Originally Posted by Turbonut

Do you know:
Stopping distance 60-0 with A/S tires
Single piston f/r 131 ft
Brembo front single rear 130 ft

Not worth the effort.

Originally Posted by Timbert

Speaking of the job of the brake pressure proportioning valve, would not the pressure/volume of fluid having to push not one but four pistons on an "upgrade" actually decrease the force of the pads against the rotor? That's if you upgrade the rears and not the fronts. Don't upset the balance!

Demonstration: Find a safe place and hit your ebrake to lock or come close to locking the rear wheels. Keep the wheel straight. The car slows at rate X. Pretty poor stopping distance. Get back to the same speed and floor the normal brake pedal. The car slows at rate more like 5X. Do the math. Your front brakes/tires are doing 80% of the stopping.

I get that the parking brake is not actually using the calipers but the little shoes and a lever instead but the point is the dramatic shift in weight from back to front as you increase braking using the front wheels.

Originally Posted by 94eg!

A floating caliper (stock) uses one piston to do the work of two. Fluid is displaced to press on the backs of both the inside & outside pads. This is why you compare only half the pistons of a fixed caliper to all of those on a floating caliper. If half of the pistons in a "fixed" multi-piston caliper have the same "area" as all the pistons in a standard floating caliper, then system pressure will be exactly the same.

The differences come into play because the fixed multi-piston caliper is stiffer and has less play. Therefore brake system response should be increased (like adding stainless flex hoses). The other major benefit of a fixed caliper is that the of sizing of the leading & trailing pistons can be tuned to allow the pad to wear more evenly than floating calipers.

As for the brake balance (bias), it is also impacted considerably by rotor diameter. A larger front rotor increase front brake torque. This is bad considering OEM brake systems are already front heavy for the sake of stability. To offset this, you use less total piston area than stock in the front calipers. This maintains stock bias or even push it slightly rearward (this is when you get shorter stopping distances). The reduction in total piston area will actually make the brake pedal stiffer too. Win win, but it has to be done correctly.

A rear BBK could go another step further with larger rear rotors (more rear bias) and possibly the same or slightly smaller caliper pistons depending on how the math and real-world-testing plays out.

Systems like the TL's EBD may or may not be able to cope with these changes. Again this requires real world scientific testing. You definitely don't want to simply throw parts at a brake system and go drive hard on the street.

Originally Posted by I hate cars

That basically says it all. The tires determine stopping distance assuming you don't have other problems with the car, not the brakes. The stock brakes can lock the wheels just as the aftermarket ones can lock the wheels. On the Stoptech BBK but most importantly on the Hankook RS-3 255/40/17 tires I had a best of 91' 60-0mph and an average around 94' I believe. They were stopping quicker with every stop because they need heat so 91' would be hard to do without warming them up well. In other words, in the real world, 94' is the more likely number but it's still a vast improvement over stock.

I did drop a few feet of stopping distance when going from the Rotora BBK to the Stoptech. Stoptech keeps the stock bias with less piston area than the stock 1 piston caliper to make up for the additional torque of the larger rotor and the caliper is considerably stiffer than the Rotora giving better feel at the limit.

The only bad thing about the 1pc Stoptech kit is the rotors just won't stay true even in normal driving but there's nothing worse than the Rotora junk.

Originally Posted by I hate cars

There seems to be a bit of learning with the EBD but it's still a mystery to me. Just having sticky tires changes target brake force distribution. I've found the best thing when making changes is to stomp the brakes like an idiot several times from different speeds.

Brake pads seem to make a big difference on stopping distance when ABS is involved too. The apply and release characteristics seem to be very important on the TL. That was another thing I hated about the Rotoras. The pads would bite hard but didn't release very easy. You had to back off the pedal a considerable amount to get them to release. The ABS would apply and then almost let off the brakes completely on a pulse which was scary a few times.

I feel that ABS holds the TL back on good tires in good conditions.

My biggest problem is with EBD. If anyone knows how to modify it or train it, reprogram it, or pull the fuse, I would love to know a way around it.

Originally Posted by bshotts

I guess a little background on where I'm coming from. Wife's RDX currently has Conti DWS (which granted aren't Max Performance Summer tires) but they do hold their own in terms of dry grip and Akebono ceramic pads. After a hard pull to 100+ not too long ago, got on brakes and literally had to stand on the pedal to haul it down and even then brakes felt spongy and unresponsive. Never wanted to have that happen again. Could not lock the tires or get ABS to activate.