Brake Rotors Effect on Stopping Power

[Oldswagon]

I am overhauling the brakes system on an old Ford Torino. I am looking to get the best performance from the stock disc/drum setup. I was going to upgrade the brake pads and shoes to Porterfield's R4-S compound. I could also go with EBC pads, but Porterfield is the only vendor that makes brake shoes that fit my car with a high performance brake compound, so I thought having a matching set might work better.

My question is how much effect does the brake rotor have on stopping power? I am very limited on the rotor choices if I want to stay stock. My choices are basically a standard steel rotor, such as Raybestos R-Line or a Centric C-Tek. I can also get some slotted and painted rotors by StopTech or Dynamic Friction. Will the Slotted and drilled rotors actually offer any real world braking performance difference? They appear to be the same as the basic rotors, with the addition of clots and paint. The rotors being painted is not a concern as the car never sees bad weather and is stored in a garage year round.

I am not looking to drive this car on the track or anything, so thermal capacity isn't a big concern. I just want the best stopping power I can get with stock type components. So please don't suggest upgrading to modern Baer brakes, etc. I am sure anything will be better than the 30+ year old organic pads on there now.

 

[skyactiv]

Tires make a big effect on stoping distance. Look at dry stopping distances with various tires on the Tire Rack.

 

[Imp4]

They're drum brakes.
They're never gonna be great.
Buy what's available and move on.
If it were me, I'd pick the Porterfields you mentioned.

 

[Oldswagon]

They are front disc brakes and rear drum brakes. The stock brakes are actually pretty good, but I want better with modern traffic. I know tires have a big effect but I just want to keep this discussion to brakes.

FWIW, I know Mustang guys have got excellent performance with stock disc drum setups using high end pads and shoes. I am basically looking to do the same, but I don't want to throw money away on slotted rotors if they do nothing for stopping power

 

[andyd]

I've never had drilled or slotted rotors. Are they a racing thing? Is it gonna be a fast Torino?

 

[skyactiv]

Another suggestion you might not care to hear is nose dive. Those old cars like to nose dive during hard braking which hurts. Firmer shocks up front will help. Test below.

 

[andreigbs]

Slotted rotors should (in theory) help keep rotor temps down and reduce the gases trapped between the pad and rotor under hard braking, all of which prevents (or at least delays) brake fade.

If this Torino is going to see track time, slotted rotors and ceramic pads should hold up nicely, along with fresh brake fluid and hard lines.

Otherwise, I'd stick with good quality rotors and pads, call it a day.

 

[mightymousetech]

Slotted rotors are purely for show. The only difference the rotor will make is how much heat it can absorb and shed. The pads is what determines how much friction you generate. Get a good set of pads and a quality plain rotor.

 

[samven]

Forget the slots unless you are racing or just like the look. The slotted might be a little less rotating mass but standard rotors have more surface area. During normal operation standard rotors work best. As for pads, the most aggressive are also the dustiest and hardest on your rotors. If you stick with ceramic you will get 2 pad sets to the rotor but you may not like the feel of them in the cold or first stop in wet weather, Semi metallic pads are more aggressive and consistent in all weather but they tend to be noisier, dustier and eat rotors so every time you need pads you will probably need rotors too. I use ceramics on the car and semi metallic on the pickup truck.

 

[mightymousetech]

Forget the slots unless you are racing or just like the look. The slotted might be a little less rotating mass but standard rotors have more surface area. During normal operation standard rotors work best. As for pads, the most aggressive are also the dustiest and hardest on your rotors. If you stick with ceramic you will get 2 pad sets to the rotor but you may not like the feel of them in the cold or first stop in wet weather, Semi metallic pads are more aggressive and consistent in all weather but they tend to be noisier, dustier and eat rotors so every time you need pads you will probably need rotors too. I use ceramics on the car and semi metallic on the pickup truck.

Nobody who does real actual racing will use slotted rotors.

 

[samven]

Nobody who does real actual racing will use slotted rotors.

Forgive me, Track days then.

 

[RooflessVW]

Nobody who does real actual racing will use slotted rotors.

I beg to differ.

Almost every single race car with steel brakes has slotted rotors. Nascar, BTCC, Australian Supercars, GT3, GTE, etc...

 

[benjy]

a rotor with higher carbon will stop better with the correct pads + prolly most important is the caliper, 4 FUNCTIONAL pistons make a big difference!!

 

[Oldswagon]

I was not only interested the slotted vs unslotted, but if the metallurgy between the high end rotors and low end rotors made any difference. For example Centric has the CTEK line rotors and StopTech slotted rotors for this car. The StopTech description reads as follows:

Premium e-coated rotor with advanced metallurgy that greatly reduces pad squeal Especially effective with higher friction, European style brake pad compounds Slotted for increased bite, improved looks and better performance

While the CTEK desciption is as follows:

C-Tek Standard Brake RotorNon-Directional Finishes. Machined non-friction surfaces. Widest application coverage in the aftermarketExcellent performance; service life and value for a wide range of applications.

The StopTech rotors are also 3 times the cost of the CTEKs. Unfortunately, the specs for the StopTech rotor are not listed, because I was interested in comparing the weight.

Also, for the car itself, it has makes around 400 hp and 450 ft-lbs of torque. It also has a fully overhauled suspension with high rate springs, upgraded bushings, large anti-sway bars and Bilstein performance shocks. So brake dive is not an issue at all, it is better than some modern cars. This car looks almost 100% stock, but I have managed to make huge improvements utilizing upgrade "stockish" parts. I want to do the same with the brakes, keep it stock appearing but perform much better than original.

It's not that I don't want to hear about tires and brake dive, it's just that I am aware of that stuff and have addressed it. I want to keep this discussion focuses entirely on the brakes. Thank you!

 

[edyvw]

Slotted rotors should (in theory) help keep rotor temps down and reduce the gases trapped between the pad and rotor under hard braking, all of which prevents (or at least delays) brake fade.

If this Torino is going to see track time, slotted rotors and ceramic pads should hold up nicely, along with fresh brake fluid and hard lines.

Otherwise, I'd stick with good quality rotors and pads, call it a day.

On track ceramic pads only if you are taking M3 or Porsche 911. But those ceramic/carbon pads are $700 a set.
Ceramic pads from your parts store down the street should not be seen near the track let alone on the track.

 

[97prizm]

The Porterfield brake pads are awesome. That's what I have on my 84 RX-7 racecar

 

[Timmastertech]

Nobody who does real actual racing will use slotted rotors.

Watching a replay of the NASCAR race from the Roval this past weekend. In some of the camera shots where you can see a wheel off in the pits closely you can clearly see the rotors are slotted. Carbon brake rotors will never be slotted but steel/iron race rotors are. That said, you will never see the benefit of slotted rotors on the street

 

[vavavroom]

On my BMW slotted rotors solved the problem of the pads glazing due to excessive heat buildup during lengthy spirited mountain road driving. Slotted rotors will stay cooler and help evacuate brake dust, gasses, and water. For normal driving there is probably very little benefit to be gained from slotted rotors.

 

[edyvw]

On my BMW slotted rotors solved the problem of the pads glazing due to excessive heat buildup during lengthy spirited mountain road driving. Slotted rotors will stay cooler and help evacuate brake dust, gasses, and water. For normal driving there is probably very little benefit to be gained from slotted rotors.

Which BMW is that? I use regular solid rotors on track and don’t have issues. Last time i did 1 1/2hrs session on track and brakes worked great. Both front snd rear solid ones.
Aftermarket pads? Rotors?

 

[Jetronic]

I am overhauling the brakes system on an old Ford Torino. I am looking to get the best performance from the stock disc/drum setup. I was going to upgrade the brake pads and shoes to Porterfield's R4-S compound. I could also go with EBC pads, but Porterfield is the only vendor that makes brake shoes that fit my car with a high performance brake compound, so I thought having a matching set might work better.

My question is how much effect does the brake rotor have on stopping power? I am very limited on the rotor choices if I want to stay stock. My choices are basically a standard steel rotor, such as Raybestos R-Line or a Centric C-Tek. I can also get some slotted and painted rotors by StopTech or Dynamic Friction. Will the Slotted and drilled rotors actually offer any real world braking performance difference? They appear to be the same as the basic rotors, with the addition of clots and paint. The rotors being painted is not a concern as the car never sees bad weather and is stored in a garage year round.

I am not looking to drive this car on the track or anything, so thermal capacity isn't a big concern. I just want the best stopping power I can get with stock type components. So please don't suggest upgrading to modern Baer brakes, etc. I am sure anything will be better than the 30+ year old organic pads on there now.

The rotor has a big influence in some cases... depending on the pads you are using. During a braking event the temperature rises at the contact surface between disc and pad, and with that the coefficient of friction changes. Standard street pads will likely get a lower friction coefficient as the event takes longer (stopping from high speed) and sport pads might get a higher coefficient. The heat will be concentrated on the surface at first and starts to migrate to the cooler parts of the disc as time goes on. heat gets rejected later, possibly taking minutes depending on the disc design. The more mass in the disc, the faster the heat will move away from the surface and the cooler the pads will stay.

There's no significant cooling taking place in the first few seconds so it's all down to surface area and heat sink capability. Slotted and grooved rotors reduce both... bad if you use street pads, might be ok if you use pads that need heat to work well.

Get the heaviest discs you can, and a pad that can handle heat to some extend. if there's technical drawings available for the discs, less gap in the vented area will help in your case.