Master Cylinder Sizes

[24seven 104]

Anyone know the master cylinder sizes of the following pugs, and whether they're interchangeable or not?

 

205 GTi 1.6

205 GTi 1.9

306 GTi-6

306 XS (247mm front brakes, smaller MC than gti-6 but how smaller ???)

405 Mi16

206 GTi-180

 

Other than that, does anyone have any recommendations as to what size MC would achieve quite short pedal travel with standard rear disks and GTi-180 calipers up front? I've a very sensitive left foot, so quite short pedal travel would help me with heel & toeing as my heel stays put on the brake, while I point my foot to blip the throttle.

[McDude 33]

I can't help you with MC sizes, but surely if you are left foot braking, you don't heel and toe. I say this because how can you give a throttle blip if the clutch is still engaged? Plus you wouldn't need to heel/toe because your right foot is free to use the gas pedal, which was why you left foot braked!!!

 

When I left foot brake I swap feet mid braking so that my right goes on the brake pedal leaving my left free to do the clutch work. I was also taught that the safe way to heel/toe is to use the ball of your foot to pivot on the brake pedal and use your heel to blip the throttle - actually it is more like the side of your foot.

[24seven 104]

sorry I meant sensitive right foot. my left foot operates the clutch exclusively while my right foot operates the brake and throttle. I've tried left foot braking and rev-matching on the gear shift but find that without the quick response of a light flywheel (standard weight on both my cars) heel & toe on the throttle/brake is the quickest way I change gear. plus my left foot is a little useless and more often than not is a little clumsy on the brake pedal, what with being used to using all of the travel of the clutch pedal or sustain one position.

 

my feet are weird and point outwards more than usual, very evident if you ever see me standing still (remnants of an injury I had to my right leg which left me walking at a funny angle, and thus I got used to it). I physically can't turn my right foot around far enough to put my toe on the brake and heel on the throttle.

 

plus I find that doing it that way requires a synchronised action of more muscles than by placing your heel on the brake and pointing your toe - pointing your toe means keeping your leg & knee locked in one position on the brake, while the ankle points at the throttle. the other way round requires the leg & knee to straighten on the throttle while rolling your ankle to keep the brake pedal constant... if that makes sense.

 

Can you tell I've analysed this way too much?

Edited November 11, 2008 by 24Seven

[jengis 0]

You swap feet mid braking!??

 

Surely left foot braking is a gentle brush of the pedal mostly employed during high speed turns to trim the line leaving your right foot planted on the accelerator? (Or, when on gravel, to keep front wheels spinning to keep the revs up)

[24seven 104]

You swap feet mid braking!??

 

Surely left foot braking is a gentle brush of the pedal mostly employed during high speed turns to trim the line leaving your right foot planted on the accelerator? (Or, when on gravel, to keep front wheels spinning to keep the revs up)

 

 

it's also used as an alternative to rev matching when changing down under braking. as above on the standard flywheel I find my engine responds too slowly to throttle inputs to rev match quickly, so I find it less time consuming to heel/toe.

[McDude 33]

You swap feet mid braking!??

I used to do this all the time when I had my Elise, but don't so much in the 205. Essentially:

- Hard on the gas approaching the bend

- Left foot on the brake as this saves the 0.4s to swap pedals! It also allows you to bias the brakes: in a RWD it shifts the bias to the front, in a FWD to the rear

- here comes the tricky bit to do smoothly and it MUST be done smoothly. Edge your left foot off the pedal whilst edging your right on to it. The pedal pressure needs to remain constant or you will upset the balance of the car

- use left foot to operate clutch

- heel and toe with the right

- 'swap' braking pedal feet back again smoothly so that you can apply gas 0.4s quicker!

 

It is actually very easy to do once you've practiced it (on a track) but the realities are I have much more wrong with my driving that will lose me more than 0.4s a time!!!

[tom_m 0]

You swap feet mid braking!??

 

look it up on you tube, there are numerous clips of rally drivers and race car driversr doing just this.

 

think there is a good one of walter rohl in a porker at the nurburgring where his feet are constatly moving peddles.

[24seven 104]

just to bring back an old thread, Does anyone have any info on master cylinder sizes? Preferably I'd like something at least equal to that of a GTi6, if not slightly bigger to reduce the pedal travel even more.

[welshpug 1,626]

ZX 16v uses the same M/C as the gti6, don't know of any larger.

 

oddly it uses this large M/C but the same 54mm piston in its 266mm brakes exactly as the S16, which IIRC uses 22.2 M/C

 

gives a nice pedal feel as the effective pressure exerted is lower than the standard gti6 setup, but better for it IMO, more control under heavy braking I would imagine?

Edited February 24, 2009 by welshpug

[24seven 104]

yeah that's the kinda feel I'm after, only I've got the front calipers off a 206 GTi180, basically th same as a gti6.

 

[edit] thinking about it, 406 coupe uses big ass brembo calipers, maybe it has a big ass m/c to go with it.

Edited February 24, 2009 by 24seven

[EdCherry 34 1 Cars]

20.6mm for a 1.9 GTi and 20mm for a 1.6

[welshpug 1,626]

hmm, dont the 180 calipers have the smaller 54mm piston unlike the 57mm of the gti6?

[petert 554]

Stay clear of 405 m/c's. The pin depth is different, meaning you'll have no free play and the brakes will never release.

[24seven 104]

do they? Thought they were the same pistons, but slightly different calliper castings. They're the same 283mm discs and pads tho.

 

Thanks for the heads-up peter

Edited February 24, 2009 by 24seven

[tom_m 0]

hmm, dont the 180 calipers have the smaller 54mm piston unlike the 57mm of the gti6?

 

correct

[welshpug 1,626]

also, the 406 uses a 23.8mm M/C just like the 306 gti6, even with the roughly 20% larger piston area.