Bias Pedal Box with No Booster

[Rally Pack 2000]

Just doing some research for a friend regarding brake options. The car his highly powered turbo charged Pinto of which manifolds etc take up space where the standard brake booster traditionally sits. So space even for a remote booster on the inner guard is at a bit of a premium. I think the cleanest solution is to go with a cable clutch bias pedal box, with two small reservoirs beside the bonnet hinge. I think this would be the neatest and easiest obtainable solution and moving the master cylinders completely from the engine bay. It will have 4 pot calipers and vented disks with a disk rear with a caliper setup of unknown effectiveness at this stage so it hits home the importance of a bias pedal box so once install the bias between front to rear can be determine as the relationship of sharing around the breaking effort is better known. Now the grey area is to go remote booster or will a non booster set up be sufficient on a 250 to 300bhp approx vehicle? Do any of you guys run just a bias pedal box with a YB or similarly powered car to great effect? Or do you find it a bit scary when you put the boot in? Any other recommendations most welcome

[RWL81P]

my mate had a 400hp cosworth mk1 escort, that only had a bias pedal box, 8" rear drums and capri 2.8i front brakes behind 13" superlites. worked fine but it was only for the street.

[meXEco]

As you probably know a servo wont make the brakes any better it just makes the pedal easier to push-most people with bias boxes don't use a servo.

[meXEco]

And if he wants one put it under passenger side dash.

[Rally Pack 2000]

my mate had a 400hp cosworth mk1 escort, that only had a bias pedal box, 8" rear drums and capri 2.8i front brakes behind 13" superlites. worked fine but it was only for the street.

 

Its for a street car as well so your stated usage is just what I wanted to hear and this car will have better front and rear brakes than that.

[Rally Pack 2000]

As you probably know a servo wont make the brakes any better it just makes the pedal easier to push-most people with bias boxes don't use a servo.

 

 

And if he wants one put it under passenger side dash.

 

To save costs, since its not dangerous to do so, it would probably be best to try a bias pedal box first before adding a servo and only add one if the need arises for less pedal effort.

 

What size cylinders do most of you run then without boosters?

[meXEco]

.625 front

.700 rears

[Vista]

I have a bias box with no servo in the van. The brakes are good enough but I would prefer them with a servo.

 

It's an age and comfort thing I think.

[colr6]

I know khandlad has just installed a servo on his bias braking system only on front circuit with quite good results. No doubt he will stick his two penneths in.

[Danish]

I know khandlad has just installed a servo on his bias braking system only on front circuit with quite good results. No doubt he will stick his two penneths in.

 

That's what I was recommended to do - servo only on the front circuit.

[Rally Pack 2000]

I know khandlad has just installed a servo on his bias braking system only on front circuit with quite good results. No doubt he will stick his two penneths in.

 

Thats an interesting idea, I havent heard of anyone just doing one before. Is the benefit of that so you get away with a much smaller servo under the dash or something?

[khanlad]

How rude col! As col said I fitted a remote servo under the dash, front only, have 260mm disc and willwoods with disc rear. They stopped you, but was never totally happy with them, I used car for a week constantly and began thinking they weren't as bad as I thought, then I got in my daily and nearly put my face through the screen! Like already said they aren't any better, just come in harder straight away, which I think is much closer to modern brakes? I used the same set up I had before and fitted a mgb remote servo, which seems the way most people do it? brackets, servo, and all the pipe work cost about 100 quid?

[khanlad]

 

Not the best pictures but you get the idea, Maybe?

[Rally Pack 2000]

Thanks for that information. You have it inside your glovebox? LOL I dont think he would cut up his glovebox, it would have to fit above the glovebox or some other place.

 

Are MG servos the main one people use or is there specific after market ones used for upgrades?

[khanlad]

Yeah inside the glove box and it still works, well you can get your spectaculars and a phone charger in there, oh and some sweets! Would imagine any would do, that was the most popular when I read up on it,

[jamie956]

I have a high spec braking system on my car Tilton floor mounted peddle box big AP brakes it dose stop but man you have to push on it, one other thing to think about doing this is bulkhead flex a friend has a bias box on his mk1 escort and it moves quite abit when you really stand on it,

 

Car builder solutions do a compact double ended servo for dual circuit systems not cheap but do you really want to skimp on brakes.  

[Vista]

 

Car builder solutions do a compact double ended servo for dual circuit systems not cheap but do you really want to skimp on brakes.  

 

Ooh, I like that.

 

http://www.carbuildersolutions.com/uk/compact-dual-circuit-remote-brake-servo

[jamie956]

Ooh, I like that.

 

http://www.carbuildersolutions.com/uk/compact-dual-circuit-remote-brake-servo

yer its a neat solution if your using a dual m/cy system they even do a nice mounting bracket for it, i had also found a one way vacuum valve rated for 45psi positive pressure you need a reliable one way valve when running boost if it gets to the servo its going to turn it inside out.

 

The only issue is getting a decent take off the YB manifold i think you really need a 1/2" connection, the other option i looked at as a budget method was finding and adapting an alternator with a vacuum pump to fit.

[colr6]

Could you not use a belt driven vac pump and fit where the pas pump would be fitted to get over the boost problem on a turbo ? The type that I remember fitted to early diesels

[Danish]

Could you not use a belt driven vac pump and fit where the pas pump would be fitted to get over the boost problem on a turbo ? The type that I remember fitted to early diesels

 

I *think* the alternator from some Transit diesels have a vacuum pump on the rear.

[jamie956]

Lots of turbo diesel cars seam to run them so im sure theirs something out there that would work, i also looked at the electric vacuum pumps but it turns out they get quite complicated to run correctly needing a reservoir and a vacuum switch to switch the pump on and off. 

[JP.]

Its quite simple. Use an electric vacuum pump as used on several Volvo's. Hella UP28. Don't need no reservoir as the brake booster is one.

 

Connect it to the brake light switch to activate the pump.

Hella UP28 pulls 28in of vacuum.