Manifolds, Cats N Stuff

1. user_15300 Saxperience Post Whore Joined: Apr 2007 Mansfield Posts: 6663 Astra Coupe Edition 100

   #1 18th January 2008, 19:17

   Hi Peeps,
   
   I'v got a 2001 VTR and currently got a custom Powerflow stainless steel backbox and middle section. I want a 421 manifold, but i dont want to decat it because of mot. Only problem is my cat and manifold is all at the same end obviously... gay. I've thought about fitting an earlier VTR exhaust system so the cat would be underneath and I could have a manifold, but will this fuck back pressure's and that up? Or am I getting confused about it all and there's a more simple way?
   
   Thanks In Advance!!
2. Coonper Saxperience Post Whore Joined: Aug 2007 Coventry Posts: 5182 Lupo GTI

   #2 18th January 2008, 21:23

   Just buy an aftermarket manifold, which will inturn decat it and free up the exhaust flow! Then get a straight through centre section with a back box of your choice! Then when mot time arrives, just stick your old manifold on, or slip a tennor in the testers back pocket
3. gd16 Frequent Poster Joined: Nov 2003 Tayside Posts: 893 S/c VT!?

   #3 18th January 2008, 21:38

   Manifolds can be a pain in the arse to change.
   
   Easiest way would be to get an aftermarket manifold, as well the Powerflow system you have just now. That means you've lost your cat entirely. Then find someone who is selling a Mk1 VTR exhaust. Then swap it over at MOT time. Much easier to swap the exhaust than the manifold IMO.
   
   You could however try and find a friendly MOT station. Or your car could possibly scrape through the emissions without a CAT - depending on how good a condition the engine is actually in.
4. user_15300 Saxperience Post Whore Joined: Apr 2007 Mansfield Posts: 6663 Astra Coupe Edition 100

   #4 20th January 2008, 16:47

   It's just the cat thats bothering me because i dont want to be arsing around at mot time. I just want to put a manifold on. I just wondered if a mk1 cat would fit into my system, sounds like it would though?
5. KamRacing Saxperience Addict Joined: Nov 2006 A farm shed in Aylesbury Posts: 14916 Corolla AE86 Peugeot 205 B18C (in bits)

   #5 20th January 2008, 17:18

   okay the main thing to consider is that the VTR manifold is quite restrictive .. more so IMO than the VTS. I'd fit a performance manifold.. fit an early version of the cat under the car and then fit a decent exhaust from there to the backbox
6. user_15300 Saxperience Post Whore Joined: Apr 2007 Mansfield Posts: 6663 Astra Coupe Edition 100

   #6 20th January 2008, 19:36

   Thanks pal. That was pretty much my idea, just wasnt sure it'd be possible to make the mk1 cat fit without messing back pressure up. Thats what I'll do then thanks!
7. Alex_3589 Regular Poster Joined: Mar 2007 Posts: 388

   #7 20th January 2008, 19:50

   milltek manifold with sports cat form cituning, pricey but amazing bit of kit. pulls loads better and no messin on with changing manifold.