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2.7T CAI / airbox/ BMC-CAI help

Discussion in 'A4/S4 forum(B5 Chassis)' started by OllyS4, May 15, 2008.

  1. OllyS4
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    OllyS4 Member

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    [May 15, 2008]
    I've been looking at getting a induction kit for my S4.
    When i looked at my air box i noticed two sensors plugged on to the top of it (not the MAF) what are these?
    Do most induction kits account for this and incorporate it?
    Aspecilly a BMC kit because thats the one I'm ideally after.
    Any info or help appreciated.
    #1
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  3. ALPINE
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    ALPINE Yes its diesel, now cry u lost

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    [May 15, 2008]
    that little sensor needs to be keeped cold as they get very hot. thats all i know on them, i have a small induction pipe running purley to this sensor to keep it cool, it runs fine.

    if you look in the air box mod thread you will see pics of my induction, and in bottom left corner the tied back sensor in question.
    #2
  4. Siena
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    Siena Active Member

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    [May 15, 2008]
    The 2 sensors on the S4 airbox are the ignition amplifiers (Power Output Stages).

    My advice as per an induction kit for your S4?
    Don't bother.
    #3
  5. OllyS4
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    OllyS4 Member

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    [May 16, 2008]
    Thanks for the info.
    The air box intake slot looks very small, has anyone managed to fit a kit on a 2.7T with no probs?
    Maybe a modded air box might help instead with a good filter.
    #4
  6. docurley
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    docurley Moderator Staff Member Moderator

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    [May 16, 2008]
    RS4 setup

    [​IMG]

    S4
    [​IMG]
    #5
  7. andybnwc
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    andybnwc Member

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    [May 16, 2008]
    I got that kit on mine , does not come with the rubber connector to the original air intake in grill also, the piping to that was rubbish and kinks when bent notice the very sharp angle
    #6
  8. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [May 16, 2008]
    tbh its a turbocharged engine and imo your wasting your time with induction kits etc

    by all means enlarge the intakes on the stock airbox if you feel they are restrictive, but as for "Cold Air Induction" do you really think that when your driving along with wind blowing through the engine bay at 30/40/70/90mph that theres going to be a build up of heat? Its ********, you might get some heatsoak with the car sitting stationary but otherwise forget it.

    Not to mention the fact that after the air flows along about a foot of pipework it gets dumped into a compressor and heated up to 80C or something. Spend your time/money fitting larger intercooler/s and make some larger holes in the stock airbox if you wish some extra noise (pre filter remember)
    #7
  9. stapo69
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    stapo69 All hail the mighty quattro!

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    [May 16, 2008]
    I bought this set up from the states, by far the best I could find, and the only one that seem to come recommended, doug at MRC has fitted a couple, emailed him and he said they worked well.

    Uses the standard cold air intake and seals completely against the bonnet when shut.

    Not cheap by any means though, and only available from the states. Explains all on the site though, and emailed em a few times, very helpful guys.

    http://sdr-research.com/x1/intake.htm
    #8
  10. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [May 16, 2008]
    companies can make all these claims but any experimentation they do is always biased... a pressure drop in the inlet of a whole PSI could be seen equally with a panel filter in the stock airbox with enlarged openings, costing about a tenth of the price.

    I had an air temp sensor fitted in the inlet tract on my old car just to see what kinda readings the cone filter would give without any form of shielding or ducting and sure enough as soon as you were moving at anything more than about 10mph the temps were within 1c of ambient.

    If i get a chance i'll try to get some readings from the A4 comparing the stock airbox with the stock ducting and the stock airbox with some holes drilled in it.
    #9
  11. OllyS4
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    OllyS4 Member

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    [May 16, 2008]
    So very good points there by all :thumbsup: keep them coming.

    I am stating to go towards a good panel filter and mod the air box, i also need the standard cold air feed, because it didn't come with the car when i got it.
    #10
  12. audivro
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    audivro Member

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    [May 18, 2008]
    Manufacturers spend the income of small country's designing air box's,Unless it is an overly restrictive airbox they really are the best way to go.Most manufacturers,audi included,design very efficient induction systems which provide good torque(probably the most influential in road use) good economy and reliability.When i tested various setups on a rolling road for my gt4 i found the airbox to be as good as if not better than the HKS,BLITZ and a CAI.The BLITZ and HKS gave 2 bhp more but that was when the airflow was at its greatest at around 6400 rpm!!!These are the open filter types and gave drops in power at all other times...although they sounded nice!The cai gave around the same torque and bhp but for the £320 it cost was no better than my airbox with a panel filter.

    So in short,standard air box,air flow modded,panel filter(non oiled type so not to fubar tha maf) and save the rest for something shiny!!!!:w00t:
    #11
  13. mwarrey
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    mwarrey Member

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    [May 18, 2008]
    Anyone recommend a good non oiled filter for the s4 ?
    #12
  14. audivro
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    audivro Member

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    [May 18, 2008]
    i think the green cotton filters are still non oiled.Have'nt seen one for a while though so could be wrong.
    #13
  15. docurley
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    docurley Moderator Staff Member Moderator

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    [May 18, 2008]
    well this thread reminded me of the CDA/BMC I had in my old 2.8 that work real well so I had a hunt round ebay and with that snipe Auction thing I one this Link.


    So at some point I will be dropping it in.:happy:
    #14

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