On the Car Chemistry website they use the analogy of water coming from a hose. "Pinch the hose and the increased backpressure increases water speed". Yes the velocity has increased, but through a smaller aperture. Overall volume of flow has decreased. Doesn't seem like an ideal scenario with your exhaust.
Well taken MrBHP....is why I also don't buy Ford's analysis on the CMCV's as they follow the exact same dynamics in reverse in order to gain increased air velocity into a cylinder so in effect they're a slight restriction due to compressibility factors of the airstream thru the CMCV plate....
I actually saw this occur when I initially installed my FPIM vs the OEM IM w\ CMCV's thru the PCM live data at idle.....the MAF gms\sec actually increased along w\ the TBA decreased to retain the same idle speed proving the CMCV's were a restriction in the OEM IM when closed....
The ONLY real purpose for these things are for emissions....to aid in air\fuel EGR mixing in the cylinders by creating turbulence which also has a CC cooling effect so any extra TQ gained is from a cooler cylinder chamber to support increase spark timing and\or maintaining VCT at 0* (full cam advance timing) due to less NOx emissions output......the same output results (both TQ & NOx reduction) can be obtained by installing a larger radiator & cooling fan w\o the CMCV's....
Now back to this topic. This is why I want to call & speak to these folks to find some things out before I do anything w\ them.......
When gasses are expanded due to heat they exert less of a restriction thru an orifice as opposed to cooler denser gasses thus can actually speed up flow velocity w\o creating an undue back pressure ahead of the orifice as long as the orifice is sized to not exceed the gasses critical compressibility factor (after this point is exceeded is when gasses can no longer compress which then an actual back pressure or pressure drop is created ahead of the orifice w\ gasses or air flow) until at some point down the tube when the flowing gasses temp has sufficiently dropped increasing it's mass along w\ increasing flowing friction thru the tube to negate any velocity gains.
The question is how long the full exhaust has to be to maintain the velocity gains.........................
I understand the dynamic principle. They maintain\claim that these work in full exhaust systems.....so I'll need to see some verifiable proof of this before I move.....otherwise it's a marketing trick to entice buying by using some general scientific truths....or snake oil as some have referred to. The old saying goes..."The best lies told has some truth lodged within em."
I'm really curious to know their story.
Merge collectors work! They maximize scavenging based on volume and velocity of exhaust gasses pulling on adjacent tubes while reducing gaseous expansion and turbulence. The cone after the choke point is for anti-reversion.
This is not a merge collector. I don't see this as doing anything positive. No disrespect to you intended. Personally, I think this is snake oil, a Tornado for your exhaust. I definitely do not see it working after the cats. Yes, it would increase velocity at the new choke point, but it would reduce velocity everywhere after that.
I would think that a better entry and exit shape for the cat housing would produce more useful gains. If you have gone through Ed's Infopak, you know how much Ed talks about "gaseous expansion" and how it slows velocity.
That's not going to happen, it's a closely guarded secret. Mr Burns et al get paid for exactly that. My former coworker and I had a set of collectors specced by Burns, we received everything except the choke and the taper from the cloverleaf, the two critical dimensions. You only receive that information in the form of a collector.
BTW, Mr Burns is awesome to talk to.
None taken, Flusher.
Now what you've posted concerning Ed Burns @ HeadersbyEd I can fully understand....at least he has put forth some verifiable data to prove the concept but even he mentions these can work in a full exhaust system but you have to call them to get the sizing specs based on your setup's sizing & layout......
Why Ed has perked more of my interest w\ this...................
Just by applying consensus this concept used in a full exhaust system is considered impractical (no laymen are using these in a full exhaust setup) due to having to account for a lot of variables that most won't have\take the time to work thru.....and the OEM's have worked most of this out already from a general standpoint but I think that even they have left some on the table to get......the issue is how much has to be put into it to attain it & if this is worth the effort.
Why I was wanting to make contact to find out...............otherwise it's all a moot subject but since I've never heard of this before the geek in me wants to know all about it before just dismissing it out of hand.