Shocking News: Stock E30 brakes aren't really up to S50 swap track use....

[FredK]

3200 lbs? Is this an E30 M3 with an S50?

[Wh33lhop]

3200 lbs? Is this an E30 M3 with an S50?

M3 vert with a huge stereo and an sfittyfo'

[Chris916]

Interesting.. I have stock brakes with pfc06's on my m50 swapped track car. Ran a full 45min race last weekend without issues. No ducting.

[priapism]

Not when you are cracking them in multiple places from hub to rim, all the way through. :). That's why I put DTC-70s on my do not use list. PFCs don't do that, even with ducting.

Good to read after putting a set on last weekend. Now I gotta go look at my rotors.

Maybe you should upgrade your tires or suspension so you don't have to brake so much? :weak:

[priapism]

Jeebus, you weren't kidding. Front rotors cracked after one weekend!

[EtaSport]

I am not fully understanding this either. I have run summit point main a few times coming down from around 125-130 and have never had braking issues after I switched to PFC-06s. Stock OP parts rotors (like 3-4yrs old) all around with PFCs. I've had motul and ATE blue in the past. Run this set-up 24-7 whether its on the street, track, or autox.

I know I dont drive as fast as some of you guys but the car is no slouch either pacing vettes and faster M cars at driving events but wow...

[jeffmn8]

Just came across this. Last October I tracked my s50 powered car for the first time (Gingerman Raceway.) Being a semi experience driver on track, I was slightly concerned about the thermal capacity of the stock braking system. And I was right, without ducts I was getting all sorts of fade after 4 laps. I was running pfc06's and fresh super blue. I ended up going through half of the brand new pads in one day.

Since then, I've done a 5 lug swap with e36 m3 brakes all around. The car nearly rips your head off under braking now. And that's with ht-10s! Also, not a single hint of fade after a 20 minute session at blackhawk farms raceway, a track notoriously hard on brakes.

[nrubenstein]

Good to read after putting a set on last weekend. Now I gotta go look at my rotors.

Maybe you should upgrade your tires or suspension so you don't have to brake so much? :weak:

The truth is that the answer is really that I shouldn't track this car much, and I don't really plan to. I just ran it for giggles because I wanted to see what it would feel like. It's my daily, so I don't really want the suspension stiffer, and spending on r-tires is pretty silly.

[nrubenstein]

3200 lbs? Is this an E30 M3 with an S50?

No. That's with me, a brimmed tank of gas, 100lbs. of ballast, and a 12" Lukebox. The car is in the mid-lower 2,800lbs. the way most people would weigh it.

[TobyB]

...well, Brembo rotors have developed a reputation as track- crackers...

hee

t

[nrubenstein]

I am not fully understanding this either. I have run summit point main a few times coming down from around 125-130 and have never had braking issues after I switched to PFC-06s. Stock OP parts rotors (like 3-4yrs old) all around with PFCs. I've had motul and ATE blue in the past. Run this set-up 24-7 whether its on the street, track, or autox.

I know I dont drive as fast as some of you guys but the car is no slouch either pacing vettes and faster M cars at driving events but wow...

I'd bet that you are a lot lighter than me, you run stickier tires, and you probably had a few supporting brake mods. Even simply removing the front backing plates would make a meaningful difference. My backing plates got so hot that one of them heat warped into the rotor.

[EtaSport]

Good points. Mine is pretty light, I've had decent tires but no r-comps and I do still have backing plates but will probably be taking them off or adding ducts. I know I don't drive my car as hard as someone with a lot of racing experience like yourself. I think thats what I mostly comes down to.

You've had my wheels spinning all day about a 280 or 300mm brake kit :)

[Jonny Cash]

HT-10s suck. They don't have very good braking torque and they don't last and they have mediocre feel. The only virtue is that they are a lot cheaper than PFC, but PFC pads (even the 01s) last so much longer that it's cheaper to run them.

And yes, with ducts and a few tweaks, you should be able to make the stock system usable. However, if you are using it seriously and spending more time than I was on track, you will probably end up saving money by upgrading to larger brakes. When the brakes are undersized, you tend to eat rotors and eat pads. I also need to rebuild all the calipers as I crisped all of the dust boots as well.

Keep in mind how little time this was on track. I grant that I made no supporting mods other than pads, but this was 1.5 short sessions.

all good points, but my point is something else must be wrong/faulty. That shouldnt have happened so quickly.

[e30s50dan]

Just came across this. Last October I tracked my s50 powered car for the first time (Gingerman Raceway.) Being a semi experience driver on track, I was slightly concerned about the thermal capacity of the stock braking system. And I was right, without ducts I was getting all sorts of fade after 4 laps. I was running pfc06's and fresh super blue. I ended up going through half of the brand new pads in one day.

Since then, I've done a 5 lug swap with e36 m3 brakes all around. The car nearly rips your head off under braking now. And that's with ht-10s! Also, not a single hint of fade after a 20 minute session at blackhawk farms raceway, a track notoriously hard on brakes.

I have seen your videos..nice runs dude..enjoyed!!

[Earendil]

I realize that nrubestein was giving us a fun anecdotal story, not trying to prove a specific point (despite the title), nor was he really looking for advice. I'm sure he already knows the following, but for everyone else here it goes:

(1/2)mv^2
This is one of those few areas where physics is actually super helpful in understanding what's going on.
A Pro3 car with slicks dropping from 120-80mph at 2650lbs has stupidly less energy to dissipate into the brakes than a street car going from 130mph-70mph at 3200lbs.

So that's the energy that needs to dissipate. Proper ducting will help make sure that all that energy gets out of the brake system before the driver adds more energy to it by braking for the next corner.

His pads weren't a problem, because he wasn't experiencing fade. He obviously chose pads capable of withstanding that kind of heat.

Lastly, nrubestein is by all accounts a decent driver. He was probably braking harder and for shorter periods of time than those people claiming that street pads should work fine :)
I speak from experience as a noob here on that. When I go out on the track I'm still focusing on corner entrance and exit, not threshold braking, which is how my pads last on my car. I've also been able to overheat them though, it just took a a passive curvy road and 1200ft of elevation drop in under 2 miles.

I'm sure everyone knows the above. I'm just reminding you ;-)