Silver Bullet

I wanted to know what the braking ratio on our cars are because I just replaced my rear pads after going through 2 sets of pads on my fronts. This after 67k miles with some mix of heavy braking at a road course one time plus my normal "spirited" driving. I still had 1/4 pad left on my rears after all of this!

Braking ratio is the amount of brake pressured applied between the fronts and rears. My prior car was a 96 Impala SS, and it came out of the factory with 90% front and 10% rear. This was because they used the same brake master cylinder with the Caprice. After someone did the research they determined you could remove a valve in the master cylinder and the brakes worked at about 60/40. It was a great improvement on braking with the car actually sitting down when braking hard instead of nose diving.

Since I replaced my rear pads (EBC Red Stuff Ceramic--all around now) I notice I was getting more grab from the rears. Which made me think, are we getting the best braking ratio out of our braking system. I have an MT so I have Brembos on the front.

Did Acura take into account the difference in braking between the AT brakes and MT brakes? What is the braking ratio for our cars?

trancemission

thats a good question

Silver Bullet

Why thank you! Worth investigating.

mishar

Acura TL has 60:40 weight distribution. When you are hard braking on a surface with good traction and with high performance tires, you get close to 1g deceleration. That “shifts” more weight to front wheels. Distribution under hard braking goes to 80:20. So that is about how braking ratio is engineered. Generally they use smaller discs and callipers at rear and same oil pressure.

It could be that with Brembos there is some space for improvement at the rear, but it is not an easy task.

Weight “shift” creates nose diving. It depends on suspension and center of gravity height, not on braking distribution.

Silver Bullet

^^ Thank you for the feedback. Yeah, I wonder how much more you can push to the rear brakes, they are definitely smaller and don't look like they could take too much more braking. I'm sure with the weight distribution occuring under braking any more braking mike cause rear wheel lock/ABS kicking in.

I did notice with the Impala that the car did sit more when braking as opposed to transfering the weight to the front. Maybe with more rear brake you would get less weight distribution.

I'll continue my research and see if anyone has done anything to increase rear braking.

mishar

Some suspension designs use torque created by brakes to minimize dive. All motorcycles and some cars rear suspensions are like that. BMW motorcycles had front suspension like that, but not for long. It could be that Impala has one of those rear suspensions. Acura TL unfortunately does not, but it is better in any other way.

I think that the easiest way to improve rear braking would be to install matching Brembos at the rear. But not the cheapest for sure.

01tl4tl

With only 30 percent of the braking force coming from the rears, upgraded pads are fine for most.
I have no experience with reds and their compound design/friction component-coefficient

IF you go to upgraded rotors and do many track days, have adjustable suspension you like to play with etc...that type of driver

Then you can install a brake bias valve/proportioning valve
You may hear racers say, dial in more rear brake- its because the fronts are locking up- so they move the bias rearward

ACTROS

iTrader: (7)

sorry not a TL specific info but a great article from the pros on the brake balance/bias issue in general: http://www.stoptech.com/tech_info/wp...formance.shtml

bluenose

The TL has Electronic Brake Force Distribution which adjusts the braking front to rear depending on the way the vehicle is loaded.

trancemission

^^^now that I didnt know

mishar

Yes, but it can not make rears to brake more than they can. It can only limit Brembos to make balance. Compared to Brembos they really look poor. For the worse, they are originally paired with single piston calipers.