Important! : big loss in back pressure.....loss in performance???

  1. Frequent Poster Joined: Mar 2007 Nantwich Posts: 692 '07 zetec S
    #1
    yo guys,

    soon, i will be in the market for a full exhaust system including manifold for my VTR.

    I have thinking about the "Supersprint mainfold", which would obviously de-cat the car, combined with the "Supersprint Race Exhaust System for Saxo."

    However, i am slightly concerned as some people have told me that with this setup, i would have very little back pressure which would lead to a loss in performance rather than a gain.

    So, do people think, would i be better with the supersprint mani and the 'Supersprint Race Exhaust System with Mid Silencer for Saxo' which would provide more back pressure????

    By the way, i am not bothered about the noise levels of the setup.

    Does anyone have either of these setups???
    cheers ppl
  2. Regular Poster Joined: Mar 2008 Camborne Posts: 287 Saxo VTR
    #2
    ive got a supersprint mainfold and full decat system and its great many people here will say the same for the price you cant beat it

    i'll wait for someone to explain about back pressure, its a subject thats been discussed many time
  3. Saxperience Post Whore Joined: Dec 2005 MaDchester Posts: 8432 Vts
    #3
    get the one with the middle box as itll give more back pressure and itll still sound mint and give the best performance
  4. Frequent Poster Joined: Mar 2007 Nantwich Posts: 692 '07 zetec S
    #4
    Quote:
    Originally Posted by megabob View Post
    ive got a supersprint mainfold and full decat system and its great many people here will say the same for the price you cant beat it
    cool thanks. can i ask if there was much noticible difference in performance with this system? I take it performance didnt suffer because of the lack of back pressure?

    Quote:
    Originally Posted by b0t13 View Post
    get the one with the middle box as itll give more back pressure and itll still sound mint and give the best performance
    Ok, i might. However your sig says you have a raceland mani and magnex with decat..... surely your contradicting yourself slightly? And again, how did your car change with this system. Thanks.

    BOTH REPPED
  5. Saxperience Forum Bum Joined: Dec 2007 Brighton, East Sussex Posts: 3577 saxo 1.4 westcoast, vts
    #5
    yeah go for the one with the silencer in the middle i didnt and have seriously low back pressure
  6. Regular Poster Joined: Mar 2008 Camborne Posts: 287 Saxo VTR
    #6
    well i got a new vtr engine at the same time so for me it was a big improvement but if you search around you'll see loads of positive comments
  7. Saxperience Post Whore Joined: Dec 2005 MaDchester Posts: 8432 Vts
    #7
    my magnex has a middle box and backbox, the decat and manifold. magnex make two systems, with silencer and without.

  8. Saxperience Addict Joined: Nov 2006 A farm shed in Aylesbury Posts: 14916 Corolla AE86 Peugeot 205 B18C (in bits)
    #8
    Quote:
    Originally Posted by b0t13 View Post
    get the one with the middle box as itll give more back pressure and itll still sound mint and give the best performance
    it doesn't. the extra silencer reduces the gains when compared to the full race setup.

    My understanding of how exhaust systems work is thus:

    At its extreme a small diameter exhaust will restrict flow (creating backpressure) but have high gas velocity
    but the restriction of flow hurts performance

    a large diameter will have no backpressure and low velocity of gas
    but the low velocity hurts performance.

    so really you want a system that will create minimal restriction to the flow but maintain a high gas velocity. When looking at the centre pipe options that means a pipe with no cat / no silencer and mandrel bends

    Silencers are not a performance mod. The straight through designs minimise performance loss but the most efficient exhaust is one without the silencer. Performance at the expense of noise