Braking Efficiency and Rotor Diameters

[85AW20v]

I'm thinking of changing the rotors on the AW11 from std to the AE101 set I have from the wreck that the 20v came out of for the racecar. Any one have any ideas which works best assuming the same swept area - a small rotor(AW11) with a wide pad contact or a larger diameter rotor with a narrow pad contact but a bigger radius? I don't have problems with brakes but need new pads so thought I might as well change to the bigger rotors if they are going to be more efficient.

[Rumad]

not 100% sure, but my thinking on it is: bigger rotors equals a bigger area for the disc to dissipate heat over (downside being more unsprung mass). i would imagine the braking would be a bit more aggressive tho, as the calipers would be acting on a bigger lever point (techies out there feel free to correct me if i'm wrong here) and as less force would need to be applied because of this, it would also lower the temperature. need to make sure the pads will still get up to operating temp tho

i think it boils down to "unsprung mass vs maximum braking force"?

[Rumad]

oh yea, and the latest "Fast Fours" magazine had an interesting article on the development of a twin-disc braking system for each wheel by a manufacturer in aussie...nice bit of tech in there you should find enlightening mentions that for a larger pad area you will still have the same force applied, as the fluid thru the brake lines will still be applying the same forces to the calipers...heaps more tho...

[suckymotor]

try some better pads ie the mintex ones from 0800brakes

[atmosports]

Yes a bigger/thicker rotor does offer better heat dissipation, but then so does changing the number of cooling vanes in a vented disc as well. The main things effecting braking are usuable pad area(i.i how much actually contacts the rotor) & the force able to be applied to it & how it is applied. Hence the reason we run 4-8 piston calipers for motorpsort use & run larger rotors. The larger calipers allow larger pads which gives you a larger friction area, the more pistons you have the more evenly you can apply the force over the friction area. The larger/thicker rotors are to facilitate the larger pads & also to dissipate the extra heat. Other factors come into it like piston bore sizes, rigidity of the caliper etc. But for road use & light track use a simply upgrade of pads/fluid & possibly lines is usually sufficent. If you go changing calipers then more than liekly you'll need to change the master cylinder sizes to retain the same feel & ther same front to rear brake bias.

[85AW20v]

The 101 calipers are the same as the std MR2 ones so I won't be changing those. I haven't had any braking problems at Taupo over the past 4 years and thats with Metal King Plus pads!! Just thought that the bigger disks would probably work better for the heat dissipation etc but was also conscious of the ratio of front/rear bias.
Thanks for the thoughts. Might have to get hold of the FF mag.

[KinLoud]

Taupo Car Club Winter Race Series...5 weeks to go Simon. I just can't wait!
Got a replacement for that enduro?

Ken
Taupo
021 408 863

[85AW20v]

I think its Dual Sprints only on 23 May - with Clubmans on 27 June.

Yes - got a replacement for the Enduro. I'm buying the four Dunlops my brother used on Targa last year. He only used 2mm off then so they should be about right for trackwork now. I've also added a swaybar to the back off a Prelude from the dump. I know I'm mixing Honduh and Toyota but the price was right!! SO the sprints might be just the thing for a few test laps before the racing.