Master cylinder brace: Grimmspeed vs Perrin

[orthojoe]

I just wonder if these braces will cause any damage to the master cylinder in the long run, particularly if you are tracking the car and are really tough on the brakes....?

[JoeBoxer]

Originally Posted by f0rge

i was debating getting one of these, but i'd like to hear from people who have one if they actually notice a difference.

like how hard do you need to push that pedal to actually flex the firewall? in normal driving does it improve anything?

I haven't noticed anything in normal driving but I made a couple hard stops on the way home a minute ago and it definitely feels better than the last time I made a panic stop. I do have different tires too though but I think it's worth $60, I don't think I would pay $100 for the others though.

[OrbitalEllipses]

Originally Posted by f0rge

i was debating getting one of these, but i'd like to hear from people who have one if they actually notice a difference.

like how hard do you need to push that pedal to actually flex the firewall? in normal driving does it improve anything?

It will make the bottom of the pedal stiffer. You'll want it if you're tracking.

[7thgear]

whichever one resists corrosion the best

but looking at the pics i would go with the GrimmSpeed units because it seems to spread the pressure over a greater area, it would seem that in a very severe case the Perrin could impale the cylinder? I'm no engineer but that's why my gut-physics tell me.

[Juvenile]

No point starting a new thread so, besides the Beatrush brake stopper, has anyone found the Cusco one anywhere? I've seen them fitted with the strut brace but I have also seen them on their own too, mainly Japan... Is the stopper available on it's own?

[LeeMaster]

Originally Posted by orthojoe

I just wonder if these braces will cause any damage to the master cylinder in the long run, particularly if you are tracking the car and are really tough on the brakes....?

@GrimmSpeed can you chime in on this?

[bkblitzed]

i just got the built in cusco one since i was gonna buy a strut bar anyways.

[wparsons]

I've got a grimspeed one, simply because of the cap that better distributes force against the MC.

[Wonderbar]

Originally Posted by LeeMaster

@GrimmSpeed can you chime in on this?

You can't ask a manufacturer... Of course they will give you the answer you want, alway seek 3rd party info.

[Efferalgan]

Originally Posted by wparsons

I've got a grimspeed one, simply because of the cap that better distributes force against the MC.

Just ordered GrimmSpeed for the exactly same reason. Leaving just a tiny bolt cap to act against the cylinder seems "unfinished" solution for otherwise "overbuilt" Perrin... Olso ordered GS's hood dampers which seem to be the best in the market for our cars.

[GrimmSpeed]

@LeeMaster I just saw this even though I'm nearly a month late. I don't know if anyone ever answered your question:

Originally Posted by orthojoe

I just wonder if these braces will cause any damage to the master cylinder in the long run, particularly if you are tracking the car and are really tough on the brakes....?

I'm not sure if any 3rd party can give you better info than what I am about to give you: We manufacture MCBs for several different chassis, and over the years of the thousands sold, we have not once had a single unit cause damage to a master cylinder. Many of these vehicles are raced, tracked, and beat within an inch of their lives, no problems ever None of this is opinion, HOWEVER, I do agree with asking a third party, I just wanted to add that peace of mind. There are some great reviews for the BRZ one specifically on this site, especially in the original development thread.

As for how we feel about the contact interface between the master cylinder and the two different MCBs, I dug up this post from November:

Originally Posted by GrimmSpeed

Functionally, they both operate the same way. Our method offers a bit more adjustability for manufacturing tolerances in your vehicle. Additionally, we much prefer to counter the pressure from the master cylinder with the machined cap. This helps distribute the massive forces of the cylinder across the back of the casting, rather than to focus it all on a single point with a bare threaded stud (the end of a bolt isn't flat, so there is a very high stress concentration on a very small amount of surface area without our machined cap or an alternative).

EDIT: I did some quick math for fun if anyone's interested. The surface area of our machined cap is approximately .665in^2, while the surface area of an M10 bolt appears to be approximately .048in^2 (it's not flat, but for the sake of illustrating this, we'll assume that it is). In a panicked stop, the 95th percentile male can typically exert 200-300lbs of pressure to the pedal. Ignoring the mechanical advantage of the pedal and the brake booster, we can calculate the pressure that your master cylinder is exposed to where the cap or bolt react the forces that you apply. Pressure equals force over area. So, the pressure that your master cylinder casting sees with our brace is 300psi or so. If we were to remove the cap and push only with the bolt, that pressure rises to 4082psi or so. That's an increase of around 1300%. If we take into account the fact that the end of the bolt is concave and has a much smaller surface area, you're looking at an increase in pressure of nearly 5000%.

If you've got any questions or need additional help with anything, don't hesitate to call!

Matt Beenen
Engineering
612-379-0000

Again, I apologize I didn't see this thread earlier, but I'm happy that I could answer that for you. Please let me know if there is anything else I can help with!

Chase
Engineering

[Vracer111]

I was thinking of going with the Grimmspeed brace because of the surface interface with the master cylinder end, but really like the look and lighter weight of the Perrin one... in this application aluminum is fine and the preferred material for me. Well I'll be going with neither of those now there is another option that combines both designs into one and costs less as well...from Radium. I figure since I have Radium air-oil separator/catchcan on the passenger side might as well have a Radium master cylinder brace on the drivers side:

http://www.radiumauto.com/Master-Cyl...-BRZ-P372.aspx

[kuhlka]

I have the Perrin brace on my STI and it made a noticeable difference immediately. The brake pedal firmed up a lot. You'll be surprised by the difference. No matter which one you choose, it would be best to have a flat smooth surface mating to the master cylinder and make sure the bolt is adjusted nice and firm against the MC before you tighten down the nuts.

[Turdinator]

@GrimmSpeed any plans for a RHD version?