Funny the the night I finished my turbo kit rebuild, the next afternoon afterwork I see a reward package that came in for my extra hard efforts on finishing the turbo rebuild...... My Wilwood BigBrake kit came in last night.

These are pictures of it out the box.
http://users.adelphia.net/~dsuthar/b...igbrakekit.jpg
http://users.adelphia.net/~dsuthar/b...torcaliper.jpg
http://users.adelphia.net/~dsuthar/b...odcalipers.jpg
http://users.adelphia.net/~dsuthar/brakes/rotor1.jpg
http://users.adelphia.net/~dsuthar/brakes/rotor2.jpg
http://users.adelphia.net/~dsuthar/brakes/rotor3.jpg

Then these are the pictures that Ramius83 (Erik) helped me install the kit last night since we some anxious little buggers. Dont mind the wheels being dirty and chipped, this is my spare, the good one (now bad) is being repaired.
http://users.adelphia.net/~dsuthar/b...alledfront.jpg
http://users.adelphia.net/~dsuthar/b...lledangle1.jpg
http://users.adelphia.net/~dsuthar/b...lledangle2.jpg

What amazed me is the calipers weighed only about 3lbs. it was amazingly light cause of the forged superlite calipers. Installed with Hawk Ferro-Carbon pads.

Dixit

 

looks great! Where did you get it from and how much? What size are those rotors?

 

those look awesome! where'd you get them from and how much?

 

Uhhh, those aren't superlite6 calipers. they're only 4 piston.

They look more like their old Superlite II series.. Yes, they're still good calipers, but they're not Superlite 6..

 

Matt your 100% right, typo. Thats why we got Mods around to MODerate mistakes According to the paper work this is what they are "4 piston Wilwood 120-7429 (forged Superlite)"

The kit cost me $850, gotta a deal on it cause some idiot alty owner bought it and didnt realize his wheels wouldnt clear so he shipped it back and precision brakes charged him a restock fee and I took them from there. They were never used, just installed. Rotors are 323mm which is 12.75"

Dixit

 

ahh okie...
I even went and looked at wilwood's website and didn't see any like it. I figured they were the new forged series. me likes. will probably upgrade to those calipers for myself soon.

Just wanted to mention that so you didn't get skrood if you had actually paid for the SL6. they're NOT cheap. the ones you've got are about 1/2 the price of the 6 piston!

 

Yea but my only thing is how much are they really better? This is where my knowledge on calipers aint as strong as maybe yours or other people. I know there is a guy in the 5th gen FS forum trying to sell these 8piston calipers, Im thinking, damn thats alot..... But someone also told me that having 4 pistons on one side of a caliper pad that are say 1" in diameter aint necessarily better than having 2 pistons on the same pad that are 2" in diameter.

I dont know if im talking out my azz or what.... I would like to know the whole deal around calipers though.

Dixit

 

Looks awesome!

 

Now you can stop after boosting.

 

Yeap, pretty bad when last night had the car upto 120 and then hit the brakes and by the time it got down to 60, the car didnt want to stop, I heard major brake pad noise (like a grinding/pad giving up cause of too much heat) even though there was like 3/8" of pad and the rotors were slightly warped.

Its amazing how people thing you dont need it, shiet.... yea you do..... otherwise you will need a new front end.

Dixit

 

my bros friend had a s600 benz w/ the brembo big brake kit and he was doing 100+ and his brakes locked up. He ended up totalling that car.

 

I wonder if that was from the "brake by wire" system they have now.

 

they don't do that unless you stick the brake pedal through the floor. you can't rely on ABS to keep you from doing stupid stuff.

 

the main difference between the 4 and 6 piston calipers are to minimize pad taper.
when you smash the brake pedal, the caliper deforms a bit.. basically, the inner edges spread apart from the pressure against the rotors.

On my Dynalites, I can pull the wheel off and watch the caliper flex as someone mashes their foot on the brake pedal.
The forged calipers are made with stronger construction techniques to minimize the flexing from brake forces like that.



the higher piston count is there to help minimize longitudinal pad taper- the leading edge of the pad (that the rotor hits first when turning) will wear faster, due to a greater heat difference between the front and rear of the pad. it's also the end that gets to deal with any crap scraped off the rotors.
Thus, they make 6,8,10,even 12 piston calipers (yes... F1 cars use 12 pistons in some designs!).. and they'll make the leading edge pistons smaller than the trailing edge to reduce pressure on the leading edge of the pad and reduce taper and wear and provide more even and consistent braking response.

Of course, you can easily get around that like I do by rotating your pads every few months. on calipers like these, there's no designated inner/outer pad like on OEM calipers. What I do is just pull the pads out and swap inner/outer ones in the caliper every couple of months.

The dynalites I'm using are also a much smaller caliper, so they're more prone to pad taper than the longer pads used in the superlite series. look at the dimensions on both sets of calipers and you'll see that the dynalite pads are about 1/2 the surface area, and 1/2 as thick. which of course means my pads last about 1/8 as long as superlites! DOH!

but that's the price you pay when there's no spoke clearance on the wheels. I couldn't fit any larger caliper in there when I built the kit... now that I've got bigger wheels, I've got more room to play.

 

Matt

Thanks....always wondered about that. Also, don't more pistons require more fluid volume to build the same amount of line pressure? So, either pedal travel will increase or you'll need a bigger master cylinder piston to push a larger volume of fluid. If so, I think Dixit should look to see if the 2K2+ or 350Z or another Nissan model uses a similar MC, but with a bigger piston. I know the '91-94 Sentra's swap in an Altima MC with their BBK.

 

I love it!

 

not really. it's a matter of overall piston area.
If you look at your factory calipers, they've got a single piston about 2.5" diameter (just pulling this number out my @$$, but it works).
2.5" dia = 4.91 sq. in piston area.

say your master cylinder is 1" diameter
1" dia = .79 sq in area.

now it's a simple matter of ratios.
say you press 10lb on the brake pedal (there's vacuum assist brake booster involved too, but it doesn't matter for this illustration)
so 10lb on the brake booster.. * 4.91 / 0.79 = 62.15lb of force on the brake pad against the rotor.

Assume that in order to do this, the brake pad has to move 1/16" to push against the rotor. (explains the small amount of brake pedal travel before they start doing anything) that means you have to pump a volume of fluid into the caliper.
using the 2.5" dia piston = 4.91 sq in area * 1/16 in= 0.307 cu in of fluid.


NOW, let's go to a 4 piston caliper with 1.75" pistons.. (exactly like the ones pictured above in the precision brake kit)

( 1.75" dia/2 ) ^2 * pi = 9.62sq in. (note this is almost double what the factory caliper is.)
we're still using the same 1" master cylinder, so...
10 lb of force on the brake pedal =

10 * 9.62 / 0.79 = 121.8lb of force on the pad!

let's convert that to volume.. you have to move the pads 1/16" still.
9.62 sq in * 1/16 in = 0.601 cu in of fluid.

So you can now see that by increasing the PISTON AREA by double, you have twice as much pressure on the brake pads, BUT you have to move the brake pedal twice as far.
So if you want the same force on the brake pedal, you should move the pedal the same distance.
(the inherent problem with my statement is that we're assuming the 1/16" of pad movement is actually there. in reality, there's a small amoutn of airspace before the pad contacts the rotor, then there's a small amount of pressure built up on the pad before it starts doing anything... so the numbers don't come out exact.)


What does this mean in English?
That means for the same force you press on the brake pedal, the front brakes are stopping twice as hard as what they used to... That's assuming the pads have the same friction and other aspects. I don't want to complicate it with rotor diameter and other such issues (which also play a HUGE role in this.)...

so now, you have to move the pedal twice as far, but you only have to press half as hard to get the fronts to do the same braking.. What does this do to the brake bias? that's right- the rears are now doing half the work they used to when you reference them to the stopping power of the fronts.

So if your factory brake bias was 70% front, 30% rear.... it's now 85% front, 15% rear.

this is why a properly designed brake kit is essential. by the time you factor in the larger rotors up front, the front brakes are often doing more than 90% of the work, as compared to 70% you had before!

that's why many places will change to a larger master cylinder.
the larger piston causes a slightly lower change in brake bias between front and rear, BUT the best way to fix it is to properly size the caliper to the job.
Wilwoos makes calipers with 1.35" and 1.75" diameter pistons. the one you should be using is the 1.35", NOT the 1.75" like most kits use. this will help fix the horrible front brake bias problem seen in the basic big brake kits.

there's a novel for ya.. I've finished off my bottle of wine, and it's midnight. bedtime here!

 

Son of a.... talk about a moderator coming out and teaching like no one has ever done before. High praises to you Matt.

Now one question i dont understand in your reading, what do you mean by 1" Master Cylinder?

 

Not to hijack your thread BigDog, but I got a question for Matt93SE:
I got these Precision 13" 1-piece rotors and 4 piston calipers. Bought it used off another local guy. Wondering what the exact name/model is of my rotor and caliper? Any ideas?

 

No offense taken, its open forum, ask away.....

 

Inside the master cylinder that attaches to the brake pedal arm, there is a piston that pushes the brake fluid.

He was using 1" as an example of the diameter. The larger the diameter, usually the more fluid it displaces, which builds pressure faster then a smaller piston.

I'm still trying to digest the rest.

 

He pulled those formulas out like as if I was in physics in highschool

 

Interesting....

 

Matt, do you run a proportioning valve on your car? I guess you might not have to since you upgraded the rear brakes. Basically (pending wheels ) I have 300zx Calipers and Rotors that I would like to install, but I was planning on leaving the rears stock until I could look further into my options.

What about if I were to do a setup like Jeff's, with the 13" Cobra Rotors? I ask this because I have a feeling you are going to say a proportioning valve would probably not be necessary for just upgrading the calipers.

(psst. I betcha you could make some brake kits and they would sell )
btw, I wasn't one of the kids who asked "when are we ever going to use this (pi*r^2) in life?"

 

http://images.cardomain.com/member_i...02_42_full.jpg

If they're the same as that pic, you have Billet Dynalite calipers. I'm running the "ugly version" of those on mine. They're simply cast/forged, where yours are cast a bit larger and machined down for a nice pretty finish. Overall size and performance are exactly the same though.

The rotors, I'm not really sure on. I might venture a guess that they're dBA rotors, but I wouldn't bet my life on it.
Looking at their website, they list one from a C4 that looks the same, but without the crossdrilling.
http://www.precisionbrakes.com/preci...rofirebird.jpg

 

LOL!! I thought about putting together brake kits for 3rd/4th gens, but everyone else is doing it at prices that I can't compete with. I'd actually have to get a distributor liscense and such so I could buy stuff at wholesale prices before I would have a chance at even breaking even there.

Proportioning valve.... in your case, what you're suggesting is to put huge brakes on the front, then dial them back so they'll meet the rears. That's do-able (I've seen it), but not really recommended. Ideally, you don't want to dial back the pressure on the fronts. you want them 100% when you mash your foot into it. the best thing to do is put something bigger on the back, then use the proportioning valve to dial the rears back down to the proper level.

In your case, the 13" rotors with Z calipers shouldn't be too bad. The Z calipers aren't a lot bigger than the factory ones as far as piston area, but there is the larger rotor and such to deal with. You will run into some bias issues, but it's not that bad. If you DO run into those type of issues, then stick some Z31 rotors on the rear, make some new mounting brackets out of some 10mm plate steel and call it a day.

 

BDJ, I read off the Z forums that the Wilwoods dont have dust boots on the pistons. If so, you'll have to keep that VA/DC salt and road grime out of there. They look great!

 

Timmeh, since you aint around as much I have moved from DC to HOTlanta. I live 15mins from bags533 (my turbo friend I can relate to ) and 20mins from Jay25 and 20mins from Ramius83 who just put his t4 ball bearing turbo kit from pfi on. No worries about SALT and stuff here,

Im also converting the car to a 5spd next month, going to take off for modding a month, the car was down for 35days while I rebuilt the whole turbokit from the ground up. I did all the pipe work, welding, cutting, and stuff myself.

Nice to hear from you, been a while. Say hi to your wife for me.

Dixit

 

WOW, way to go DIXIT!!!

Your gonna be faster than Kev pretty soon! How long is the rebuild gonna take u?

 

Igor, did you miss the part where i said it WAS down for 35days? Its fixed now, been driving it to work for the past 3days now. Drives good.

And im only going to be faster than kev after the 5spd cause his engine had a bad/low compression cynlinder. After he fixes that, I got no chance in hell against his t4 ball bearing. Probably got no chance in hell now since he still is boosting the car and just enjoying it till it dies.....

Dixit

 

I was talking about the tranny re-build for a 5spd...missunderstanding

 

Yea you confused me because its not a tranny rebuild, its a conversion.

Its going to take 2days. Just going to get all the parts together and get the best of the best parts and slap it on there with the help of Jay25 and Ramius83

 

Nice!

When are u taking it to the track?

 

Kinda as Tim said.. you really shouldn't need dust boots on them unless you live up north. the pistons are Stainless Steel, so they won't do much.
I rebuilt mine after running a set of naaasty pads on them and they ruined the rotors. pop the pistons out, clean them with steel wool, and replace the seals. easy stuff! took about an hour and a half.

Again, you shouldn't have to mess with it though. I did that about 2 years ago, and haven't messed with rebuillding them since then. they're still running great, and no seal leakage.

 

heh, how's that Jack!? No stuffed toys are safe around that 4 pawed pimp!

If I can find someone to do a clear mask on the G soon, I'll be coming through Atl in early November. I'd love to see that monster. I'll give you a few days notice if it works out.

Good to see you didnt give up on the max. I was looking at doing a stereo much like yours, I had the cash ready. Then one day I was passing the Infiniti dealer....

 

Btw, I've been watching the Wilwood kit (or Rotora) for the Z's. That kit you got was a hell of a deal! Not much chance of anything being cheap on the G.

Just alittle OT factoid... Brembo rotor, OEM Nissan, just 1... $494

Caliper? $1196... yeah, each!

 

Tim... when it's time to replace the rotors, buy one from a junkyard, or send me one and I'll have one custom made to fit.. much cheaper.

 

thx, with AT, I dont have Brembos.. I'll probably look at that ROTORA kit first.. I'd love to find a set at the junkyard, but I dont see that happening on the cheap.

 

Man that is expensive, hopefully other rotor companies come around and make one for $100-200 range.

Dixit