dual and single diaphragm brake boosters

[the rocket]

Could someone please explain the difference between dual and single diaphragm boosters? I want to fit it for a disc front and rear, v8 setup.

Any advice would be appreciated thanks.

[fingers]

Check this out Rocket ...............hope it helps mate .....Fingers

http://www.ehow.com/about_6048376_singl ... oster.html

[resto]

As you know a booster uses a vaccuum/atmospheric pressure differential to multiply the pressure applied to the piston in the mater cylinder - thus providing more force on the brakes. A dual diapragm booster simply does this twice. The advantage of a dual unit is that you can get the same level of boost from a 7 inch dual as from a 9 inch single. This saves space in a tight area


Resto

[the rocket]

thanks for the info guys, guess I can now know that the dual setup is for me

What is the setup you'll run on yours Fingers? The V8 version that is?

[MeFB]

I always thought the major advantage of dual diaphragm was that you could run dual circuit brakes and still have boost (either front-back or diagonal) if one of the circuits failed.

[MeFB]

Nope, went away and educated myself. Split from the master cylinder outwards.

Never stop learning

[bootlegger]

My 427 vette has 425 hp, 4 wheel discs , single circuit master cylinder and no booster. Pulls up great.

[resto]

You can achieve the same result by changing the master cylinder bore size or by changing the pedal ratio. It is all about fluid pressure.

Resto

[Harv]

Rocket,

There are a few things that may sway your booster choice:
a) some engineers demand a booster, even though all they do is multiply brake pedal force (Dave's Vette is a good example - his brakes would be no better with a booster, just easier to push on).
b) some engineers demand dual circuit brakes. This means using a dual circuit master, and a booster to suit (i.e. booster and master need to be compatable). Engineers may also demand a brake fail circuit.
c) boosters can be mounted on the master or remote (alongside the engine on the inner guards, or under the front guards). Some engineers frown on boosters under the guards unless they are protected by stone shields.
d) there is not a massive amount of room in the drivers side rear corner of an FB/EK to fit a booster in - the bonnet hinges often get in the way. It needs some careful planning to make the booster, master and brake lines fit.

A common setup for V8 conversions that fits, gives dual circuit brakes and a circuit failure light is to use a &*#@ XA/XB master mated to a Gemini booster. The pushrod in the booster has to be lengthened slightly to correctly preload the master. The lines can be run, though have some pretty tight turns in them near the hinges.

Cheers,
Harv.

[the rocket]

Thanks again guys.

I wish I had a corvette

Spoke to my new engineer today and he has advised me to have a dual cct master with a single booster (should be plenty). Need a brake fail light as well.

One thing that thew me was he didn't see any reason i would need a chassis kit like scoobs set up But did say if I can't find a history of the engine block (350 010 block on mine) I'd have to run a charcoal canister and cat converters

Good news is all the work I've done is ok.

Rick

[Harv]

Rocket,

Check engine number on the block, then use google - lots of free online databases that will give you the age of the block. Once you have that, you can tell if it is older than the pollution ADRs... otherwise it will need cats/ULP restrictor etc.

Cheers,
Harv.

[Blacky]

Rocket - try http://www.mortec.com , they have lots of info on early Chev blocks , it has all the info on how to date the block using the castings the factory put there for that purpose.

[bootlegger]

The build date of the block is usually on the right hand side near where the starter motor goes. Its usually cast upside down . If its not there it may be on the other side where the casting number is near where the gearbox bolts on.
The engine number might give some clues if it hasnt been restamped.