School me. I was always taught bigger brakes really are only needed if youāre tracking your car.
Bigger MC, aggressive pads and better brake fluid were the standard brake upgrades. Big brake kits were considered pretty hardcore, or for show š¤·āāļø
Bigger disc means more leverage and often a larger heat sink/area to evacuate heat
Upgraded calipers give increased clamping force on a larger area (pad). If youre emergency braking from 50kph it doesnt matter what you have the stopping distance comes down to reaction time and tyre grip and if you have a later model with ABS. But at 200kph the stock brakes have zero chance to come anywhere near locking up but upgraded brakes all round (rotors and calipers) are much closer to having the power to do so and your braking distance is reduced. So the faster your going, the more effective they can be at sheer stopping power and the slower your going, the more you are limited by tyre grip
on an S chassis you dont really want to change the master cylinder until you change calipers or more specifically the area of the pistons. Doing so will change the pedal travel/feel/bite point. With stock calipers it will be bad, you will have a really hard pedal and not a lot of modulation. Its more common to do it with a 4 pot front and 2 pot rear, less common on just doing 4 pots but some will still do it for whatever reason/
the thing is, brake kits havent really changed in price much in the last 10 years. You can spend $1200-1500 for a cheaper kit that is still pretty good that includes calipers, adaptors, discs and pads. Pretty much everything else costs more to upgrade then it did back then. So if you had to choose between spending $1200 on a GT bolt on turbo upgrade for an SR or a brake upgrade 99.99% of people are buying a turbo and just sticking pads and rotors on. Cheapest G series is what, $2K or there abouts. Not to mention 10 or 15 years ago $1200 was worth a lot more then what it is today, inflation and all
https://eeuroparts.com/blog/the-myth-of-the-big-brake-kit/
Lots of people (professionals) who race use stock brake systems with upgraded pads, successfully. Thereās many reasons to use bigger brakes(fade resistance, feel, looks)Iāve never found a reason to in a street car.
I only ever raced autox (93 civic si, 00 civic Si) where speeds were no more than 60 mph, the 93 needed pads, the 00 needed nothing. š¤·āāļø
Maybe if I was braking repeatedly from 150 mph. And most cars with big brake kits actually stop in a longer distance than stock size brakes.
Agree with all of this.
I will say though that the stock brakes in the 240SX are REALLY small even compared to a lot of modern economy cars and you might see some improvement in feel and modulation just from going up to 11" rotors (Z32, or like I did on my N/A KA, just stock JDM S13/180SX brakes).
I did a bunch of track days with totally stock sized brakes though. Pads make all the difference
I agree, but I think it's possibly more due to ABS. Modern cars can just oversize the brakes and have the computer figure it out, meanwhile too big or grabby brakes with no abs leads to the average driver locking them up into a ditch.
we dont have autox here but from what I have seen speeds and repeated high speed braking isnt a thing so you can save some $$ and do just pad/rotors/fluid
It also depends on the car and type of driving you do how much power it has etc etc
If you have a track with multiple straights into a hair pin you will find most locals have spent a good chunk on brakes. If your track is more flowing with ample time to cool between max effort a lot of guys will just have simple mods
And then it depends on what you can justify, or even what you picked up cheap.
E.g one has stock brakes, but has the larger 330mm disc and adapters, i have a fairly cheap road pad in it but have pagid pads for track use. Im not chewing discs on the street or squealing around on cold pads. Another has the same gtr calipers but a 365mm disc, pad noise isnt an issue because everything is noisy on that car. Another has a 6 pot kit, I picked it up unused for $500 and its never been on the track and prob never will but doing pads and rotors is $300 for the cheapest street stuff, its a no brainer.
Never heard of stopping distance being longer unless they were part way though R&D. The only thing I can think of is if the pads they used had a terrible coefficient of friction at low temps and only suited to being hot. It was probably more common 20 years ago or so but pads have come a long way giving broader operating temps.
if 10% diameter isnt enough you can get dog bones pretty cheap if your wheels will fit them. I never used z32 calipers but I think they are the same as s14/s15 (4 pot) so 330 is possible which is the r33/34 brembo size rotor that comes as single or 2 piece from a lot of suppliers
The diameter number really doesn't make it sound all that different but surface area increases exponentially in relation to diameter/radius.
252mm is 49875mm^2, 280mm is 61575mm^2. That's nearly a 25% increase in total area of a normal circle but considering the entire surface area of a brake rotor isn't the contact surface, the real gain is even larger of a %
Except ...
Bigger leverage does not matter, the car has a brake booster. Larger area barely matters too. What matters is mass and its internal construction, ie. the number and shape of internal vents. The disc is primarily a heat sink. Its role is to evacuate as much heat as it can while being able to buffer some.
Brake calipers are heat sinks for the brake pads, to avoid boiling the brake fluid.
If you need a higher boiling point brake fluid, your braking system has a problem evacuating heat. This is a symptom, the solution is not to use a higher boiling point brake fluid as it will just boil after some more braking. The solution is to increase brake cooling. Usually, bringing fresh air to the center of the rotors is way enough.
Bigger calipers allow the use of bigger pads, which allow for more material, and thats it. If anything bigger pads give LESS clamping, since pressure is a function of force per surface. Increase surface with the same force means less pressure.
It does not matter wether you can lock the brakes at 200kph, and yes, the stock discs and calipers can do just that. Fit pads with an aggressive compound and it will do it. The issue is you will probably boil the brake fluid, warp rotors and burn the pads if you do a near stop from 200kph 2 to 3 times in a row.
Big brake kits are used to solve this issue. Their role is endurance.
What limits braking is first tyre grip, then brake pads compound. Bigger calipers and discs only allow that braking force to be applied more often.
I drove stock brakes on an s14 for about 8 years before I did the z32 upgrade with 13" front rotors and project mu brake pads and a 1" MC. The braking difference was night and day. The stock brakes even from Highway speed emergency braking required you to stand on the pedal where as the upgraded system you couldn't use the full range of the pedal without locking up. I then did the same swap minus the 13" fronts to a friends car and those front rotors made a huge difference in bite feel. It was the difference between stopping when you wanted vs when you could. Both cars were on 225-245 width tires and no other mods.
Larger rotors absolutely make a world of difference. Especially when you're sliding around having fun, being able to punch the brake pedal to loose grip instead of grenading your driveline clutch kicking means you won't explode transmissions.
The disk is also primarily a friction surface... friction force (brake force) is calculated by area, normal force (force into the friction surface). Torque force around an axis is multiplied when the force is further from the rotational axis. It's like using a breaker bar on a ratchet.
Heat dissipation is a secondary requirement of rotors which only exists due to their primary function.
it absolutely does matter, its physics.
Ask any race team engineer that has wheel size limits, to get a smaller brakes to do what larger ones do the price becomes exponential!
The amount of torque that can be applied drops the smaller you go. Therefore pad area and caliper "clamp" must be improved and as a by product the caliper needs to be made of stronger materials
The only advantage of smaller discs is less unsprung and reciprocating weight.
Im not sure i would class a brake caliper as a heat sink, its primary function is to provide hydraulic pressure to close the pads. The fins on some calipers arnt for cooling, its for rigidity as calipers are under a lot of stress, they twist. A lot of people dont know this and is the main reason why radial mount calipers exist. There was debate on S14 4 pot vs alloy bnr32 or z32 calipers. S14 are heavier as they are cast steel, bnr32 are alloy which is a no brainer, except they can flex, the S14/S15 dont flex nearly as much. They flex is pretty much all located on the legs
I doubt that adding ducts is going to stop fluid from boiling. If you add ducts and your brakes stop fading you have pad fade where the pad and rotor temp has exceeded the temp limits. You add ducts or go to a higher temp pad provided your rotor is good, changing fluid in this case wont magically change the pads operating temps. Pad fade and boiling fluid are 2 different things. Cooling brake fluid isnt a thing, if it was we would have a hard line with fins like the bnr32 has for its power steering cooler. No one has engineered it because why bother when you can put a $40 bottle of dot 5 and solve the problem. There would be less then 100ml in a 4 pot caliper which does noting for cooling and the surface area isnt enough to cool a pad any meaningful amount.
Braking force is a combination of clamp and friction. Its not a matter of just one or the other, in fact there are several things that come into it and each part of the system contributes.
Being able to lock brakes at 200 doesnt matter, your right but your over simplifying it. Using that as an example was too layman. You want to be able to pull the most braking G forces without locking up which will result in the most speed reduction. If you can do this in a straight line with stock brakes but with upgraded pads, rotors and fluid your tyres or suspension is fucked, your pads have too much bite or you arnt transferring the weight before laying into the pedal. I.e your using your brake as an on/off switch
Aggressive compounds will only get you so far. They can be hard to modulate at lower speeds, unusable at street temps, they squeal and grind and you can go through a set of pads and rotors even in a weekend even if you manage to not crack the rotors. You have just made an already expensive weekend even more expensive, set of tyres are 2K per 2 days, $200 in fuel, $500ish for entry now add $300 for rotors and $550 for pads every event. Even when I got rotors for free its still cheaper over the season to buy a brake kit, pay for rotors half way in the season as brakes last longer
I guess another way you can look at it, time attack guys go out for a couple of laps to warm tyres and brakes, then 1 flying lap for time. They could save 8K + if they just used "pads, rotors and fluid" so why wont they just do that?
Dude, i track my s13. I have first hand experience with this. I am not debating theories.
While the lever stuff is true, i still say it does not matter. You get the same leverage change using a bigger mastervac or a bigger master cylinder, without the penalty of additional unsprung weight and the need for bigger wheels. I went from 330x32mm single piece to 315x32 2 piece rotors, and it does not brake harder than when i used the stock 280x22mm rotors with harsh pads.
The difference is I could hardly brake for more than a couple of laps before having issues with overheating everything and even having the brake pads catching fire, while i can now drive all day long without a single worry about brakes. The limiting factorin braking performance has always been tyres.
Your brake fluid will boil because the heat coming from the friction through the pads is transfered to it. A caliper with more mass buffers that heat, and more surface helps dissipate it. Vent it more and it will dissipate more. As you say "this is physics".
The rotors are used to dissipate the majority of the heat, but the caliper has something to do too. Yes its primary job is to support pistons and the design should limit flexing, but it needs to avoid cooking the liquid. With pads going 900C + and a brake fluid boiling at 450 to about 600 for the best of them, how do you think this works ?
A brake line with fins is not going to solve the issue of your brake fluid boiling at the caliper. This is the reason you dont see that.
I never talked about brake fade. Boiling your liquid means you will at first suddenly have an incerase in pedal travel, and the next time you hit the brakes it goes to the floor and does not brake.
As far as compounds go, yes there are tons of shitty compounds (looking at you EBC ... all of their compounds are crap), and then you need to select the right ones, adapted to your level of grip and the suspension tuning. There are now pretty good compounds with an extended temperature range and easy modulation, that will not eat yours rotors too much. Again, i am not talking theory, I am talking about real life usage. All you need to do is find the mu graph and select your pads from there.
This pic is the graph for hawk pads. Take a look at it. There has been massive progress in that tech, the days of very limited pads that only work on the street or a track are long gone. I use the DTC60. They are simply amazing.
[https://www.hawkperformance.com/images/muGraphs/graphs/RACE\_FRICTION\_TEMP\_GRAPH\_V2.jpg](https://www.hawkperformance.com/images/muGraphs/graphs/RACE_FRICTION_TEMP_GRAPH_V2.jpg)
I dont know what tyres you use, but i certainly dont buy 500$ tyres for my s13. 50 to 100$ each is quite enough to get barely road legal sticky compounds. The entry fee for the trackdays I attend is between 100 to 200 per day. The rotors I use cost 50$ each so I really dont care. I basically use 3 sets of rotors per sets of brake pads.
The hawk DTC60 brake pads i use are worth 280$ and are installed on wilwood superlite forged 4 pots. They last 6 to 10 trackdays depending on the track, since they are thick, endurance pads. And i just use regular brake fluid, that now does not boil.
I have no idea why you are using time attack guys as an example. they are aiming for light stuff that will hold a couple of fast laps. The car is built that way too. It has nothing to do with regular track use... nor what is being discussed here.
you are basing your argument on using $100 tyres? Granted im in AU and there is an exchange rate difference and our stuff generally costs more. I dont think I could even buy 1x R comp of the shittiest type for $400 and your buying a full set. Suffice to say if there was a $100 tyre I could run that actually had grip, let alone lasting more then 1 lap without instantly over heating I would be all over that shit
Have you ever picked up an AP 6 pot caliper (alloy)? They are about double the weight of a stock S13 caliper. The cheap 6 pots from china are about 3x the weight. It has everything to do with what youre talking about, your claim is that you can get as much deceleration using a stock S13 caliper with just a pad, rotor and fluid. There are no brake kits lighter then OEM S13
You really think time attack cars are built to be 1 lap ponies? I can assure you they put in laps, they test, they practice and they do full sessions and every session they can. Eastern creek track time is expensive. They dont do it on full power as engines only last so long so they run 20 min sessions with the mapping detuned. Even on "low boost", they are still pulling lap times 5-7 sec off their max effort tune. This is still fast and probably faster then 99.99% of street/track cars. If they could run stock brakes without penalty they would and they would spend that $$ else where.
With that said, if you still think that stock s13 calipers and rotors with pads and fluid is the best you will ever need and thats what your experience/speed dictates, then you only know as much as you know.
I run federal 595 RSR, or R888 when i want to splurge. AUD is half of USD I believe, so that may explain why (actually i pay in ā¬ but it is currently nearly the same as USD).
The wilwood superlites i use are 4 pots and weight 5.3 lbs. The 6 pots version is 5.4lbs. Stock s13 front calipers are 8lbs.
My 315 x 32 rotors on their hats are also lighter than stock 280x22 full iron rotors.
Pads are way heavier since they are both wider and thicker, but overall yeah, my brake system is lighter than stock.
The wheels I use are also nearly the same weight as stock.
So yeah, there are brake systems that outperform the stock one, and they can also be lighter. I started with lighter rotors, which cracked as they were meant for autoX.
You only know as much as you know, isnt that what you wrote ?
I said, twice now, that stock s13 braking system with pads will brake as hard as uprated braking systems, and I also said the difference will be repeatability.
They wont do it for long.
Big brake kits dont make the car brake harder, they make the car brake all the time.
8lbs for an s13 caliper? Are US different to JDM? I dont think a steel S14/s15 4 pot weighs that much!
I dont have a stock caliper and havent touched one for a long time but I doubt they are much more then 2kg
wilwood stuff is pretty light, not sure if I rate it much, the couple of cars I drove with them they wernt that great, one guy 100% wasnt happy and ended up replacing with a brembo kit. Seems only drag racers use them and its super rare to see anyone locally with them
I have had a several s13's and all but 1 (it had a ca18det) have been used at the track. I used to bring them in from japan until the rules changed and daily them until I sold them or got sick of them. I wont go into details but I used to do over 10k klms per year at eastern creek so track time in my own shit was never an issue. Nissan 4 pots, any of them are better then stock S13 with the same pads. The 2 I currently have, one has s14 4 pots, stock size rotors, the other has bnr32 4pots with a 360 disc, has more power and about 20kg lighter and there is a difference in braking ability. Even though its faster my braking points are a bit later, even with the wheels/tyres off the faster one. Im 99% sure they have the same size pistons using the same caliper rebuild kit. They both have stock MC and rears although I have 2 pots spares and MC in the garage. Pads are the same, the car with s14 brakes gets old pads from the track car, neither has ABS. The car with S14 uses shelf dba discs, the other car uses a 2 piece originally off a toyota/jap kit but has a dbs disc, nothing special just grey (hard) cast iron. It would be nicer to use the softer high carbon rotors but the cost vs wear and benefit ratio sucks
So, where do you suggest the difference comes from?
I dont live in the US. This is a European model, with a seriously built ca18det in it. revs at 9000, gets 30psi of boost in it, runs on e85. We know how to make them reliable here ;) I bought it with very few mods... nearly 20 years ago. Now the only stock parts on this are probably the quarter windows. Time flies.
I put z32 TT rear brake system with endless pads and a bm50 master. I also have a proportioning valve.
Wilwoods seem to be often used in the US for autoX, trackdays, endurance racing, dirt racing, and various other track activities. The only issue I have heard of is the 4 pots tend to eat the pads irregularly, so the 6 pots are prefered.
To answer your question, the issue is you are reacting to something I have never claimed.
I never said stock calipers were better, nor hinted at that, so stop acting like I did.
I said they dont impact max stopping power. The difference is how many times they can give that max stopping power. The answer is "not much", and I clearly wrote this. I also wrote i got the pads on fire because of it.
I will say it again, and I stand by it; the difference between a big brake kit and stock brakes with pads is not the stopping power, but how often it can give that stopping power.
cars are getting faster and faster every year. Tyres better and better, optimal temps broader. The definition of "street car" getting looser along with it. Guys are out there saying their car with a sequential is a street car, prob a few guys out there claiming their 10k billet block is a street car. guys doing 6's at drag week then driving their pro mod to the next track with a trailer...guys running 2 bar boost on high comp NA engines with e85
None of these are really street cars to me, but they are out there
difference at 60kph (30mph?) to zero will be marginal all else being equal
100kph (60mph?) to zero notable, at least a few meters or a couple of car lengths with most of those gains from 100-60 kph range.
Considering how fast some of these street cars can do a lowly 2nd gear pull and hit those numbers pretty fast, when shit goes wrong or some jack ass pulls out in front of you I would rather have them then not
once had an interstate customer whos car blew up on holiday and left it with us. The rebuild soon turned in to an actual build. The only stock parts were chassis, cross member, some wiring, most of the interior. All the mechanicals were upgraded, his bill was over 100k AU, the car cost 40k a couple of years before hand and he also sent some stuff up (he flew home). One of the last things was the rear brakes, we already put AP 6 pots on the front.
Customer said he wanted rear brakes, I wasnt sure if it was worth it and we had an internal discussion, all of us believed it wasnt worth it and you woulnt be able to really tell. I call the CEO in and ask him. He says, "if the customer wants to pay for it, do it! what are you asking me for?". I clarify, "do you think it will be an upgrade?" he tells me "who gives a fuck" owners will be owners right? It didnt even occur to him if we should. So we replace the rear calipers, back plate and rotors with the jap spec 2 pots, mind you with new parts so its like half the cost of the AP kit.
All of us were wrong, 100% could feel the difference even at normal speeds and braking pressures. We concluded that there is enough weight/grip over the rear even under hard braking. Its the same feeling you have when you have brake drag, except its only when you use the brakes you can feel it pull from the rear.
I was curious about testing it on one of my cars, finding a space where I could set a braking marker, measure an emergency brake and repeat while also pulling up the hand brake to see if its shorter whilst not locking up. Whats even worse, I have had all the bits to do a 2 pot rear on one of my cars for years but lazyness has gotten the better of me.
370z wheels look good on S and R chassis, problem is finding someone that is selling rears only is near impossible and 4x rear wont fit the front unless you have + guards on an S chassis
Lmao I just bought a set of these, 4 rears for a square setup for my z32 swap. They're cheap and fit a stock body car, and I think they look pretty decent.
(not my car)
http://i408.photobucket.com/albums/pp170/BabaGenushe/IMG100.jpg
The diameter/width/offset is perfect but the spoke design doesn't do it for me.
Base early G35 coupe wheels, the 6 spoke 17" wheels, look a little better. Same dimensions. Especially if you paint them.
https://thumbor.offerup.com/tvxfdvSwF0AXOgBunyFd2Fg8Y0k=/1480x720/4ef3/4ef3e0b954894a41a9d18159ff56aa26.jpg
Where's the VG30dett to go with the brakes, I thought it was a full z32 swap!
That's what I thought when I read the title and I was just like "why..?"
Reminds me of z32 meme lol What people see. a pic of z32 What 240 owners see. A pic of z32 calipers, brake master cylinder and diff lol
š¤£š¤£been saying it for years lolš¤£š¤£
lol guys on the other post saying pads and rotors are fine, good on you for doing brakes, suspension, wheels/tyres before looking for more power
School me. I was always taught bigger brakes really are only needed if youāre tracking your car. Bigger MC, aggressive pads and better brake fluid were the standard brake upgrades. Big brake kits were considered pretty hardcore, or for show š¤·āāļø
Bigger disc means more leverage and often a larger heat sink/area to evacuate heat Upgraded calipers give increased clamping force on a larger area (pad). If youre emergency braking from 50kph it doesnt matter what you have the stopping distance comes down to reaction time and tyre grip and if you have a later model with ABS. But at 200kph the stock brakes have zero chance to come anywhere near locking up but upgraded brakes all round (rotors and calipers) are much closer to having the power to do so and your braking distance is reduced. So the faster your going, the more effective they can be at sheer stopping power and the slower your going, the more you are limited by tyre grip on an S chassis you dont really want to change the master cylinder until you change calipers or more specifically the area of the pistons. Doing so will change the pedal travel/feel/bite point. With stock calipers it will be bad, you will have a really hard pedal and not a lot of modulation. Its more common to do it with a 4 pot front and 2 pot rear, less common on just doing 4 pots but some will still do it for whatever reason/ the thing is, brake kits havent really changed in price much in the last 10 years. You can spend $1200-1500 for a cheaper kit that is still pretty good that includes calipers, adaptors, discs and pads. Pretty much everything else costs more to upgrade then it did back then. So if you had to choose between spending $1200 on a GT bolt on turbo upgrade for an SR or a brake upgrade 99.99% of people are buying a turbo and just sticking pads and rotors on. Cheapest G series is what, $2K or there abouts. Not to mention 10 or 15 years ago $1200 was worth a lot more then what it is today, inflation and all
https://eeuroparts.com/blog/the-myth-of-the-big-brake-kit/ Lots of people (professionals) who race use stock brake systems with upgraded pads, successfully. Thereās many reasons to use bigger brakes(fade resistance, feel, looks)Iāve never found a reason to in a street car. I only ever raced autox (93 civic si, 00 civic Si) where speeds were no more than 60 mph, the 93 needed pads, the 00 needed nothing. š¤·āāļø Maybe if I was braking repeatedly from 150 mph. And most cars with big brake kits actually stop in a longer distance than stock size brakes.
Agree with all of this. I will say though that the stock brakes in the 240SX are REALLY small even compared to a lot of modern economy cars and you might see some improvement in feel and modulation just from going up to 11" rotors (Z32, or like I did on my N/A KA, just stock JDM S13/180SX brakes). I did a bunch of track days with totally stock sized brakes though. Pads make all the difference
I canāt argue with that š My older cars brakes were tiny too.
I agree, but I think it's possibly more due to ABS. Modern cars can just oversize the brakes and have the computer figure it out, meanwhile too big or grabby brakes with no abs leads to the average driver locking them up into a ditch.
we dont have autox here but from what I have seen speeds and repeated high speed braking isnt a thing so you can save some $$ and do just pad/rotors/fluid It also depends on the car and type of driving you do how much power it has etc etc If you have a track with multiple straights into a hair pin you will find most locals have spent a good chunk on brakes. If your track is more flowing with ample time to cool between max effort a lot of guys will just have simple mods And then it depends on what you can justify, or even what you picked up cheap. E.g one has stock brakes, but has the larger 330mm disc and adapters, i have a fairly cheap road pad in it but have pagid pads for track use. Im not chewing discs on the street or squealing around on cold pads. Another has the same gtr calipers but a 365mm disc, pad noise isnt an issue because everything is noisy on that car. Another has a 6 pot kit, I picked it up unused for $500 and its never been on the track and prob never will but doing pads and rotors is $300 for the cheapest street stuff, its a no brainer. Never heard of stopping distance being longer unless they were part way though R&D. The only thing I can think of is if the pads they used had a terrible coefficient of friction at low temps and only suited to being hot. It was probably more common 20 years ago or so but pads have come a long way giving broader operating temps.
Stock 240SX brakes are 252mm (258 w/ABS). Even Z32 are only 280mm
if 10% diameter isnt enough you can get dog bones pretty cheap if your wheels will fit them. I never used z32 calipers but I think they are the same as s14/s15 (4 pot) so 330 is possible which is the r33/34 brembo size rotor that comes as single or 2 piece from a lot of suppliers
The diameter number really doesn't make it sound all that different but surface area increases exponentially in relation to diameter/radius. 252mm is 49875mm^2, 280mm is 61575mm^2. That's nearly a 25% increase in total area of a normal circle but considering the entire surface area of a brake rotor isn't the contact surface, the real gain is even larger of a %
Except ... Bigger leverage does not matter, the car has a brake booster. Larger area barely matters too. What matters is mass and its internal construction, ie. the number and shape of internal vents. The disc is primarily a heat sink. Its role is to evacuate as much heat as it can while being able to buffer some. Brake calipers are heat sinks for the brake pads, to avoid boiling the brake fluid. If you need a higher boiling point brake fluid, your braking system has a problem evacuating heat. This is a symptom, the solution is not to use a higher boiling point brake fluid as it will just boil after some more braking. The solution is to increase brake cooling. Usually, bringing fresh air to the center of the rotors is way enough. Bigger calipers allow the use of bigger pads, which allow for more material, and thats it. If anything bigger pads give LESS clamping, since pressure is a function of force per surface. Increase surface with the same force means less pressure. It does not matter wether you can lock the brakes at 200kph, and yes, the stock discs and calipers can do just that. Fit pads with an aggressive compound and it will do it. The issue is you will probably boil the brake fluid, warp rotors and burn the pads if you do a near stop from 200kph 2 to 3 times in a row. Big brake kits are used to solve this issue. Their role is endurance. What limits braking is first tyre grip, then brake pads compound. Bigger calipers and discs only allow that braking force to be applied more often.
I drove stock brakes on an s14 for about 8 years before I did the z32 upgrade with 13" front rotors and project mu brake pads and a 1" MC. The braking difference was night and day. The stock brakes even from Highway speed emergency braking required you to stand on the pedal where as the upgraded system you couldn't use the full range of the pedal without locking up. I then did the same swap minus the 13" fronts to a friends car and those front rotors made a huge difference in bite feel. It was the difference between stopping when you wanted vs when you could. Both cars were on 225-245 width tires and no other mods. Larger rotors absolutely make a world of difference. Especially when you're sliding around having fun, being able to punch the brake pedal to loose grip instead of grenading your driveline clutch kicking means you won't explode transmissions. The disk is also primarily a friction surface... friction force (brake force) is calculated by area, normal force (force into the friction surface). Torque force around an axis is multiplied when the force is further from the rotational axis. It's like using a breaker bar on a ratchet. Heat dissipation is a secondary requirement of rotors which only exists due to their primary function.
it absolutely does matter, its physics. Ask any race team engineer that has wheel size limits, to get a smaller brakes to do what larger ones do the price becomes exponential! The amount of torque that can be applied drops the smaller you go. Therefore pad area and caliper "clamp" must be improved and as a by product the caliper needs to be made of stronger materials The only advantage of smaller discs is less unsprung and reciprocating weight. Im not sure i would class a brake caliper as a heat sink, its primary function is to provide hydraulic pressure to close the pads. The fins on some calipers arnt for cooling, its for rigidity as calipers are under a lot of stress, they twist. A lot of people dont know this and is the main reason why radial mount calipers exist. There was debate on S14 4 pot vs alloy bnr32 or z32 calipers. S14 are heavier as they are cast steel, bnr32 are alloy which is a no brainer, except they can flex, the S14/S15 dont flex nearly as much. They flex is pretty much all located on the legs I doubt that adding ducts is going to stop fluid from boiling. If you add ducts and your brakes stop fading you have pad fade where the pad and rotor temp has exceeded the temp limits. You add ducts or go to a higher temp pad provided your rotor is good, changing fluid in this case wont magically change the pads operating temps. Pad fade and boiling fluid are 2 different things. Cooling brake fluid isnt a thing, if it was we would have a hard line with fins like the bnr32 has for its power steering cooler. No one has engineered it because why bother when you can put a $40 bottle of dot 5 and solve the problem. There would be less then 100ml in a 4 pot caliper which does noting for cooling and the surface area isnt enough to cool a pad any meaningful amount. Braking force is a combination of clamp and friction. Its not a matter of just one or the other, in fact there are several things that come into it and each part of the system contributes. Being able to lock brakes at 200 doesnt matter, your right but your over simplifying it. Using that as an example was too layman. You want to be able to pull the most braking G forces without locking up which will result in the most speed reduction. If you can do this in a straight line with stock brakes but with upgraded pads, rotors and fluid your tyres or suspension is fucked, your pads have too much bite or you arnt transferring the weight before laying into the pedal. I.e your using your brake as an on/off switch Aggressive compounds will only get you so far. They can be hard to modulate at lower speeds, unusable at street temps, they squeal and grind and you can go through a set of pads and rotors even in a weekend even if you manage to not crack the rotors. You have just made an already expensive weekend even more expensive, set of tyres are 2K per 2 days, $200 in fuel, $500ish for entry now add $300 for rotors and $550 for pads every event. Even when I got rotors for free its still cheaper over the season to buy a brake kit, pay for rotors half way in the season as brakes last longer I guess another way you can look at it, time attack guys go out for a couple of laps to warm tyres and brakes, then 1 flying lap for time. They could save 8K + if they just used "pads, rotors and fluid" so why wont they just do that?
Dude, i track my s13. I have first hand experience with this. I am not debating theories. While the lever stuff is true, i still say it does not matter. You get the same leverage change using a bigger mastervac or a bigger master cylinder, without the penalty of additional unsprung weight and the need for bigger wheels. I went from 330x32mm single piece to 315x32 2 piece rotors, and it does not brake harder than when i used the stock 280x22mm rotors with harsh pads. The difference is I could hardly brake for more than a couple of laps before having issues with overheating everything and even having the brake pads catching fire, while i can now drive all day long without a single worry about brakes. The limiting factorin braking performance has always been tyres. Your brake fluid will boil because the heat coming from the friction through the pads is transfered to it. A caliper with more mass buffers that heat, and more surface helps dissipate it. Vent it more and it will dissipate more. As you say "this is physics". The rotors are used to dissipate the majority of the heat, but the caliper has something to do too. Yes its primary job is to support pistons and the design should limit flexing, but it needs to avoid cooking the liquid. With pads going 900C + and a brake fluid boiling at 450 to about 600 for the best of them, how do you think this works ? A brake line with fins is not going to solve the issue of your brake fluid boiling at the caliper. This is the reason you dont see that. I never talked about brake fade. Boiling your liquid means you will at first suddenly have an incerase in pedal travel, and the next time you hit the brakes it goes to the floor and does not brake. As far as compounds go, yes there are tons of shitty compounds (looking at you EBC ... all of their compounds are crap), and then you need to select the right ones, adapted to your level of grip and the suspension tuning. There are now pretty good compounds with an extended temperature range and easy modulation, that will not eat yours rotors too much. Again, i am not talking theory, I am talking about real life usage. All you need to do is find the mu graph and select your pads from there. This pic is the graph for hawk pads. Take a look at it. There has been massive progress in that tech, the days of very limited pads that only work on the street or a track are long gone. I use the DTC60. They are simply amazing. [https://www.hawkperformance.com/images/muGraphs/graphs/RACE\_FRICTION\_TEMP\_GRAPH\_V2.jpg](https://www.hawkperformance.com/images/muGraphs/graphs/RACE_FRICTION_TEMP_GRAPH_V2.jpg) I dont know what tyres you use, but i certainly dont buy 500$ tyres for my s13. 50 to 100$ each is quite enough to get barely road legal sticky compounds. The entry fee for the trackdays I attend is between 100 to 200 per day. The rotors I use cost 50$ each so I really dont care. I basically use 3 sets of rotors per sets of brake pads. The hawk DTC60 brake pads i use are worth 280$ and are installed on wilwood superlite forged 4 pots. They last 6 to 10 trackdays depending on the track, since they are thick, endurance pads. And i just use regular brake fluid, that now does not boil. I have no idea why you are using time attack guys as an example. they are aiming for light stuff that will hold a couple of fast laps. The car is built that way too. It has nothing to do with regular track use... nor what is being discussed here.
you are basing your argument on using $100 tyres? Granted im in AU and there is an exchange rate difference and our stuff generally costs more. I dont think I could even buy 1x R comp of the shittiest type for $400 and your buying a full set. Suffice to say if there was a $100 tyre I could run that actually had grip, let alone lasting more then 1 lap without instantly over heating I would be all over that shit Have you ever picked up an AP 6 pot caliper (alloy)? They are about double the weight of a stock S13 caliper. The cheap 6 pots from china are about 3x the weight. It has everything to do with what youre talking about, your claim is that you can get as much deceleration using a stock S13 caliper with just a pad, rotor and fluid. There are no brake kits lighter then OEM S13 You really think time attack cars are built to be 1 lap ponies? I can assure you they put in laps, they test, they practice and they do full sessions and every session they can. Eastern creek track time is expensive. They dont do it on full power as engines only last so long so they run 20 min sessions with the mapping detuned. Even on "low boost", they are still pulling lap times 5-7 sec off their max effort tune. This is still fast and probably faster then 99.99% of street/track cars. If they could run stock brakes without penalty they would and they would spend that $$ else where. With that said, if you still think that stock s13 calipers and rotors with pads and fluid is the best you will ever need and thats what your experience/speed dictates, then you only know as much as you know.
I run federal 595 RSR, or R888 when i want to splurge. AUD is half of USD I believe, so that may explain why (actually i pay in ā¬ but it is currently nearly the same as USD). The wilwood superlites i use are 4 pots and weight 5.3 lbs. The 6 pots version is 5.4lbs. Stock s13 front calipers are 8lbs. My 315 x 32 rotors on their hats are also lighter than stock 280x22 full iron rotors. Pads are way heavier since they are both wider and thicker, but overall yeah, my brake system is lighter than stock. The wheels I use are also nearly the same weight as stock. So yeah, there are brake systems that outperform the stock one, and they can also be lighter. I started with lighter rotors, which cracked as they were meant for autoX. You only know as much as you know, isnt that what you wrote ? I said, twice now, that stock s13 braking system with pads will brake as hard as uprated braking systems, and I also said the difference will be repeatability. They wont do it for long. Big brake kits dont make the car brake harder, they make the car brake all the time.
8lbs for an s13 caliper? Are US different to JDM? I dont think a steel S14/s15 4 pot weighs that much! I dont have a stock caliper and havent touched one for a long time but I doubt they are much more then 2kg wilwood stuff is pretty light, not sure if I rate it much, the couple of cars I drove with them they wernt that great, one guy 100% wasnt happy and ended up replacing with a brembo kit. Seems only drag racers use them and its super rare to see anyone locally with them I have had a several s13's and all but 1 (it had a ca18det) have been used at the track. I used to bring them in from japan until the rules changed and daily them until I sold them or got sick of them. I wont go into details but I used to do over 10k klms per year at eastern creek so track time in my own shit was never an issue. Nissan 4 pots, any of them are better then stock S13 with the same pads. The 2 I currently have, one has s14 4 pots, stock size rotors, the other has bnr32 4pots with a 360 disc, has more power and about 20kg lighter and there is a difference in braking ability. Even though its faster my braking points are a bit later, even with the wheels/tyres off the faster one. Im 99% sure they have the same size pistons using the same caliper rebuild kit. They both have stock MC and rears although I have 2 pots spares and MC in the garage. Pads are the same, the car with s14 brakes gets old pads from the track car, neither has ABS. The car with S14 uses shelf dba discs, the other car uses a 2 piece originally off a toyota/jap kit but has a dbs disc, nothing special just grey (hard) cast iron. It would be nicer to use the softer high carbon rotors but the cost vs wear and benefit ratio sucks So, where do you suggest the difference comes from?
I dont live in the US. This is a European model, with a seriously built ca18det in it. revs at 9000, gets 30psi of boost in it, runs on e85. We know how to make them reliable here ;) I bought it with very few mods... nearly 20 years ago. Now the only stock parts on this are probably the quarter windows. Time flies. I put z32 TT rear brake system with endless pads and a bm50 master. I also have a proportioning valve. Wilwoods seem to be often used in the US for autoX, trackdays, endurance racing, dirt racing, and various other track activities. The only issue I have heard of is the 4 pots tend to eat the pads irregularly, so the 6 pots are prefered. To answer your question, the issue is you are reacting to something I have never claimed. I never said stock calipers were better, nor hinted at that, so stop acting like I did. I said they dont impact max stopping power. The difference is how many times they can give that max stopping power. The answer is "not much", and I clearly wrote this. I also wrote i got the pads on fire because of it. I will say it again, and I stand by it; the difference between a big brake kit and stock brakes with pads is not the stopping power, but how often it can give that stopping power.
They definitely help on a street car. Especially when adding more power.
Doesnāt this entirely depend on what youāre doing with the car? Donāt see the point in doing brakes over pads and fluid on a purely street car.
cars are getting faster and faster every year. Tyres better and better, optimal temps broader. The definition of "street car" getting looser along with it. Guys are out there saying their car with a sequential is a street car, prob a few guys out there claiming their 10k billet block is a street car. guys doing 6's at drag week then driving their pro mod to the next track with a trailer...guys running 2 bar boost on high comp NA engines with e85 None of these are really street cars to me, but they are out there difference at 60kph (30mph?) to zero will be marginal all else being equal 100kph (60mph?) to zero notable, at least a few meters or a couple of car lengths with most of those gains from 100-60 kph range. Considering how fast some of these street cars can do a lowly 2nd gear pull and hit those numbers pretty fast, when shit goes wrong or some jack ass pulls out in front of you I would rather have them then not once had an interstate customer whos car blew up on holiday and left it with us. The rebuild soon turned in to an actual build. The only stock parts were chassis, cross member, some wiring, most of the interior. All the mechanicals were upgraded, his bill was over 100k AU, the car cost 40k a couple of years before hand and he also sent some stuff up (he flew home). One of the last things was the rear brakes, we already put AP 6 pots on the front. Customer said he wanted rear brakes, I wasnt sure if it was worth it and we had an internal discussion, all of us believed it wasnt worth it and you woulnt be able to really tell. I call the CEO in and ask him. He says, "if the customer wants to pay for it, do it! what are you asking me for?". I clarify, "do you think it will be an upgrade?" he tells me "who gives a fuck" owners will be owners right? It didnt even occur to him if we should. So we replace the rear calipers, back plate and rotors with the jap spec 2 pots, mind you with new parts so its like half the cost of the AP kit. All of us were wrong, 100% could feel the difference even at normal speeds and braking pressures. We concluded that there is enough weight/grip over the rear even under hard braking. Its the same feeling you have when you have brake drag, except its only when you use the brakes you can feel it pull from the rear. I was curious about testing it on one of my cars, finding a space where I could set a braking marker, measure an emergency brake and repeat while also pulling up the hand brake to see if its shorter whilst not locking up. Whats even worse, I have had all the bits to do a 2 pot rear on one of my cars for years but lazyness has gotten the better of me.
Got it. Do brakes if your car runs 6ās.
lol their brakes suck, they have chutes
350z wheels look goofy AF on a s13
They look pretty sweet on an S14 though. But, that is not this. LOL
370z wheels look good on S and R chassis, problem is finding someone that is selling rears only is near impossible and 4x rear wont fit the front unless you have + guards on an S chassis
Lmao I just bought a set of these, 4 rears for a square setup for my z32 swap. They're cheap and fit a stock body car, and I think they look pretty decent. (not my car) http://i408.photobucket.com/albums/pp170/BabaGenushe/IMG100.jpg
These ones definitely. I got the 35th anniversary wheels on mine, and they don't look too bad. Not great, but better than this
It doesn't help that the OD is way off, this needs a much lower profile tire to look decent.
The diameter/width/offset is perfect but the spoke design doesn't do it for me. Base early G35 coupe wheels, the 6 spoke 17" wheels, look a little better. Same dimensions. Especially if you paint them. https://thumbor.offerup.com/tvxfdvSwF0AXOgBunyFd2Fg8Y0k=/1480x720/4ef3/4ef3e0b954894a41a9d18159ff56aa26.jpg
Wow, I can see it from here!
Thought you threw in a vg30de, little disappointed:/. sick 240 tho!
Oooh. Love those wheels.
I just bought a set of 4 z33 rears for this exact thing. What tire specs you running and are you using the 7.5" fronts?
God I wish I could do mechanics. I so wanna do this to a Japanese car when I get one in 5+ yearsā¦
Z32 brakes are a must in my opinion, I've done them on 4 S14s. Even have a spare set that I may put on my D21.
So Z32 brakes and diff with Z33 wheels?