56 replies to this topic

[VXJON]

nice :-) any issues with the ABS?

Mine seems more prone to lock up after fitting the ali bells

[alanoo]

AP don't do a standard 290mm disk

Btw, the pic does not look like an AP disc for me

[Thorney]

Standard cars tend to lock the rear brakes first because the front gets over use, gets hot and forces the driver to press harder which makes the disks even hotter and grabby and the resulting weight imbalance under braking means the rear brakes tend to lock before the front, by putting a larger caliper kit on the front this does more work proportionately so lessens this effect (some people mix different pad compounds front to rear to try and get a similar affect). Running ali belled disks (which are wider with extra cooling) lessens this heat build up (which is one of the main reasons the AP kit works so well, not the size but the cooling).

AP don't do a standard 290mm disk

Btw, the pic does not look like an AP disc for me

Then I bow to your greater knowledge and experience.......I'll rely on the fact they come in a big box with "AP Racing" written on the side

nice :-) any issues with the ABS?

Mine seems more prone to lock up after fitting the ali bells

Interesting, which ones are they?

[ianrm]

and I ordered them from AP

[alanoo]

So AP added a CG8 pattern on their 290mm discs ? Because these patterns were only available on 295mm discs

[Thorney]

I guess so, they are pretty new.

[jules_s]

[devils advocate] Ok, understandably some of us would do some web searching on this matter.... as I (for one) would be happy to pay a few more £££ over the price of the OEM disks if a better alternate was an option. Right now I'm plain confused. Plans seem to do AP disks of a similar spec for £565 per pair (not sure if thats Inc VAT or TMS for that matter) Eliseparts do all four AP for an S2 @ £900. It seems there is a statement on eliseparts that running under 190bhp will see you needing lesser disks costing under £500 a set for four any thoughts on us NA guys here??? [/devils advocate] Bugger, why are these things so confusing?

[chris_uk]

so you have upped the disk size and kept the caliper / pad size the same? wouldnt this just result in the same braking power (force on the disk from the pad/caliper) but with better cooling (due to the size of the disc and it haveing a bell housing on it??) also if the disk was infact bigger, wouldnt the caliper position need to be moved? the only real advantage of this sort of disk is saving weight.. and to spend £1200 on a set of 4, which is just for the bells and rotors, wouldnt you then (assuming again) have to get a set of new calipers for the back. in short we would be spending £1200 to save 4kg of weight, look good, have better cooling (which is 'lets face it' pointless on a car that isnt being tracked) and to finish off would be pointless on standard front tyres. John when you did your test, did you do them on a standard n/a or turbo? or did you do them on your race car? for someone who never really goes on track days but does like to have a blast round country roads.. would you say this is a worthwhile purchase?

[Jase_MK]

Standard car has same size disks all round already.

Yes I know
So how does fitting bigger discs all round affect the brake balance front to rear? (ignoring the fact that the pad is in the same position as with std discs)

[chris_uk]

Standard car has same size disks all round already.

Yes I know
So how does fitting bigger discs all round affect the brake balance front to rear? (ignoring the fact that the pad is in the same position as with std discs)

and size m8

[VIX]

for someone who never really goes on track days but does like to have a blast round country roads.. would you say this is a worthwhile purchase?

No.

[chris_uk]

for someone who never really goes on track days but does like to have a blast round country roads.. would you say this is a worthwhile purchase?

No.

i came to the same conclusion myself, and decided i would get another opinion.

cheers

[VIX]

[Thorney]

Plans do a set of grooved disks for £565 but these aren't AP, they do an AP set for £640 a pair. Eliseparts do a set for the S2 but these won't fit the VX220 and are broadly same price for AP (not own branded stuff). Yes they are more expensive but thats because we have to make up bells custom for the VX bolt pattern and that means short runs rather than 3/400 hundred at a time for the Elise market. I'm not sure I'm missing the point on disk size now? Sorry. We went with 290mm as it was a better fit (no requirement to move calipers) and offered the same balance fore and aft. Testing was done on the 2.2 and the VXT race cars both with AP kits (VXT) and the standard front calipers (2.2) over the course of the season. Do you need these for road work? No, a set of Mintex pads is all you need to improve the braking for most but those on track will notice a difference especially if moving to Pagid pads which again raises the bar. The reason we developed these is that a lot of people asked for a mid way upgrade for brakes that was cheaper than the AP kits, what we've done is try to develop that as well as a nice additional upgrade to those already with the AP kits on. Price includes VAT.

[Jase_MK]

I'm not sure I'm missing the point on disk size now? Sorry. We went with 290mm as it was a better fit (no requirement to move calipers) and offered the same balance fore and aft.

290mm was chosen as the weight distrubution on the VX220 is different to the Elise so 290mm front and rear made the best possible brake balance for the chassis

VX and Elise both come from the factory with same size discs front and rear (288mm). You implied that the reason you chose 290mm discs front and rear (+1mm radius) was to correct/improve the brake balance on the VX, when in fact it makes no difference at all.

[Thorney]

Jase, I'm sorry if you took it that way, I was suggesting that that we stuck woith 290mm f and r to keep the balance, that was my point, on Elises the traditional upgrade is a larger disk on front, hence we are bing different to the other upgrade for Elises, that was my point.

[VXJON]

nice :-) any issues with the ABS?

Mine seems more prone to lock up after fitting the ali bells

Interesting, which ones are they?

These ones




Brembo 288mm with bells made by one of the Scottishelise guys who owns a precision engineering company.

[Spindoctor]

Do you need these for road work? No, a set of Mintex pads is all you need to improve the braking for most but those on track will notice a difference especially if moving to Pagid pads which again raises the bar.

Do you think that's still the case if you're running with the power now available through stage 4?

Edit: I'm assuming that with that power you drive on the road with spirit but not as if you are on the track...

Edited by Spindoctor, 07 November 2007 - 07:03 PM.

[Thorney]

Good point, the stage 4 cars are well beyond the Mintex pads/pagid set up imo, of course braking is downt o the driver but I do feel a bit exposed when we do a stage 4 and brakes are basically stock.

[jasvxt]

Must agree the amount of people that tune away, without brake upgrades, is beyond me. Upgrade Brakes and Tuning at the same time, if you can afford it. If not, brakes first job, tuning later No good having Stage 4 with shite brakes, simple principle of more power = more braking required.