Mazda Rotary Club

Cars by Model Type => 3rd generation RX-7's => Topic started by: DR SCHNITZEL on February 15, 2010, 12:40:05 PM

Title: Fitting a CAt to a screamer pipe,
Post by: DR SCHNITZEL on February 15, 2010, 12:40:05 PM
May sound silly but.
 
I have a small CAT knocking about in the garage, my question is this, if i fit it to my screamer pipe will it quieten the screamer to track levels. I sure it would take some sound out especially if the end points to the floor. If this doesnt work im going to find a small muffler. does anyone have a muffler not too large i could use instead. their is a large flexi in this pipe. i thought this may take some volume out too. ANy help appreciated before i get this welded up.
 
Cheers :)
Title: Fitting a CAt to a screamer pipe,
Post by: DR SCHNITZEL on February 15, 2010, 12:44:44 PM
Or what about fitting a standard yamaha R6 exhaust to the screamer? 2nd option
Title: Fitting a CAt to a screamer pipe,
Post by: TRex on February 15, 2010, 01:41:50 PM
Or how about just plumbing it back into the Exhaust system like everyone does... :2Rolleyes
Title: Fitting a CAt to a screamer pipe,
Post by: Laurenzo on February 15, 2010, 01:47:26 PM
On most tracks it is a static test, i.e. if you bring the revs to 2/3rds without punching in the turbo, then there is no problem, if it is a drive through, then just get someone to point out the positions on the track where you will be recorded and don\'t back off, or change gear at that point. QED :evillaugh
Title: Fitting a CAt to a screamer pipe,
Post by: DR SCHNITZEL on February 15, 2010, 03:24:03 PM
Ok cheers guys, I might get it plumbed back in but id miss the screamer option, cheers for the other advice too, i might risk it leave it as is.
Title: Fitting a CAt to a screamer pipe,
Post by: dthebuk on February 15, 2010, 03:59:53 PM
Quote from: TRex;672531Or how about just plumbing it back into the Exhaust system like everyone does... :2Rolleyes

i was told over on fduk that this can lose you 50ish bhp.

and the sound of a screamer pipe puts a smile on anyones face
Title: Fitting a CAt to a screamer pipe,
Post by: m1tch on February 15, 2010, 04:18:39 PM
I have seen an FC run a large secondary silencer on their screamer pipe, but best option is to plumb it back into the downpipe much further down stream so it doesn\'t mess up the gas flow coming out from the turbo.
Title: Fitting a CAt to a screamer pipe,
Post by: jackaleks on February 15, 2010, 04:49:35 PM
Quote from: DR SCHNITZEL;672549Ok cheers guys, I might get it plumbed back in but id miss the screamer option, cheers for the other advice too, i might risk it leave it as is.

 
you can plumb in a valve that will allow the screamer to vent to atmosphere or back into the rest of the system, so if you measure over the noise limit you can just switch it.
 
not sure where you get them from, didn\'t someone on here get RE:Worx to put one in?
Title: Fitting a CAt to a screamer pipe,
Post by: DR SCHNITZEL on February 15, 2010, 04:53:23 PM
Im on track 6th march with very little spare time will the cat option work?
Title: Fitting a CAt to a screamer pipe,
Post by: SiH on February 15, 2010, 05:55:59 PM
If you want a silencer, get a silencer, not a cat.
Jetex, job done.
Title: Fitting a CAt to a screamer pipe,
Post by: L18M on February 16, 2010, 02:11:46 AM
Quote from: jackaleks;672569you can plumb in a valve that will allow the screamer to vent to atmosphere or back into the rest of the system, so if you measure over the noise limit you can just switch it.
 
not sure where you get them from, didn\'t someone on here get RE:Worx to put one in?

sth like this bad boy
http://www.nengun.com/apexi/exhaust-control-valve
Title: Fitting a CAt to a screamer pipe,
Post by: SiH on February 16, 2010, 07:33:18 AM
Quote from: L18M;672697sth like this bad boy
http://www.nengun.com/apexi/exhaust-control-valve

Nope, the ECV is just a flapper plate designed to reduce noise volume -w orks well too, but strangles the car a lot - was good for my early morning starts though!
However, putting one of those on an ext-wg would be a bad idea, unless you love boost creep (or are running your turbo at that utopian state whereby it doesn\'t actually need a wg to control boost, as it\'s sitting in the perfect part of the compressor map).

What Jack is talking about is a 2 position valve that diverts the gasses one way or another.
Title: Fitting a CAt to a screamer pipe,
Post by: jackaleks on February 16, 2010, 10:38:57 AM
found it! (http://shop1.actinicexpress.co.uk/shops/Rat_Sport/index.php?cat=Exhaust_Cut_Out_Valves)
 
so you have one route going to a Y-pipe just before the cat/midpipe and another left open! sorted.