I think I am going to try and modify a stock plenum in order to have the exit port of the plenum larger so that it matches the larger intake port on Kenne Bell.

I will take a closer look t it tonight. If it can not be modified to 100% of the KB opening then I will most likley do it s much as I can and then modify the reducer plate that comes on the kenne Bells (the one that allows you to use stock plenum).

Any thoughts on this? Anyone think about doing it? Am I not thinking about a snag that does not make this possible?

 

A couple things would have to be addressed. For one the bolt pattern for the stock upper cannot be simply drilled and tapped into the KB case as two of the bolt holes are inside the KB opening, and the third is on the edge. Plus the size of the stock upper isn't nearly the size of the KB opening which you can see on the adapter pics below. Notice the second pic which shows the outline in sealer for the KB inlet size. It's about twice as big as the stock inlet.

I'd either get a JLP or similar custom manifold or else just port the stock one to the max size you can staying with the factory bolt pattern and KB adapter plate. Match the KB plate to the upper plenum and call it good.



Jody

 

From a engineering standpoint....um.. let me express it this way. What happens when you try to breath in through a straw? Now start running and still try to inhale through that same straw.

Make sense?

As the load on the motor goes up so will the volume of air being sucked in through the inlet.

It's not wise at all to choke off a motor in the inlet side. Exhaust side is debateable. But not the intake side.

Rich

 

I dont think I understand what you are saying here. My plan was to modify the reducer plate that cam with the KB and make the opening bigger and then use that as the attaching plate by welding that to the plenum. It would therefore bolt on to the KB using the existing holes and hardware. Does that make sense? Or am I missing your point.


This is exactly why I want to modify it. I want to see about cutting the bottom portion of the intake plenum and fabricating the needed pieces and weld it together making the outlet of the stock plenum. Its hard to explain in words.

 

Basically we are restricted on the inlet side by the size of the throttle body.

I understand what theory you are talking about but I don’t think it "fully" applies to this situation.

The kenny bell is being restricted here. They place a reducer to allow you to bolt on the stock plenum. If you remove this reducer then the larger inlet on the blower is exposed. By increasing the outlet on the plenum you increase the inlet on the blower. See what I am getting at? It will allow the KB to be more efficient.

I would agree that all things remaining equal yes just increasing the outlet of the plenum will not be effective. However the direct result of increasing the outlet for the plenum will be increasing the inlet of the blower allowing for more velocity in the plenum and therefore more volume. Think of it in respects to the KB rather than in respect to everything else remaining equal.

Does that make sense to you? I didn’t pay much attention in Fluid dynamics class but I am pretty sure what I am saying applies.

 

Gotcha, but the plenum itself isn't really any bigger than the outlet, so even with a larger fabbed outlet it won't flow any more than it's smallest section.

Jody

 

Again I dont fully agree. By using the larger inlet for the kenne bell the kenne bell can "suck" better if you will, therfore increasing velocity and increased velocity translates to more air. Yes there is no physical increase in volume of the plenum but by allowing the Kenne bell to suck in the air better then the end result is more air. More air = more fuel. Mor fuel = more power.

I am not expert. These are just theories I am making up. LOL

 

Give it a shot. My thoughts are no matter how big the inlet to the blower it can only flow "X" cfm, and that will be determined by the biggest restriction in the inlet. That is my opinion is in the stock upper plenum on your truck. It might help at part throttle areas, but once you get to the airflow limit of that upper that's all you'll get no matter the shape of the inlet after that.

Jody

 

I am curious to see if it will help or not. I do understand what you are saying but I feel that if I allow the kenne bell to pull in more are then there will be more gains. Now if the gains are worth the time, money and effort.. Well that is another question.

Think of it thise way. You have a pump that is sucking air through a 2" straw. You increase the suction power of the pump and you should be pulling more air through that same 2" straw, no?

 

Well I took a look at the bottom of my intake plenum and it looks liek my idea is not going to work. There is just not enough room to do it.

 

Can you take pics of the upper on the plate, from the bottom, sitting on the KB, from the side, and any other way?

How close does the upper sit to the fire wall?

 

If I have the pics of the plate right, you need to remove the parts in the red square.

Get the upper blasted first, bolt it togeather, then weld the upper to the KB plate, and weld in new walls.

But how close does the upper sit to the fire wall?

 

That is correct. Also by reducing the pressure loss across a given length will also increase flow. As in a straw that is 2" in diameter along its whole length will flow less then a straw that starts off at 2" in diameter and increased to 4" in diameter along it length, given the same working pressure.

 

If you put a spacer plate on top of the KB that is about an inch thick you can do amazing things with it. That was last years project for me. I sold the KB but still have the plate. I have some pictures of it on the computer at work I think.
Dale