Hydratech vs ABS Electric vs Manual Brakes

[wmhjr]

Guys, looking for some advice. My ride is 3720lbs empty. Weight distribution is actually very good (50.6% front, 49.4% rear) considering. Running Wilwood 12.2" 4 piston brakes with 7/8" manual master cylinder. Brakes modulate pretty well, and car is very comfortable to drive.

However..... I'm hoping to get to some events like MMCC, Motor State, and RTTH this year. Even after switching to BP20 pads, I'm not all that satisfied that I'm yet delivering enough pressure for panic and threshhold braking. The car is a completed project and appearance is also important. The engine compartment is very finished, smoothed firewall, etc. I think I have a few options. In no particular order:

1) More aggressive pads, and check my line pressure. Advantage is low cost, no real fabrication or modifications. I could use the really aggressive pads only for the HPDE type events. Disadvantage: No real help during normal driving.

2) Hydroboost. Advantage: Only need to modify plumbing in the engine compartment, assuming I don't need major changes in my steering pump/reservoir setup. I will need to modify my setup which has the line lock and clutch fluid reservoir mounted to the master, as there will be insufficient clearance against the inner fender with the master moving forward toward the front of the car. Disadvantage is more cost than manual, but probably less than ABS electric. Also, that I'm hearing mixed reviews as to "frothing of fluid" and steering/brake feedback during spirited driving - as well as increased steering noise. Also, lots of hydraulic lines in an otherwise very clean engine compartment.

3) Electric ABS. Advantage: Apparently highest power assist pressures. I could possible mount the pump and accumulator back in the void in front of my trunk. That would keep the engine compartment relatively clean from a plumbing perspective. Disadvantage: No means to mount clutch/linelock with the master used by ABS. ABS master is totally proprietary - only one company makes it, so long term? Need to run two lines all the way from the master back to the trunk area.

Does anybody have any good advice concerning this? Here's a pic of the engine compartment

[Sieg]

Pedal leverage ratio?

6 piston calipers?

[wmhjr]

Pedal ratio is already about 6:1. 6 piston calipers help with some things, but typically not with this. Clamping pressure, surface area and coefficient of friction are the main factors. I may switch to 6 piston fronts and larger rotors but I don't expect that to have a big effect here. They'll certainly help with maintaining brake performance rather than overheating the rotors.

[Payton King]

on PT.com. Let me know if you have any questions

[ccracin]

Just put me behind the wheel Bill. I have a bigger foot and more junk in my trunk to push!

Seriously, Which caliper do you have on the front. If it is the Dynalite 4 piston, they also make that caliper with different bores. 1.75" and 1.62" are common. Obviously, if you have the 1.62" then stepping up to the 1.75" would increase your mechanical advantage and normal force.

Also, Did you check into the 3/4 MC like we talked? Doing the rough numbers it looks like this:

With 100# of force on the pedal at a 6:1 ratio, you get 600# force to the MC. With your 7/8" MC you are creating 998psi line pressure.

With a 3/4" MC you would create 1358psi line pressure.

If I assume you already have the 1.75" bore caliper, that has an area of 4.81in^2. The normal force created by the 7/8" MC is 4800#. The normal force that would be created by the 3/4 would be 6532#. 35%+ more normal force is nothing to sneeze at.

As long as you have enough pedal travel to compensate for the reduced volume of the 3/4" bore, I would try this first. If for some reason you can also switch calipers to larger bore, that is even more increase.

Forgive me if I made an error in my math as I was going pretty fast, but you get the picture.

Cost should not be crazy and it should have no impact on the shiny nice stuff! Give me a call if you want to brain storm.

Later!

[Sieg]

Chad - Thanks for the education, much appreciated.