Large S2 master cylinder

[Audi_CQ]

Does anyone know of a large master cylinder(larger then std 25.4mm) that would fit a S2?. A bit to much pedal travel with Cayenne calippers so need 27mm or larger.

[AndyP]

I thought Ben ( S2avant ) looked into this when he first fitted 8pots to his car and found that all the new Audi's with multi piston calipers still only used a 25.4mm master cylinder?

[quattrostyle]

AFAIK the LHD RS2 one is slightly larger.

[Audi_CQ]

AFAIK the LHD RS2 one is slightly larger.

It's the same 25,4mm I'm afraid. Same part nr.

[Jamo]

There's two part numbers for the LHD RS2

The common RHD S2 and LHD RS2 master cylinder is part number 441 611 021 B

On the LHD there was another master cylinder 4A0 611 021 C for the 95 cars.

The 2nd one is bigger according to Jade who had them both

[saltinot]

The larger MC came on the later LHD RS2s. The hydraulic servo is also larger on the later cars.

[Audi_CQ]

The larger MC came on the later LHD RS2s. The hydraulic servo is also larger on the later cars.

Different part nr. , but same size cylinder:
In Norwegian, but states 25,40 for both part numbers.

[Audi_CQ]

Will try to adapt something like this:

http://www.summitracing.com/parts/WIL-260-8556-BK/
http://shop.aerospacecomponents.com/...8boresize.aspx

[macspring]

Hopefully still on topic,

http://ultimot.de/

So does that mean that if one bought the Audi S2 BK650 kit, (365mm disc), the brake pedal would be much closer to the carpet ?

Btw, does anyone have the part numbers for the disc and the caliper in this kit and what Audi car it comes on as oem kit ?

Is it not possible to change a rod or piston in the brake cylinder to make it longer to change the length of travel required for the brake pedal ?

[macspring]

The hydraulic servo is also larger on the later cars.

Which bit are you referring to here ?

Thanks.

[terrybullwon]

food for thought

http://www.markwilliams.com/braketech.aspx

[saltinot]

Which bit are you referring to here ?

Thanks.

The hydraulic brake booster.

[rs200]

what will happen if you use bigger brake line? that could help you. I thing so.

[Error404]

it is the amount of fluid displaced by the master cylinder, lines won't make a difference. If you calculate the area of each piston then you see how much further the master cylinder has to travel to move the caliper pistons the same distance with big multi-pot calipers.

[rs200]

it is the amount of fluid displaced by the master cylinder, lines won't make a difference. If you calculate the area of each piston then you see how much further the master cylinder has to travel to move the caliper pistons the same distance with big multi-pot calipers.

of course . you are right.
now I take a look in ETKA and there is the same cylinder for
S2 (3b,aby) 25.40mm even the 7A have the same
s4 ,s6 - 25.40x13/22.5
,RS2 - 25.40x13/22.5
200 20v - 25.40x13/22.5
audi V8 - 25.40x13/22.5

they all are the same, and have same code. only 7a have different.