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

[88Racing]

Jack and David,
Got so gunho on this decided to make pit stop on the way home and basically came back with what I saw on David's pictures. I do not think it was over engineering more like pooling ideas but speaking different languages.

Great job once again

-Lars

[kd4crs]

Please don't take my comment the wrong way, I just meant that there is no need to go out and buy a dozen different things and try to cobble them together to accomplish what we are trying to do. I like to keep the KISS principle in mind when doing little projects like the DWV intake mod. I am in no way criticizing anyone's efforts to mod their vehicle. Sometimes the simplest solution is often the best.

[88Racing]

Do not worry, not stepping on my toes. KISS is a good policy. Thanks for posting pictures.

-Lars

[Jackpine]

This is in response to the excellent posts by Jim Allen and Grabber523. I was typing it but had to stop for lunch and three other posts snuck in on me!

Both Jim and Grabber make good points, and one's that worried me too, but for a different reason. First though, I have a degree in Aerospace Engineering and know that airflow theory is SUPER complicated. I've been concerned that these modifications would induce turbulence in the intake (due to a non-streamlined cross-section in the modified area) that would actually work against the increased intake area. Then too, the "squared off" end of the new intake may in fact promote turbulence too.

However, Bill brought up the point that the CAI design doesn't really come into play until you're at high RPM's, and, something he said in one of his posts convinced me that he thought the airflow was increased under those demands with the bigger opening. (I think this was reprised in one of the posts that beat me to this one).

Grabber, there IS the inverse relationship between velocity and pressure, but there's also conservation of mass. You're not going to get anything more downstream of the inlet than you had AT the inlet, and, since the flow is moving, the static pressure is always less than ambient (meaning the air is less dense than ambient). I think the restricted opening can ultimately cause a lower pressure condition to exist throughout the inlet tube and at the throttle body if RPMs are high enough. At that point, it's going to be difficult to increase power since the MAF sensor is going to say "not enough air".

Jim, I liked your "smoothing" analogy. It goes back to what I was saying about turbulence possibly restricting airflow. And, it may well be the case that you are right on this. I certainly would like to see some objective data and won't throw my trumpet snorkel away until I'm convinced it's worthless. I will say, though, that the trumpet/bellows assembly is not the most streamlined, laminar flow design I've ever looked at with the inside "bumps" just downstream of the inlet, the rings at the bellows end of the snorkel and finally, the accordion folds of the bellows itself. And, the trumpet end widens too rapidly to my eyes. It seems like it should cause turbulence of its own due to this. It doesn't look like a reasonable airfoil curve to me.

Finally, since the cross-sectional area of the tube increases with the square of the radius, we have an intake cross-section of 3.14 sq inches with the trumpet, but 7.07 sq inches with the mod. That's over twice as much intake area for a 0.5" radius increase! I feel this almost HAS to increase the flow potential!

And, AgentOrange's "RAM" air mod probably provides even more. It's possible that the increased pressure from the RAM tube sort of cancels the fender inlet contribution at high speeds, but I'm nearly certain the combined effect provides even more air mass than one of them acting alone.

Again, gentlemen, I'd love to see some objective data and I'm delighted you two were not afraid to bring this point up.

As I said in another post, maybe a month ago: That trumpet restriction is there for a reason! You can bet on it. I'm betting it's there to reduce power potential at the upper end, which might reduce engine damage and warranty claims from those who abuse their engines.

- Jack

[Jim Allen]

One difference in my Land Rover example was that the trumpet was right at the end of a cylindrical filter housing with a cylindrical filter element inside. The trumpet was fairly close to the filter and not far away from the intake plenum itself. I think that scenario would be HIGHLY sensitive to any changes, where a change at the end of a system with such large interior volume would be far less sensitive to changes at the inlet.

As to the power increase, that's very telling if it was on a chassis dyno. If you can pull that much power out consistently over the margins for error that seem constant in a chassis dyno, you are doing good! What I wonder is whether what Bill tested was the J&J design, or the Agent Orange unit that eliminated the expansion chamber? Bill???

Like I said, I am willing to flow bench these mods. Can use my old housing and you guys can send the rest of the modified stuff to try. Before we start exchanging addresses, however, I'll have to make sure I can borrow the flow bench and a competent operator for a coupla hours.

[Jim Allen]

Oh, I just saw and followed Agent Oranges link and it sounds like Bill was just averaging the results of a CAI system, not speaking specifically to the modified stock system we are talking about. Am I correct?

[Jackpine]

Done, David -

If you'll go to this thread, in the permanent "How To" forum of f150online, you'll see I've provided a link to the FAQ post here, and, you'll notice I "chided" the members there for not being more receptive to you. It's post #4 in the thread right now and should not get lost with the passage of time like the more ephemeral threads.

http://www.f150online.com/forums/art...ml#post3624441

- Jack

[kd4crs]

Thank you very much, Jack. I do appreciate it.

[jimmyv13]

Am I the only one to not find the 4x3 downspout connector at HD or Lowe's? It also appears that I'll have to paint the PVC since no one carries in in black.

[Jackpine]

Originally Posted by jimmyv13

Am I the only one to not find the 4x3 downspout connector at HD or Lowe's? It also appears that I'll have to paint the PVC since no one carries in in black.

The painted PVC will work fine. It seems there is a great variance in what you can find in different stores around the country! I have not found the 4x3 downspout connector here either.

- Jack