Do all cars really need bigger brakes?

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David S.
Update by David S. Wallens to the BMW M3 project car
Dec 26, 2023 | BMW, M3

Some cars greatly benefit from a big-brake kit, as the factory pieces just can’t handle the heat. Just see how the upsized hardware transformed our Corvette Z06 and Toyota MR2 track cars.

But does every car need big brakes–like, for an example, an E46-chassis BMW M3 that primarily sees street use? So we asked BimmerWorld’s James Clay. He knows BMWs and …

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Comments
LostInTransit
LostInTransit New Reader
3/23/22 2:05 p.m.

For the time being, we went with Powerstop's carbon fiber/ceramic brake pads and we've been amazed at the stopping power with hardly any brake dust on the wheels. could be an alterative tot he stoptech brand.

codrus (Forum Supporter)
codrus (Forum Supporter) GRM+ Memberand PowerDork
3/23/22 3:45 p.m.

I mean, really it comes down to use.  The Z06 and MR2 are track cars, they need track brakes.  The E46 "sees primarily street use" so street brakes (the stock ones) are just fine.

 

Tom1200
Tom1200 UltraDork
3/23/22 4:31 p.m.

In reply to codrus (Forum Supporter) :

It really does come down to use; for street car I just use quality components.

wspohn
wspohn SuperDork
3/24/22 10:44 a.m.

90% of big brake kits are installed not for braking but for showing off purposes. On the BMWs you generally have more than adequate systems that can be optimized as done in the article, using only a proper pad choice and perhaps the steel Aeroquip style brake lines which expand less under pressure and can give a firmer pedal.

There were some cars that were designed with inadequate brake systems by the factory.  Take a look at the early Mini discs that were 7" or analyze the wisdom of Sunbeam sticking an American V8 in a Tiger and leaving it with brakes that were all but uncoolable inside 13" wheels.

David S. Wallens
David S. Wallens Editorial Director
3/24/22 10:57 a.m.

In reply to wspohn :

See also: If I remember correctly, doesn't the 240Z have solid, non-vented rotors up front? 

gearheadE30
gearheadE30 Dork
3/24/22 11:59 a.m.

On the street, I don't think I've come across a (modern) car that wasn't just fine with good pads and rotors. Even my notoriously bad GMT400 pickup works fine with good parts.

I thought my E30 had decent enough brakes for the track stock, but eventually I got better at using them (as you have to with no power to make up time on other parts of the track), and even with brake ducts and DTC70 pads, I was melting the backing plates (imprints of the pistons in the backing plates) and cracking front rotors every few sessions, and completely killing the front pads in one day at the track. So now I have big brakes. It doesn't stop any faster than the originals did before they got too hot, but it can stop just as fast over and over and over.

Can't seem to find pictures of the pads, but it was a good thing these rotors were so cheap.

wspohn
wspohn SuperDork
3/25/22 10:42 a.m.
David S. Wallens said:

In reply to wspohn :

See also: If I remember correctly, doesn't the 240Z have solid, non-vented rotors up front? 

Indeed they did - fine for the street but not for track.

 

A couple of friends were running a 240Z and having all sorts of brake problems and the rules did not allow brake substitutions. What they came up with was brilliant and elegantly simple. Wheels were free and all the 240s ran allots of course (on the track) and some bright bulb figured out that if you took the alloy engine fan from a Corvair flat 6 and machined it so they could attach  it to the outside of the wheel it would act as a powerful extractor fan and would suck air past the overheated brakes.

The ended up with wild looking wheels and brakes that actually worked well through  whole race.

Tom1200
Tom1200 UltraDork
3/25/22 11:17 a.m.

My little Datsun 1200 as what are huge brakes for it's size; 280ZX front (vented rotors) and 240Z alloy drums  (1" larger than stock 1200)

They aren't on there for the extra stopping power, it's purely a case of my trail braking and left foot braking puts a ton of heat in the brakes. The 280ZX brakes added 2lbs of unsprung weight....................well worth the trade off. 

Jesse Ransom
Jesse Ransom GRM+ Memberand UltimaDork
12/26/23 2:21 p.m.

It depends on the car, doesn't it?

If you're starting with an E46 M3... That seems more like an outlier than a baseline.

A lot of older stuff (and we don't have to go Bronze Age) benefits from increased brake torque for a given pedal pressure from a control and enjoyment standpoint, even if heat management isn't an issue.

j_tso
j_tso Dork
12/26/23 3:26 p.m.

In reply to wspohn :

I saw something similar but it was a fan insert behind the wheel:

This was at the SCCA races at COTA.

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