Re: 4kq brake master cyl upgrade

["Romeo Shayne Pavlic'" <bcpi@arias.net>]

I know that todd phenneger knows about this.  We were talking about it last
night.....


Shayne




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----------
>From: "Doug Johnson" <ur-quattro@msn.com>
>To: "Gerry Snow" <gsnow@iea.com>, "quattrol list" <quattro@audifans.com>
>Subject: Re: 4kq brake master cyl upgrade
>Date: Tue, Oct 26, 1999, 11:41
>

> ----- Original Message -----
> From: Gerry Snow <gsnow@iea.com>
>
>> Is anyone aware of a good upgrade to the brake master cylinder on my 84
>> 4000q?  I have heard something about fitting a larger piston bore master
>> cylinder from a 5kq, 200, or maybe from an 80/90.
>> I want to achieve a shorter pedal stroke and a harder
>> pedal for better heal and toe use on the race track.
>
>
> You're correct about a larger diameter master cylinder providing a shorter
> throw at he pedal, because the volume of fluid displaced to move the caliper
> pistons (hence, the distance the caliperr pistons move) remains unchaged.
> Your proposed diameter increase will result in a decrease in required travel
> for the same braking effect.  However, the force you will need to impart
> upon the brake pedal (with your leg!) is proportional to the master cylinder
> diameter.  So, if your new master cyllinder is _twice_ as large as the
> original, you will need _twice_ the force from your leg to achieve the same
> braking effect.   Again, this doubled force will only move the pedal _half_
> as far, but it is worth pondering before swapping master cylinders (could
> get tiring on the streets, or maybe _dangerous_ if someone special to you
> drives your car and is not ready for (forgets?) how your brakes respond...
>
> Would a shorter pedal throw not leave the brake and accelerator pedals
> _futher_ apart than they are now, and _tougher_ to heel-and-toe?
>
>> I am also searching the archives on this.  If anyone can point me to any
>> threads on this, I would appreciate it.  If I learn something new, I'll
> post
>> it.
>>
>> Best Regards,
>>
>> Gerry Snow
>> Spokane, Washington, USA
>>
>>
> FWIW,
>
> Doug
> Renton, Washington USA
> '87 4kcsq - 181k
> '83 Ur-q - 69k (up on blocks)
> http://members.tripod.com/ur-q/inreno.jpg
>
>
>