333pg333

What are the opinions as to brake upgrades. I know some people swear by them whereas others don't feel that they are justified. What's the general consensus as to vendors/costs and how much more hp is needed to push all the extra weight around? For example would you need to upgrade for road and track if you went for a Vitesse SIII kit?

RKD in OKC

Depends on your driving style. If you are overheating or boiling your brake fluid iwith high temp fuild and the correct pads, then you need bigger brakes. Otherwise the stock ones work fine.

Jeremy Himsel

Personally, I believe a brake upgrade is not a worthwhile mod unless you are upgrading the wheel/tire combo or go to a sticky tire. The stock 951 brakes, properly maintained with a quality pad, will out perform the available grip of a stock sized tire. Once I upgraded to 255 width 18’s I purchased a big-red set-up because the stock brakes weren’t enough for my particular liking.

Porschefile

I second that, Jeremy. Pads make one of the biggest differences on the stock setup. Also, if you are using stock tire sizes, or close to stock size tires then the stock 951 brakes are more than enough to overcome the traction available. I'd upgrade your pads, wheels and tires before the brakes. Tires alone make one of the biggest overall performance improvements in most cars (handling, braking, etc).Though, it really depends on how you are using the car. Hard, competitive track use could benefit from a brake upgrade.

Rick

I'm with Jeremy on this...the first thing I'd do is go to a better type of pad (depends on your actual use of the car) and my experience has shown that the next thing to consider is cooling for the brakes. If you got to a much larger or grippier tire you may want to think about the upgrade then. I don't think going up in power warrants a brake upgrade.

RennBod

So, do you think that because the current setup is able to lock up the wheels or defeat friction at the tyre, there isnt much point in upgrading the brakes to something bigger (apart from thermal or cooling issues)?

RKD in OKC

It is not just whether the current brakes can lock up the tires. It is a matter of how long and how many times in a row the current brakes can hold the tires at their threshold. And again that demand depends a lot on your driving style, pads, etc.

Yes, bigger tires, heck even stickier tires have more grip than the stock tires/sizes and will work the brakes harder.

Driftomagnifico

I don't think the 951 needs larger brakes. Better pads and some airflow make marked increases in braking ability.

If you just street drive the car there is zero need for a larger brake setup, and you will see small increases in actual braking ability, if any, with a larger rotor.

RennBod

Isnt there a point though, where the standard brakes will go from applying slowing force to the disk and then any more force will cause the disk to lock up.. where as with bigger brakes, because of the increase in distance from the centreline, the calliper will be able to apply much more slowing force before the disk locks up, therefore allowing you to slow up faster without locking up the tyres than with a smaller disk... A little like the way that a long lever bar allows you much more control and more force over a short one?

RennBod

So the question is.. with a standard or MO30 disk, does the wheel lock up because the pads have locked the disk up, or is it because the tyre has been pushed to its absolute limit.. Although both causes have the same effect, on a 944 turbo, which is the case?

Porschefile

With stock tire sizes, it's due to the lack of traction provided by the tires. The original 205/225 stagger is REALLY skinny for performance related driving. Sure, R compounds or slicks will make a huge difference, but it would be beneficial to go wider, especially for street tires. I run 225/245's when I'm using my Fuchs and still can't brake to the potential of the stock brake system. I'd improve your braking in this order: fluid, pads, ducting (if the primary focus is track use), larger wheels/tires, then larger rotors/calipers. Of course, this is assuming all of your brake components are in good shape (brake lines, master cylinder, etc). If you stick with stock wheels or are trying to keep costs down, move up to the 225/50/16 F 245/45/16 R setup that's fairly common. Even better, find another pair of 8" rears and run 245's all around. Personally, I really can't see any reason for sticking with the stock sizes, unless of course you are racing in a class that largely requires stock sized tires.

Driftomagnifico

You have to think of it in terms of a force modulation rather than movement as the caliper is fixed.

Basically you have X braking ability afforded by the tires.

If your current brakes can lock up then you really stand to gain very minimal amounts of braking ability.

Braking force is a factor of pad friction and rotor diameter. The resistance to this action is the friction force found at the tire : road contact. Pad friction is worked off of three variables. Clamping force from the caliper (factorization of pad area / hydraulic pressure), friction as a result of pad material composition, and the surface area of the pad (pressure at rotor face determined by pad area / clamping pressure).

With the same master cylinder your hydraulic pressure modulation is the same, so the only other variables are pad area (typically bigger), and rotor mechanical torque. Meaning at (arbitrary number) 50% pressure the larger brakes are more likely to lock-up, reducing the actual effective pedal depth.

It all boils down to if you are overheating the brakes, get more air to them, if you are still overheating them then upsize. If you have vast amounts of aerodynamic or traction modifications and have room to spare in terms of tire ability then by all means upsize to the larger brakes and use the additional torque.

Too many people run overkill brakes and think they are great, when in fact they haven't even increased braking performance. The light pedal pressure = car stopping sooner feeling puts a false sense of performance in their minds.

Driftomagnifico

The brakes only lock-up when they produce more torque than the tire's opposition force.

So there is only one solution to this problem because the two choices are complimentary.

Olli Snellman

Just go the "Hard Core Route" like Pete and i did.Check out pictures of Pete car

https://rennlist.com/forums/944-turbo-and-turbo-s-forum/268211-brake-project-pictures.html

333pg333

Hey RennBod
I know it's off the topic, but while I've got your attention (I think) can you answer my enquiries that I made of your short shift kit from 9xx? Did you get it from Jon Mitchell? How much was it? Is it similar to http://www.paragon-products.com/product_p/944ssk.htm
Sorry to hijack my own thread but I'm finding it really hard to get some answers from many retailers/posters on this.