CRB

Depending on the size of your feet and sole composition of your foot ware....

VF84

c&d on brake fade, various bbks

anyway, clamping for is probably gonna be all very similar for the calipers.. probably gonna need to upgrade the master cylinder to push more fluids thru for higher pressure in the hydraulics. bbk address issues of deflection and heat dissipation/resistance.. fade resistance..

oh, and it looks nice

Kurtz

iTrader: (1)

If your flintstone system could produce enough force to engage ABS it'd stop -exactly- as well as your current one. That's the entire point here.

100% of the force your brakes can produce in excess of the ABS threshold is totally useless.

The brakes stopping a locomotive probably need to deal with slightly more significant fade issues than the typical street car brakes so that might not be the best comparison. Plus, they use air-brake systems, not hydraulic braking systems.

Kurtz

iTrader: (1)

Good article... and the most relevant bit to this topic from there-

Our objective here was primarily to test brake fade, not stopping distances. Assuming a brake system is properly balanced, strong enough to lock a wheel, and not yet hot enough to fade, the stopping distance is largely a function of tire traction, not brakes. Think of it this way: All brake systems, stock and aftermarket, are able to activate the ABS, so how could a stronger brake shorten a stop? Eric Dahl, a brake engineer from Brembo, put it this way: "Don't expect the brake kits to stop you sooner, but expect the 20th lap to feel like the first."

VF84

i'm curious.. given normal traction of tires on normal roads, for those panic stops from 70 mph/high speed, do the abs kick in immediately? i don't think most normal street cars can do that immediately. my recollection on the track is the abs kicks in a bit later... seems as tho if abs is not immediate, improvements could be had. probably larger master cylinders.. maybe i'm just not that good of a driver to force abs immediately on the track

Joe Z

iTrader: (10)

Kurtz.. I know exactly what your saying...

MY point is that "Brake Pads" stop the rotors, which stop the wheels that are turning where the rubber meets the road...

or in the trains case, where the metal wheel meets the metal track...

Kurtz

iTrader: (1)

ABS should be pretty near instant on any modern car... the sensors are checking wheel speed every 5-10 milliseconds

Here's a nice article explaining how ABS works (though it inflates the times a bit to make the math easier)

It ALSO explains why a big brake kit that creates -more- force is a bad thing for systems like ABS/TRAC/VSC/EBD/ETC

http://www.stoptech.com/tech_info/wp...rakekits.shtml

Big brake kits are great for reducing fade if you're gonna abuse the hell out of your brakes at a track or down a mountainside. They might save you a couple lbs of weight too if you buy REALLY expensive ones. Otherwise they are, apart from cosmetics, a total waste of your time and money...and if you buy one made with no regard to the stock braking systems configuration it can confuse a lot of your chassis control systems.

VF84

oh, that's not what i meant. i meant generating enough maximum brake force at 70 mph to force the tires to almost lock up immediately and get the abs kicking in. i wasn't talking about the abs's reaction time itself.

lobuxracer

iTrader: (2)

Most people are not confident with brakes and don't push hard enough to engage ABS at high speed. It can be done very easily but you have to be willing to put some pressure on the pedal.

Changing the master cylinder size only changes the feel of the brakes. Smaller diameter gives more travel for the same amount of change which lets you modulate the brakes with greater confidence. Larger applies more force in less travel, so you'll engage ABS far more quickly than with a smaller master cylinder.

On race bikes we play with the diameters to suit the rider since race bikes don't have ABS and the rider actually has to judge impending lock up accurately. Lots of guys like smaller diameter master cylinders because it feels more like power brakes and allows a lot of travel adjustment when feeling front wheel traction. And yes, you can lock up the front wheel on a bike even with slicks.

VikH

iTrader: (5)

I would think Brake Assist takes care of this problem.

windex

iTrader: (1)

2K!?!? I would be all over that maybe if we get a few people to do it sewell would be open to the idea

javyLSU

iTrader: (21)

So I've been getting a bunch of PM's since Sewell announced their fantastic group buy on the OEM IS-F Brembo's. I had previously posted that the OEM IS-F Brembos were not a direct bolt-on to the IS350 - however Sewell posted a video featuring an IS350 wearing those same brakes. If we go back to the original post in this thread, we see:The fact that the hubs are different between the IS and the IS-F is the main reason why this is not a direct bolt-on, unless you also install the hub from the IS-F. When you try to install the IS-F rotor on an IS350 (using the IS350 hub), this is the problem you run into:



You're looking at an IS-F rotor that won't fit on an IS350 hub. As you can see above, the inside of the IS-F rotor actually grinds on the lower ball joint because the IS-F rotor is about 1/2 inch deeper than an IS350 rotor. The only way this problem can be solved is by pushing the disc further out, which is what the larger IS-F hub accomplishes.

Sewell says that their IS-F big brake kit includes the following:
Unless Sewell is also including the IS-F hubs in that kit, this is not a direct bolt-on. It should also be mentioned that even if the hub were included, you're required to transfer the ABS sensor from the old hub to the new one (can be seen below, in the center of the knuckle where the harness is):



I post this because I'd like for everyone (both Sewell and CL members) to avoid any confusion - I'd hate for CL members to start ordering these only to find out that they're not direct bolt-ons, and I'd also want to prevent Sewell from buying and stocking these if they're not aware that the installation requires IS-F hubs.

Javier

javyLSU

iTrader: (21)

By the way, although there's not much size difference between the two calipers, the difference in weight between the IS350 caliper and the IS-F caliper is GINORMOUS. The IS-F caliper weighs about 1/3 of what the IS350 caliper weighs...


Also a big thanks Joe Z and Lance (lobuxracer) for all their help with this!

Javier

t0e

iTrader: (1)

And the OP question has been answered!

And how many times, do I have to hear "is it worth buying a BBK question?"

Can we create a link for this on the FAQ? LOL

Joe Z

iTrader: (10)

Hey .. how did my arm get in this picture!!! ??? j/k

Yes its true, the IS-F Brembo Caliper is very very light. I was easily holding it for the photo with one hand...
Now the IS-F Rotors are a completely different story.. Those things are ridiculously heavy..

Many thanks to Javier for taking the time to re-verify our previous findings and many thanks to Lance for giving us a hand over the phone with researching these issues.

For the record so far, the Front IS-F Brembo Caliper & Rotor are NOT a Direct Bolt On Swap to an IS250 or IS350

Also, another point to mention:

* If IS-F hubs are used in this installation process, the front track will most likely end up approx one inch wider on an IS250 or IS350.
Which may cause front wheel & tire fitment issues in certain applications or combinations.

Joe Z