembered that with a V8 only 2 cylinders are opening at once correct? So it's not really that much different? Except for a convoluted intake path, a filter media and unexplained holes in both the resonators and intake tube.

If I'm remembering correctly I believe you posited somewhere here that the holes might actually be to remove some of the "springyness."


I rounded the edges of my PVC with the Dremel and a file because it just seemed to make sense. Probably didn't make a difference but...

[88Racing]

Here's some ?'s for you guys also to ponder.

Do you ever think of where our filter is on a stock location compared to a cai?

Do you ever think of how much more volume a vacuum needs to displace when you have a cai?

Do you think the snorkle nozzle help to create vacuum and velocity at the same time?

Just some thoughts as I was doing a fire pump test today and had to use reducer nozzles to increase flow pressure at the hose monster pitot gauge.

Lars

[kd4crs]

I just got around to purchasing the alternate rigid 3 inch tubing that fordmt08 on f150onloine.com used for his intake modification and it looks like it will work well installed a couple of different ways. The tubing required is made by Spectre Peformance. It is part number 8741 for the black color (8742 is Red, 8746 is Blue, 8748 is Silver) and it is called: 3" Flexible Air Duct. It is priced ~$20 and should be available at O'Reilly Auto Parts and Autozone stores. I installed it completely collapsed using one of the two connectors that come with the kit to go into the fender inlet and using the downspout connector to connect to the stock flexible section. It fits perfectly and does not require any hose clamps. I will be testing it out with my Gryphon Custom 87 performance and Custom 87 towing tunes this week. This variation completely eliminates any possibility of the downspout connector collapsing or getting sucked inside out.

[schwinn1weld]

Originally Posted by AgentOrange

Hi guys & gals, brand new to this forum. I stumbled across it while checking out other homemade CAIs after tinkering with one of my own and this was the first one I've seen that had an excellent one for the 2004 +. I like the caron fiber idea.
Here is a pic of what I came up with (hopefully the pic works):

Looks Great, but what did you use to cap the holes on your main intake tube? Looks awesome how you did that...

[Longshot270]

First I want to say WOW! this thread has exploded since the first time I skimmed over it. I did the gotts with my 08 4.6L and here are some of the pics.

The first one is the section of PVC that goes into the fender and the second shows how it fits. The big section taken from the 'bottom' of the pipe lets it fit in the flat area of the fender hole snug. The little cuts on the 'top' help hold the pipe in place. I cut it like that because I didn't have any large grit sand paper and I think they work pretty well because they bend to hold the pipe in place. I also used a 3 in flexible coupling to attatch it to the intake. Pretty soon I may work on a ram air type of intake but I'm still working on the idea. Making stuff fit in the 4.6's is difficult. :nerd:

[Jackpine]

Nice pics, Longshot. I think what you've designed will work just fine. I clamped the bellows on my snorkel tube so that the bellows are nearly fully compressed. That way, if the engine moves, and it will under high acceleration, it won't pull the snorkel out of the fender.

- Jack

[Longshot270]

Thanks, I'm thinking about making some kind of ram but there isn't much space so I'll keep looking at it. I believe that if something didn't have those "stop and scratch head" moments then it's not finished.
Well one thing that is kind of good about the 4.6s is that part of their box is attatched underneath so they dont move at all. But the tube afterwards has enough play to handle any movement the engine makes.

[kennyd]

Hi Jack, thanks for the info on the gotts mod, I think its a logical starting point. Do you think I should also use K+N filter.

Originally Posted by JackandJanet

OK - I've been reading about this approach to a CAI mod long enough that I decided to try it. Here's what I did - and I take no credit at all for any of this, it was just my implementation of the excellent ideas put out by people that came before me.

In the 2004-2008 trucks, the intake snorkel has only a 2" diameter at the end where it goes into the fender well. Other than that, it's a Cold Air Intake - so, the goal is to increase the intake opening.

We start with the intake ducting. Remove the holddown bolt (red circle) in the picture below and pull the snorkel out of the fender wall (red arrow). Once you do that, you can pull the duct away from the filter box. It will make a lot of noise that sounds like something is breaking - just smile and ignore the bad sounds.



Now that you've got the intake duct out, turn it over and you'll see two rectangular "bumps" at each end of the bellows that look like they might be "release tabs". They aren't! Instead, they sit over raised areas on the inside tube that act sort of like "tire irons" to separate the bellows from the other parts of the ducting. I separated the bellows from the duct using the circled "bump" in the picture below. (Notice I like to work on the tailgate of my truck). :o



To do this, I put the duct between my knees and then twisted the base of the bellows (where I'm holding it with one hand) all the way around, and it comes right off. (I had to use two hands to do this, but in the picture, one hand was holding the camera).



Now that it's off, you can see the duct opening, which is 3" wide here and the little square bump at the top that was the "tire iron".



Compare the 2" flared opening of the snorkel that fits inside the fender with the 3" opening of the duct upstream of the bellows and you see why the engine might have trouble getting enough air at WOT.



I went to Home Depot and bought a 2 ft length of 3" ABS pipe and a 3" to 3" rubber coupler. I wanted to make sure my new duct went into the fender as far as the original snorkel, so I marked my new 3" tube with a white line to match the gasket position.



Now we have a complication. The hole in the fender is an oval, about 3 1/8" high by 3 1/2" wide. There's actually a small "lip" inside this oval too and I got rid of that lip with a Dremel grinding wheel. The resultant hole is now closer to 3 1/4" high and 3 1/2" wide. (Ignore the dirty fender wall). :o



The hardest part: I had to reshape the end of my new snorkel tube back to the white line to match the 3 1/4 x 3 1/2 oval opening. I used a "Mouse" sander, pictured here with the end of the tube that I shaped.



Here's the finished tube, looking straight down the intake end. The outer surface is cut down so it will just fit into the fender opening. The inside opening is a true 3" intake.



The new snorkel tube will have to be angled slightly from the rest of the intake to fit into the fender properly. (It needs to enter the fender at close to a right angle), so, the other end of the tube was cut at an angle try to match the truck's tube opening angle. The length of the new snorkel on the long side is 12 1/2 ". The length of the short side is 12".



Here, I've joined the two pieces with a 3" to 3" rubber coupler. Leave the "hose clamps" loose for now.



I put my new snorkel into the fender (at a right angle) and it goes in right up to the line where I stopped shaping it. It's actually through the second hole in the inside of the fender at this point. It fits quite tightly through the opening, so I'm not worried about it getting "warm" engine air.



Next, I reinserted the stock intake into the filter box opening and reinserted the hold down bolt. This pulled the new snorkel out of the fender a bit.



I worked with the snorkel to redirect it back into the opening as far as possible. It's not quite perfect, but I think it's good enough. (A "bellows" connector would be ideal here). Once I got the snorkel in place, I tightened the hose clamps.



This is the finished assembly. A true 3" CAI for about $13. Best of all, I can return it to stock in just a few minutes if I want to.



I've disconnected the battery overnight so the PCM will learn a new LTFT strategy and whatever else it has to learn.

So now, Bill: is there any thing wrong with this setup and, I don't need new tunes, right?

And please, this was not an attempt to one-up anyone. I have not seen a pictorial for the 2004-2008 models and this is my feeble attempt to put into practice what other, brighter people have been talking about for my model truck.

I hope it can be useful.

- Jack