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looking for info on building a forged engine

karl210 Aug 7, 2012

  1. karl210

    karl210 Member

    Hi there, My s3 hasnt been feeling 100% from day one and everyday i feel like i loose that bit more power.
    After all the car has done 175k! so instead of replacing parts willy nilly and never have it running 100% due to the allover wear im thinking about saving up over the next couple of months and starting an engine build.
    The car will be used for daily driving but a reliable 300-350bhp would be what i am after, i'm just wondering what options i have and what people think is the best way to do it?

    eg: Buy a used lowish mileage engine, stick some forged rods in it etc etc or is a 175k mile engine save'able? by re-honing the bores and a new set of piston rings and bearings all round? obviously the second option would be cheaper but is it worth the hassle? Its starting to get tappy on startup so i dont think theres much life left in the oil pump as ive already cleaned the oil pickup pipe out.
    I have built engines before and i have built 1 forged engine which was a ford crossflow so im sure with a bit of learning over the next couple of months i am definately compatent enough to do it myself.

    If buying a used engine and sticking rods in it is the way to go which engine codes should i be looking at? my engine at the moment is AMK, also what would be needed to get the figure i want? Is this figure acheived with forged rods, standard pistons and which turbo would be best? injectors? i dont mind lag but i do want the car to be driveable off boost which it isnt at the moment, i even bloody stalled it yesterday as it has 0 power below 3k.
    Im not going to be doing this straight away but a heads up would be great so i can get learning and saving, thanks

    Obviously it goes without saying brakes and suspension definately need to be uprated as theyre on par with a boat at the moment but i can deal with that lot in the mean time, i was thinking about getting a mk5 golf r32 as i came from a mk5 golf and i do like them, but it will be cheaper to do this and i do enjoy tinkering with and tuning cars so why not ey, you only live once.
    Last edited by a moderator: Aug 7, 2012
  2. <tuffty/>

    <tuffty/> Badger 5 Edition...Its all about the flow... Staff Member Moderator Audi S3

    Most engines at 175k will have quite a bit of bore wear even if they may continue on with fairly moderate tuning it wouldn't be the best for 350hp on a daily tbh..

    You could go out and buy a donor bottom end but there is no way to tell easily if its going to be any better than what you have as a base..

    Personally I would be looking to rebore, new pistons, rings, big end shells, main shells, thrusts, crank seals, drilled rods, mains bolts with a bottom end balance...

    OEM pistons are good for 400hp and on the 210/225 blocks are 9:1 comp ratio as std... you could get an over size set to suit the rebore or go for aftermarket ones like JE's and go up a ratio to 9.25:1 or similar

    Plenty of build threads on here to look at... best turbo is an open question and depends what you want out of it... to get a reliable 350hp then hybrid K04's are out the window so your are moving into GT2871/GT3071 areas... then things change a bit... as does the potential budget..

  3. karl210

    karl210 Member

    cheers tuffty, i would be worried about re-using my engine as the top end is tapping on startup quite loud but even when warm there is still noticable tapping coming from the exhaust cam side, plus if i do fork out for a new engine i could take my time and not worry about rushing to do it in a week so i can drive again. Obviously i want to do it cheap as possible and not be buying things i dont need like aftermarket forged pistons etc.
    What would be the best engine codes to be looking at? and i can start the hunt obviously i would want a large port head and the other benefits of certain codes.
    Turbo wise yeah i was thinking between the gt28 and the gt30, i will have to do some revision on the benefits of each turbo and if the 28 can flow enough for 350bhp daily without pushing out too much hot air, and definately go front mount.
    So if i was to get:
    AMK engine
    IE rods? is it all about the rifle drilled rods or arent they needed for this spec?
    full bearing and shell set, piston rings and all seals, belts etc
    3 bar fpr?
    uprated fuel pump?
    gt2871 turbo
    exhaust manifold?
    r32 throttle body?
    custom mapping
    uprated clutch
    bore hone
    diy port+polish with all valves re-lapped and head skimmed

    would i be cooking with gas?
    is there anything ive missed or anything in that list i dont need? any info would help alot as im looking up as much as i can but can only take in so much, thanks
  4. moredoor

    moredoor Member

    550cc or 630cc at 3 bar will cover your needs, 440's at 4 bar will also do at a push.
    Std throttle body isn't an issue at 350hp.
    GT28 71 ftw
  5. karl210

    karl210 Member

    i really need to make my mind up, i met a guy the other day who is breaking a couple of s3's and he is selling a k04 hybrid, he says he paid 1300 and got it from TurboDriven.com - BorgWarner Turbo Systems how would i know if it was a hybrid? i had a look at it but it looked normal to me.
  6. beachbuggy

    beachbuggy Well-Known Member

    Get a picture of the compressor wheel inside the housing and also one of the turbine wheel, very easy to tell if it's a hybrid from a picture

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