Does anyone know what piston sizes are used on the ST-40 calipers for the 350Z front kits? Maybe someone from stoptech like JRitt can chime in here. Thanks.

 

You need to be more specific. They use different piston sizes for the 13" kit, 14" kit, 14" all around kit, and 14" front 13" rear kit. Stoptech is not a "one size fits all" shop. They R&D every kit and size every application individually.

 

I know that. That's why I said kit"s". Okay fine I'll list them out in order of preference.

332x32 Front Kit ST-40 Caliper

355x32 Front Kit ST-40 Caliper

355x32 Rear Kit ST-40 Caliper

355x35 Front Kit ST-40 Caliper

 

Anyone?

 

I don't know if this answers your question but they have 4 and 6 piston fronts for the 350z now. The rear calipers are offered in 4 and 2 only i believe. Hope that helps unless your going for the actual piston size in mm and not the number of them. Good luck

 

Yes, I want to know the actual sizes of the pistions in mm. I know the different sizes that are available but I would like to know specifically which ones are used in which kits. Thanks for the help though.

 

Curious why your interested in this info, could you say why you want to know?

 

I'm in the market right now for a front bbk. I'm doing my due diligence in research and doing comparisons in the different offerings out there. Just doing my homework before I plunk down a couple thousand.

 

Thats a good idea, im curious as well.
Such as, if the Stoptech uses 4piston calipers and they are say 25mm a piece that would be 100mm or whatever.
Then he'd compare that with like a Rotora 6piston and they might be at 15mm a piece for 90mm total. Im guessing the more larger the piston the better your stopping should be regardless of the number of pistons.
Good Idea!

 

Not necessarily. The main factor in braking is the relationship between the tires and the ground. As long as you have enough brake torque to exceed the limits of the tires, larger pistons or more brake torque, doesn't necessarily equate to better braking.


I'm guessing that dklau33 was asking about piston sizes because he wanted to do his own research on "brake balance or brake bias". Those terms have been the popular topic of conversation lately. Brakes are very popular upgrade right now and it seems that the # of new or wannabe brake companies has seemed to double over the last year or so. Every one wants to set themselves aside from one another and everyone seems to have a different way to describe or use "bias" and "balance" as a determining factor about why their brake kit might be better than another.

If people better understood "bias" or "balance" and how they relate to each other, they would see that it's actually allot more basic than some companies make it sound. AND when selecting a brake kit there are allot of other factors you should be paying attention.

 

Check this out....I posted this on another thread when someone asked the difference between "bias" and "balance"

Brake bias, as defined for use in this thread, is the ultimate amount of brake torque as it is distributed between the front and rear axels. This is generally a fixed factor dictated by the master cylinder, disc diameter, and piston area.

Brake balance, as it should be defined, is the way the vehicle responds under various braking conditions. The is an ever changing factor dictated by the suspension, and shifts in weight distribution...the tires, and the grip between the vehicle and the road...and chages in brake bias, determined by the coefficient of friction.

Now and days there are allot of choices for aftermarket brake kits. Every company wants to stand out and claim to be the better kit.
Bias is a baseline for properly engineering any aftermarket brake system.
Since balance is an ever changing factor, there is no such thing as a magical brake bias that is correct for every driver or every situation. The goal is usually to find a "sweet spot" or range that is functional for both the vehicle and driver. Paying allot of attention to pedal feel and control.

Bottom line...if you want to dial in an exact bias to match your driving style or conditions then you'll probably want to pick the brake company by the amount of brake pad choices, or possibly install a proportioning valve. If you want the best brake system available, make your choice by paying attention the quality of the kit, the history of the company, the availability of replacement parts, and the reputation of the company within the industry.

 

This pic is from a thread that a member posted here a long time ago.

 

Thanks! If those are the calipers that come with the front 13" 350Z kit then I have my answer.

 

Does anyone know how the "electronic brake force distribution system" on the Z works?

To me, this means the Z uses an electronic proportioning valve to control front to rear brake torque using the ABS sensors to compare wheel speeds.

True?

 

I used this static brake bias calculator to figure out some numbers. Not sure how accurate the calculator is so I have to take it as a educational tool rather than cold hard fact. If any brake experts want to chime in here feel free. More education is always good.

http://www.tceperformanceproducts.co...alculator.html

Anyways using this calculator and number gathering from Stoptech's site and the service manual for my G I got the following.

Stock OEM Brakes Non-Brembo (Before the rotor upsize in 2005)
Front: 62.4%
Rear: 37.6%

Stoptech 13" ST-40 Front Kit (38mm, 40mm pistons)
Front: 65.4%
Rear: 34.6%


Looks like the Stoptech kit does a good job in retaining the stock bias.