anyone have experience with STOPTECH?

[sykikchimp]

I'm curious if anyone here is running stoptech's big brake upgrade on the 240?

If you are out there, can you give me your opinion on it? quality, fitment, feel?

thanks!
Charles

[hurleyboi514]

the only cars ive seen with stop tech's are show cars and magazine project cars... it'd be nice to get some hands on real world thoughts about them, b/c stop tech is usually slipping those guys some cash...

[the tech]

We have the Stoptech's on a few of our Supras. They performed better than the Brembos. Very high quality setups.

[TRUENOCOUPE]

You have a 240. You don't need that of a bigger brakes.

[MakotoS13]

from what i hear Z32 calipers are overkill in almost every application but feel free to waste the cash.

they do look awful nice though

[Zoom8112]

stoptechs are high quality - what do you expect from that expensive of a setup.

they are really popular in the wrx tuning crowd.

[Heartwork]

i have no experience with Stoptech on Nissans, but they are generally high quality and actually engineered around your own car, not just a general big brake kit...meaning, they actually setup their piston sizing, proportion, etc around your Nissan, where as Brembo's just set theirs up generall around a car manufacture and its up to the owners to "fix" their brake master cylinders accordingly

[sykikchimp]

I'm not really looking to buy them (yet). I've spent a lot of time talking to a couple Stoptech engineers, and have discovered the approximate brake bias, and exact piston sizing for their calipers in the system for use with the stock 7/8's MC and rear brakes.

I am curious as to how well they work in a real world circumstances, to see if the bias they are using is truly ideal, and in what situations it works best. (i.e. tire compounds, track conditions, etc)

Since I will likely be running sticker tires than they would have used to test the car, I'm thinking I may need to make the car a bit more front biased than they have. This is speculation though as I don't have the ability (at the moment) to test my car with a bias like they have, with the tires I will be running. This is where user experience's come in.

The whole goal here is to build a setup around 300zx brakes that will utilize a brake bias ideal to the 240sx to allow for maximum braking potential. If I know the Stoptech's kit works perfectly as advertised, then I know the ideal bias, and can reverse engineer from there. (the typical 300zx brake setups are NOT ideal.)

...300zx brakes are just adequate for a track preped 240 (stock KA w/speed limiter) with a capable driver. Add a turbo to that, and they become too small real fast.

[Ahhsk]

I think you guys are putting too much thought into it. As far as them building specific piston displacements per application, all that would change is pedal feel, unless the sizing was way way way off.

Big brakes= resistance to fade. can you do it in a 240 yes, overkill..whatever Brakes #1, everything else is secondary IMO.

You can do way better than stoptech pricing (and track proven performance)

http://www.precisionbrakescompany.com/custom.asp

[kandyflip445]

I assume you would care about pedal feel if you were racing or even just driving around.

Big brakes do make you stop in shorter distances. Not just add resistance to wear. Brakes are meant to convert the energy of the car moving into heat, so the more heat the brake can produce the better it will slow the car. The bigger the brake the more punishment it can take. I would say the people at Stoptech know what they are doing as I've only read good things about their brakes.

[sykikchimp]

Ahhsk - did you actually do any testing with your brake upgrades?? I think maybe you haven't put enough thought into it.

Brake bias is what controls the ability of the car to take full advantage of all traction available when stopping. BIAS is what allows the car to stop in a shorter distance. NOT SIZE.

Bias is modified in any # of ways, one of the bigger ways is changing piston diameter. (this is how stoptech "tunes" their calipers)

A properly sized big brake system will allow for better bias, AND heat control.

Interestingly enough, your Big brakes may not just be causing you shorter stops b/c of the crappy bias, but may also cause you to actually overheat your brakes!! (at least the fronts) If you have too much front bias, then your front brakes are doing all the work. This means they must absorb more heat than they would have to if your car was properly biased. In your case maybe this is unlikely considering the extreme size of your setup, but not totally unfeasible.

I experiece this with my current setup. 300zx calipers front, and stock everything else. The increased front bias not only decreases my stopping distances, but causes my front pads to fade prematurely as they are being overworked.

[Ahhsk]

I forgot this is Zilvia and I should of made my post more PC. Dude its not a pissing contest post up some total caliper volume numbers for some Stoptechs well crunch the numbers versus stock, and versus what I have and youll see a very marginal change in bias.

Interestingly enough, your Big brakes may not just be causing you shorter stops b/c of the crappy bias, but may also cause you to actually overheat your brakes!! (at least the fronts)

What? dude you couldnt be more wrong, If available I would swap to a colder pad.

If you have too much front bias, then your front brakes are doing all the work. This means they must absorb more heat than they would have to if your car was properly biased. In your case maybe this is unlikely considering the extreme size of your setup, but not totally unfeasible.

heres my exact setup calculation:

27mm^2x2 1458, 31.8mm^2x2 2022.48, 38.1mm^2x2 2903.22= 6383.7
-355mm diameter rotor
-54mm wide pad

effective rotor diameter: 355-54 = 301
effective piston area: 6383.7
"brake torque" = 1921493.7

300ZX rear brakes (OPZ11VB)

- 2-piston fixed caliper
- 38.1mm diameter piston
- 297mm diameter rotor
- 36.5mm wide pad

effective rotor diameter: 260.5mm
effective piston area: 38.1^2 x 2 = 2903
"brake torque" = 756231.5


front brake bias = 1921493.7/ (1921493.7+756231.5)= 72% hmmm


for comparison:

300ZX front brakes (OPF25B)

- 4 piston fixed caliper
- 40.45mm piston diameter
-280mm diameter rotor
-50mm wide pad

effective rotor diameter: 230mm
effective piston area: 40.45^2 x 4 = 6545
"brake torque" = 1505350

rear brake torque with 240sx MC at 569 psi line pressure
504016 x (569/569)
front brake bias: 1505350 / (1505350 + 504016) = 74.9%


Do you still think my bias is off? Are you talking about my new setup maybe? the one with bias control?

Ok ill try again maybe make it more digestable: I havent seen any stoptechs that were realistically priced. The marketing pitch about "tailored to your car" is not enough for me to cough up the extra cash.

[sykikchimp]

Dude, If the stock bias is only 70.5% front, then don't you think the 72% + the lower CG will make the car more front biased than it should be? Maybe having the staggered/larger tire sizes helps enough to make the difference.

I'm trying to find out some more specific info on the stoptechs right now to see exactly what it comes out to.

I'm not pushing Stoptech's kit. I'm not trying to start a pissing match with you. I am simply trying to find out the ideal Bias for a 240sx.

[dsilcrazy]

I am currently running stoptech st40 calipers with a 332x32mm rotor in front on my s14, which I bought used for a reasonable price. I beleive this kit was purchased by the first owner as an upgrade on an r32 gtr, so the kit that I have is not specifically for a 240sx. My rear brakes are z32 and I am running an 1 1/16 mc. So far the car feels slightly front biased yet but I have only been running 225/45/17 avs sports all around. I have yet to see what they are like with sticky tires. I have a set of 255/40/17 bfgoodrich g-force t/a kd's waiting to go on so hopefully in a week or two I will find out just how ballanced they are. I am no mathmatical genius so I really don't have actual numbers but I do have to say it feels pretty damn good, and was well worth the money at $1700 for all four calipers, rotors, stainless lines and the mc.

[Ahhsk]

I am simply trying to find out the ideal Bias for a 240sx.

I guess it what be dependent on how big your balls are, especially during trail braking. But hey, when you find the caliper displacement post it up, lets see what they feel is optimum.

BTW if you havent heard me say it before ill say it again here, Just buying individual components through Precision or Pit Stop USA is sooo much cheaper than buying a kit. Then go to AP Racing or Wilwood and get the specs on the calipers.

The hat offset that works is .81" for a 1.25" rotor if you feel like putting something together for shits and grins.

[AKADriver]

You know, the S14 rear pistons are larger and will adjust the bias quite a bit, if you've got too much to the front with Z32 fronts. It seems to work in the S14 and S15 Silvia.

Honestly, I know I'm not the best driver, but my previous stock 240SX never had problems with my stock brakes. But, I was on 205mm street tires.

[sykikchimp]

I kick myself all the time since I went to the 300zx brakes.. I never had a problem with the stock brakes either. I wish I had just stuck with them, and ran some really aggresive pads like Carbotech XP9's or something.

Ahhsk, thanks for the info. I got the dimensions for the piston diameters.. They ask me not to share the actual diameters, but I will post the area.

total piston area: 5200
332mm rotor diameter
54mm wide pad (I think.. they use porsche 944 pads.. I measured the pads from their caliper print out, and it close to this.)

Effective rotor diameter: 332-54 = 278
Effective piston area: 5200
"brake torque" = 1445600

Using Asad's stock rear caliper brake torque number:

1445600/(1445600 + 756231.5) = .74 74%.
This is obviously too high.. So I asked them WTF?? why a higher bias than stock even though on YOUR site it says ALL stock systems are front biased.. Theire response was that most 240sx owners that use their kit run 300zx rear calipers.. and that they recommend running their calipers with 300zx rears, and the 15/16's MC.

So I did the calc's on that.. comes to about ~65% that way. A little more rear bias than I expected, but possibly not unreasonable.

So now I emailed them back asking WTF and explained ALL my calculations. And asked why would you sell kit's to people without telling them that they should run 300zx rear calipers with teir kit, and that with just their fronts they are still worse off than stock? Which goes against their whole marketing mantra of a "Balanced Brake Systems". I basically got shrugged off as not important enough to answer b/c their "engineer's are too busy".. So I emailed him back and told him that they should never be to busy for a potential customers questions, and to answer my question, or suffer his product getting bad mouthed for bad R&D all over the net.

We'll see what he says, but I'm betting I get no more good info.

[sykikchimp]

AKADriver - Thanks for that info!

I pulled the s14 FSM.. the rear diameter is 38.18

SO
38.18^2 *2 = 2915.4

- 258mm diameter rotor
- 40mm wide pad

Effective rotor diameter: 218
effective piston area: - 2915.4
"brake torque" = 635557.2

300zx front "Brake torque" = 1505350

1505350 /(1505350 + 635557.2) = 70.3% Front bias. which is pretty much the same as stock.

AWESOME!~ I think I just found my new setup.

300zx front calipers, S14 rear calipers, and 15/16 ABS MC.


Anybody got any S14 rear calipers and a 15/16's MC ??

[Ahhsk]

haha, crazy. I bet that 65% would be way fun going into a corner hot but definitely not for the daily grind.

[sykikchimp]

Originally Posted by Ahhsk

haha, crazy. I bet that 65% would be way fun going into a corner hot but definitely not for the daily grind.

haha. yeah. I'd probably kill myself at a track like lowes with that setup.

They also told me that the Brembo Grand Turismo kit comes with 40mm and 44mm pistons. WAY too big.

3872 + 3200 - 7072
332mm - 278 eff.
probably a 54mm pad
brake torque = 1966016

stock 240sx rear:
504016

bias: 1966016\(504016 + 1966016) = 79.6% front bias. Ouch.

with 300zx rears: 72% This is what Sport compact car had on their project silvia. They said this setup actually caused the REAR to lock up first. they used the stock MC.

I think I need to know more specifically what kind of brake line pressure is created on the 240 when threshold braking..

[Ahhsk]

In germany there are brake dynos everywhere, as part of thier TuV inspections. A brake dyno and a Proportioning valve would be nifty, but in the end the % really doesnt matter, what ever you are comfortable with. Kinda like the Pirate's code, more like a guideline, HARRRR.

[sykikchimp]

well, I agree that it is personal preference in an actual driving situation, but for a given car there will be a brake bias that utilizes 100% of all 4 tires braking potential.

I'm guessing that it's from about 65-70%. But I'd like to know that it was, say, 66-68%. get my drift..?

I got a response from the Sales guy at Stoptech. Apparently I have caused quite a disruption. Read this from the US Sales manager:

Our chief engineer is drawn into a discussion (typically he is involved only at the highest level...speaking with engineers at OEM's and pro race teams, etc). Steve takes time from his dozen+ projects to 1) reply to you and 2) fill sales in on what's going on. Concurrently, I am drafting a response, and our General Mgr. is brought into the discussion via Steve. Essentially, 3 of our company's top executives are drawn into a discussion by a single, unknown end-user that is asking for technical information that we typically don't give out. That is the situation on our end.

He goes on to tell me that he is going to get my questions answered, but it may take a little time. He told me to contact him again in a few days if I have not heard anything. So I may yet get to the bottom of my questions yet.

My #1 question was:
Was testing with the 240sx actually done? If so, what were the
components used in the test? The outcome of the tests? (the 300zx testing
info is provided on your web page, albeit in editorial form, all I am
interested in are the #'s. what rear brake calipers, MC? what were the
before and after stopping distances? rotor temps?)

We'll see what happens.

[SR_TeXaN]

my brain is fried from reading all that. Anyway Chimp what conclusions have you came to on the most efficent brake setup so far.

[CoasTek240]

well, this has certainly changed my output on the overall end project of what brakes i will try to run. for now i'm sticking my z32 calipers up front, and s14 rotors and s13 calipers in rear. when i have a lil more time i'm, going to try and pick up and install the 15/16 mc and the s14 calipers as well.

does anyone know where i can pick up the 15/16 mc?

[aznpoopy]

well since this thread is back... i was curious. did sykik ever get another response from stoptech?

[OptionZero]

This has been a VERY interesting thread, and has motivated me to look up some more crap and learn about brake bias.

Question:
Are JDM and USDM rear s14 brakes identical, or does the JDM silvia utilize larger (Different) 300ZX brakes in back? Just get better pads, possibly better rotors, and viola....and dont forget to paint your calipers neon green!

I take it this is good news for s14 owners, because they only need the front rotors and MC...buahah

Can we do this with the Q45 setup and see also?

Question:
If the goal of determining brake bias is to find a setup that utilizes 100% of the tires grip available, and there are an infinity of tire options based on size, compound, etc,...then isn't an ideal brake bias almost completely dependent on each person's car?

I know the JDM S14 uses 300ZX (or NEARLY identical) calipers in front.

If your calculations are correct (i have no reason to think other wise), and your conclusion is that we should use 300ZX front, s14 back, 15/16 MC...isn't that the same as the STOCK SETUP on a jdm s14?!!!
Thats bit amusing to me...

[aznpoopy]

Originally Posted by OptionZero

If your calculations are correct (i have no reason to think other wise), and your conclusion is that we should use 300ZX front, s14 back, 15/16 MC...isn't that the same as the STOCK SETUP on a jdm s14?!!!
Thats bit amusing to me...

i think you're getting ahead of yourself. remember sykik was doing calculations for his car which is a s13. most likely the ideal brake bias on a s14 will be different. by how much i don't know.

if running s14 rear calipers and 300zx front calipers was ideal bias for a s14, that would mean that the usdm s14 came with compromised brake bias with stock s14 front calipers; which i highly doubt.

[sykikchimp]

Remember that mechanical bias is what all those calculations were for. Were weren't factoring in any hydraulic bias from the factory bias valve.

the s14 cam with a couple different ones (from FSMs)..
95-96 - 284psi x .4
97-98 - 427psi x .4

Both of these are lower than the S13 which is 569 x .4 (more rear bias)

As for finding the correct MC I'm hanging onto a possiblity with the Pre 9/86 300zx NON-turbo MC's. It's hard to find them anywhere but the dealer where they want like $165. I have a couple leads I'm working on now. I will update when that info comes available. Check this thread for some of the MC info I've been trying to find. http://www.zilvia.net/f/showthread.p...aster+cylinder

Also, I had done some calculations based on a few theoretical max brake line pressures, and what the bias was at those pressures, and The Q45 brakes with s13 rear calipers with NO bias valve came out to about the same as the theoretical ideal setup with the bias valve. So, something to try for a tracck car might be Q45 front, S13 rear with the bias valve disabled.

I'm also still waiting for the tech info from Stoptech I asked for. The email me about once every 1.5 weeks saying.. "we haven't forgot you, our cheif engineer is still very busy. You will get your answer soon."

[aznpoopy]

all this brake talk is making my head spin @_@

sykik i got one question for you. you mentioned the calipers for s14 95-96 are different then the 97-98. now im worried about putting on the 97 calipers i bought to replace my stuck calipers. any thoughts or concerns :X

[sykikchimp]

where did I say that? I thought at one point they might be different, but I've been unable to determine that for myself.

The FSM's says all s14's have 1.5031" or 38.18mm. The 97' calipers I have downstairs is more like 1.399" while My stock s13 calipers are 1.329" (both measured with dial caliipers) where the FSM says they are suppose to be 1.3370" So I am still very confused about what is what. If I could get people to measure the pistons with dial calipers from the other years, That would make for some very interesting information.