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My E46 V12 6speed swap

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This is the video I was telling you about Richard.    And is the reason I decided not to fit X pipes to my own E55 headers.    

They work at low speeds to mix the gases/sound but at high speed they do next to zero (maybe some scavenging but you wont notice the difference on a dyno imo).     As you can see if you watch the leading edge of the exhaust pulse gas it likes to follow what I would call the inside edge or short radius bend of the tubes.

This is also why I do not tend to make what I would call a parallel centre to parallel entry/exit design X pipe and like Richards I prefer the Splayed centre to parrallel entry exit design as it forces the gases to mix more.   This is all from my own experience doing this on old restomod chev and ford v8's.     If your after outright flow out of an x pipe the parallel centre to parallel entry/exit x pipe is the best bet if you want an x pipe.    

H pipes I wouldnt even bother with but thats just me.    Of course I will fabricate whatever the customer wants.

I prefer just twin straight through totally separate exhausts on v8's.   My ears like that the best.

Its all a matter of opinion and everyone has a different one on how they want their car to sound.   Obviously street cars are a different scenario to race cars.

I have never really seen anyone make any real hp from a x pipe or h pipe or Y pipe its all 1-5hp or nothing the scavenging effect that far down the line is usually not a massive factor imo.

If it was me I would be semi gutting the rear mufflers now.    But I agree with michael on what he says about the duals.


Edited by Skylinerd1
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RE: the motor handling HP and internals, I'm at about 500hp motor right now with a rebuild using OEM parts.  Nothing special.

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