Larger rotors (?) - Even though the not all of the surface is being contacted by the brake pad, I was wondering if the extra surface of the rotor would allow for more “cooling”.
The Hawk pads, (super blue racing) better brake fluid, and blank rotors are a standard on my list.
Are You planning / looking into going with composite rotors as well as pads?
The ceramics are “supposed to” have better thermal properties; whereas: while withstanding the “more rapid” temp changes (heavy braking and more efficient cooling).
Other then that, I would think that a larger rotor would aid in more rapid cooling, but You have to start modifying things on the spindle for the new caliper position… yes?
With rapid cooling after heavy braking (what I was trying to touch on above), are there any realistic concerns of warpage? As an extreme example, throw a 800* F. rotor into a bucket of 60* F. water… Obviously Your system won’t work that well, but is it even a valid concern?
the calipers dont really see that much heat. you want to focus on the relationsip between the pad and the rotor. larger rotors, 2 piece design, cooling vanes, slots…all supposedly help with cooling. after upgrading to slotted rotors on my car, i cant really comment on cooling, because this is also the first aftermarket pad i have run since buying the car. yup thats right, 60k with many auto-x’s and highway pulls on the original, stock pads and rotors.
anyways, i decent pad if you arent already using one would be a great help. stainless lines imo are a waste on the street, only justifiable on the track, but i am sure this varies form car to car. brake ducts are great, but again i think they are a track benefit upgrade. larger rotors are the way to go. more surface area/more surface per rpm maens less heat. thats the way to go, but i fear that a caliper upgrade, or at least some adapting brackets are needed.
imo a good rotor and pad upgrade is the ebst way to go…and then a kit after that (larger rotors/more pots per corner) stainless lines and ducts are only for track use imo. good luck
going with just larger rotors without accounting for the change somewhere else like the caliper or master cylinder is going to change your brake bias. which could be detrimental to the handling of your car under braking. just upgrade with slotted rotors, pads, and brake lines and you should be good…even at the track.
Honestly… for what howie uses his car for… I say get a set of high quality replacement rotors, DBA made some nice ones for my WRX, I dont know much about the DSMs… Look for something heat treated or cryo treated with better than standard internal venting.
The most important think is to make sure you have the right pads on there… Look for something that doesnt need to be warmed up a ton, but is “colder” than your stock pads. Axxis Ultimates were an amazing pad that were surprisingly inexpensive for my WRX, I really couldnt overheat them in autocross or 95% of highway/road conditions. The downside was that they dust a lot.
SS brake lines will improve the durability of the lines themselves againts cuts, abrasion, and give you a more solid pedal feel, but its really not something I would consider unless your lines are bad, or you get them cheap.
Brake Ducts are an excellent idea, another thing you could do is get more “open air” wheels, they will allow your brakes to cool faster.
What are you planning on doing where your brake temperatures will become a concern?
can you explain this to me in more detail? i could understand the bias being effected by not changing both rear and front rotors in porportion. but how does chaning to a larger rotor in the front, without upgrading the caliper/piston (i think what you are implying is the load seen by the caliper). the clamping force of each caliper at each corner is static, therefore the only real variable can be the effects of that clamping force at each individual corner. eg having three street pads, and one track pad. the track pad having more bite will effect the grip, without any change in the pressure on the rotor via the caliper assembly.
no, which is what i had said in my previous post. my question was how does increasing only rotor size (same increase front and rear) affect the caliper/piston in its task, possibly hurting the bias which is what i thought d3x was saying
your right the load is static…but the speed of the larger rotor at the clamping point will change in proportion from the stock rotor. if you upgrade the rear in the same proportion then theoretically your bias wouldnt be effected. ive talked to the guys at stop-tech and they warned about the effects of a “big brake kit” front rotor size increase. stop-tech changes the bias with the calipers that come with their big brake kits. but just slapping on a bigger rotor and changing the bracket to move the stock caliper further out is gunna screw with the bias unless you change front and rear in the same proportion.
I may be wrong but I believe a larger diameter rotor changes the moment and increase the resulting stopping torque.
In any cae to increase brake performance you need:
better pad material: Hawk or Pagid
more rotor material: IE THICKER rotors
increase swept area: surface area of calipers in contact with rotors
larger diameter rotors: more brake torque … more rotor material(assuming thickness is not reduced)
Multi piston calipers: you dont necessarily have to change the master cylinder out… there is some room to work with
Any of these changes other then thicker rotors will change your brake bias.
You always want more in the front. If you are not sure always bias the front more even if its wrong. Its MUCH easier to control/recover a car with front lockup then one where the rear locks up first and you are spinning across the road.
gotcha. thats what i thought, ans since this is a tech thread i wanted to make sure it was clear.
people still do that with their s4’s, upgrade the fronts only, leaving the rears stock. independant tests show this WORSENs straight line braking ability, even in an electronically controlled bias car. not to mention how hairy trail braking could get.
so i guess everyoen agress that pads and rotors in stock size are prolly good enough, even for the occasional track use. then if you fade the next upgrade could be ducts or a kit.
one thing i wanted to point out about slots in my experience, is street driving in the rain is alot less worrysome. because of the slots, water is channeled away from the pads, and it results in a better bite. braking in the rain for me before was scary due to a clearing effect the rotor and pad had to experience. i was kicking and screaming purchasing a slotted rotor, but now after experienceing them, and hearing no additional noise, no vibration (both of which i have experienced in other cars with slotted rotors), and only positive effects i am extremely happy. fwiw my car has DBA’s at all four corners, the only company to offer a cryoed rotor at every corner for my car :tup: to DBA as dozer suggested
I really dont see how more front brake bias is going to hurt much… It may not make you faster on the track, but as far as a safety concern, I dont see there being one, unless of course you have massive brakes on the front and worn drum brakes in the rear or something…
It may make it a little more tail happy under braking while turning, but as long as you are aware of it, its not totally a bad thing.
Most race cars allow for adjusting the bias anyway, the optimal bias will change depending on the conditions.
The most important thing is to be aware that something is different on your car and you may need to take it easy and learn how you car reacts differently and adapt to it.
Too much stop in the front, and your ass end is gonna come around… Dive can be adjusted through suspension settings, but I don’t think we are talking about changing your suspension geometry. If you really wanted to… when you brake you could have the car squat… with proper setup. If you are debating suspension pick up points tho, Im sure the car doesn’t see street time.
I wouldnt recommend just slapping larger rotors with stock calipers… First off you won’t be effectively using the whole surface of the rotor, with the stock swept area of the pad unchanged, and second, this just seems silly… as a mounting bracket will be needed and it would be stupid to have a rotor half rusted, and half shiney bare metal…
It reminds me of the dual exhaust , in which the second muffler isn’t hooked up to the exhaust.
Effective cooling methods would be, cooling ducts… and also… as ricer as it seems, I believe the “fins” or “gills” cut outs in the vendors allow for air to escape from the wheel well… more effectively moving air through that area… more air flow, more coolness.
since a few people have mentined going to slotted and crossed drilled rotors for more cooling, I’d like to point out that they actually increase the temp of the rotors not reduce it. Slots and cross drills remove material so the lesser remaining material has to soak up all the heat produced. Plus the slots and cross drilled holes increase friction thus increase heat soak.
past couple of days i have looked for research on this. do you know of anyplace i can read about this in more detail. i am not understanding how removing of material and transferring heat somehow creates more heat? if the heat is transferred to new material it is going away isnt it?
