SMIM Showdown! Lets figure this out once and for all!

[JET]

Alright, I was holding off on saying anything about this until I saw how the test was going to be performed. I think there are a lot of people that are going to misinterpret this data. The test is NOT representative of the numbers that will be seen inside the engine.

One of the first things many people will notice is that there is no Heimholtz resonance taken in to effect because that can only be seen with the valves opening and closing. In a manifold with a straight back wall, this will not create a difference in flow balance between cylinders, but may change the flow numbers either plus or minus.

Another thing that is a larger issue is that there are no restrictions farther down line in this test (both sets of valves and turbo). This restriction downline from the IM will help to even out the flow of the intake manifold, so you will not see the imbalances to the degree that this test shows. Think of it this way, you have a 5" exhaust with a 1" outlet, will a 6" pipe with a 1" outlet flow any more? No, they will both be limited by the 1" restriction, the restriction is the valves and turbo. The degree of this can't be known unless a running engine is tested at a high flow rate.

I am not saying this test is not useful at all, but people need to be informed to really see what these results mean and I bet the vast majority of the people that will look at these results will not meet that criteria.

[wheelhop]

Originally Posted by JET

Alright, I was holding off on saying anything about this until I saw how the test was going to be performed. I think there are a lot of people that are going to misinterpret this data. The test is NOT representative of the numbers that will be seen inside the engine.

One of the first things many people will notice is that there is no Heimholtz resonance taken in to effect because that can only be seen with the valves opening and closing. In a manifold with a straight back wall, this will not create a difference in flow balance between cylinders, but may change the flow numbers either plus or minus.

Another thing that is a larger issue is that there are no restrictions farther down line in this test (both sets of valves and turbo). This restriction downline from the IM will help to even out the flow of the intake manifold, so you will not see the imbalances to the degree that this test shows. Think of it this way, you have a 5" exhaust with a 1" outlet, will a 6" pipe with a 1" outlet flow any more? No, they will both be limited by the 1" restriction, the restriction is the valves and turbo. The degree of this can't be known unless a running engine is tested at a high flow rate.

I am not saying this test is not useful at all, but people need to be informed to really see what these results mean and I bet the vast majority of the people that will look at these results will not meet that criteria.

AMEN!!! I'm glad most havn't chosen an intake manifold based on constant volume flow. Resonance or not, the intermitant flow demand placed on the intake manifold will make a compressable fluid like intake aircharge act VERY different than a flow bench. The only way to tell which manifold flows the best is th put it on a motor with a known reliable maf like a 2g maf. If you want results for each cylinder, put a wideband on each cylinder and see how lean each is. . . Otherwise look at the whole picture like the real world has to

[Andrew7dg]

Originally Posted by JET

Alright, I was holding off on saying anything about this until I saw how the test was going to be performed. I think there are a lot of people that are going to misinterpret this data. The test is NOT representative of the numbers that will be seen inside the engine.

One of the first things many people will notice is that there is no Heimholtz resonance taken in to effect because that can only be seen with the valves opening and closing. In a manifold with a straight back wall, this will not create a difference in flow balance between cylinders, but may change the flow numbers either plus or minus.

Another thing that is a larger issue is that there are no restrictions farther down line in this test (both sets of valves and turbo). This restriction downline from the IM will help to even out the flow of the intake manifold, so you will not see the imbalances to the degree that this test shows. Think of it this way, you have a 5" exhaust with a 1" outlet, will a 6" pipe with a 1" outlet flow any more? No, they will both be limited by the 1" restriction, the restriction is the valves and turbo. The degree of this can't be known unless a running engine is tested at a high flow rate.

I am not saying this test is not useful at all, but people need to be informed to really see what these results mean and I bet the vast majority of the people that will look at these results will not meet that criteria.

Well put...

I am kind of interested in the LSE manifold design. It is interesting to look and compare the pictures of the designs and then try to figure out why they flowed like they did.

I am curious, why isn't the LSE manifold taper at the end like the rest of them? or is it and I am just at a bad angle?

Or is the design Top Secret?

I have been reading up on intake manifold designs (in actual BOOKS!) and just curious why it is designed that way compared to other aftermarket intake manifolds.