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Thread: zetec turbowith let pistons

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    zetec turbowith let pistons

    Hi guys,
    ive done various searches and come up with lots of differing answers,

    what cr would i expect to get from this setup and what head gasket would be best
    the plan is to have an engine capable of 250-300bhp using a t34 or similar turbo

    st170 cylinder head
    silver top 2 ltr bottom end bored to 86mm standard deck height
    standard c20 LET pistons
    williams rods to take vauxhall pistons 136.25 x 49.90 x 21.00 mm



    hope thats enough info, any advice welcome



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    Re: zetec turbowith let pistons

    Over complicating things for that power level. Standard blacktop will do 240bhp and blacktop head with st170 bottom end will do over 300

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    Re: zetec turbowith let pistons

    see what you mean but ive already got the bottom end which is bored to 86mm and been offered the pistons and new rods for £400 so sort of makes sense to have a good strong bottom end thats not on the limit, its also most likely going in a fwd mk3 escort so silver top is easy for waterpumps/ alternator etc

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    Re: zetec turbowith let pistons

    as far as the compression ratio goes your just going to have the do a trial build and measure pistons height, combustion volumes etc

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    Re: zetec turbowith let pistons

    Thanks Graham but as its been done many times before i was after a rough guide before i buy the parts in case its too low without having the deck blocked etc

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    Re: zetec turbowith let pistons

    not sure about many times, if its been done that much then the info will be out there.
    i cant help as such but a couple things come to mind,
    1, you dont even try such a build if your not prepared to deck blocks etc,
    2, with a boosted engine the 86mm bore isnt going to benefit its just going to weaken the block
    3, buying parts just because they are cheap rarely works out cheap or best in the long run

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    Re: zetec turbowith let pistons

    Pretty sensible points. 'Cheap build' turbo installs usually end in tears (particularly if std. cast pistons are involved!)

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    Re: zetec turbowith let pistons

    Quote Originally Posted by Graham View Post
    not sure about many times, if its been done that much then the info will be out there.
    i cant help as such but a couple things come to mind,
    1, you dont even try such a build if your not prepared to deck blocks etc,
    2, with a boosted engine the 86mm bore isnt going to benefit its just going to weaken the block
    3, buying parts just because they are cheap rarely works out cheap or best in the long run

    all very good points m8, think ill just pass on the bits ive been offered

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    Re: zetec turbowith let pistons

    About 15 years ago i did a 2ltr Zetec turbo , from memory this is the spec ... there was 8 injectors so it ran on the stock 4 Puma injectors until @ 8psi then all 8 kicked in ...

    Scrapyard 200k 2ltr "silvertop" bottom end (acid dipped & decked)
    Scrapyeard stock head " acid dipped refreshed" with stock cams & Piper valve springs re-cut valve seats and skimmed.
    Stock crank on a standard grind and OE shells.
    Stock rods / shot peened & APP rod bolts
    Stock MLS head gasket and bolts
    CE 20 LET pistons ... pretty sure it was @ 9.1cr
    Spark plugs 1 grade cooler
    1.8 Zetec escort alley inlet manifold with 4 extra injector bosses welded underneath
    8 1.6 Puma injectors.
    Stock 1.8 zetec sump with boss welded on for turbo drain.
    Escort RS Turbo stock exhaust manifold / head re-drilled to suit bolt pattern.
    Turbo was a mixture of T3 and SAAB (water cooling not used)
    Stock zetec flywheel
    Mk 1 Focus RS AP clutch
    Stock RS 2000 gearbox with APB LSD and ST200 crown wheel and pinion (Had to mod inside the gear housing so that the AP cover would fit inside)
    Pectel T2 mapped on Harvey Gibbs SCS Superflow dyno

    In the end it made 272 hp & 315ft @ 3200rpm @ 19psi and it went like a freshly fooked cat !
    Last edited by Dan Johnston; 10-01-2018 at 15:34.

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