Vented front brakes

Post by **griffo20022** » 11 Oct 2007 06:47 pm

Hey guys just been using the search button to find some stuff out about brake upgrades. Read 340's thread on his all round disc conversion which looks fricking awsome I must say mate welldone! Although my dilemma for going for something like that is I have 13" rims which some how I don't think it'd fit lol! Plus I'm not after anything that serious!

Was just wondering if any of the 340's or 360's had vented brakes up front which I could stick onto my 340 as it's only got solid discs. I've not had any problems with them yet in all honesty, but then again I don't want to get into any problems either lol!

I'm hopefully going to get my shocks sorted next month so the car will be more stable and I just know i'm gonna end up getting cocky going into corners knowing the roll is reduced, then i'll f*ck up when the brakes do f*ck all lmao!

Post by **Ronnie** » 12 Oct 2007 10:02 am

The standard brakes on the 300 are very good if properly serviced. They are powerful, progressive and have lots of feel. Your decelaration will be limited by grip, not your brakes. Not meaning to diss Adam, as I agree his brake conversion is fantastic, but I really don't see the need to upgrade the brakes on the 300. Unless of course your going extreme and doubling the horsepower.

Post by **classicswede** » 12 Oct 2007 01:10 pm

300 brakes are very good when in good working order. The advantage of vented discs is under loads of heavy braking the will disapte the heat quicker but even so can over heat when you drive like a tit. The important thing I would say is to make the thing stick so well to the road there is no need to slow down for bends

Post by **griffo20022** » 12 Oct 2007 03:40 pm

Yer I must admit as I said in the original post I havent had a problem with the standard brakes at the moment in all fairness I do rate them well considering there only solid discs. At a rough guesstimate i'd say my cars about 170BHP/tonne. The car weighs 960KG without me in and half a tank of fuel.

Post by **Carl** » 12 Oct 2007 06:32 pm

If your brakes can lock up your wheels (from a highish speed) then you wont be able to increase your stopping power by changing the brakes - tyres are your limiting factor. But, as Dai says, vented brakes are all about heat dissipation - if you keep trying the 'lock up' test after a few goes it won't work as the brakes will have over heated. Vented discs willhelp in this situation.

But there are other ways to combat this. FOr examples the alloys you use will have a big effect on cooling, for example mk3 GLT alloys are not well designed for getting rid of heat. Mk2 GLT alloys are much better, as I found out. Cooling ducts can also help - using the fog light holes for example.

Seems obvious, but make sure all your brakes are in good working order. A fresh set of discs/pads, and even shoes can make a substantial difference. Uprated discs pads are also available off the shelf.

Also, many people confuse brake fade with boiling brake fluid. Decent brake fluid is essential as the older it gets the more contaminated it gets and the boiling point gets reduced. Once the fluid boils it comes useless leaving you with a very 'soggy' feeling pedal. So a change of fluid can help things a lot, and dot5.1 is the best stuff to use (NOT dot5).

With 170bhp/tonne I'd definitely be wanting vented discs. That implies you'll be driving fairly hard, and if doing stuff like track days I'd definitely want an upgrade! But unfortunately there's nothing thats a direct fit. As you've probably seen in your searches on here there's plenty of rumours though of things that may work!

Post by **Fuse** » 12 Oct 2007 07:08 pm

In track use the problem with the stock brakes is that the heat is dissipated more on to the hub than it is on the wheel. (Because the disc is between the hub and the strut, not between the hub and the wheel like in most cars..) So if you don't loosen up the bearing a bit in hard use, you might cook the bearing grease and then you start breaking bearings too.

Post by **jtbo** » 15 Oct 2007 08:28 am

Stock brakes are really good for standard road use, but do few 150-0 stops and measure distances, you can't lock up wheels, because of brake fade that is caused discs overheating.

I have fried wheel bearing grease few times, also once boiled brake fluid (bad fluids then) also several times I have got brake fade because disc heated so much. I do use brakes rather hard on track, I also use them for weight transfer etc. also that my car did have more power than stock did not helped.

240 then, damn that thing stops, even I can lock 360's brakes on hard braking force required to lock brakes increases when braking as brakes heat up, but in 240 nothing, it just stops, those kind of brakes I would like to have

Post by **Chris_C** » 15 Oct 2007 11:14 am

I've cooked bearing grease on mine too, and from the sounds of what was coming over MSN yesterday, so has Aleks, although that could be knackered bearings causing that.

I'm loving my new brake pads, I can hit them hard again and again, and all they do is squeek, no fade at all. I found the worst problem was the fact I couldn't drive, I was trying to be smooth and trailing the brakes, when you really have to stand on the brakes to scrub as much speed in as short as time possible, then they will cool down. Then again, thats only when I'm rallying, normally they are fine

Post by **classicswede** » 15 Oct 2007 12:57 pm

Has anyone tried using cold air ducting to the back of the disc to aid cooling? I've never felt the need to do it but I would be interested in the results.

Post by **Carl** » 15 Oct 2007 05:26 pm

I was trying to figure out a way using the CVT bumper vents on my GLT, as I cooked the rears on my first GLT and didn't want it happening again. Decided the fuel tank was in the way though and never really looked it it properly. Might be doable with a 340? but I'm not really sure how the air was directed as it went though the car and out the back.

Post by **Damir130** » 16 Oct 2007 01:02 pm

classicswede wrote:Has anyone tried using cold air ducting to the back of the disc to aid cooling? I've never felt the need to do it but I would be interested in the results.

Nice to see that this forum is finally beginning to see some sense, jump of the big-brake bandwagon and first try to see what they can achieve with what they've got. To answer your question classicswede: Yes we've done it to our track volvo..like I wrote almost every time that the brake issue surfaced on the forums. Did it work? Hell yeah! Dramatic difference. I could go on and on about it, but its such a small effort to install some ducts that I would really recommend people to just go and find out for themselves,

Post by **classicswede** » 16 Oct 2007 01:08 pm

Niow you mention it I do recall you mentioning about that. I did not take any interest at the time as the brakes have always been 100% but now I'm going for more power I would like to try and improve heat disapation so this is the way I will now go.

Carl - the only time I've evr cooked the rears is when the linkages were sticking but that should not be the case with a 360 unless the hand brake cables were sticky. The fornts do most of the work and 360 drums are bigger than 340 ones so should be better able to cope

Post by **Carl** » 16 Oct 2007 02:02 pm

Oooops, didn't read you post properly Dai. I thought you were talking about rear brakes. I had been incredibly hard on the rears on an event and they were completely destroyed and red hot - to the point of starting to melt things. But that was my own fault because money was tight and the car wasn't prepared as well as it could have been and I was driving a bit too enthusiastically!

I did start to add some cooling at the front too. I can't remember which GLT it was on but I drilled some holes in the disc shield to allow air in. On Fioner I removed the front foglights to act as an air duct to the brakes and even without any proper ducting it made a difference. Eventual plan was to buy proper 'scopes' (available from places like Rally Design/ Demon Tweeks) and put some proper ducting in to take the air directly to the back of the disc. Definitely a worthwhile and fairly cheap mod.