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The mkiv Supra Owners Club

Brake upgrade


Chris and Alana
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Hi guys, I fancy upgrading my brakes soon and have a couple questions and could do with some opinions please. I currently have a full J-spec setup that seem to be working fine. I dont do any track day's just the occasional spirited driving moment. Anyway I'm not sure whether to do the following with my J-spec's:-

DOT 5.1 fluid

Fast Road Pads (endless possibly) (Front and Rear)

3G Drilled and Grooved Disks (front and Rear)

Goodridge Braided Lines

 

Approx £500

 

Or buy a new set of UK callipers (Front and Rear) and do a similar thing but the price would be more around the £1200 mark.

 

I know the UK setup would be the best option but would I really need it. What are peoples experiences with upgraded J-spec brakes? Do you find they do the business?

 

Also if I bought a set of braided lines would they fit the j-spec calipers and the uk calipers or are they specific?

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This is my next upgrade too, I had quotes of Gaz for uprated jspec 3g disk and endless pads, braided hoses and high heat fluid.... i'm not sure its worth spending a huge amount for normal driving personally :) I'm going to the ring next year with a few mates so I thought the above would be good :)

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Full set of UK's - no question. I did it to mine and they totally transform the car. It always amazes me that people are willing to spend £000's on power 'upgrades' and pay no attention to the brakes. My opinion only, having done it myself - others may disagree.

Maybe your best option is to try a car with UK's on and make your decision then.

Goodridge hoses are the same for both UK and Jap calipers.

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Full set of UK's - no question. I did it to mine and they totally transform the car. It always amazes me that people are willing to spend £000's on power 'upgrades' and pay no attention to the brakes. My opinion only, having done it myself - others may disagree.

Maybe your best option is to try a car with UK's on and make your decision then.

Goodridge hoses are the same for both UK and Jap calipers.

 

:yeahthat:

 

I didnt do any mods that increase power until i had UK brakes.

Saftey comes first in my eyes :)

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thanks for the input guy's :) Second hand UK callipers may be an option if I can get them. Does anyone know how much a refurb kit cost for a full UK setup (all four callipers)? If I was into lots of track action I would definitely get the larger brakes but I'm not. I do think safety is important and brakes, suspension, tyres etc shouldn’t really be skimped on but would the larger brakes be overkill for road driving and therefore an unnecessary expense. . . . Toyota seemed to know what they were doing when they made the supra and they must of thought the j-spec brakes were good enough, surely, so upgraded j-specs should be more than adequate for road use, or am I barking up the wrong tree.

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Around £20 - £25 for the front and the same for the rear is what I was told, might be wrong on this though.

 

Per caliper yep.

 

If your not doing any mad driving, stick with the J-spec's with the upgraded parts Chris, it will make the stock setup significantly better.

 

Gaz.

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I use the 8 pot D2 setup, anyone thats been in my car will tell you how well it stops, full kit is about 1k from ebay i think.

 

Yeah, but thats for the front brakes only... what about the rear?

 

Per caliper yep.

 

If your not doing any mad driving, stick with the J-spec's with the upgraded parts Chris, it will make the stock setup significantly better.

 

Gaz.

 

I stand slightly correct :D

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if your disks are not worn out forget uprated ones. IMO its the pads and braided lines that will give you the better bite/pedal feel and resistance to fade on repeated braking.

 

All things (pads disks etc) being equal obviously uk's are better, however £400 worth or brake pads on their own with no other mods will transform the bite and the performance of the brakes over sustained/prolonged use.

 

The j-specs are far more prone to have sliders seize with age and when this happens their performance does suffer. At this point (hopefully combined with disk and/or pad wear) i would seriously consider the move to UK brakes.

 

Also another factor can be the possiblility of being faced with the need to buy a new set of wheels if you go for UK's.

 

What i'm saying is you can track or use a supra hard with Jap spec brakes and i would still maintain that stock UK's with stock pads are not as effective as J spec brakes with say (as I can talk from direct experience with this specific pad) CW race pads.

 

So if it was me i'd have a good look at the Jap calipers as they will almost certainly be the originals to see if the rubbers on the sliders and pistons are in good condition.

If so i'd get some very good pads, research is required here, I'd say CW's RACE ones are very good performance wise but i would hesitate if you are precious about your wheels as they are dusty. Hawk, Porterfield and Endless are others that spring to mind.

 

If the calipers look tired then i'd look into uk's, but just get plain stock disks and spend the money on the pads.

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Thanks guys, alot to think about there, I'll have to get out and have a look at the condition of the callipers first and decide from there then.

 

I've seen the D2 kit on ebay and it looks pritty nice :)

 

Jamie, does having 1pot's on the rear not affect the overall braking at all? Is it ok to have such small brakes on the rear and such large brakes on the front?

If so then this also might be an option.

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Im still on J-spec rears and mine stops perfectly so never bovered upgrading them.:)

 

I thought you had UK rears, oh well...

 

I use a 6 pot set up at the front and a 4 pot alcon at the back.. Now that does stop..... But it all depends on your budget.

 

And how much power you got :eyebrows:

 

Also without trying to sound like an idiot here . . . . Is it possible to put the front 2pots on the rear?

 

What about UK fronts on the rear? Would that work?

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Plenty of people run uk's up front and jap rears, and it seems the abs system in the supra copes ok.........

 

FYI though i have copied and paste'd the following info from Chris Wilson

 

Time to repost my little brake article "wot i wrote"

 

Brake upgrades can set out to try to achieve several objectives.

The commonest are to increase resistance to fade and or increase

braking effort for a given pedal effort. IE, the pads are

pushed against the discs harder for a given pedal effort than

before the upgrade, or the brakes will stop the car from 100 MPH,

hard, for more times before fade sets in, than previously. The feel

from the pedal, that almost intangible quality, can also be addressed

and sometimes improved upon by brake size, or pad material changes, or

brake flexi hose upgrades to something less squashy than rubber.

It's easy to get carried away by the thought of brake upgrades.

The limitation in most cars as to how short a distance they can

stop in is tyre friction. Leaving aside pedal feedback, and fade,

it is almost certain that a Supra on stock Jap spec brakes will

stop in just as short a distance as one with an AP six pot kit on

it, a Brembo kit, Pauls KAD kit, or whatever. It may not feel to

the driver that it does, but usually such is the case if you just

nail the pedal as hard as you can. The fancy kits may *FEEL* to

stop the car faster, due to less pedal effort, and a better bite,

but in reality, if you hit the pedal as hard as you can with stock

Jap spec brakes, UK spec brakes, AP kit, KAD, whatever, the car

will stop in the same distance. Repeat this test 10 times and stock

Jap brakes may be on fire and long since faded, or the fluid boiled,

UK ones may be very hot and bothered, but the upgraded ones will

probably still be working within pad, disc and brake fluid temp

limits. Add in the intangible "feel" factor, and a desire to brake

as hard as possible, using as little skill as possible, but WITHOUT

relying on the ABS to take over, and for sure a well set up brake

upgrade may well allow more finesse.

 

Herein though lies the rub.

 

Upgrade only the fronts and the brake balance of the stock car may

well be compromised. Let's take stock brakes. You press smoothly on

the brake pedal with (say) 50 pounds force. The car stops fine. 70

pounds, the fronts are just beginning to lock (car makers ALWAYS aim

for the fronts to lock first, as rear wheel lock makes the car very

unstable and liable to swap ends). The rears are doing as much work

as the brake engineers deemed safe to prevent premature rear lock up.

The ABS cuts in, and maximum retardation has been reached. Now, take

a car with big front discs and calipers. Only 40 pounds pressure now

gives a smooth, lock free and powerful retardation. 50 pounds and the

new, more powerful, (for the same pedal pressure), fronts are locking.

The ABS cuts in. BUT, and this is the crux, those original rear

calipers and discs are still well below the caliper pressure where

they are able to achieve maximum retardation without fear of the

rears locking.

 

In other words the FRONT brakes are doing TOO MUCH work, albeit without

breaking into a sweat, and the rears are, to exaggerate a bit,

just along for the ride. The BEST scenario is to upgrade front AND

rear brakes, carefully ensuring the original balance of effort at any

given brake pedal pressure remains as designed, but that the more efficient

front AND rear brakes stay cooler for more hard stops, and that old

intangible "feel" from the brake pedal is improved, at lower rates of

driver effort on the pedal. The latter may or may not be good or

desirable, and can be engineered out by changing BOTH front and rear

caliper piston sizes, or pad areas. In a race car the balance would

be adjustable via 2 brake master cylinders, with a driver selectable

change in mechanical leverage effort between front and rear brake circuits,

one cylinder operating the front brake calipers, the other the rear. This

can also be achieved on road cars, but to do so is usually complex and

expensive, especially if ABS and brake circuit failure safeguards are to be

maintained. It is far easier to calculate the caliper and disc sizes, along with

pad area and compound to achieve this, as near as available off the

shelf equipment will allow.

 

Caveat. I said before makers engineer more effort on the front brakes to

encourage straight line stopping if the tyres are locked up . They err on

the excessive side, as, in the wet, the rear tyres can take a lot more

braking effort than in the dry, due to less weight transfer onto the front

tyres, as they will lock before as much weight is transferred when the grip

of the road surface is reduced. So adding yet more front brake effort worsens

this existing imbalance, especially in the wet. If it were not for the

ABS the front wheels would be locking up very early. On the Supra a

relatively sophisticated ABS allows some effort to be taken off JUST

the fronts, and an artificial and very inefficient balance is returned.

On cars with lesser (1 or 2 channel) ABS, or no ABS at all, a brake

upgrade on just one end of the car can be lethal.

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Thanks Scooter, interesting read. I suppose keeping the rear j-spec's the way they are for the moment and putting new uk's on the front would be an option. Better than what Iv got now, the ABS system should be able to cope fine and keep the balance right and then when I have more spare cash I can upgrade the rears later if need be.

 

What about disk's. . . I've read that standard disk's are best but alot of people use drilled and groved disk's, whats the difference in performance? Is one better than the other or is it a looks thing?

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What about disk's. . . I've read that standard disk's are best but alot of people use drilled and groved disk's, whats the difference in performance? Is one better than the other or is it a looks thing?

 

i've never had anything but standard disks on any of my supras. If you like they are not the weak link in the system, and money spent on pads will give you far more improvements in feel and fade. Basically if you jumped from one car with stock pads to one with race pads i believe nearly all drivers would notice the difference........whereas if you went from one car with stock pads and stock disks to one with stock pads but uprated disks i'd expect hardly anyone to notice the difference. There improvement over stock is questionable and at best very minor IMO.......

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