size of v6 brake discs?

[cav_2.0_gli]

hey,

can anyone please tell me the dimentions of a cavalier 2.5 V6 CDX front brake disc?

as i want to replace them with some drilled and grooved ones, but im not sure which size disc i need.

cheers

[himselfunknown]

The cav v6 brake discs are 283mm. I've heard some of the later V6's had 288's, but I can't confirm. The discs that were on my old L reg were 283's though.

However, I have drilled discs and uprated pads on my new V6 and I have to say I don't think much of them. The car came with black diamond discs and predator pads, and I wouldn't say they are much of an improvement on the standard setup.

I'll be uprating to larger veccy V6 discs as soon as I can get the car into the garage, and would recommend the same to anyone else.

[cav_2.0_gli]

if i have 283/284mm discs on mine atm, is it possible for me to fit 288mm ones, and they will fit fine?

only asking, as ive been offered a cheap set of 288mm x 25mm ones, which were for a calibra 2.5 V6 apparently.

cheers

[Cavyman_130]

the cavalier came with 286mm discs, the vectra ones are 288mm

[HAIRIBO]

Cavs are ment to be 286 (same as turbos). and vectras 288. you cant fit vectra discs, as the cavalier hubs are too big, you need to grind down the hubs inorder to fit them. buts its only worth grinding down the hubs if you are fitting 308's. The vectra calipers will fit straight onto your cav as far as i know. the have better clamping than the old cav ones. and lets face it 286 or 288. your not going to notice the difference even if you did fit the vectra discs. yopu might notice the differnce with the vectra calipers tho. and at only £20 a set from the scrappy its worth a try.

[DiplomaXE]

as the guys are saying, and to sum up if you like, the std v6 ones are 284mm with a 54mm (IIRC) pistons. tiny cav brakes are 256mm with 52mm pistons. then theres uber tiny girly sized small engined ones too.

you can (and I have, as many have) fit the later really common saab 900/9-3/calibra/vectra 288mm calipers, IF you either also fit the later hubs that are smaller diameter and fit under inside the slightly different shape inner part of the 288/308 disc, or you can grind down the std hubs on the car with it in gear and using a std grinder (nasty mess) or turn down the larger hubs in a lathe. I'd find some later ones if I were you off of a late calibra of vectra. the part is the same.

then you can go for either the 5 stud 288 calipers or 308mm ones off some of the gsi vectras the hydraulic bit is the same, it's the brackets that are cast 10mm further out, thats all.. this fits under most if not all std 16" vx. rims.
what happens then is you will get more effective brake torque at the piston as its now spaced out further, as long as no other parameters in the system have changed..

288/308 pads are huge too, maybe even bigger than the v6 pads and easily cheaper too, so they will usually last longer for the same amount of grief you give them, if you now can get them hot enough to work well, you wont get better brakes because of the bigger pads, but they go down the disc further than std so you are spreading the load as it were... but,

on the hydraulic side, the 288 caliper has a larger diameter piston so for the same equivalent torque compared to the smaller piston calipers you will be pushing the pedal further down to achieve it.
on mine i went from 2.0L 256 brakes to the 288's then the the 308s, so i have a longer pedal than ages ago..
this got slightly better when i fitted a turbo/v6 master cylinder which is just a tad bigger so moves more fluid (providing more pressure for the same pedal travel, in turn closing that travel down a bit so its now not so bad.
if you go 308's keep in mind the rear will now be "under braked" compared with your sexy new front ones and a rear conversion to the later 286mm up from 260 or v6- 270mm rears will redress the balance.
if you need any more advice I have all the calculations collated in a spread sheet if you want to delve into it further.

personally i would always go for a std nice quality disc with proper heat treatment from a good manufacturer, avoid the expensive eBay specials with dots and spirals and sh1t, u need a good quality casting. std vauxhall ones seem superb. then either police spec 288 pads or something reliable after market wise. I have some new spec Saab 9-3 ceramic red stuff front pads and I'm loving them. mines like throwing an anchor out at all speeds and just got better and better at a whole day of Combe thrashing.