32 replies to this topic

[jasvxt]

[andyroo]

I assume the ally belled jobbies reduce heat build up and therefore brake fade which prolongs the effectiveness of the pads?

[robfenn]

Quite impossible to agree with the percentages quoted. The reason for four (or more) pistons is as follows-

If the brake master cylinder has a cross section of A and the brake pistons have an area of A x 4, then four times the pressure you exert upon the pedal is exerted upon the disc. To increase the pressure, you need to increase the size of the pistons, but you soon reach the size limit of the piston inside the caliper and the caliper upon the disc. Moving to more smaller pistons allows a larger piston area and therefore more pressure.

However good your pads and discs, they are nothing without pressure

To suggest rotors will have any impact above a few percent is plain wrong. Ali-bells are good for unspring weight, but the pad is the wearing part of the brakes and unless you want very soft discs they will not impact upon the overall performance to any great degree.

You're comparing theory with practice....

Does the bigger discs necessitate any change to the calipers? I've had bigger discs which which required the caliper to be spaced out = bigger pivotal force = better braking.

[furby123]

This is a very interesting thread... Has anyone fitted the hi spec brakes which are a four pot for the VX, they are about half the price of AP racing brakes - and are essentially the same thing.... I would be interested to hear if anyone has them fitted. There was a group buy on these a while back. IMO talking from experience I had some standard 288mm brakes on my VRS (daily driver), I swapped them to the TT brakes which are 310mm discs and bigger calipers, its a straight swap and the difference was immense, the car now stops way better than I will ever require, whereas before it stopped like a sack of poo. I am getting a VXT for weekend fun etc, I drove it and yes the brakes are hopeless - bit like my vrs was, working on the same assumptions if you fit four pots with braided lines on a car as light as the VX its going to throw you out each time you hammer the pedal I would be keen to hear from anyone who has fitted the hi specs as they ar bound to be the answer at a reasonable cost - on a gb they will be even less. Im no mechanic but perhaps someone else could help me out here, for my furby I just swapped to a bigger disc / caliper option in the VW stable the answer was the TT. Surely there is a straight swap for the VX from a bigger Vauxhall......Im suprised this hasnt been hit on before, being a newbie Ive probably missed something Furbmeister 200BHP/310lbft (diesel)

[covert ops]

Furby123

Search for Hi Spec and all your questions will be clear.
I dont think the group buy went ahead in the end, I think there was quality control issues and no conversion to include the handbrake??

(Mechanical numpty as well )

Andy

Edited for you as I have just read this

http://www.vx220.org...pic=48280&st=40

Andy

Edited by covert ops, 17 October 2007 - 04:40 PM.

[alanoo]

We'll have our own separate ali belled AP disk upgrade in stock soon, will be cheaper than Plans (although I disagree on the percentages quoted). We've got 100 sets coming in.

Woot need !
Hope they will be a bit lighter than my Eliseparts ali belled items too (5.6 Kg)

[furby123]

Furby123

Search for Hi Spec and all your questions will be clear.
I dont think the group buy went ahead in the end, I think there was quality control issues and no conversion to include the handbrake??

(Mechanical numpty as well )

Andy

Edited for you as I have just read this

http://www.vx220.org...pic=48280&st=40

Andy

See what you mean about the hi spec jobbies - I think Ill stear clear of that make - what about a bigger vauxhall brake set up?

Hail to all mechanical numpties

[jasvxt]

Furby123

Search for Hi Spec and all your questions will be clear.
I dont think the group buy went ahead in the end, I think there was quality control issues and no conversion to include the handbrake??

(Mechanical numpty as well )

Andy

Edited for you as I have just read this

http://www.vx220.org...pic=48280&st=40

Andy

This thread is about the front discs and calipers not the rear

However.

If you can run Pagid Rs14's on the front or indeed Ferodo DS2500 pads, preferably with 4 pot calipers, and Rs14's on the rear standard Brembo caliper, then this is all you need to achieve a decent balance or braking bias.




Jas

[voice of reason]

I have a question. I have fitted a set of the AP 4 pot calipers to my 2.2 VX but the wheel is very close to the wheel (about 1mm close). My VX has the Turbo wheels fitted is this the cause or should it be like this??? Please don't tell me I have to change my wheels.

[covert ops]

Furby123

Search for Hi Spec and all your questions will be clear.
I dont think the group buy went ahead in the end, I think there was quality control issues and no conversion to include the handbrake??

(Mechanical numpty as well )

Andy

Edited for you as I have just read this

http://www.vx220.org...pic=48280&st=40

Andy

This thread is about the front discs and calipers not the rear

However.

If you can run Pagid Rs14's on the front or indeed Ferodo DS2500 pads, preferably with 4 pot calipers, and Rs14's on the rear standard Brembo caliper, then this is all you need to achieve a decent balance or braking bias.




Jas

Thanks Jas
(teach me not to speed read!! )
But I think he got the idea

Andy

[Joe-Turbo]

I have a question.

I have fitted a set of the AP 4 pot calipers to my 2.2 VX but the wheel is very close to the wheel (about 1mm close). My VX has the Turbo wheels fitted is this the cause or should it be like this???

Please don't tell me I have to change my wheels.

yes, thats how they are supposed to be

[speedster]

Furby123

Search for Hi Spec and all your questions will be clear.
I dont think the group buy went ahead in the end, I think there was quality control issues and no conversion to include the handbrake??

(Mechanical numpty as well )

Andy

Edited for you as I have just read this

http://www.vx220.org...pic=48280&st=40

Andy

This thread is about the front discs and calipers not the rear

However.

If you can run Pagid Rs14's on the front or indeed Ferodo DS2500 pads, preferably with 4 pot calipers, and Rs14's on the rear standard Brembo caliper, then this is all you need to achieve a decent balance or braking bias.




Jas

I always wonder how different can different makes of 4 pot calipers be? Apart from the quality of seals and materials used in manufacturing the units piston and sleeves operation should be very similar.
So what makes the AP's so so expensive? Is it just the brand name? Or are they using vastly superior parts and fluid management techniques?

Edited by speedster, 19 October 2007 - 11:12 AM.

[jasvxt]

A bit like the Top Gear comparable IMO Lotus = Armarni Vx220 = Millets AP = Armarni Hi Spec = Millets But hey what do i know , and whats in a name ? Jas

Edited by jasvxt, 19 October 2007 - 11:01 AM.