4-2-1 and 4-1 manifold difference

1. iw_laurence Established Member Joined: Apr 2008 Isle of Wight Posts: 1971 BMW E30

   #1 10th June 2008, 06:57

   as tile, just wondering the difference between the 4-2-1 and the 4-1 manifolds. is there a difference in power gains?
2. immense Established Member Joined: Jan 2008 Northampton Posts: 2241 Citroën Saxo VTR

   #2 10th June 2008, 07:49

   Not to sure about 4-1 manifold but 4-2-1 manifolds seem to be the most popular option, and will add about 5/6 bhp max.
3. user_15989 Saxperience Forum Bum Joined: May 2007 Posts: 4857

   #3 10th June 2008, 08:24

   I have tried quite a few on the past and always ended up going back to the BTB 4-1 as it always gave best results for my self. I know a few people have used the very long pug sport manifold for really high revving normally aspirated engines and that is a 4-2-1 but there very long pipes.
   
   It does not matter so much if its a 4-2-1 or 4-1 but rather its about the length of the pipes. A 4-1 is much easier to get the required length on the primaries for a tuned engine. A 4-2-1 you have to end up having the pipes going up over and you can end up paying two or three times more for a good 4-2-1.
4. iw_laurence Established Member Joined: Apr 2008 Isle of Wight Posts: 1971 BMW E30

   #4 10th June 2008, 08:26

   4-1
   http://www.kamracing.co.uk/peugeot-2...-steel-76.html
   
   4-2-1
   http://www.kamracing.co.uk/peugeot-2...-steel-13.html
5. evans1089 Saxperience Post Whore Joined: Jun 2007 Chesterfield Posts: 8935 Ibiza Cupra 204bhp

   #5 10th June 2008, 09:37

   theres guide explaining this exact question...
6. Dax24 Infrequent Poster Joined: Aug 2007 Essex Posts: 189 mk1 Saxo VTS

   #6 10th June 2008, 09:38

   may be wrong about this as can just about remember but sure someone will correct me if i am. the differences are back pressure.
   the 4-2-1 has more seperation of the exhaust gasses for longer so that the gas can flow easier down and through to the exhaust which makes the car rev alot more freely. a 4-1 manifold allows the gasses to be released from the engine quickly but then build up again when the pipe joins to a 1, this allows the gas to flow quick at start but keep good back pressure for top end speeds/revs.
7. SaxoAlex Frequent Poster Joined: Mar 2007 Nantwich Posts: 692 '07 zetec S

   #7 10th June 2008, 09:57

   It explains it in the BIG exhaust thread. Its to do with if you want low to mid rev range improvements of performance or mid to high.
8. KamRacing Saxperience Addict Joined: Nov 2006 A farm shed in Aylesbury Posts: 14916 Corolla AE86 Peugeot 205 B18C (in bits)

   #8 10th June 2008, 12:42

   it is explained in the big exhaust thread so I won't repeat it all here except to say that replacing the o/e manifold will most of the aftermarket ones get you gains everywhere top / middle / low down.
   
   There are differences in the way a 4-2-1 and 4-1 perform and this is often dictate by the other mods on the engine; cams, headwork etc.
9. nufc70 L-plater Joined: May 2008 Trimdon, County Durham Posts: 59 CITROEN SAXO MK2 VTR BLACK 2003 (03 REG)

   #9 10th June 2008, 20:31

   Quote:

   Originally Posted by KamRacing it is explained in the big exhaust thread so I won't repeat it all here except to say that replacing the o/e manifold will most of the aftermarket ones get you gains everywhere top / middle / low down. There are differences in the way a 4-2-1 and 4-1 perform and this is often dictate by the other mods on the engine; cams, headwork etc.

   hi there was just wondering if this manifold > Piper 8v 4-1 Exhaust Manifold (Stainless Steel) from your site is a direct fit onto a MK2 vtr?? cos i know the raceland 4-2-1 manifold needs the oil filter modifying.
10. KamRacing Saxperience Addict Joined: Nov 2006 A farm shed in Aylesbury Posts: 14916 Corolla AE86 Peugeot 205 B18C (in bits)

    #10 10th June 2008, 21:19

    the piper ones are a direct fit..
11. Andy_OZ Infrequent Poster Joined: Mar 2008 Jersey Posts: 222 Saxo VTR 2003

    #11 11th June 2008, 18:34

    do the aftermarket manifolds do much in changing the note of the exhaust if attached to a full performance system?
    
    mk2 vtr i have so it would be decat aswell, or is it more a performance upgrade with no aesthetic benifits?
12. nufc70 L-plater Joined: May 2008 Trimdon, County Durham Posts: 59 CITROEN SAXO MK2 VTR BLACK 2003 (03 REG)

    #12 11th June 2008, 18:41

    Quote:

    Originally Posted by KamRacing it is explained in the big exhaust thread so I won't repeat it all here except to say that replacing the o/e manifold will most of the aftermarket ones get you gains everywhere top / middle / low down. There are differences in the way a 4-2-1 and 4-1 perform and this is often dictate by the other mods on the engine; cams, headwork etc.

    where do i find this 'big exhaust' thread i cant find it ???
13. Ashleyp Saxperience Hardcore! Joined: Apr 2008 Bedford & Manchester Posts: 17504

    #13 11th June 2008, 18:43

    http://www.saxperience.com/forum/showthread.php?t=87854
    
    read that