Brake system drain

[RevNev]

Actually, in saying that, the main reason could have been crappy pads that came with the 6 pot, i actually noticed a bigger difference when i eventually changed the pads and put Brenbo ceramics which aren't the bitiest pads but were an improvement on the original pads.

Stock V8 to stock Redline isn't a mind-blowing better feel as the stock V8 Brakes feel pretty good. Pads with more bite than stock will make a difference. I'd like set of Brembo pads that'll do more than 3 stops signs without a wheel clean!

 

[dassaur]

I did, and i can't say i noticed any significant difference , but in saying that i didn't notice any thing significant when i put the 6 pot from standard, maybe if i was racing on a track i could pick a difference.

Nice. somehow I missed that. So @kleanphil what made you go for 27mm after having the brembos with 25.4?

 

[dassaur]

Stock V8 to stock Redline isn't a mind-blowing better feel as the stock V8 Brakes feel pretty good. Pads with more bite than stock will make a difference. I'd like set of Brembo pads that'll do more than 3 stops signs without a wheel clean!

I'm using DBA XPs on front and SP on rear. No where near as dusty as I thought they'd be. You might be pleasantly surprised.

 

[RevNev]

A good set of tyres and don't tailgate, there is no need for big brakes on the street other than to look pretty.

I bought in a set of Harrop 6 spot front, 4 spot rear brakes with semi floating rotors for a bloke with a VS SS in '99 and they were 11k, crazy money in the day. After fitting them he said, "these will look tough when I pull up at the lights." It was all for wa&k value!!

 

[kleanphil]

Nice. somehow I missed that. So @kleanphil what made you go for 27mm after having the brembos with 25.4?

I thought it was the right thing to do being the Redlines had the 27mm originally with their Brembo's but i only grabbed one as i happened to notice one at Salvage Auto's and Deano sorta owed me a bit of credit for a pair of rear quarter windows i had returned so i grabbed it , it was all by chance and opportunity really.

Stock V8 to stock Redline isn't a mind-blowing better feel as the stock V8 Brakes feel pretty good. Pads with more bite than stock will make a difference. I'd like set of Brembo pads that'll do more than 3 stops signs without a wheel clean!

This is how much dust i got from the ceramics compared to the original pads i had. Both wheels were totally cleaned when i changed the front pads to Brembo ceramics , this was approxamatly 10,000k ago at my last service , the rears will be changed this weekend at my next service.

 

[KING46Calais V]

Thanks everyone for your replies. I'm pretty sure I'll keep the 25mm on there. It will save me the ABS draining drama as well.

 

[KING46Calais V]

I did, and i can't say i noticed any significant difference , but in saying that i didn't notice any thing significant when i put the 6 pot from standard, maybe if i was racing on a track i could pick a difference.

so if you didn't notice anything significant, what were the small differences between the two?

 

[kleanphil]

so if you didn't notice anything significant, what were the small differences between the two?

TBH I'm not sure , when ever i embark on costly endeavors i'm more relieved that it wasn't worse. When i put the brakes on, maybe i would have noticed more of an improvement if i had decent pads at the time , When i put the cylinder , once again i was happy it wasn't worse but i was probably expecting alot more of a difference , which i don't think there was. I think to notice any difference i would have needed to jump back a forth between 25mm to 27mm to pick it, and if there was any perception of it being better may just have been placebo.
For me it was more about completing the task in full

 

[Skylarking]

With a bigger master cylinder, you need to press the pedal harder but a shorter distance than a smaller master cylinder for the same braking effect. A bigger master cylinder reduces free play from pedal off to the depression point where the brakes begin work.

Fitting a smaller master cylinder makes the brakes feel better as if you've fitted pads with more bite.

Personally, I think Holden increased master cylinder size to 27mm with Brembo's without realising the 25mm isn't on the cusp, it's massive overkill for the stock brake system. Probably the same bloke who stuffed up the Redline wheel widths and offsets!

That‘s very true with old style non boosted brake systems where the pedal effort strictly follows Archimedes geometric reasoning regarding pedal leverage and Pascal’s theory regarding the hydraulic pressure. That is, the effort you exert via your leg is what is translated through the pedal leverage to the hydraulic system and impacts the brake pedal feel in a very analog way without other things masking said pedal effort & feel. Its something even I can understand

But I’d have thought that in modern boosted system, especially where ABS plays in the mix by offering front to rear and side to side brake bias through a secondary control system that impacts line pressures, the brake vacuum booster would have a bigger impact on pedal feel and pedal effort than the master cylinder size (as would the calibration of the secondary system wrt ultimate brake behaviour). Modern stuff just seems more complicated with many more things in the mix

Whatever the case, the master cylinder must be dimensioned for the callipers fitted to the vehicle so one doesn’t run out of master cylinder piston travel during application. And if I’m not mistaken, it needs to cope with the fluid volume needed to move the pads from their rest position to rotor contact which is based on slave cylinder sizes and actual rest to contact distances they travel. And as has been said a few times, 25mm or 27mm are sufficient to do the job with Brembo‘s all around so I suspect it was marketing or engineer over exuberance to put 27mm MC on some variants.

The more interesting issue is what Holden did from a compliance perspective so as to verify the downgrade from 27mm to 25mm is ok (given that when one picks up a 27mm MC from spare parts they are almost certain to get the 25mm calliper). I’d have thought Holden would have needEd to lodge some paperwork with Department of Infrastructure, Transport, Regional Development, Communications, and the Arts when such critical parts are superseded and replaced with different parts, especially when the authorities make our life harder than it needs to be when it comes to brake mods

 

[Skylarking]

A good set of tyres and don't tailgate, there is no need for big brakes on the street other than to look pretty.
.

And there is even less need for big brakes on performance electric cars which can stop on a dime just by using regenerative braking.

Guess performance EV owners are even bigger wankers