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Thread: brake upgrade technical Q

  
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    brake upgrade technical Q

    Hi, Planning on building a mk4 1.8 sri track car after xmas. I know nova's/corsas inside out. This will be my 4th mk4 astra (currently have a prodrive kitted sri as my daily driver) I know the mechanicals on the astra off by heart, just im not that clued up on what the best upgrades are, as my astra's have always been my sensible car, so mods were minmal.

    Ive tried searching, but all i seem to get is people on 4 stud being told to upgrade to 308mm gsi brakes.

    Anyway, im wondering what will be he best setup on a budget (so alcon 4pots arent first choice) Car wil have a 250-300bhp z20let fitted

    Firstly, the fronts:
    what size disks and calipers will fit under a 17" wheel? 322mm?(what models do they come on std?)
    or will it have to be astra gsi 308mm ones

    Rear:
    Do i just stick with the std sri later spec setup (what size ar these?) Or is there a worthwhile upgrade?

    Will upgrading the calipers require bigger master cylinders to improve pedal feel?
    Gary

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    Joereynolds89's Avatar
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    322 are standard on astra vxr, second hand sets can be picked up between 200-300 and fit under 17s...

    308s with decent disk/pad set up will be fine running 250bhp! Will fit easy under 17s and can be had for 100-170

    Apparently iirc you dont feel much difference between the 322 to the 308s on a mk4 astra

    Personally ive never seen the need to upgrade the size of the rear brakes unless running silly power, good disk and pad set up is more then sufficient

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    thats great, Have you heard of anyone making/buying/using mk4 gsi calipers with spacers to fit 322mm disks? (these type of kits are available for other vaux stuff, eg 16v calipers and 288 disks rather than the std 256mm ones)

    bigger disk = more leverage (think on tightening a bolt with a breaker bar, rather than a ratchet)


    Also what master cylinders are on the vxr? (as even between my mums mk5 1.8 sri, and my mk4, the pedal feel in the mk5 is amazing, so sensitive)
    Gary

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    i dont think you would need that much power for your first track car. imo
    Astra VXR - Arden Blue, Diamond cut 19's, Cruise Control, Debaged, Folding Mirrors, CD70 NAVI and CID + Aux-In, Factory Bluetooth, Piano Black Interior Trim, Full Milltek Unresonated Exhaust

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    Quote Originally Posted by rizo View Post
    i dont think you would need that much power for your first track car. imo
    No point building something slow to then have to re-do it. Ive had the nova on track (1.6 16v, 176bhp, sbd tb's, cams, headwork, forged pistons, steel rods,quaiffe lsd etc.. and through the corners its quicker than my mates 250bhp let mk3 astra, and keeps up with alot of expensive stuff, just on the straights the turbo boys have the edge.

    Plan was to either convert the nova to full track spec, but im going to get another summers use/show season out of it. And build the astra instead (also fancy something turbo'd as all my previous cars were n/a) Im just trying to get a basic spec written up, so i can source parts, and complete the project in 4 months.
    Gary

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    back to the top
    Gary

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