Big brake kits

[captainchaos]

What do you run and what do you think of them?

[Mike B]

I run 6 pot rotoras on the front, two pot toyota on the rear. Since I did this I have learned that the fronts have to be balanced with the back; otherwise they are worse... I should really have 4 pots on the back, as the fronts have too much power and the back not enough (stock brake balance out of tolerance).

 

The only reason I did not take them off is that the fronts weight a massive 6kg less per corner than the uk spec brakes...

 

They don't suffer from fade though... even at repeated 170+ stops.

 

make sure you are balanced (fronts to match backs) then get the lightest you can.

[tooquicktostop]

AP's 6 pots up front, very strong brake with a nice progressive feels not too sharp, I have just purchased some of CW's carbon pads for these so will be interested in the performance

[captainchaos]

I run 6 pot rotoras on the front, two pot toyota on the rear. Since I did this I have learned that the fronts have to be balanced with the back; otherwise they are worse... I should really have 4 pots on the back, as the fronts have too much power and the back not enough (stock brake balance out of tolerance).

 

The only reason I did not take them off is that the fronts weight a massive 6kg less per corner than the uk spec brakes...

 

They don't suffer from fade though... even at repeated 170+ stops.

 

make sure you are balanced (fronts to match backs) then get the lightest you can.

 

So would putting the 4 pots off the front end sort this out?

[captainchaos]

mike how much did you pay for the rotora's

[AshBhp]

Front: Brembo 4 Pot Gran Turismo with Ferrari F50 calipers.

 

Rear: UK rears

 

Very happy, great stopping power with min brake effort.

 

Also have a set of Porterfield Racing Pads to try.

[Carl_S]

I think big brake kits are a waste of time and money. the jspec ones are fine with the right pads.

[SUPRASUZUKI]

I think big brake kits are a waste of time and money. the jspec ones are fine with the right pads.

 

Depends what you're using the car for really.

[captainchaos]

gonna have a BIG power increase so im thinkin brakes a definate upgrade i need

[captainchaos]

anyone know anything about D2 brakes?

[SUPRASUZUKI]

Search "brakes", they were discussed a couple of days ago.

[spidermonkey]

anyone know anything about D2 brakes?

 

Hasn't JamieP used these?

[captainchaos]

hmmmm anyone else got rotora's and how much did they pay if you dont mind me asking

[b_have]

I have KAD 6 pots with UK rears,great brakes. Only problem was finding some 18s to fit over them.

[captainchaos]

KAD what are they never heard of them got 19's so no bother there

[uk-rich]

Front: Brembo 4 Pot Gran Turismo with Ferrari F50 calipers.

 

Rear: UK rears

 

Very happy, great stopping power with min brake effort.

 

Also have a set of Porterfield Racing Pads to try.

 

 

i have driven this car, and the brakes are superb

[Class One]

I think big brake kits are a waste of time and money. the jspec ones are fine with the right pads.

 

And you qualify this statment how exactly?

[Guest Nicholas]

I think big brake kits are a waste of time and money. the jspec ones are fine with the right pads.

 

[Mike B]

mike how much did you pay for the rotora's

 

Think they were around 1400 by the end, the rears were priced at around 1000 as well. To be honest I wouldn't bother; the uk cost of the pads is stupid, like 350 quid or something. Go ap as they are a better brake and spares are much easier to get. Don't know much about their weights though, but at least you have someone in the uk you can go to.

 

I think big brake kits are a waste of time and money. the jspec ones are fine with the right pads.

Come to marham with a single. I'll lend you a fire extinguisher. Try a few 175-185 hard stops to a second gear corner.. they will be pulling you out of the field... lol

Even on the road, do a hard stop from high speed and you will be smoking when you pull up, do two and you will have dangerous fade. Pads help, but jspecs are just to small to dissapate the heat.

 

So would putting the 4 pots off the front end sort this out?

I don't know.. but you are in the realms of fabrication to make them fit.. I suppose they might.

 

To be honest I would check with CW as he has raced, prepared and built brake systems before. He had a really good post a while ago about preparing a car between him and his mate. His mate spent days trying to eek more power for little gain. He spent a day tuning the brake balance and pulled 3x as much off the lap times. Although my rotoras have more bite, better feel and huge fade resistance, I still think that full stopping power was better with uk spec due to the balance.

 

The thing is that toyota spent time getting the balance right; when we put even a whole kit on there is no way that the fronts will be balanced to the rear.. they are just generic kits... so you will be at a disadvantage aside fade resistance.

 

After chris sorts the sus and geometry on mine the last build job i have is to get a brake kit to fit the ultralight new wheels which are the correct offset, but may not fit.... I don't want to go back to uk's because of the weight issue.

[garethr]

Interestingly, the TRD big brake kits (using the Supra 4-pots or the LS430 4-pots) replace the front calipers only.

[Mike B]

Interestingly, the TRD big brake kits (using the Supra 4-pots or the LS430 4-pots) replace the front calipers only.

 

is that on jspec's, or are they designed to go alongside the uk/us/euro spec rears, as they are larger. UK spec is 4 pot front, so I understand, jspec is only 2, and jspec rears, only 1pot.

[Chiefgroover]

I have the rotora F&R. Great brakes that dont fade, but you problem will be wheel clearance with the 6 pot fronts. Stoptech should have a bigger selection of wheel choices you are quite limited with the Rotoras. If you are mainly doing 140mph or less stops the UK spec with Endless CCX pads F&R will do an excellent job @ around £230 delivered from Import pimp. BBKs only benifit over UK with the right pads for high speed stuff and track work.

[RobSheffield]

I think big brake kits are a waste of time and money. the jspec ones are fine with the right pads.

 

What the hell?!

 

Please come back when you have more experience of different set ups.

 

The Jspec brakes are WELL known to be prone to fade, UK setups are a major improvement, and with the power most of these cars in this thread put out, the larger brake kits are NOT a waste of time or money

[Chris Wilson]

I'll post this article I wrote ages ago about brake upgrades. It's been posted before, but it seems appropriate to post it again. I'll talk to you about the brakes later Mike, once i get the thing to handle sort of right, they don't feel a million miles out on balance to me though. To get as much bias to the back as you need in the wet, yet retain a dry balance, needs either different rear calipers and a bias valve, or dual master cylinders, in which case you lose the servo and ABS, and gain a much heavier pedal. Much MUCH heavier...

 

 

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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.

 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[Chris Wilson]

I can make the J-Specs live on track, but the pad cost is very high, disc wear will be high, and if dust and noise is an issue, you'll hate them Modern pads will allow you to run too small a brake set up, but still not fade. I used to be able to have the plastic tyre valve caps drip onto the paddock as molten plastic, and light my fag off the front discs on my MKIV, ages after coming off the circuit, but they didn't fade, or boil the fluid. Bigger brakes are for sure better, but they are not vital if you wish to persevere with the small set up.