Exhaust - Twin Box to Straight Through

1. VTS_16v_Boy Saxperience Post Whore Joined: Aug 2006 Dartford Kent Posts: 5251 Pug 1007 HDi Sport (daily) / Abarth 500

   #1 1st February 2007, 13:58

   Just thought Id mention:
   
   I booked the S in to have my Janspeed Twin Box system (Centre Siliencer + Rear Siliencer) converted to a Straight Through System (Just Rear Siliencer) to slighty increase gases flow but truth be known I new liked the sound of my Janspeed systems and I cant justify a new system so Im 'cut and shuttin'.
   
   Gona be using 4Extreme Performance in Crayshill between Basildon and Billericay. You can look up some of his prevous work at www.viperracingsystems.co.uk
   
   Used him quite a few times in the past and Im well happy with his work.
   
   The Cars going in on the 9th Feb also go him to quote for fitting all my suspension bits - Full Kit, Poly Bushes full set, Lower Strut Brace and 25mm Anti Roll Bar for about £300 which I thought was pretty good.
   
   Thats about it really
2. mattcp Established Member Joined: Aug 2006 Essex Posts: 1029

   #2 1st February 2007, 14:43

   That's like 15 mins from my house. Might pop down on the 9th and see the result (be nosey)
3. williamsvts Saxperience Post Whore Joined: Feb 2006 northumberland Posts: 7693 pulsar gtir, mk4 astra sxi

   #3 1st February 2007, 16:36

   janspeed exhausts are already 'straight thru', that term does not mean no silencer. you should have boxs in aswell with N/A engines, to help with pulse tuning.
4. Saxo_Steve Frequent Poster Joined: Apr 2006 Prestwick Posts: 952 Saxo VTR mk2

   #4 1st February 2007, 23:36

   If you take the centre silencer out, there will be a drop in back pressure which will reduce the cars performance.
5. mattcp Established Member Joined: Aug 2006 Essex Posts: 1029

   #5 2nd February 2007, 00:17

   Make it pop n bang like a good'n tho
6. VTS_16v_Boy Saxperience Post Whore Joined: Aug 2006 Dartford Kent Posts: 5251 Pug 1007 HDi Sport (daily) / Abarth 500

   #6 2nd February 2007, 09:15

   Quote:

   Originally Posted by williamsvts janspeed exhausts are already 'straight thru', that term does not mean no silencer. you should have boxs in aswell with N/A engines, to help with pulse tuning.

   The System is VERY quite and isnt much louder than an OE to behonest, plus the car is not DeCat'd (im running a Janspeed sports cat) so that will aid back pressure abit.
   
   

   Quote:

   Originally Posted by Saxo_Steve If you take the centre silencer out, there will be a drop in back pressure which will reduce the cars performance.

   If Im rite in thinking (Im no expert) as long as the bore of the pipework isnt too big and I keep my Cat (Janspeed Sports cat) I shouldnt loose to much pressure.
   
   

   Quote:

   Originally Posted by mattc Make it pop n bang like a good'n tho

   Yer I know thats why Im doing it
   
   
   Just a quick note on back pressure, I do understand that a completely straight through system from the manifold back with large diameter piping and just a Large back box would cause a loss in performance at low down speeds and destroy any torque.
   
   But keeping a aftermarket exhaust diameter and just lossing the centre box (Im still Cat'd remember) I cant see a Major change in performance for the worse, but we shall see :-)
   
   Looking forward to giving it a blarst around the lanes of Billericay once its done