Daewoo

What is the difference performance wise? Is there a noticeable difference? a ~$500-700 differnce?

What is the size of the stock brake? Track?

Thanks!

Audito350Z

iTrader: (1)

you will not be able to tell a difference on the street... you probably won't even feel a difference from the OEM brakes to either of the BBKs.... where you will notice a difference is in the BBKs ability to dissipate heat after repeated stops from high speeds, so if you plan on running in the 24 Hours of Le Mans or some Speed World Challenge races, you will only have a less-performing bank account


non-Brembo
front = 11.7" x 0.95"
rear = 11.5" x 0.63"

Brembo
front 4-piston with 12.8" x 1.18"
rear 2-piston with 12.7" x 0.87"

Cheers,

PeteH

Daewoo

Thanks Audito350Z but if the Brembos r supposed to be pretty good @ ~12" why not just upgrade from stock to 13"?

Why would one pay $500-700 more for 14"s over the 13"s? Would you just do it for looks? Can you really see the difference visually?

I am stock and feel the fade at the track. So I would liek more/better. I just need to know y I should pay more for 14" over 13"s

thanks again

Audito350Z

iTrader: (1)

you can't put a larger rotor on with the OEM Brembo caliper... you would need a new bracket on the caliper to make room for the larger rotor, and, since the bracket is molded into the caliper, that's not an easy fix...

the OEM Brembos with a good track pad and better fluid are more than adequate at any track event you are likely to attend... keep in mind, all the teams racing the 350Z in the Grand American series use the OEM Brembo calipers and the same size rotor as OEM (althought they use a 2-piece floating rotor)

I've done more than 2000 miles on the track with my OEM Brembos... I use Motul 600 fluid, Goodridge stainless lines and Carbotech XP racing brake pads... no fade ever, I'm very happy with the OEM Brembos

If you don't have Brembos, and you want a very good upgrade, all you need is the Stoptech 332x32 front brake kit... this is a 13.1" 2-piece floating rotor with Stoptechs ST40 4-piston caliper... these work extremely well with the OEM rear brakes, very balanced... you will never have any fade! The kit is about $1900.

Going with a 14" kit will not make any performance difference unless you are trying to win Daytona or LeMans... most people do 14" kits just for the looks... and, yes, you can see a difference in the size.

Same with a 14" 4-wheel kit... all show, no real performance gains


So, get the Stoptech 332x32 front kit and use the $500-$700 you saved to pay for two weekends at the track!

Cheers,

PeteH

RIVET

If you track AT ALL, a well engineered BBK (14" fronts, 13" rears) is a huge advantage, especially if you left foot brake. Absolute statements ("Going with a 14" kit will not make any performance difference unless you are trying to win Daytona or LeMans") never apply in real life.

4myZ350

iTrader: (-1)

has any one put on ROTORA's big brake kit? 13" w/rear pad s Axxis ultamit performance street.

J Ritt

iTrader: (4)

The only real advantage of a six piston caliper over a 4 would be potentially improved pad wear (more surface area on the pad). The amount of clamping force is a result of the size of the pistons. Therefore, a 4 piston caliper with bigger pistons could have more clamping force than a 6 with tiny pistons.

As for 14" vs. 13"...it depends. There are real performance benefits to a 14" kit, but as Audito is alluding to, it comes at the extreme performance envelope. For most people, our 13" front kit would be sufficient for track use. If you have 500hp, and you're hitting 150mph+ multiple times each lap, you may opt for the increased heat capacity of the 14" setup. Then again, if you choose that route, you can't run lighter 17" wheels, and you won't have as many tire choices (you need an 18" wheel for our 14" kit). It's all tradeoffs. For performance reasons, your objective should be to get only what is necessary to get the job done. If a 13" kit will give you enough heat capacity, then anything more is added dead weight and wasted money. We've had many Track model owners put our 355mm or 332mm kits on the front of their car because they did not have enough heat capacity. Don't forget, the width of the rotor plays a huge factor in heat capacity. Our 332mm and 355mm kits are 32mm wide, or 1.26"...the Brembo's are a couple mm's thinner...makes a big difference. If you want aesthetics and need more heat capacity than a 332mm can offer, then it's worth the extra coin for the bigger kit.
Our ultimate performance kit would be our front 14" 4 piston and 12.9" rear 2 piston (which will be out very, very soon).

zzzya

iTrader: (2)

Don't forget that the larger rotors will add unsprung weight to the car and decrease acceleration to a degree, especially if you add the 14" rotors to the front and rear. I added the front 13" kit and just upgraded the rear lines and pads. I also upgraded the rear rotors but kept them the oem size. The braking improvement was dramatic. I would imagine that with SS lines and new pads you would feel a nice improvement.

Resolute

iTrader: (2)

J Ritt,
First, I am always impressed by the support and enthusiasm displayed on this forum from Stoptech. I own a base Z, and a bbk is finally in order after my last track day. I was almost sold on AP Racing's CP7040, but again, the enthusiasm and response from Stoptech has me waiting to see the new four wheel kit with the ST-22 rears. I searched Stoptech's site, however, and failed to find piston diameters for the ST-40. As you wrote, piston size is really the determining factor for clamping force. Also, won't six pots better handle deflection and provide more even pressure across the face of the pad with staggered pistons? Does the ST-40 have staggered diameter pistons, or has Stoptech not found this to be a problem with the Z? I am especially concerened with the rear set-up. With the two piston calipers, the pad size seems small enough to avoid deflection and give even pressure, but the amount of bias in the Z has me wondering about a significant advantage with staggered four pot rears. I realize the price difference will probably be sizeable, but was wondering what Stoptech's findings were with a four piston rear and six piston front caliper, if any. Has there been any research into it, or were the four and two piston calipers deemed enough? If so, was it a cost constraint to the consumer or no real advantage to go larger? Sorry not to e-mail the site directly, I am not trying to put you on the spot, I just read this thread and thought others might be wondering the same.
Thanks,
Will

xswl0931

Larger diameter rotors also increase rotational mass which will decrease acceleration.

J Ritt

iTrader: (4)

We do not publish our piston sizes. Because we size differently for each application, it's proprietary information. Sure, a competitor could go out and buy a kit to find the piston size, but we don't want to do any extra leg work for them!
Our ST-40 does in fact have a staggered piston bores...let's take a couple of steps back. I'm leaving big holes in the fabric of physics here, but this illustration should help clarify the basics.
1. What is the primary goal of the 6 piston caliper vs. a 4 piston of comparable size? A bigger pad surface area for better initial heat absorption and extended pad wear. That said, how is that bigger pad surface area accomplished? The backing plate of the pad grows...typically in length. Additionally, the caliper has to grow in length to accept the longer pad in the six piston. Think of two rectangles made of balsa wood sitting on their side. The longer of the two is the 6 piston caliper, and the shorter is the 4 piston. All things equal, which rectangle would be able to hold more weight placed in the center on top? The one that has shorter sides, and is more like a square, right? This is the same as with pads and the calipers needed to support them...as the length grows, it loses strength and resistance to flex. So what do you do when you increase the length of the pad, and you need to support the pad across it's entire face?...you add a couple of pistons...voila, you now have a six piston caliper. From this description, you should be able to see some of the risks. The caliper is likely to be less stiff as a basic structure. Therefore you need more supports to maintain stiffness (if you are able to). This comes at the costs of added weight and complexity. More parts to maintain and replace. Pads are more expensive, even though they may last slightly longer.
As for staggered pistons, our ST-40 does have this feature...on ALL of our front applications. Another name for this is differential piston bores. You'll also notice that the leading piston is always smaller than the trailing one. This is to prevent tapered pad wear. As material and debris from the leading edge of the pad is trapped between the pad and rotor, it tends to float the trailing edge of the pad off of the rotor. In other words, the entire pad would not be making solid square contact with the rotor. A larger piston at the trailing edge of the pad provides more pressure to compensate for this debris buildup, and keep the pad flat against the rotor. I'm not sure what exactly you mean by deflection. Are you talking about knockback? http://www.stoptech.com/whitepapers/knockback.htm

As for the rear...the rear brakes of the car have very different demands, particularly on a front engined, RWD vehicle. The amount of heat that is generated in back is very small relative to the front temps. Therefore, you can get away with running a lot less brake in the rear. That said, the Z definitely uses more rear brake than most comparable cars. The base brakes use a pad that is about the size of a postage stamp. They are so small, that they don't have a whole lot of heat capacity. Additionally, the rear rotors are tiny given the Z's mass and speed. That leaves you with a couple of options. 1. Grin and bear it...replace the pads every couple of events. They are cheap, and easy to replace, so definitely a feasible option. 2. Go to a rear system with more heat capacity. The 328x28 rear ST-22 setup is a massive upgrade in heat capacity...as much as just about anybody would ever need for this car. To my knowledge, guys with the Track model have not had major problems with burning up the rear pads. With our setup, you will have that same pad, with a better flowing rotor (our AeroRotor flows a lot more air than the stock track model brembo rear rotor), and the rotor will have more mass to absorb heat in terms of diameter and width. I've said it a million times on this site...you want the absolute minimum needed to fulfill the requirements of what you will use the car for...anything else is dead weight. A 4 piston caliper isn't really going to do give you any benefit in the rear, if the smaller, lighter 2 piston is efficient, and you won't be burning pads up.
No worries...that's what this site is for...sharing of info! Let me know if you have any other questions.

True, but a larger 2 piece rotor with aluminum hat is many times lighter than a much smaller 1 piece cast iron part. Also, tiny amounts of improved acceleration won't do you any good if you fade your brakes to the point where it's not driveable...or at least not any fun to drive! This isn't a big issue on the Z. It's more of an issue if you put a 15" rotor setup on an Elise.

Resolute

iTrader: (2)

I certainly know the stock rears are pathetically small, Carbotech doesn't even sell race compounds for them anymore. Porterfield R4 is all that is left, hence my increasing need to upgrade. The Brembo rears on the track seem to hold up well, but that pad is also pretty small, and has been known to overwork (read warp) the rear rotors. The ST-22 will come with two piece rotors then?
Thanks for the info and answers man, always good to read what you have to write.
Will
EDIT: removed excess quotes

J Ritt

iTrader: (4)

Correct.

The size of the pad doesn't directly have anything to do with 'warping the rotors.' A warped rotor is typically not a warped rotor at all in fact. The vibrations people get are due to uneven pad deposits on their rotors. Please read this article for a much more eloquent explanation than I can provide in this space: http://www.stoptech.com/whitepapers/...otors_myth.htm
The size of the pad does affect heat capacity...overheating the pad above it's max operating temperature can cause uneven deposits. Our rear setups are all fully floating 2 piece AeroRotors...just like what is on the front of our kits. The 328x28 will provide more than enough capacity to dissipate the heat from the pad. This rotor is the same size that we run on the FRONT of many of our kits...like the NSX, S2000, RX8, some BMW's, etc. Trust me, it won't be an issue with this setup. Our 355mm rear setup is overkill to the umpteenth degree...we've been telling people that all along. My guess is that you would never see a properly prepared pro 350Z race car with a 355mm rear. It would need to have massive power and be able to achieve consistently ridiculous speeds to necessitate such a thing. Take a look at the Schuitimaker (sp) and Unitech racing 350z's...they run the stock rear Brembo's without any drama. Unfortunately, the rules don't allow them to run our front kits...because they do exceed the capacity of the front factory Brembo setup.
If people are running into problems with the rear factory brembo's overheating, my guess is because of pad choice. Factory pads, and any street pad for that matter, are only designed to work in a specific temp range. A good quality race pad like a PFC97 out back will go a long way to solving any issues.