bmwe21.net forums

Hello.

What options do i have to make a vented brake conversion on a E21 320-6 ? Apart from the obvious of course using the 323 brakes. Theese are not readily available so i was wondering if anything from E30 or any other models can be used ?

I am not looking for a brake upgrade regarding diameter and 4 pot etc.. Just want vented discs

Hope you guys can point me in the right direction

Cheers, Ruben

Then why do you want just vented discs? Did you already give your brake calipers a full rebuild?

Hi Ruben,

Where are you?

The easiest way of getting vented discs is to fit 323 items. I imagine you could buy some from someone on here and have them shipped?

Thankyou for the answers. I want the wented discs as i really REALLY use my brakes. I will be driving hard at times in the car, and dont want fading and wobbly discs becourse of the heat on the solid discs.

A set of vented discs and some greenstuff pads has suited my driving style really well the last couple of cars, and will do so too on this car i recon

Also as i will be using a brake bias adjustment to completely brake on the front wheels, they will need to take the entire load with little or no help from the rear brakes.

I guess the 323 parts are the ones to use, but as said, the calipers for a 323 are not easy to find here, and new ones are very expensive. Something used from another car would be preferable If anyone on here has something i can use , i will most certainly be interested

I am from Denmark.

Cheers, Ruben

Point is that E21 discs are only small, so if you really use your brakes, they will overheat. So you can keep things fairly standard with stock vented discs and 323i calipers (easy to locate using eBay Germany). Combined with steel braided brake lines, DOT 5.1 fluid and good pads that will give ok performance at a fair rate. If you really use the brakes you should defo consider larger diameter discs and better brake calipers like the Volvo and Wilwood conversions imo.

Hawk pads work way better than EBC Green pads too!

I would also keep some rear braking. Most goes to the front end anyway but having it ALL to the front isn't a good idea.

Jeroen > What are those conversions, i have used Volvo Calipers on Opels before, but how do they fit on the E21, and what disc do i use ? If there´s a guide somewhere i would love to get a link

Mark > One brand or the other, i think thats a matter of taste and temper, i have used greenstuff on several other cars with great results. However there should always be place to expand my horisont, so trying new stuff could be a coming project Regarding the brake bias, i am not talking about a simple shut off valve, i am talking about adjustable brakes, and the posibility to shut the rear ones off completely. In competition use (track and road, not rally) most will drive with a 100% front brake bias setup here as the tracks are small and with no extremly sharp turns. On the tracks in the UK i figure another setup might be better when combining high speed and cornering while braking the result with a 100% front brake setup could and will most often result in a lockup of the front brakes

With a couple of years of racing experience, I can only agree with Mark, you need some stopping power at the rear as well. How much, that very much depends on your driving style, the entire setup and the track, but around 20% defo helps stopping power a lot, gives you more stability and prevents overheating at the front indeed. And in my opinion, EBC brakes aren't too good on the track. For normal trackday use on road tyres they're ok, but if you really start pushing they will either glaze or crumble. My minimum requirement for a road car is Ferodo DS2500 and if you're really going for it, Hawk's are real great material that can handle a lot of heat.

In our top tech topics, a subsection of this tech section, you will find a few threads on brake upgrades already:
http://www.bmwe21.net/forum/viewtopic.php?f=61&t=756
http://www.bmwe21.net/forum/viewtopic.php?f=61&t=9043

Then there is the rear brakes where you defo want discs. E30 rear calipers are relatively easy to adapt for use on an E21 (expect a thread on this in the near future) and that also gives you a wider choice of decent pads as I found there wasn't much good stuff available for the E21 rear anymore. Sometimes Mintex pops up but they didn't cope very well when I tried M1144 on the track.

Jeroen wrote:With a couple of years of racing experience, I can only agree with Mark, you need some stopping power at the rear as well. How much, that very much depends on your driving style, the entire setup and the track, but around 20% defo helps stopping power a lot, gives you more stability and prevents overheating at the front indeed. And in my opinion, EBC brakes aren't too good on the track. For normal trackday use on road tyres they're ok, but if you really start pushing they will either glaze or crumble. My minimum requirement for a road car is Ferodo DS2500 and if you're really going for it, Hawk's are real great material that can handle a lot of heat.

In our top tech topics, a subsection of this tech section, you will find a few threads on brake upgrades already:
http://www.bmwe21.net/forum/viewtopic.php?f=61&t=756
http://www.bmwe21.net/forum/viewtopic.php?f=61&t=9043

Then there is the rear brakes where you defo want discs. E30 rear calipers are relatively easy to adapt for use on an E21 (expect a thread on this in the near future) and that also gives you a wider choice of decent pads as I found there wasn't much good stuff available for the E21 rear anymore. Sometimes Mintex pops up but they didn't cope very well when I tried M1144 on the track.

Again it depends. On my Monza i used adjustable brake bias too and i dont think i ever adjusted it 100% to the front. On my VW Derby mk1 (car weighs 600kg) i used 100% front brake bias. This is the car i have most race experience in. Wether this has to do with this car beeing fwd instead of rwd i don´t know. The monza was rwd but it was also a heavy and big lump to handle (1200kg)

I do participate in racing, hillclimb only in historic classes. I also attend the training days in spring where trackday rules apply

What is important is that the car also is drivable on the streets by my mrs´ So i cant go all-in creating a racecar.. Hope that i can do that with this car some day though, then i will try the Gruppe 5 bodykit. I have never seen this on the streets before

Anyhow, i will take a look at the threads you have linked me

Just a quick observation.

I can read that the Volvo calipers can be used. This is great, those things can really grip. Looking for info regarding discs i found that the E28 525 drives discs that are 284mm and has a height of 76,2mm (the E21 has 75,5mm). So a spacer of 7mm could be placed inside the disc hat and that would make a 284mm disc dead on center for the volvo caliper. But as i understand it i will need to put a washer of 1 mm thickness between the mounting of the caliper to make that sit straight centre on a stock 323i disc. I recon the 7mm more of the E28 disc will cover this issue. So as i see it the E28 525 284mm disc will be a perfect combo with Volvo 4 pots.

Only thing is that the Volvo runs 263mm discs so there is a risk that the disc quite simply will be too big for the calipers. But this should be easy to fix by getting 10mm removed from the diameter of the disc. I recon the E28 discs will need redrilling all the same. Or maybe one of the guys here who use the Volvo calipers on 323 discs can measure if there is room for 284mm discs ?

Please correct me if i am wrong about this brake setup, or if i have missed anything.

Is there no-one to confirm or dismiss this combination of Volvo 4 pots and E28 284mm vented discs ?

I don't have the Volvo's, eh well that's a lie, I do have a set of those 4 pots painted in decent red but they're MIA for a couple of years now so that's why I went for Wilwoods. But there are a few on here using the Volvo's, otherwise try some of the people in the topics quoted. Haven't heard of the E28 discs being used, worth an experiment with a used disc from the wreckers or something.

Jeroen wrote:I don't have the Volvo's, eh well that's a lie, I do have a set of those 4 pots painted in decent red but they're MIA for a couple of years now so that's why I went for Wilwoods. But there are a few on here using the Volvo's, otherwise try some of the people in the topics quoted. Haven't heard of the E28 discs being used, worth an experiment with a used disc from the wreckers or something.

Ok, thanks Jeroen, that was all i needed to know If anyone had done it with succes or failure i would have been a given. So ill give it a go this summer and post the results here. Could be this could be a very cheap, and good solution for a big brake conversion that doesnt involve massivly expensive parts

That's why the Volvo conversion is a popular one, anything that adds to this is most welcome!

As far as i've read, people use the volvo calipers on the std 323i discs. So you'd need to use some sort of adaptor/extension plate to mount them for a larger diameter disc, similar to the ones I've just had made for my new wilwoods.

Ben