SE-R Brake Performance Tips
Written by Mike Kojima
Last updated: 12/22/98
If you want to go, First you must stop. One of my favorite sayings is "Speed doesnt kill, rapid deceleration does"!
As braking is critical to your safety and modifying your brakes can affect your own and others safety, please read the disclaimer below before continuing.
The Classic SE-R and the 200SX are both blessed with pretty good brakes right off of the showroom floor. Power assisted 4 wheel disc brakes with vented front rotors come as standard equipment. With proper preparation I have raced totally stock brakes right down to stock pads with pretty good results. I guess I should start off this section with an explanation of some common brake problems encountered in fast driving and how to counter them.
Brake fade is the number one high performance driving braking problem that is encountered. Brake fade is a dangerous situation when after braking hard several times in a row such as when you are racing, you lose brake effectiveness. This usually occurs gradually so you can compensate in your brake point by braking sooner, but sometimes happens so suddenly you can end up going on a wild off-road excursion with sometimes fatal results.
There are three kinds of fade commonly encountered in fast driving; pad fade, green fade and fluid fade. Below are listed an explanation of each.
The mechanics of this decline in the coefficient of friction are varied. At a certain temperature, certain elements of the pad can melt or smear causing a lubrication effect, this is the classic glazed pad. Usually the organic binder resin starts to go first, then even the metallic elements of the friction material can start to melt. At really high temperatures the friction material starts to vaporize and the pad can sort of hydroplane on a boundary layer of vaporized metal and friction material which acts like a lubricant. Pad fade is felt as a car that still has a decent, non mushy feeling brake pedal that wont stop even if you are pushing as hard as you can. Usually it builds somewhat slowly giving you time to compensate for it ,but some friction materials have a sudden drop off of friction when the heat is put on them resulting in sudden dangerous fade.
Green fade is a type of fade that manifests itself on brand new brake pads. Brake pads are usually made of different types of heat resistant materials bound together with a phenolic resin binder. These are thermosetting plastic resins with a high heat resistance. On a new brake pad, these resins will out-gas or cure when used hard on their first few heat cycles. The new pad can hydroplane on this layer of excreted gas. Green fade is dangerous because many people assume that new brakes are perfect and can be used hard right off the bat. Green fade typically will occur much earlier than normal fade so it can catch a driver that is used to a certain cars characteristics unaware. Typically the onset of green fade is rather sudden, further increasing the danger factor. I was a victim of green fade once. The crew forgot to tell me that new brake pads were installed on the car and when I went out on the track, I was flying down the escape road at about the third corner! Some teams have a new pads warning sign that they place on the steering wheel to inform the drive to be careful on his first few laps.
Green fade can occur if you change the pads and drive on the street for a few hundred or even thousand miles, never braking hard, then suddenly start using the brakes hard. I think that this is the fade that many list member complain about on their own cars.
Green fade can be prevented by bedding the pads. This is a simple procedure to boil off the resins and break in the pads under controlled conditions which I will explain later.
Fluid fade usually has a gradual onset.
If you are having an exceptionally bad day your brakes can fade from all three of the above reasons at the same time! The reason why I am explaining them to you is so that you can identify what kind of fade that you are suffering from and do the proper thing to fix the type of fade that you have with the correct countermeasure. If you are experiencing pad fade, switching brands of brake fluid wont help. If you are getting fluid fade, the trickiest carbon pads wont stop you a bit sooner. If you have the finest brake parts available, you could still fall prey to green fade.
Reducing Pad Fade
Pad fade is fixed by getting pads with a higher coefficient of friction at higher temperatures. On our cars the stock pads, Genuine Nissan only, are remarkably good. At the 12 hours of Sebring we miscalculated the wear rate of our trick Performance Friction carbon pads. During practice, we ran out of replacement pads for our two car team. We did a mad dash to a local Nissan dealer and put bone stock pads in one of the cars, the one that had no chance of winning, the one I was driving!
I bedded the pads and went out, braking carefully. As it ended up, the pads worked pretty well, fading slightly then stabilizing. We ended up running the race on those pads for one car.
Granted, Sebring is not a super heavy braking track, but it still means that the stock pads, if bedded properly are not half bad. So dont pitch them in the trash unless you feel that you really need them.
Brake pads can be roughly broken down into about 4 types:
If you are overdriving your pads you will notice a gradual onset of lack of braking. If this happens you will have to back off and maybe the pads will recover. If you continue to beat on them, the pads will be ruined by becoming permanently glazed. If you keep going, the pads will chunk and start to physically break up. If you still insist on going, the pistons will wear through the backing plates causing a major loss of hydraulic pressure in the brake system and you will die. Dont laugh. On an Escort endurance race that I was working, one of our drivers did just that at Mid Ohio. Ever see a 3600 lb. turbo Supra fly 60 ft in the air? After clearing a couple of motorhomes the Supra landed right in the middle of a BBQ flattening it. Fortunately no one was seriously hurt but the Supra was very totaled and the BBQ was around ½ inch tall.
As a warning for you weekend warriors that commute in your race car, or for street bombers that drive hard on the street, usually in the case of brake pads, friction materials that work well for higher temperatures work worse at colder temperatures. This can make the first few morning stops kinda hairy. In the rain or cold days can be sketchy as well. Some extreme pad materials never get up to operating temperature on the street. Brake pads that work well at high temps usually have a higher metallic content which makes for more squeals and squeaks also.
For the money, I think its pretty hard to beat Axxiss Metal Matrix pads, if you are a Solo competitor, or just drive hard. These pads last a long time, dont kill rotors, and are reasonable in the cold (be careful at the first couple of morning stops!). These pads are about ½ the price of carbon pads. They are even good for light use race pads. Best off (for me!) they make very little dust, minimizing cleaning chores.
If money and cleaning are not an issue, you can go for the techy carbon pads. Carbon pads have the widest operating heat range making them the best multipurpose pad. Hawk HPS compound pads are good for street and even some pretty good race action. If racing on a heavy braking course, the Hawk Blue pads will not even fade at all! Do not even think of using these on the street. I put them in my twin turbo Z and in about 1000 miles they totally ate my rotors! A few people have told me (Steve at SMC, Terry at KVR) that if they are operating at normal (hot) temperatures the rotor wear is better. It was a sad sight to pull my rotors that were ground off about close to 1/8 inch on either side to find that the brake pads were like brand new! Porterfields R4-S and Performance Frictions Z compound are good carbon pads for mild racing or hard core street also. Porterfield and Performance Friction have more aggressive, higher temperature compounds available also but I have never had to use them, even when racing. Just stick with the more mild entries unless you have a specific need to go to an aggressive pad. Be sure and remove the black dust from your wheels frequently or it will become permanent. The black menace can even eat up the paint on the sides of your car if you leave it there too long.
In short, to avoid pad fade, select a pad whose operating temperature matches the type of driving you do. If you drive mostly on the street, be realistic and select a pad whose operating temperature matches street conditions, as a pad with poor cold characteristics can actually be dangerous. You can change to a more aggressive pad for weekend action in less than an hour so dont give yourself pads with poor cold stopping for everyday use!
Reducing Green Fade
It is better to bed new pads on older rotors. Older rotors are seasoned and more dimensionally stable making them less likely to warp or crack while bedding. Older rotors for some reason are less likely to glaze new pads. I am not sure why on this but Carrol Smith, the renowned race car engineer once told me this as a tip. You should always run a new rotor in with bedded pads also for the same reasons. I have gotten away with violating this rule many times but Carrol is super smart so I at least try to follow his sage advice.
When replacing your pads, sand your rotors with an electric drill with a 220 grit sanding disc, putting a light cross hatch pattern on them. This helps break the glaze on the rotor and aides in bedding the new pads quickly. Install your new pads and go for your bedding run. Before making the first stop after changing pads pump the brake pedal before you really need to stop. The pistons are fully retracted into the caliper when you change the pads and the pedal will be real long at the first brake application. I witnessed a serious racing accident caused by this where the driver was nearly killed. It was the 12 hours of Sebring and we drove under a yellow for almost one hour while they cut the poor guy out of his Prelude. The car had just pitted, the crew had changed pads and a new driver was put in the car. In a red mist the driver tore out of the pits and jammed down the pit road and front strait. He did not touch the brake pedal until turn one when he discovered that the pedal went to the floor. The Prelude hit the tire wall head on at well over 100 mph. The car was very totaled and the driver suffered serious leg, arm, head and internal injuries.
When bedding the pads, be very careful as the brakes will not work to well until you are done. The way that I bed brakes is as follows:
Note that these are general bedding instructions. Some pad manufactures have very specific bedding instructions that you should follow. Call the maker of your pads to find out what is the best for them.
When returning to the pits or home, be sure not to apply the parking brake until the brake are completely cool as this might warp the rear rotors. In fact it is a good idea to take a cool down lap if you are at the track to allow your brakes to cool off before coming into the pits. Heat soak after hard running can damage the caliper seals and warp the rotors.
To bed the brakes on the track, simply drive carefully at about 80%, anticipating the green fade and maybe dragging the brakes lightly on the straits. When you feel green fade coming, back off and drive without braking for about ½ lap to let the brakes cool. Repeat until you dont get any green fade. Never start a race on new unbedded pads. All of your spare pads should be bedded beforehand. Even if you have bedded pads, if they are freshly bedded I would still be cautious about green fade for a few laps especially until you get a good feel for the bedding procedure with your favorite brand of pads. If you are new to bedding, you may not bed your pads completely and still get some green fade, a nasty surprise if you are not anticipating it.
Many of the new generation Carbon pads do not need to be bedded much. When running those I simply bring them up to operating temp while allowing myself some extra run out just in case, before I go all out. On the street, I would run them through one bedding cycle to burnish them in. Consult with the maker of your Carbon pads though, as some of them may have some different bedding procedure than what I am describing.
Harder, high temperature pads usually have an overall lower coefficient of friction even when they are in their ideal operating temperature. Because of this you can expect having to push on the brake pedal much harder with them installed unless you go to a bigger brake system with more pad area. Softer, lower temperature pads generally have more initial bite and require less pedal effort but they will fade much quicker.
Through proper selection of brake pad material and careful bedding you should be able to reduce pad fade to a manageable level except in the most extreme racing conditions.
Reducing fluid fade
Brake fluid is hydroscopic which means it has an affinity to water and absorbs water from the air. When brake fluid absorbs water its boiling point drops rapidly. That why it is important to use only very fresh brake fluid, preferably from a recently opened bottle where the factory seal has just been broken. When bleeding brakes, keep the bottle capped except when you are poring the fluid out. It is also a good practice to keep the cap of the master cylinder reservoir on, but only loosely screwed about ½ turn while you are bleeding, as the brake fluid pulls in the humidity from the air thus you want to minimize its exposure to the air.
You should also bleed your system and change your fluid at least once a year to get the moisture laden old fluid out. Your brake system will last much longer this way as the moisture in old fluid causes corrosion of the brake systems internal parts. If you are racing the fluid changes should be much more frequent than that.
If faced with fluid fade you can sometimes save your ass by rapidly pumping the brake pedal. This sometimes builds up enough pressure for you to stop or slow enough to avoid disaster. A better way to deal with this is to properly prepare and maintain your vehicle to avoid fluid fade.
My own personal close call with fluid fade goes back to my wayward youth. Being young and dumb (after reading Bob Bonderants book on high performance driving) I decided to go out and practice. I bombed around for quite a bit and noted that my brake pedal was getting kinda low. I was hauling around a long radius turn when I noticed , much to my dismay that a whole family was about to cross the street in front of my speeding car. They underestimated my approach speed and proceeded to cross the street. It was Dad, Mom, a Toddler and a stroller. I slammed on the brakes and much to my horror, the poor, abused 10 year old brake fluid gave up the ghost and the pedal went to the floor! I frantically pumped the pedal in a near panic and with the grace of God managed to slow enough to swerve around the family. I can remember with crystal clear clarity the fear in the adults faces as I almost creamed them. I was real fortunate to have missed those people for if I hit them I would have ruined a lot of lives including my own. So folks never drive fast on the street in an uncontrolled situation!
So sparked my interest in brakes!
Fluid fad can be avoided nowadays to a large degree with modern high-performance brake fluid. When I began racing I used Castrol LMA. I chose that because LMA seemed like a cool name! With LMA Id have to bleed the brakes system several times in a race weekend to keep the pedal firm. Later when I started learning more about things I bought some AP550 brake fluid, which at the time was the best that you could buy. With AP550 the pedal would stay firm for the greater part of a race weekend, but you would still have to do some bleeding. The trouble was that the stuff cost like 15 bucks for a ½ pint tiny little bottle. So I read somewhere that Ford brake fluid worked well. For $6 a quart, it seemed like a good deal. Ford fluid was great! It worked nearly as well as AP550 and cost just a fraction of the price. I still recommend Ford fluid as a great poor mans racing brake fluid.
At one race, the Motul rep gave me a bottle of their DOT 3 brake fluid. At the time Motul was well known in the racing motorcycle world but they had not really gotten into the car market yet. I tried the Motul and was amazed. When I previously had to bleed my brakes at least once on a race weekend, I now did not even have to touch my brakes at all! This was a boon to in-between round pit work as fiddle farting with the brakes was a time consuming chore. Motul would last a half season of sprint races! During a three hour endurance race, we would normally have to do quickly bleed the brakes during one pit stop. With Motul the brakes were nearly as good at the end of a race as they were at the start. Motul was more expensive than Ford, at $12 a per ½ liter but was much cheaper than AP550. With Motul you used about ½ as much fluid so price wise it was a wash.
Motul has since improved their fluid. For racing you can buy Motul 600. This has a boiling point of over 600 degrees F! There is also Motul DOT 5.1 Both of these fluids have superior performance over that of the original Motul that I fell in love with. Motul 5.1 has a slightly thinner viscosity to work better with ABS brakes but I have used racing 600 in ABS equipped cars with no noticeable loss in performance. Note that DOT 5.1 is not the same as DOT 5. DOT 5 is silicon based brake fluid which is a big no-no. Silicon fluid is compressible and you will be plagued with spongy brakes. I have read that DOT 5.0 fluid is thicker and more prone to cavitation produced bubbling also. The major advantage of silicon is that it has a very high boiling point, does not eat paint and does not absorb water from the atmosphere. These properties make it an excellent brake fluid for museum stored cars and such. Some performance gurus plug silicon but my advice is for you to stay away from it.
Some of my fellow list members that I supply with Motul, report that its track performance is excellent with some reporting to me that Motul 600s pedal gets even harder once the brakes get hot. I dont understand why this happens, but that is a good thing.
I am so enamored with Motul that I do not have any other experiences with any other brake fluids because I have stopped searching. I have never experienced any significant fluid fade with Motul and its cheap so I havent bothered experimenting with any brands. If other list members have good experiences with other brands of brake fluid let me know for the extension of our database.
The following is based on recommendations made by brake guru Mac Tilton. Mac is best known as the man that brought Carbon pads and rotors to racing. He is also the owner of Tilton Engineering; one of the main suppliers of brakes and clutches to Indy and F-1. I have added some things based on my own experiences also.
When bleeding brakes it is best to manually bleed them as pressure bleeders can cause cavitation and bubbles inside the system. Empty the brake reservoir with a turkey baster then fill the reservoir with a high quality brake fluid. Start bleeding at the furthest wheel away from the M/C and progress to the closest. So that would go RR, LR, RF, LF. Attach a length of clear Tigon tubing (available form any auto parts store) to the bleeder nipple, put the other end of the line into some sort of container so the other end will be submerged in brake fluid and open the nipple. Have someone in the car to pump the brakes. Slowly pump all of the old fluid out of the line until new clear fluid comes out, then have the person in the car hold the pedal down while you close the bleeder. Have the person lift the pedal up slowly and then push down slowly while you open the nipple. You have to communicate with the pumper because the bleeder should only be open on the down stroke of the brake pedal. It is important to pump slowly to avoid bubble-forming cavitation. Continue to pump until you cannot observe any bubbles in the clear Tigon tube.
Get a rubber mallet and tap the caliper to dislodge any bubbles that may be stuck inside the caliper and bleed some more until no more bubbles come out. Do this at all the wheels and you are done. Be careful not to let the reservoir run dry or you will have to start all over. On ABS equipped cars you want to be extra careful about this because it takes forever and a lot of fluid to bleed a completely dry ABS system. Some ABS cars require bleeding from nipples on the ABS modulator so check your manual.
You have now done the basic steps of brake prep and should have some brakes that can handle quite a bit of abuse. To get more performance out of your brakes we will now get into hopping your brakes up.
As you modify you car for more power, you may need some more stopping to make for a better balanced machine. We will talk about some of the common brake mods and what they do for you.
Braided steel lines
SMC, Stillen and Goodridge all make good hose kits. SMC uses high quality forged end fittings that are reusable so I myself like them, but they are not DOT approved. Like I said, I dont think a small plastic sleeve alone makes for a safe brake hose.
In short, I feel that braided hoses make a big difference in brake feel and being reasonably priced, I think that they are worth it.
Drilled sport rotors
I myself think that drilled stock rotors or sport rotors may be somewhat questionable because since small stock brakes are run close to their thermal limit with high performance pads, the drilling can contribute to cracking. If you are buying drilled rotors check to see if the holes have be chamfered. Chamfering helps reduce the likelihood of cracking. Drilled solid rotors like the rear rotors on SE-Rs make a weird whirring noise when the brakes are applied. Some people have said that drilled rotors cause faster pad wear but I myself have not experienced it. Drilled real racing brakes with sufficient thermal capacity are functional and useful. Better than drilling but perhaps lacking some of the racy pizzazz are slotted rotors. Slotting does the same thing as drilling but without the cracking problem. I dont think slotted rotors cool any faster but they are a lot less likely to crack. If you are running stock sized rotors , Id go for slotted for this reason.
Overall, I feel that drilled sport rotors are mostly a cosmetic trick and have never tested drilled, slotted and solid back to back. They really look cool though and fall in to the disco/rice boy category as all of my personal cars have them!
This thickness allows the rotors to dissipate much more heat than the stock Sentra rotors thus enabling a lower operating temperature. The thick rotors also resist warping. About their only disadvantage is their increased weight.
[We have more information on the B13 brake upgrade (AD22VF)]
The part number as carried by Nissan Motorsports is 99996-B13BK. The AD22VF brakes require 14-inch rims and the removal of the front backing plates for fit. They are a direct bolt on. Nissan Motorsports also recommends a different M/C with more front brake bias. I dont like it too much as I think our cars have a little too much front brake as it is but if you wanted to follow Motorsports recommendations the part numbers are: 46010-69Y20 for non ABS cars and 46010-60Y71 for ABS cars. Other list members have said that the Motorsports recommended m/c makes the pedal more mushy.
As a warning to you NX owners, several NX driving list members had had their brakes fail because the first owner of their car installed regular thin Sentra front rotors. Perhaps they had been told by the parts counter guy that "all of them Nissans take the same rotor" or something. It will work for a little while with new pads right until the piston comes past the seals in the caliper bore and yow no brakes!
I have extensively raced both an NX and a Sentra equipped with the AD22VF brakes and have found that when properly prepared, they can consistently out brake almost any other production based car that is likely to be encountered in Showroom stock sedan type racing. It is hard to imagine needing better brakes than this even for racing, unless of course you have the power to hit higher speeds on the straights.
In this case there is an even bigger option. SMC Products and KVR make what is known jokingly as the Big Ass Brake Kit or BABK for short. The BABK contains a 11.7 inch forged steel Coleman racing rotor mounted to an alloy hat with a Willwood 4 piston caliper. These huge brakes are 1.5 inches bigger than the stock rotors and are 6 lbs. lighter due to mostly the alloy hat and caliper. The bad part is that they only fit in some 15-inch wheels. 16 and 17-inch wheels are no problem. The do not fit in the stock 200SX alloys unfortunately. To run these brakes you should use an Altima master cylinder as that has a bigger piston bore (15/16" vs 7/8"). The bigger bore is needed to give the brakes better feel as the stock M/Cs bore makes the pedal feel long. The brake ports line up with the stock hard lines for a quick bolt in. On our cars the proportioning valve is located in the master cylinder. The proportioning valve cuts the line pressure to the rear brakes at a certain point to prevent the rear brakes from locking up as the cars weight transfers forward. On my car I run no prop valve as the brake proportioning is 82 percent front as is which is close to ideal for a FWD car. If you run on low traction surface like water, dirt or ice you might want to put the SE-R prop valve out of your stock M/C into the Altima one as the SE-R M/C has more rear brake bias. There is no sano kit to remove the prop valves from the Altima M/C yet either so you will have to machine some plugs with o-rings to replace the plugs that hold in the prop valves and where the brake lines screw in. Mine is rigged with lots of carefully applied Teflon tape, a method so half-assed that I cannot recommend it to the general public. Like I suggested before, just replace the Altima prop valve bits with your stock ones and you will be ok.
On the 200SX you can make a big rear brake upgrade with some brakes off of a 95-present Maxima or I30 Infiniti. The caliper is a direct bolt on with the lines and parking brake hooking right up with no fuss. KVR and SMC sell a modified Maxima rotor with a 4x100 bolt pattern re-drilled into it. The Maxima rotor is nearly 11 inches up from the stock 9.2 inches. The Maxima brake upgrade really helps balance the big front brake set up. This trick will not work on a classic because I have been told that the caliper bolt pattern is slightly different. However a simple adapter bracket could be fabricated to allow the calipers to be used.
Why go to the real big brake setup? First of the bigger brakes operate at a much lower temperature which allows you to use a higher coefficient of friction, less aggressive brake pad. This gives a lower, easier to modulate more consistent brake pedal effort. With the big brakes you get a feeling of immensely powerful stopping ability which bolsters you confidence. Since the brakes operate at a much lower temperature, the seals and other heat sensitive components last much longer. You can also run drilled rotors with little concern with cracking.
On my big brake setup, I can run a nearly organic, pretty soft, semi-metallic pad in the front and stock pads in the rear. Normally I would have to select a much more aggressive pad to avoid fade. These pads are quite forgiving and easy on the rotors. They work very well when cold and do not have much dust, squeak or squeal. So the main advantage is that I have an under stressed brake system that gives stock like performance on the street which gives excellent racing condition performance on the track, in a package that is lighter than stock. If you look at what the Sunny (Japanese Sentra) 2 liter touring car racers are running, which is a 14 inch rotor, twin caliper set up, the big brake kit looks pretty reasonable! The big brakes are totally awesome. I have raced plenty of AD22VF equipped cars and although these brakes work quite well when set up with a good racing pad, the pedal effort is still pretty high once they come up to temperature. The big brakes require only a light touch, which is a lot easier to modulate with precision. Other list members that have driven my car have raved about the brakes performance. If you want to see what they look like, check out this link to Merlins page.
The other Disco aspect of the big brakes is that they look really awesome. If you have 17 or 18 inch wheels, the stock brakes will really be exposed and look pretty wimpy. The rear brakes look especially ridiculous. If you are in to car shows, the Judges dig stuff like racing brakes because they havent caught on with general the performance crowd yet. If you have an open style of wheel, the racing brakes really make your car look special.
Soon I will be working with Brembo to help develop a 12 inch Brembo system that will be the ultimate Street/track setup for our cars.
Here are some tips that I have found useful specifically for SE-Rs.
Brake pedal Mushy after bleeding
Master cylinder staging
Wrong front rotors in a NX2000
Removing the brakes backing plates
Sticky or Bent Caliper Floater Pins
Well, these are all the brake tips that I can think of for now. Apply them with caution as brakes are the number one safety device in your car and happy hunting!
Mike Pahls writes:
Someone on the list has been mentioning brake problems lately, so I thought I'd pass along low buck things that have worked for me. I auto-x my car and due to my trail braking, I often lost my brake pedal by the end of a 50 sec run. Sure I probably dragged the brake a little more than some people, but I had to fix this problem to stay safe and comfortable driving the car.
Terry Gosse (owner of KVR) writes: