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mbc install

Discussion in 'A3/S3 Forum (8L Chassis)' started by s3dave, Jun 13, 2010.

  1. s3dave
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    s3dave TFSI Hybrid

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    had a go at fitting one with poor results....
    fitted direct and could only get 8psi out of it...:ermm: i left the n75 valve electrically connected
    what have i done wrong??
    Last edited: Jun 13, 2010
    #1
  2. Andrew@A.L.D
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    Andrew@A.L.D Cylinder Head Master

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    where did you plump it in?
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  3. s3dave
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    s3dave TFSI Hybrid

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    i just took the pipes off the n75 the charge/boost pipe, and plugged that into the vertical barb on the mbc and pulled the pipe of the n75 that goes to the actuator and pluggled that into the right angle of the mbc
    should i have blocked the n75 open tubes?
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  4. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    What MBC have you got? put simply, take the pipe from the bottom of the N75 and connect to the boost side of the MBC then the outlet goes to the pipe connected to the smaller side outlet of the N75... leave the longer side outlet of the N75 connected to the TIP and block off the other 2 (this stops vacuum leaks)...

    Make sure the MBC is set low then work up from there...

    If you are only getting 8psi I would imagine you must have it wound right in or tripped limp mode as thats actuator pressure... the same as connecting the boost pipe straight to the actuator..

    <tuffty/>
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  5. s3dave
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    s3dave TFSI Hybrid

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    thats how i have done it but i did not block the n75 up.. i did have it screwed right down i thought that was more boost... :keule:i will try again tomorow cheers
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  6. Sandip
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    Sandip Well-Known Member

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    Interesting:) What are the main benefits for having a mbc, if my car is boosting 19psi how would a mbc help?
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  7. s3dave
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    s3dave TFSI Hybrid

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    you can manually turn your boost up/instead of the ecu telling it how much with one, but must be made aware of the consequences of overdoing it on standard internals
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  8. Sandip
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    Sandip Well-Known Member

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    Hmmm may have to purchase one on these:)
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  9. sportstractor
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    sportstractor Chugger

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    I have read of people coupling these in parallel with N75 to give better delivery apparently. Surly if the boost diviates command boost its just going to bring on limp mode though.

    Slighty off topic but if any body knows, does the S3 management limit boost in lower gears like some cars?
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  10. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    The management doesn't know what gear you are in, just how much load you are applying by measuring manay factors.
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  11. Chlippo
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    Chlippo Member

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    I am very interrested getting a mbc (forge unos style) on my stock car.
    I would try get some more boost without mapping the car.
    I need someone to confirm me on this one, when mbc installed, and setted for lets say 10 psi more than the stock, will the ecu throw an order to get more fuel injected to covver the extra boost?
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  12. badger5
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    badger5 RIP S3dave Site Sponsor

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    the ecu will drop into limp is <>250mb of requested is seen, so what you propose wont work, whilst also being stupid to try on youre engine without ign and fueling to suit
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  13. Chlippo
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    Chlippo Member

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    I wont gonna try 25 PSI and expect my engine to run great! just a couple of psi's

    If the ecu wont cover anything, what is the main goal of installing the mbc.
    After i remap my car, dpipe, panel filter, 007 forge, i was thinking getting an mbc and set it at the same boost level as my map. (maybe 20 psi)

    Thanks Bill for the info :) i needed someone to get my ideas more clear
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  14. Danny Cawsey
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    Danny Cawsey Cawsey

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    sorry to hijack but has anybody fitted an electronic boost controller to there s3 and which one to go for?
    i have a 1999 apy s3 stage 2 would it be safe to to run one?
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  15. badger5
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    badger5 RIP S3dave Site Sponsor

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    EBC's can be good, however, just adding one to an unmapped car wont help much, as the deviation in request vs actual will drop into limp mode.
    some maps have the limits mapped out, most dont, so its not 100% adding an ebc to get external control, will be successfull. taking away the ecu's ability to control its boost can cause other drivability issues.
    MBC being added to clip a spike however is quite sensible, and tweaking to the limit of the ecus limp mode threshold is possible, BUT, must be done in conjunction with logging of fueling and ignition timing pull to avoid disaster.

    std rods and spikes of boost/torque are not a happy pairing.
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  16. Chlippo
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    Chlippo Member

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    Got that sir! Thanks again
    I will forget about the mbc for now, since i am not really able to get logs of fueling and timing, and cant see any advantage in having one even if the car is mapped and got some little mods
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  17. Danny Cawsey
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    Danny Cawsey Cawsey

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    cheers badger for the info.
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  18. Matt82
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    Matt82 Active Member

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    i think prawn was posting a couple months back that with an MBC his was holding consistent boost to the red line etc but does it get rid of the ko3's stupid tendency to spike the boost?

    im tempted with an MBC if i can even out the boost delivery
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  19. Westy
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    Westy Double Dark Side! Diesel & 8P

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    These babies used to be known as the "wheel of fortune" back in my R5 Turbo days! You wind it up too much and pop :eyebrows:
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  20. Welly
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    Welly VX220 SC Driver :)

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    That can be done, but if thats what you're after then it can be run in parallel with the N75 to even out boost spikes.
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  21. Matt82
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    Matt82 Active Member

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    can you point me in the direction of the right info? id love to know more

    hmmm boost guage. i dont want her car looking like the set from 2 fast 2 furious!
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  22. Welly
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    Welly VX220 SC Driver :)

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    Good info here:

    http://forums.audiworld.com/showthread.php?p=13285925

    That should be all you need, the diagram says it all. A picture says a thousnad words and all....

    The boost curves are interesting too....
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  23. Chlippo
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    Chlippo Member

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    lol so to conclude: Mapped S3 + MBC (any of those even a cheap one) is supposed to run better and safer than an S3 without the MBC, In parallel with the N75.
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  24. sportstractor
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    sportstractor Chugger

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    apparently, but cant see it myself. If you have a good map that should give same results. Like said if the boost levels diviate the mapped levels by 250mb, then it will throw in limpwilly mode then the car will be no fun at all.

    Not sure about prawn having an MBC on his agu, but he did fit a EBC on it with poor results, apparently it was just **** on part throttle.
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  25. Welly
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    Welly VX220 SC Driver :)

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    I had one on my old AGU and also had crappy result on part throttle. That is what the MBCs lack. Adaptability. The ecu knows you are at part throttle, so doesn't give the turbo full chat.

    MBCs are either on or off basically, which makes part throttle riving less enjoyable.
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  26. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Part throttle on mine is certainly different but not undrivable on mine... maybe the later spool of my BT helps matters here but the car is certainly more responsive but perfectly well behaved off load..

    <tuffty/>
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  27. s3dave
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    s3dave TFSI Hybrid

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    i think most stage two have the diveation deleted from the ecu even stage 1, i know mine as gone ...fact ...lol
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  28. s3dave
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    s3dave TFSI Hybrid

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    no luck with my mbc it must be broke.... i will make my own......cheers fleabay....lol
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  29. Chlippo
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    Chlippo Member

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    Ill buy one of the forge unos with the 007 DV and after i get my remap and the 3" dp, i will set it a tiny bit higher than the map values...see what it gives.
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  30. Welly
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    Welly VX220 SC Driver :)

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    The MBC I bought from ebay was also useless, but on the other hand, bought one from there in the past and it was great.

    A bit hit and miss. The one I had was made by Powertek - wouldn't hold a stable boost setting AT ALL.

    Last one I had was made by R Spec and was 100% bloody brilliant.
    #30
  31. s3dave
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    s3dave TFSI Hybrid

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    yeah same here bought one for my golf that was spot, on this one is :puke2:
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  32. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Forge UNOS ftw :)

    I had probs initially when using the softer spring but changed it to the supplied harder spring and mine is rock solid 1.7bar on boost

    <tuffty/>
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  33. s3dave
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    s3dave TFSI Hybrid

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    just fitted another... whoop whoop 27psi all the way baby and got the car drifting on boost...:arco:
    need to watch intake temps now as i have no fmic yet:sadlike:
    Last edited: Jun 18, 2010
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  34. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    You have rods? I would seriously turn down the boost if you haven't and get logging the fuelling in VAGCOM... intake temps will be the least of your problems mate to be fair...

    <tuffty/>
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  35. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    ooooooooooooooooooooooooooo interesting
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  36. badger5
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    badger5 RIP S3dave Site Sponsor

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    I will be waiting for the post where it has blown up
    should'nt be long


    you have just wound it up daft high
    any logging done to see how things are running on timing pull, fueling, egt's etc is a recipe for a serious engine failure

    seriously unwise leaving it at this level Mr
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  37. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Sweet baby jesus! 27psi :superman:
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  38. s3dave
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    s3dave TFSI Hybrid

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    not really mate apart from the fmic, all internal work has been done, and a hybrid turbo, need to get the fmic done asap then custom map then im off :yahoo:
    #38
  39. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    You have rods then I assume... still need to keep an eye on the AFR and EGT's though bud... 27psi is more boost than I run on my GT30!!! lol

    <tuffty/>
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  40. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    ....and should be pointed out that 27psi is prob a tad too high for a little turbo like the K04 hybrid or otherwise... I think thats how S3 Paul ended up lunching his engine....

    <tuffty/>
    #40

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