nice brake upgrade

[totta Crolla]

will fit inside a 13" wheel too.... just !!
http://www.compbrake.co.uk/Toyota%20Corolla.htm
they also do a bias adjust pedal box
http://compbrake.co.uk/shop/product_info...cts_id=356

[Ozone]

Good luck fitting 265mm discs under a 13" rim.
Lotus Elise brakes just fit under a 15" rim with the right design wheel and they are 295mm. So using that as a reference 295 - 50 (2") = 245mm.

[boo50]

golf mkI have 256mm breaks in stock
and have 13inch rims, so it might be possible.

what max discs can fit under 13inch?

[Ozone]

Golf GTi mk2 has 239mm discs with 14" wheels.
256mm discs from 16v would JUST fit under them, I know from experience.
I also owned a Honda Civic with 280mm discs that just fitted under 15" wheels.
Working back from these examples gives you a disc of 230~245mm.

[Gnugfur]

These are 15"s
Brakes are 280mm.

[Kid Karola]

I use a 262mm disc with RX7 4-pot calipers and that only just fits inside 14's with a bit of backspace...
those billet calipers must be pretty slim to get into 13's

[boo50]

http://compbrake.co.uk/CALIPERS_COMPB4R_PRORACE4.html

here is the 4pot caliper what can fit under 13inch rims.
and it can be mounted on stock rotors.

• Housing material billet aluminium 7075T6.
• Hard anodised in titanium/black/Silver to 40 microns.
• Radial mounting centres 120mm
• Side entry feeding ports.
• Pistons 4mm stainless steel 1.375” x 1.375”
• Disc thickness range 12-24mm.
• Suitable for 225mm-295mm rotors.
• Weight 3.19lbs 1450g

stock rotors are 234mm and 18mm thickness .


I'm planned to get them on my hachi, because I've already wide 13 inch rims, and slick on 13's are cheaper than 15's

[NoHachi]

If you mount them on the stock rotors, you might as well not bother at all. From a performance standpoint that is..no discussion that they will look good and probably bite a bit better during street driving.

At the track, stock discs inside a tight 13" wheel will give you guaranteed heat problems as speed goes up. If you really want the smaller rim size, then better upgrade to some seriously beefy discs (width!) as a heatsink. Take a look at TRD setups. 24mm as a minimum I would say..and even thet is just 30% extra capacity. For reference..heat loads go up with the square of speed.

One additional datapoint: The T3 Wilwood kit will (barely) fit in 14" König Rewinds..

[boo50]

24mm as a minimum I would say
- for what dia ? they are for 15 inches I suppose.

I can't understand the phisical part of your theory.

Every discs are hot as hell when driving fast.
main part of good breaking is high temp pads, what can work in such temps.
and for suere big calipers for better pedal feel.

[NoHachi]

Ah, true, discs do get really hot (and they need to, as most race pads need a minimum temp to get decent friction coefficients). What I've seen is that you can go far over 650 degrees disc temperature with small discs..and all sorts of bad things start happening.

Full race pads will usually stand up to the heat but wear at incredible rates (like one set of Carbone Loraine RC8 per track day, bye bye 280E).

Biggest problem is that the fluid (assuming that DOT4 racefluid of DOT5.1 high-temp is in the system) inside the callipers will start boiling due to heat transfer from the discs, through the pistons.
The best extreme use brake fluids (like castrol SRF) have a dry boiling point of 310-320 degrees Celsius at best. Put that fluid into a small space with a heat emitter at 650+ degrees and you have a recipe for trouble.. To get an idea of your brake temps, but don't have any tools try and use this simple reference:

degC color
400 Red heat, visible in the dark
474 Red heat, visible in the twilight
525 Red heat, visible in the daylight
581 Red heat, visible in the sunlight
700 Dark red
800 Dull cherry-red
900 Cherry-red
1000 Bright cherry-red
1100 Orange-red “{*}

(stolen from: http://hearth.com/econtent/index.php/wik...ess_Steel)

On a stock AE86 with the OEM 90 RWHP or so you will be fine with the stock system. If you are planning to upgrade, then its easy to calculate the extra load on the brakes through increased speed potential. If you are planning a N2 racing monster replica on 13inch wheels, better use the biggest and fattest discs that you can stuff under there. Even then I think a decent driver with 240hp at his disposal will boil them pretty quick. Start looking at brake duct fans and brake fluid recirculators.