Brakes

[lazybump]

Ill be glad if anyone can help me out with brakes. We want to go in for Brembo. If anyone could let us know which callipers, discs and master cylinders are other universities using, it will be of great help. What size of the disc is the most appropriate? And which one of the lot are light weight and efficient simultaneously.
Thank you in advance..

[FStotal.com]

Just take what others can be dangerous.

It depends on many factors:

vehicle mass, weight distribution, friction properties, tires, ...

You should make some calculations first.

Literature for Braking: (http://fsae.com/eve/forums/a/tpc/f/125607348/m/1956095883)

Baker, A.K., Vehicle Braking. Pentech, 1986. ISBN 0-7273-2202-8.

Limpert, Rudolf, Brake Design and Safety. SAE, 1992. ISBN 1-56091-261-8.

Puhn, Fred, Brake Handbook. H.P. Books, 1985. ISBN 0-89586-232-8.

ABS Traction Control. SAE Publication SP-744, 1988.

[exFSAE]

We want to go in for Brembo.

Why?

[kapps]

You'll be surprised how small the components can be and perform admirably. It's tough if your starting from scratch like I did last year. Google and the search function on this site are your friends. I found a spreadsheet somewhere that helped a lot. Remember, design your first system with a good amount of safety factor. This means larger rotors, larger calipers, and smaller master cylinders. I've found the bore of master cylinders suitable for FSAE are smaller than what are available from the usual suspects.

[vandit]

Originally posted by lazybump:
Ill be glad if anyone can help me out with brakes. We want to go in for Brembo. If anyone could let us know which callipers, discs and master cylinders are other universities using, it will be of great help. What size of the disc is the most appropriate? And which one of the lot are light weight and efficient simultaneously.
Thank you in advance..

why Brembo? .... there are things lighter and cheaper and all most as good as brembo available .... which part of world you are from ... first design your system, get the numbers and then first look for things available locally in your city or country ...

[rjwoods77]

I am pretty sure I saw Wisconsin and RMIT using Wilwood PS1 calipers last year. At 80 bucks a piece they obviously work.

[flavorPacket]

The PS1 is an abomination. It is flimsy as hell and cast in garbage aluminum. But Rob is right, it does work, and costs $46 in the cost report.

[Chris Lane]

I'll add a few thoughts.

RMIT had trouble locking the wheels in the braking test at the previous comp. Whether that is due to the calipers or some other factor, I am not sure.

Better brakes inspires confidence in the driver. We had seriously huge brakes on our car last year and they were great, but way larger than what we needed. I say better to err on the side of caution and get a better brake package than you actually 'need'. A person has to drive it fast in the end and they'll be depending on those anchors...

[vandit]

ya , we used PS1 for 2nd year car, after we failed out brake event in first year... they did the job of clearing the job clearing the brake test .... but they are not great things.... may be decent calipers if you are low on money ... but still there are better things... i guess AP racing are the costliest, yet very good ... i dont have idea about Brembo, but from the google images , i find them heavy....

@ lazybump

if you dont find things locally , and you decide to import stuff ... just make sure you have correct fastners... in our second year , we were stupid enough to import some parts with 'inch' system ... and then realised that in our country we use 'mm' system ... and hence it was real pain in ass to find correct fastners and joints... next year , fastners were also had to be imported ...

[kapps]

PS-1's are fine calipers for an FSAE car. We were one of the heavy cars at competition and had no issues locking up all four corners using rotors that cost us $13 a piece (I'm not going to give away all my secrets). Like I said before, you have to design the whole system to work together.

Think about what the issues are that everyone has with the PS-1. Then go find a way to eliminate it.

[Fras]

You that have used the PS-1 have you had to do anything to the pads. or did you just use the ones that come with the calipers

[vandit]

Originally posted by Fras:
You that have used the PS-1 have you had to do anything to the pads. or did you just use the ones that come with the calipers

as far as i remember , we had sintered metallic pads ..and we just did little bit of warm up, like initially braking at low speeds and then taking them to higher speeds and temperature ... i read about this thing in forum only ...i think its called 'bedding' or something ..

[Drew Price]

Originally posted by Fras:
You that have used the PS-1 have you had to do anything to the pads. or did you just use the ones that come with the calipers


There are several threads floating around about exactly this, give a quick search and you'll find them.

I think the concensus about using the Wilwood pads that come with these is that they seem to do fine, there are just no data sheets where you can see the friction profile as a function of termperature like you can from some of the other dedicated friction material manufacturers, like Hawk, or Ferodo.

Some people use the pads that come with, some people cut larger pads down to size to fit.

Best,
Drew

[Fras]

Thanks for the help

[Chapo]

There actually is a friction vs temp plot for the pads that come with the PS-1

http://catalogs.wilwood.com/_p.../BrakePadCatalog.pdf (http://catalogs.wilwood.com/_pdf/_pads/BrakePadCatalog.pdf)
page 4-5 have the pad codes, and page 6 has the friction curves for them.

enjoy

[STRETCH]

For what its worth, our Uni ran PS-1s for the past 2 years, and although they lasted the duration, they struggled in the brake tests. To get them operating well enough to lock the vehicle, also be careful of safety factors on the calipers. We are avoiding them this year due to this reason, turns out they were barely below their maximum pressure rating under heavy braking.

[Drew Price]

Originally posted by Chapo:
There actually is a friction vs temp plot for the pads that come with the PS-1

http://catalogs.wilwood.com/_p.../BrakePadCatalog.pdf (http://catalogs.wilwood.com/_pdf/_pads/BrakePadCatalog.pdf)
page 4-5 have the pad codes, and page 6 has the friction curves for them.

enjoy



Thanks Matt!

Best,
Drew

[flavorPacket]

Originally posted by kapps:
Think about what the issues are that everyone has with the PS-1. Then go find a way to eliminate it.

I didn't know there was a way around internal fluid passages, low stiffness across the bridge, and god awful seal groove geometry...

[Adambomb]

Honestly, I'm not sure why people don't like PS-1s. We've been using them for 3 years with zero problems. No leaks, predictable performance, haven't had any bit of fuss with them at all. Haven't even had to replace with pads, even after 50 hours of driving. We just use the smart pads (the only ones available, and justly so), has a very flat mu vs. temp plot. Our rotors are laser-cut Grade 50 sheet steel.

Based on most I have seen of FSAE, with the extraordinarily high ratio of engineers to mechanics, I would bank that the majority of problems with "these calipers" are more often problems with brake bleeding, pad bedding, or overall system design. Just my $0.02.

As for rotor sizing, just choose a rotor diameter that will work with the caliper, fit on the car, and meet your pedal gain. Pick a rotor thickness that will work with the calipers, and as long as you use some sort of Fe based rotors they should have sufficient heat capacity.