I was wondering if there's a big difference in changing the stock air coupler with the smooth air coupler ?
This is the one from Mid America Motorworks. (part # 638-982)

I already have the duel K&N set-up,and Corsa Sports then was told changing this makes a difference. Any truth to that ?

Any input would be great .

Thanks in advance.

 

The difference is that with the smooth coupler, there is less stress relief when the engine torques (engine roll). I have never seen any data that shows that the smooth coupler provides any performance advantage.

 

It will help make the incoming air straighter which should help airflow.

 

But you would need a really accurate dyno to see any differance, not something you would feel "in the seat of your pants" kind of mod.

 

There is a lot of debate over the smooth vs. accordian coupler. You are dealing with laminar flow that will basically allow the air to fill the peaks and valleys. A "boundary layer" of air will fill the peaks and valleys. Air (fluid) wants to travel smoothly and without interruption. If you are not pushing all the air that the diameter of the smallest opening in the coupler can handle it will take the path of least resistance to the manifold once it has filled up the void. What I'm trying to describe is that if the available space is larger than the amount of air that it needs to deliver it will basically be allowed to flow in the center that is not impeded by the ridges. What matters is that the engine gets the determined amount of air required to keep the fuel/air ratio within desired limits.

You will still see more turbulence with the accordian vs. the smooth coupler but if you are still allowing the required amount of air to enter the combustion chamber the effect will minimal. Since I am aware of the amount of bench testing that the engine and intake package received I would say that even with the turbulence you are providing sufficient airflow even in stock trim.

Now if you need all the available diameter such as from the addition of an aftermarket intake that will increase the available air flow then a smooth coupler can become more beneficial. The smooth couplers have their own issues as they have a diameter increase at one end by virtue of having to fit over the inlet pipe for the plenum. This diameter increase will actually reduce the velocity of the air as it exits the coupler.

 

Thanks for the input. Like I said before, "You always have the perfect advice." Thanks

Oh just to let you know, I'm still dealing with sale I spoke to you about before. Can you beleive that ?
I guess you cant make everyone happy. I say "it was a case of buyers remorse and they didnt do their homework", but I don't konw. Maybe they found a better deal.

Thanks again,

 

If you recall, that is the same explanation I used here on the forum about a year ago and got into a BIG HEATED discussion with a few members. Thought I would stay out of this one, but glad to see you jumped right in! I think maybe those that jumped on the smooth coupler band wagon have backed off a little.

 

Oh, I remember. You were the "debate" part in my reply.

 

Well "debate" is not the word some of the guys used to describe me at that time, but the word they used did start with the letter "D".

Kind of a funny thing today. I purchased a set of widened chrome QX3 wheels (19x12) from a fellow forum member and he threw in a smooth intake coupler for free! Had to laugh a little inside!

 

 

Thanks for your advice too along with Talon90. I guess the smooth coupler is not really worth the $$$$$ as they say.
No heated debate here I'll listen to the Masters

One question though. Why do people say it gives more/better air-flow?

Thanks

 

The only people that say that are the ones that truely do not understand airflow. Just to look at the part, it is easy to see why someone not educated in airflow would come to the conclusions they do. But when you are educated, and have experimented with, boundry layers, pressure differentials, volume, flow and so on, you then understand why things are not as they seem.

I have been designing electrostatic rotary atomizers and paint guns for the automotive industry for 28 years now and have performed so many airflow studies, it is not even funny. Airflow is everything when it comes to painting. It also is everything regarding the performance of an engine. You need to see how all the different elements of airflow work before you can truely understand how they all work together. When you understand all the relationships, you then understand why things are not as they seem or work like you think they should work.

 

I have run the numbers and I don't see laminar flow at anywhere above idle. For turbulent, or transition flow, the accordion coupler is no deterrent. It is my understanding the accordion design reduces noise, however.

 

Thanks Dave Good input.

 

A man who understands. Nice job Dave.

 

I have modeled them too. The Reynolds numbers are such that laminar flow is at idle, an argument I have had regarding the screen in the MAF. Transitional flow comes and goes quickly and turbulent flow dominates the performance range of the operation of our LS2 and LS3 motors that are not modified.

talon90 has described the hydraulics of the flow quite nicely. The hydraulic principle at work is called the 'law of the wall' which describes the flow of a fluid as it approaches the wall confining it. It essentially predicts that you will have ZERO velocity at the interface of the wall, taking the accordion shape out of play as long as it is not protruding into the flow.