normcaldwell
Go Kart Newbie
- Location
- Denver, Colorado
+1 on the Ferodo DS2500 pads.
7
Recommendations for upgraded rotors on stock calipers?
- Thread starter ImolaR
- Start date
breaking badly
Banned
- Location
- St. Olaf
More iron? Any* rotor is made from cast iron, even the cheapest,
since cast iron has proper thermal properties (thermal capacity +
conductivity) and is cheap.
Higher quality rotors have an increased content of carbon (HC =
'high carbon') for better thermal behaviour, and small amounts of
chromium, nickel (enhancing friction, wear resistance and shape
retention) and copper (for an even better thermal conductivity).
Two-piece designs have virtually nothing to do with ventilation
as you could also cast the same directional vanes into any single-
piece rotor (see Porsche).
It's to reduce deformation mainly. The rotor of a true two-piece
design is able to expand freely, while a one-piece brake rotor will
inevitably deform when it gets hot and therefore cause increased
pedal travel. Second reason is to reduce unsprung weight, third
is you could just swap the iron rotors and keep the aluminium bell
(which is common in racing for cost reasons).
* guess we're not talking about ceramic here
since cast iron has proper thermal properties (thermal capacity +
conductivity) and is cheap.
Higher quality rotors have an increased content of carbon (HC =
'high carbon') for better thermal behaviour, and small amounts of
chromium, nickel (enhancing friction, wear resistance and shape
retention) and copper (for an even better thermal conductivity).
Two-piece designs have virtually nothing to do with ventilation
as you could also cast the same directional vanes into any single-
piece rotor (see Porsche).
It's to reduce deformation mainly. The rotor of a true two-piece
design is able to expand freely, while a one-piece brake rotor will
inevitably deform when it gets hot and therefore cause increased
pedal travel. Second reason is to reduce unsprung weight, third
is you could just swap the iron rotors and keep the aluminium bell
(which is common in racing for cost reasons).
* guess we're not talking about ceramic here
BostonDriver
New member
More iron? Any* rotor is made from cast iron, even the cheapest,
since cast iron has proper thermal properties (thermal capacity +
conductivity) and is cheap.
Higher quality rotors have an increased content of carbon (HC =
'high carbon') for better thermal behaviour, and small amounts of
chromium, nickel (enhancing friction, wear resistance and shape
retention) and copper (for an even better thermal conductivity).
Two-piece designs have virtually nothing to do with ventilation
as you could also cast the same directional vanes into any single-
piece rotor (see Porsche).
It's to reduce deformation mainly. The rotor of a true two-piece
design is able to expand freely, while a one-piece brake rotor will
inevitably deform when it gets hot and therefore cause increased
pedal travel. Second reason is to reduce unsprung weight, third
is you could just swap the iron rotors and keep the aluminium bell
(which is common in racing for cost reasons).
* guess we're not talking about ceramic here
Correct. I was thinking less, and wrote more when taking about alloyed high carbon rotors. I agree two piece design has nothing to do with venting but they're performance oriented design includes improved vane design, but any performance rotor could have better vane design.
Your point on deformation is assuming it's a floating rotor design. Most that I've seen are simply bolted rotor and hat and not a floating style. I think ECS went the floating route which is good and maybe takes care of the warping issue I had when they were only a bolted rotor to hat.
[emoji1360] on the lightweight and interchangeable rotor.
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NCM
Ready to race!
- Location
- Fort Wayne, IN, USA
- Car(s)
- 2015 Golf R
That's incorrect. One-piece (stock pattern) rotors can only take in air from one side due to the continuous web of metal joining the friction ring portion to the central hat. Two-piece rotors are, to various degrees depending on the design, open on both sides and can move more cooling air.
That said, directional rotors are certainly more efficient at moving cooling air than non-directional versions.
Yes, yes and yes!
For track use there have always been a couple of schools of thought.
One is to use the cheapest reasonable quality stock rotors you can find, treat them as the consumables they are and replace them as often as needed. There are metallurgical and other quality differences between different rotor brands, but there's no easy way to tell without trying them out. A friend of mine bought some 'bargain' AutoZone rotors for his M3 and cracked one in his first track session of the weekend — hmm, not such a bargain...
The other is to go premium feature/price with two-piece floating rotors, optionally as part of a BBK. Although the replacement cost is high ($300+ for each individual Stop-Tech 332x32 friction ring on my M3) brake cooling is improved, rotors last longer and ongoing maintenance is reduced.
You choose the price/performance trade-off you want. Either approach can work.
Neil
iliveoncaffiene
Ready to race!
- Location
- Cleveland, OH
- Car(s)
- 2020 718 GT4
http://www.adamsrotors.com/232950/0/0/902/vw-mk7r-2015-vw-golf-r.html
Priced these out before, they're actually extremely reasonable and made in USA (+ completely custom at that).
Definitely check them out
Priced these out before, they're actually extremely reasonable and made in USA (+ completely custom at that).
Definitely check them out
NCM
Ready to race!
- Location
- Fort Wayne, IN, USA
- Car(s)
- 2015 Golf R
However other than in their ornamentation I don't see anything upgraded about these rotors — and that is, after all, the name of this thread.
Neil
but the lighter weight will make a difference in handling, right or not.
breaking badly
Banned
- Location
- St. Olaf
Hey Neil,
no, I have been correct. There's no air sucked in through the 'web' of a two-piece rotor.
Brake rotors aren't vented from the outer side, all of the air is coming from the inside,
since air if allway flowing from high-pressure zone to low-pressure zone. Below the
engine bay of virtually any road car there's a high-pressure zone, while at the car's
flank there's a low-pressure zone, and that's why air is flowing from inside to outside
though the wheel well. You easily recognize this when you see all the brake dust on
your pretty wheels.
Openings in the brake's hat could even cause a pressure loss but let's stay real. Properly
designed air guides, hoses and rotor vanes have a much bigger impact.
.
Best track upgrade for brakes I've ever seen [outside of dedicated track compounds for the braking material] (have about 40-50 sessions under my belt) is just adding brake ducting, no matter how ugly, to the car. It is enormously effective, far more then pretty much any other modification. (and really cheap).
The whole point of the rotor is to absorb the heat generated by the pad. But it isn't that great at dissipating it rapidly. Suddenly add a fresh air source flowing to the brake vanes, and bam, suddenly super efficient.
Of course this is not a sexy modification. It is usually the exact opposite of sexy. But it works!
I personally am in the crowd of...buy a set of decent rotor blanks just for the track. Keep a set for the street and one for the track. Swap when its track time. Avoid any etching, dimpling, or cutting of the rotor material. (you are just making it less effective at absorbing heat). Oh and top tip, KEEP A SPARE SET OF PADS AND ROTORS IN YOUR KIT (at the track). Especially if you signed up for back to back track days (four total days in a row).
Second top tip. Don't do that, track days are exhausting. Four is a row is killer!
More iron? Any* rotor is made from cast iron, even the cheapest,
since cast iron has proper thermal properties (thermal capacity +
conductivity) and is cheap.
Higher quality rotors have an increased content of carbon (HC =
'high carbon') for better thermal behaviour, and small amounts of
chromium, nickel (enhancing friction, wear resistance and shape
retention) and copper (for an even better thermal conductivity).
Two-piece designs have virtually nothing to do with ventilation
as you could also cast the same directional vanes into any single-
piece rotor (see Porsche).
It's to reduce deformation mainly. The rotor of a true two-piece
design is able to expand freely, while a one-piece brake rotor will
inevitably deform when it gets hot and therefore cause increased
pedal travel. Second reason is to reduce unsprung weight, third
is you could just swap the iron rotors and keep the aluminium bell
(which is common in racing for cost reasons).
* guess we're not talking about ceramic here
Cast iron is not equal cast iron. There are phase transitions from austenite to orthorhombic and you can argue that the iron density varies based on these lattice structures. In theory a cast iron from one manufacturer can vary a lot from another depending on the manufacturing process. You might want to check the phase diagram for steel and cast iron. I wonder what cast iron they use for rotors.
breaking badly
Banned
- Location
- St. Olaf
Where did I say "cast iron = cast iron"? I actually said in that quote there are
differences.
Cast iron used for most brake rotors is common GG15HC with 'globular graphite'.
.
differences.
Cast iron used for most brake rotors is common GG15HC with 'globular graphite'.
.
tonipepperoni77
Drag Race Newbie
- Location
- Mass
I mean they make great products and are still a little lighter than stock ones and have performance options as well. Obviously they're not a two piece light weight but they are definitely an upgrade
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