Hello all....

I have been thinking about over boring my engine and making some more performance mods for power. However, the braking is somewhat lacking, especially for those mods.

I have been looking at the brake booster from summitracing.com, see below. Wondering if I got that brake booster and the extension kit that they sell, could I fab a system like the 1800's have? From the pics that I have seen there is a tube that come out of the firewall, clears the clutch master, then attaches to the brake booster. Thus connecting the brake lever to brake booster. Feasibly I think that this could work.

I could probably then get a suitable brake master to connect onto the new brake booster, then have some new brake lines made by crown performance.

Before I started this endeavor I wanted to get some feedback.

thanks in advance



http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM%2D760120&N=700+%2D157248+115&autoview=sku

I don't know about the Summit booster, but I've had no problems with aftermarket Lockheed booster like the one sold by Skandix (and they have a good price). This is a separate unit that doesn't connect mechanically to the pedal or MC in any way -- it works just like the separate boosters that were options from Volvo at the time.

As Mr. DeWolfe correctly points out, though, all any booster will do is make the pedal effort lighter. If you can lock the brakes with the system you're running now, you can't have "more" brakes than that. You need grippier tires first, then revisit how to lock those up too.

To answer your question about the Summitt parts, you would need to measure carefully to ensure everything will fit. You might want to mock up a cardboard "vacuum canister" and see how far out you would need to mount it to clear the clutch master. Be sure to check that you don't foul the distributor or inner fender too. It looks like the biggest bracket kit they have just might clear the clutch master cylinder.

If you do go to a vacuum can, you might want to reduce the leverage on the brake pedal; it just might be really touchy if you leave it.
--
Mr. Shannon DeWolfe -- (I've taken to using Mr. because my name tends to mislead folks on the WWW. I am a 51 year old fat man ;-) -- KD5QBL

Thanks to all for the help. Not sure if it is worth the time and energy to get a better "feel" out of the brake pedal. I could probably spend my time and money looking for a 4-wheel disc conversion for braking power and efficacy rather than just the feel of it.----thoughts?

thanks again

I've been working on this myself for my Amazon's full 1800E brake upgrade.
You don't need much distance to clear the clutch MC. The 1800 short standoff will do that. Your main issue is that the booster canister (coffee-can or pancake) needs to clear the steering shaft. I found this out when I was test-fitting my 1800E booster before taking the standoff to a welder.

If you can hunt up a 140-series standoff and get the foot modified, it should work fine.

Do you have any pictures of the older system you were describing??

As TomTom pointed out, brake boosters ease pedal effort but do nothing for the braking capacity of the system. However, his local chap needs to rethink brakes if he advocates bigger is better when it comes to brake disks. The diameter of the disk has no effect on braking power. Brake pad and shoe street compound materials have a minimal impact on braking performance. The μ (mu) for street pads is typically < 0.3. Plug that number into the friction equation and you will see that maximizing system pressure produces the most gain.

Here is the equation for creating pressure in the system:

P = F/A

where,
* P is the pressure generated in the system,
* F is the force applied to the piston in the master cylinder, and
* A is the area of the piston in the master cylinder

If F goes up, so does P. The only way to increase F is to increase the leverage of the pedal.

If you consider the vacuum booster as an enhancement to F, I suppose you could make the assertion that it will improve braking. But maximum system capacity is unaffected.

Consider A: As A goes down, P goes up. A smaller diameter master cylinder will increase the system braking capacity. If you go this route, you have to make certain the stroke of the chosen master cylinder is sufficient to supply enough fluid to the system.

At the wheels, the situation is reversed:

F = P x A

P is system pressure, whatever the master cylinder is delivering. A is the area of the caliper piston or drum cylinder. F is the force applied to the brakes. You can see as A increases, F does too. Bigger wheel cylinders will produce more braking power.
--
Mr. Shannon DeWolfe -- (I've taken to using Mr. because my name tends to mislead folks on the WWW. I am a 51 year old fat man ;-) -- KD5QBL

All that math is fine and dandy but you forgot one of the most critical aspects of any performance braking system. That is its ability to absorb and dissipate heat. It's called thermal mass. One of the reasons TomTom's buddy advocates larger rotors is their inherent ability to absorb and dissipate heat more effectively. Most who drive these cars will never push the brakes to the point that they overheat and lose their braking effect. For those of us who will, larger rotors, bigger calipers and a properly balanced system is the only alternative.

And yes, larger rotors do make a difference in braking power. I believe it's called torque. You're effectively stopping the car with a longer "lever". Leave every other aspect of the braking system the same and put larger rotors on (obviously moving the calipers out to match) and you've increased the braking power of your system...


Dale

Thanks Dale,

I certainly did overlook the leverage advantage of moving the braking surface away from the center of rotation. And, heat dissipation is a valid reason to add mass.
--
Mr. Shannon DeWolfe -- (I've taken to using Mr. because my name tends to mislead folks on the WWW. I am a 51 year old fat man ;-) -- KD5QBL

Bear in mind that a brake booster will not actually make the brakes better, it just reduces pedal-pressure somewhat. My local chap, who fits out competition and rally Amazons, usually recommends uprated pads and discs to cope with a power-upgrade.

Tom