Hydratech vs ABS Electric vs Manual Brakes
 

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

http://i297.photobucket.com/albums/m...s/DSC_4884.jpg

http://i297.photobucket.com/albums/m...s/DSC_4885.jpg

Pedal leverage ratio?

6 piston calipers?

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.

left you an answer
 

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

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

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!

Chad - Thanks for the education, much appreciated. :thumbsup:

Chad, how you gonna handle clutch and brake pedals with crutches :)

Anyway, got my gauge back, so this weekend I'm measuring actual line pressure and stroke length on the car. I did talk to both wilwood and carbotech today. The one thing wilwood brought up was that I have one piece of 1/4" line on the car, between the prop valve and the rear "t" above the diff. While that wouldn't affect the front, they said it could impact the rear (though I'm not in total agreement). I also mentioned the 3/4" bore master, and they weren't wildly supportive. Who knows. I need to do some measuring first.

Some things I did pretty much decide. I think I'm pulling the 12.2" forged dynalite 4 piston brakes, and replacing them with 14" superlites. The rotors are quite a bit thicker as well as larger, which is important. If I do make some hpde events this year, I want to take no chances when I start pushing that 462 on the straights. The dynalites are perfectly good, and somebody will buy them. I even have extra pads. I'm also going to try some carbotech pads. They recommended the ax6 for the back and xp10s for street, xp12s or rp2s for the track on the front. One other nice thing is that you can order the pads pre-bedded.

Let's see what happens this weekend.

Electric booster, you dont need to buy expensive one manufacturer made aftermarket unit, you can take it out off almost any modern car with ABS. Just need to find out the electric connections witch are not difficult, stuff we use (european), there is three wires.

Here many use them in rallycars, put them in the back of the trunk.

Same gos with electric power streering unit. No aftermarket, just stock stuff= cheap buy and cheap to repair.

If you use EB out off normal car not a aftermarket you can use linelock. There is a normal mastercylinder.

,Juhani

More info please! Pics perhaps?

Shiny Side Up!
Bill

Look at Juhani, teaching the American's some Finnish car secrets!! HAHA :D

How's it going buddy? Getting lots of snow?

Hi Scott! Doing alright.
Somebody was to do it, right:D Jep, lot of snow and cold. Today weather feels like spring, only -15c/5f.
Bill, There is in my garage one '67 camaro convertible PT car under build. (Not mine!) it has willwoods all around and a hydrobooster w/willwood mastercylinder. Owner how is a good friend of mine wants me to convert it to electric booster and put it behind firewall.

Also I have to relocate the wipermotor cos this electronic controlled 8 stack injected stroked big block takes it space away.

I dont have any pic on my computer put I can go to my friends garage near by and take a picture for the unit we are using.
It is a ABS unit out of GEN 2 ('90es)Ford Sierra Cosworth 2wd. I think in US you dont have these legends.

Wikipedia:
Sierra RS Cosworth

Okey, I went to my friends garage to take pics but the rallycar is in another garage 200Ml away.
He had one Sierra in ,it has that same unit but it has an 5.0 V8TT engine ( possibly the only one street legally in here) in that so it was off limits to get any spyphotos.;)

but got a lesson how to do it:

You need:

Two (2) single hydralic cylinder, like clutch slave cylinder. He used Mersedes 123 body cylinders with separate reservoids.

One (1) ABS-unit from almost any car.
Holds: brakefluid reservoid, electric pressurepump,
pressure accumalator, pressure switch and ABS-brakediverter/valveblock.
(thats that block where all brake lines to wheels leave)

ABS-control computer is not needed. But with this you can put ABS-brakes to your hotrod, just add wheelsensors and wires.

So: Replace hydro/mastercylinder with one the (slave)cylinder (straight to the firewall or behind it) and from that a hard line to secont (slave)cylinder( this can be behind firewall, tuck inside the fender,in the trunk or almost anywhere in the car) You just need to fab a sturdy bracket that holds a(slave) cylinder and the ABS-unit together against each other so that (slave) cylinders piston push rod is the ABS-unit push rod, working together back and forth.

Electrical connections are simple, (normal 4 wire closing) relay controlled, plus, ground and control wire from ABS-units pressure switch to switch pump on and off, also brakefluid reservoir has level sensor, that is good to connect to some small led-warning light.

Brakelines are connected to ABS-units original places, usually two to front brakes and one back.

Just make sure that you are able to check brakefluid level and chance it with out any big disassembly.

here is link to Ford unit remove and refitting. There is good picture to see all components.

I hope this has opened something to atleast someone but feel free to ask if not and sorry to make it so long but please try to explane something with another Language.

,Juhani

p.s also find out that megaquirt has release seqvental injection for 10 cylinders :thumbsup: and I get to modified his intercooler for that TT V8 engine.:cool:

Thank you very much for the information! As for your English, don't worry one bit, I think you do very well! :thumbsup:

Shiny Side Up!
Bill

OK, back to the original channel. BTW - when I said "ABS Electric Brakes" I was talking about the company named "ABS". Not Anti-lock brakes. I have no desire to add antilock brakes.

Anyway, I measured front/rear line pressure today. Front goes to about 1400lbs, and 1000-1100lbs is very easy to produce. Rear was originally about 500, as I had believed unscrewing the prop valve would increase rear pressure by opening the line, only to discover it's the opposite. Now it's 1100lbs.