Hey i am planning on getting a cutout located where the cat/straighpipe. I was trying to see if when closed will it affect the exhaust flow so i came up with these two diagrams so anyone can tell me or give me ideas of how the exhaust flow will react with a pipe all of a sudden having a passage then it being closed, will the gases hit agaisnt the wall, bounce back causing distortion and reduce the speed of the flow. or will the passage cause some sort of cycle and allow flow to continue smoothly?

smooth flow caused by a circular motion


distorted flow

 

It won't really effect anything. The gases will travel the the pass of least resistance.

 

I am thinking about getting this also. I never thought about this though. I dont think it would make that big of a difference though with the extra passage.

 

yea i assume since im not putting down alot of n/a power that it might not even make a difference.. but wasnt compltly sure.

 

are you going to have it open at WOT or are you going to have a switch where you can do it yourself?

 

Well it depends on wat i get. if its electric ill hook it up to a rpm switch wen the nitrous comes on. if its a manual one i just leave it open before a run. I might loose bottom end probably but with the nitrous it should be beneficial.

 

You can put a 3 bolt exhaust flange w/gasket & block off plate on there, unbolt it to run

 

 

looks good mike, when is it that you open it? at the track? or on random days u wanna scare peeps in the street lol. i wanna do it for track use, butofcourse might occationally go up n down my block scaring all the damn kids with extremly loud scooters

 

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Basically just for the track and dyno. I have opened it a couple times on the street when I want to have some fun. But it is ungodly loud and I hate doing that to my neighbors.

 

how much louder is it when the cutout is open

 

lol. loud enough to not allowd your brain to produces thoughts!!!!! lol its extremly loud. when ever u have a day to not do anything and want to hear it. take out ur catalytic converter and turn on the car.

 

Mine actually isnt that loud. It's loud in the car since it exits right under the passenger compartment, but from the outside it's not much louder than most V8's with an exhaust. The turbo helps alot to quiet it down.

 

I would disagree. I hear some V8's with exhaust from time to time that might be as loud as my car with my cut out open, but generally it is louder than any V8 with a basic exhasut and it's a different kind of loud...more noticeable if that makes any sense. It's certainly loud enough to get a cops attention or for neighbors to hear you comming down the street. It brings attention to yourself that is for sure.

Turbo's in theory help to quiet it down by chopping up the air, but that is much more true for smaller turbo's not T4's like I have.

Here is a clip of my on the dyno with my cut-out open

http://videos.streetfire.net/player....E-3E104C29E395

 

in the video it didnt sound that much louder than a 4th gen with full exhaust but im sure if I were standing there that would be a different story. Also it doesnt really matter how loud it is because you'll only be using the cutout at the track or on the dyno