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wthcar

Toyota 86 Gt 2014 Brake modification

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Hello guys, I need help with some information...

Does anyone know where to find the information of the original Toyota 86 GT 2014 brake system manufacturer specification. Because I'm about to do my Report assignment for mechanical upgrade, where I decided to replace from the normal brake system on the Toyota 86 GT to big brake (the size of the original master cylinder, brake calipers front and rear, rotors, pads, etc). So that I will know any tolerances/clearances and wear allowances with the new modification. 

And also how do you find a full big brake kits, because all I can find is that they only sell the front without the rear.

 

I really appreciate for any comments from you guys.

thank you in advance. 

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Why have you decided to replace? Do you have planned particular usage that stock doesn't do well? Done right, upgrade to BBK is not cheap, without actual need (if for example you only daily drive yours) you won't experience pros of BBK (mostly higher heat capacity/better cooling rate) but will have to suffice cons (except obvious spending a lot of money for naught, also reduced compatible wheel selection, sometimes requiring buying new wheels and tires, possibly narrower compatible pads selection, possibly less resilency for corrosion issues if driven throughout winter with roadsalt and it's race caliper w/o dustboots & dual-piece rotors, sometimes extra noise issues). Done wrong (where i write off retrofitting used calipers from other cars with different layout/weight distribution/master cylinder ratios, considering only mechanical fitment and cheapness) may make braking even worse, introducing extra instability under heavy braking or making longer braking distances, depending to which direction such brake swap shifts front-rear brake bias.

In most cases for daily driving stock brakes are best choice. One already has them "for free", they are more then sufficient for most uses except long sessions on track, have much better wheel clearance allowing fitting most wheels including downsized ones, there are plenty of different pads for any taste available, and they are certainly MOT legal (for example here in LV legally most BBKs won't let pass MOT), and manufacturer engineers have spent lot of time to get brake bias fit best for this particular car.

Not sure why you need to know piston size/master cylinder size and other data for BBK upgrade. One just should choose BBK designed for these car models by reputable vendor that should dial with keeping brake bias close to stock, then all you have to care for, caliper wheel clearance. For later on BBK manufacturer sites usually there are downloadable brake fitment templates, which one can print out, glue on carton, cut out and check with own wheels or ones that planning to buy, if they clear particular BBK. Or if vendor lists wheels of checked clearance, or if such info on particular kit can be found in forums.

Who are "they"? There are several manufacturers/vendors making/selling BBKs for twins, often even several BBK models. There are plenty aftermarket parts shops that sell parts online. Yes, some BBKs are front-only and that's OK, if they are designed to work with stock rear brakes & retain brake bias (as fronts do most braking, and in this fashion one can reduce upgrade costs). Some upgrade both fronts and rears. There are many kits available for twins.

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Mostly it is (prerestyle GT86 with maybe a bit different interrior or exterrior trims like seats/lights/headunit/logos). Though if you delete portion of url, there was link also for 2017 USDM 86. Only exceptions should be very cheapest trim twins in AUDM/JDM with R16 wheels and non-ventilated disks (though briefly there was such also in UK), and also MY2017 BRZ with performance package or GT86 blue edition, that had optional Brembo brakes. Otherwise most twins had same brakes (IIRC fronts were also shared with WRX, and rears with Legacy GT). But specific OE brakes specs shouldn't matter much in BBK choice unless one is doing retrofit from other car, which one shouldn't. Or unless specific BBK vendor spent little care to retain brake bias when cooking up their kit, but then one shouldn't be considered to purchase too, unless other mods on car will work better with shifted bias (eg. heavy aero downforce on one end of car, uneven removal of weight of car, weight distribution change from changed rake and such. But if it's specialized tracktoy modified to great extent, it's possible that one also installs brake biasing valve and then differently biased brakes are not needed too).

wthcar: if you don't track your car, and if you don't do long track sessions (i feel fine tracking mine for 15min sessions with stock brakes with upgraded pads & fluid), then imho you don't need to invest in BBK (and maybe also wheels) 1-3K GBP, so imho worth reconsider how much and IF you need. If it's for looks only, you may consider painting calipers, or buying some covers that make it seem like you have BBK. If you only daily drive but want shorter braking distances, upgrade to grippier tires (and maybe pads, if current stock pads are insufficient to lock wheels/trigger ABS, after grippier tire install), as BBK that can brake more, won't stop car sooner, if stock brakes are still capable locking wheels, it will just change how much brake pedal will travel till wheel lock, not braking distance. Only real advantage BBK brings - increased heat capacity, which if you don't need, no actual/functional need for expensive purchase.

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The reason you don't need a BBK at the rear is that with greater front braking from a front BBK, you'll get more weight transfer to the front - and away from the rear - during hard braking. This reduces your capacity for braking at the rear, since friction force (between tyre and road) is proportional to normal force (vertical load), and you've reduced the vertical load. Up to a point that's not a problem, as long as the car is still limited by front tyre grip under braking you're all good.

If you then add bigger brakes at the rear, you'll be moving the rears closer to locking again (in reality, triggering ABS). Contrary to what you might expect, a rear BBK will likely increase your braking distances because you'll become limited by your rear tyre grip and those tyres already had less grip than the front tyres. You'll also increase your chance of binning it on track if you try and trail brake!

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On 6/11/2020 at 2:33 AM, wthcar said:

Hello guys, I need help with some information...

Does anyone know where to find the information of the original Toyota 86 GT 2014 brake system manufacturer specification. Because I'm about to do my Report assignment for mechanical upgrade, where I decided to replace from the normal brake system on the Toyota 86 GT to big brake (the size of the original master cylinder, brake calipers front and rear, rotors, pads, etc). So that I will know any tolerances/clearances and wear allowances with the new modification. 

And also how do you find a full big brake kits, because all I can find is that they only sell the front without the rear.

 

I really appreciate for any comments from you guys.

thank you in advance. 

Impreza sti hatch rear brembos and discs fit.

I have never driven mine on a track although I have driven a brz with rear brembos on track so don't believe the tosh about it ruining braking. 

It improves the car without question 

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