39 replies to this topic

[Jonny dhr]

Hey all,

 

I recently had my vx supercharged. I'm really pleased with it, but now feel I need to work on improving the brakes, especially for track use.

 

I already have Pagid pads and a decent brake fluid, so they stop well, but tend to get a bit hot after about 5/6 laps.

 

I thought maybe just putting some drilled/grooved discs up front would just help my current setup. I like the look of the Elisparts belled discs, but can't really spend £300 odd at the moment!

 

Has anyone used these:

 

http://www.ebay.co.u...type=pla&crdt=0

 

If so, are they any good for just adding a slight improvment over standard discs??

 

Or any alternatives? I've read about 308mm but don't really want the added weight..

[Johnboyhgt]

Stay away from drilled discs they have a tendancy to crack between the holes, you could go to DOT 5.1 brake fluid which has a higher boiling point.

grooved only is fine though, your real issue is getting the heat away and cold air in.

 

I believe that someone is making a brake cooling kit for the VX, try searching for that.

 

John

[Jonny dhr]

Yea I already have 5.1 fluid. It's purely a hot disc probelm I'm trying to solve...

 

I do have drilled discs as standard on my dail driver (C250), they're quite a common thing on standard and moded cars, is it just VX220 drilled discs you are referring to with the cracking problem?

 

 

[smiley]

Unfortunately there is an overlap on dot 4 and dot 5.1 boiling points, so make sure to read the label.

Here's a sample list:

 

 

I would advise anything from the second section).
(i know the castrol srf is tops, but that has a lifespan of 1 year max before going bad, according to the label, so "normal" fluid may be easier to deal with)

 

Edited by smiley, 24 May 2016 - 10:56 AM.

[slindborg]

when you say hot, I assume you mean fade? (pedal firm but doing not much). If so then you you need cooling or higher spec pads.

If its boiling fluid (no pedal feel), then thats fluid and possibly pads.

[steve-m-uk]

I would go with some decent pads , pagid are ok for road use but will overheat on track, try some ferodo ds2500 or mintex 1155. Or if you want to spend more then carbon lorraine or some of the other more exotic pads. Fluid i would use a good dot 4 , rbf600 or similar as dot 5.1 gives a spongey pedal. Stock discs are fine on a sc vx aslong as the pads and fluid are good quality. Sent from my GT-I9195 using Tapatalk

[Jonny dhr]

I would describe it as a mild buzzing noise under harder braking, after about 5 laps.

 

The braking performance and pedal feel seems to stay consistantly good, its just the noise that is is not very confidence inspiring!

 

My theory is that it's some kind of heat transfer or maby the sound of the pads starting to wear quicker?? I'm not expert though!

[Captain Vimes]

Are you using RS14's? A few of us seem to have pad transfer on standard discs with the RS14's, which causes the rumble after a few laps. This was improved for me by moving to grooved discs. I swallowed the hit and went for the EP bells rather than find something cheaper.

[Jonny dhr]

Yea they are RS14's, so sounds like the same problem!

 

Is it totally cured by grooved discs or just improved?

[Jonny dhr]

http://www.ebay.co.u...JUAAMXQLk1RE-80

 

how about something like these??

[Pidgeon]

If you want better brakes, you don't want to be looking on ebay.  All drillings and grooves do is reduce the swept area.  A little noise is not an issue, if the pedal and retardation are good, it's counseling you want.

[slindborg]

If you want better brakes, you don't want to be looking on ebay.  All drillings and grooves do is reduce the swept area.  A little noise is not an issue, if the pedal and retardation are good, it's counseling you want.

 

This!

 

5.1 is fine BTW, I ran that in mine after getting rid of the ATE superblue  

[CHILL Gone DUTCH]

I used comma 5.1 recently and its sh*t

[fiveoclock]

Standard Pagid discs, RC6 pads or similar spec, brake fluid as rec above and then you won't have to be on the brakes so long/much and you won't overheat them

[smiley]

RC6 pads or similar spec, brake fluid as rec above and then you won't have to be on the brakes so long/much and you won't overheat them

 

This basically cured my long running overheating problems i had for years.

Funny thing is that the friction rate of the RS14's causing heat are equal to the RC6 (.50), yet it's the RC6 initial bite that enspires so much confidence that it makes me brake late and much shorter periods.

 

I still don't understand why.

 

Edited by smiley, 24 May 2016 - 12:41 PM.

[chris_uk]

Dont get ebc ultimax discs. They look nice but are heavy and have very small ventilation vains in the discs.

Ebc on the bottom.



I use gulf rf1000.

And currently i use drilled and grooved discs just like your pic, (not the same make tho) and they have never cracked, im not saying they wont but ater a lot of trackdays and 20k+ they are still perfectly fine.

[alexb]

(i know the castrol srf is tops, but that has a lifespan of 1 year max before going bad, according to the label, so "normal" fluid may be easier to deal with)

 

 

About SRF, I looked at the label and can't find anything about a lifespan of 1 year. Looked at the datasheet and all it says is that it has a shelf life of 2 years. Shelf life is for the closed and sealed bottle, but manufacturers are always conservative about that. I'm also not sure what 'going bad' means. The wet boiling point is one of the main attractions of the stuff. Just curious, as everybody who's tracking the car will change it at least once a year anyhow.

[smiley]

Going bad may not have been the best wordings to use.

They say full drain and replace every 18 months.

http://msdspds.castr...486_2013-11.pdf

 

Could be commercially driven.

If i google it, some say it's due to loosing it's vapor lock capacity (ie that extremely good wet ERBP)

Edited by smiley, 24 May 2016 - 01:39 PM.

[Madmitch]

Grooving and drilling have more to do with clearing water from the disc surface as I understand it.  Brake fluid becomes contaminated by absorbing water over time (going bad?) which becomes compressible steam above 100C which is why it needs changing. As above, pads, fluid and cooling is the way to go. 

[alexb]

Thanks Smiley! I read a similar datasheet, but didn't see the 18 months. SRF supposedly uses a patented chemical process to bond the water, that's why the wet boiling point is so high. Probably some kind of limit to that and hence the 18 months.