just wondering if anyone has ever used forced induction on a car that has a vacuum brake booster (servo assisted brakes) fitted to it. Where does the line from the intake manifold under the throtle blades (in downdraught carb) to the brake booster go in a forced induction layout. Would it still work if i put it at the inlet of the turbo, would it get any vacuum, or do they remain unaffected by boost pressure and just work as normal non assisted brakes. Any info or advice would be greatly appreciated. thanks guys

Ps: the cars a datto 180b

If you look closely..you'll see that there's a 1-way valve inline between the booster and the intake manifold. So the brakes are good for 1 use while under boost. But as soon as the throttle snaps shut, the brake booster would be re-pressurised under full vaccuum.

So the secret is ..if you are under full boost..then don't use the brakes.. Not good for rallying, where antilag is used, I guess.

Chris

if u connected the hose to the inlet of the turbo, in theory the booster would always function. it would not matter if the engine was on boost or not. but it would need to be pretty close to the compressor.

Quote:

How? When the throttle is shut you wouldn't have any vacuum, or very little anyway, which is exactly when you want vacuum....isn't it?

I had a mate not use a one way valve and busted his booster. But when using a BOV as soon as you take your foot off the throttle shouldn't the Positive pressure be vented?? Is there any positive pressure after the BOV has gone off?? Then it should go into vacumm even is the turbo is spooling down causing slight boost your booster should be working??? am I right with any of this or am I talking out my arse??
Cheers
Damo

The Booster likes vaccum. The engine does a better job of creating vaccum behind a closed throttle body/carby. If you put it on the low pressure side of the turbo, you'll get bugger all vaccum (almost all of the time). It connects between the valves and the carby/throttle body butterflies. As I said.

And you need the one way valve. All booster fitted cars have this valve I talk about. Anything else, and I sure wouldn't insure your car..

Chris

cheers for that info guys
much appreciated now i can get stuck into it