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Thread: R33 gtst calipers

  1. #1
    Guest jamesd's Avatar
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    R33 gtst calipers

    Hi all
    Fitted these to my S14 and not overly impressed with the braking. Seems to take a while to stop and I was expecting it to stop much faster.
    There's plenty of meat in the pad, bled properly and pedal isn't t hitting the floor but should they not be stopping on a penny nearly?pedal feel seems normal.
    Brake pads are a bit old but don't want to shell out 100 quid on pads if they may not be the problem

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    Member daveyboydave's Avatar
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    I'm by no means an expert, but there's a lot that can influence brakes. Just changing the calipers doesn't automatically guarantee a certain effect. For starters, are they bled correctly? Are the rears stock? What BMC do you have? Are the pads bedded in correctly? What discs?

    Pads can certainly have a dramatic effect on feel and stopping performance, but there are so many other factors too.

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    Member arry's Avatar
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    Could be as simple as sticky pistons - I'd have them off and just see if they're clean / moving freely as a first port of call.

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    Guest jamesd's Avatar
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    They are old I suppose so would make sense

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    As far as I'm aware, the GTST front brakes wont add any additional stopping performance compared to S14 callipers using the same discs and pads, they are just lighter so reduces the un-sprung weight. I believe the rears are better performance wise than the standard s14 1 pots but without the BM57 master cylinder the bias will be more towards the back which doesn't feel great.
    Could be worth removing the pads and scuffing the surface up with a bit of coarse sandpaper just in case they are glazed. Also check that your brake fluid is golden and not murky at all.
    Are you using performance pads or just standard?

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    Guest jamesd's Avatar
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    Oh I thought it was an upgrade. Have a bm57 cos I put z32 on the back. Fluid is new cos I did the full system when I replaced the calipers

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    I would say a sticky piston or pistons. I ran standard brakes for years on road and on track, and they are good. Any reports of SX brakes not being great is down to something wrong.
    As above, the GTST calipers are basically the exact same as the standard caliper except made from alloy as opposed to cast iron.

    Also are the pads old from another car? They may need braking in too.

  8. #8
    Guest speedingmofa's Avatar
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    Stock S14 brakes are 280x30mm
    R33 GTST brakes are 296x30mm

    The R33 brakes should perform better, period; it's simple physics: F x r = M. Meaning the R33 combined with the larger discs will apply more (braking) torque/power

    Both however have the same body (execept for steel vs alloy), pistons, are 4 pots and use the same size pads. Just longer 'ears' on the R33's

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    Quote Originally Posted by speedingmofa View Post
    Stock S14 brakes are 280x30mm
    R33 GTST brakes are 296x30mm

    The R33 brakes should perform better, period; it's simple physics: F x r = M. Meaning the R33 combined with the larger discs will apply more (braking) torque/power

    Both however have the same body (execept for steel vs alloy), pistons, are 4 pots and use the same size pads. Just longer 'ears' on the R33's
    Ah yes the R33 larger disks will be an upgrade but there was no mention of disks. Also if the old pads are off some other car, or from the same car and not put back in in the order that they are removed, there could be alot of bedding in needed before they sit flush against the face of the disk.

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    Quote Originally Posted by speedingmofa View Post
    Stock S14 brakes are 280x30mm
    R33 GTST brakes are 296x30mm

    The R33 brakes should perform better, period; it's simple physics: F x r = M. Meaning the R33 combined with the larger discs will apply more (braking) torque/power

    Both however have the same body (execept for steel vs alloy), pistons, are 4 pots and use the same size pads. Just longer 'ears' on the R33's
    Agree with this but I don't see that the slightly bigger disc will have an overwhelming effect on the braking performance to the point that the average person would notice the difference.

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    Guest Clouder_sx's Avatar
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    What pads?

    I remember the day I switched to DS2500s and wondered how I ever managed to stop properly previously.

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    Quote Originally Posted by Clouder_sx View Post
    What pads?

    I remember the day I switched to DS2500s and wondered how I ever managed to stop properly previously.
    Even standard pads should stop you well, up to the point of repeated stops and they start to cook.

    DS2500s are amazing, but they are very dear. I ran them for years but then switched to EBC Yellowstuff as they were half the price for same braking, but they are very dusty. But dust doesn't bother me too much.

  13. #13
    Guest rich damms's Avatar
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    I run re built r33 gtst callipers on the front with grooved discs and project mu pads with braided hoses. Massive improvement over the poor standard steel callipers.
    I have full r33 set up for rears but not fitted yet.

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    Quote Originally Posted by rich damms View Post
    I run re built r33 gtst callipers on the front with grooved discs and project mu pads with braided hoses. Massive improvement over the poor standard steel callipers.
    I have full r33 set up for rears but not fitted yet.
    I would say that is mostly down to them being rebuilt and good pads, as opposed to just cast iron over alloy having a difference in braking, as it shouldn't.

  15. #15
    Guest jamesd's Avatar
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    Sorry for not updating. They were bought as a set discs calipers and pads. Fitted a few years ago but car wasn't driven as was restoring. Passed the brake test on the yearly test when it went on the road but really not confident in it stopping urgently. Should I try new pads first in case the old ones glazed over?

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    Can you remove the pads and check if all pistons move freely in each caliper? Do you have a piston wind in tool? Like this?



    It will make life alot easier for pad replacements as well as this type of testing. The pistons should compress back in smoothly and easily. You could use a block of wood to limit the travel/ block off a piston against the disk for testing.
    Last edited by markcro; 08-02-2021 at 09:58.

  17. #17
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    And the obvious question, but just to rule it out, the bleed nipples are at the top and all four corners of the car are bled?

  18. #18
    Guest jamesd's Avatar
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    Ya they are. Bled myself and got the garage to do them too before the test

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    It might be time to whip them off and check that they're actually free and moving.

    They're not going to throw you through the windscreen but they shouldn't be dreadful like you're describing. Might be pointing to a sticky piston or similar.

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