Brake Boosters and Forced induction engine conversions

[Corona]

I am still doing some research on my 3S-GTE conversion, now more so since I just got the one that Chickenman was selling.

Anyway, when putting in a engine with forced induction (Turbo or S/C) into an N/A car, does the brake booster just plum into the Throtle body as it has done before, or do I need to do some sort of conversion on this as well?

I ask this because I understand that brake boosters need a vacuum to operate, but when the air is under pressure does it still keep working?

More questions to follow at a later stage.

Thanks

Neil

[CozmoNz]

Last time i asked this question i got yelled at, at tech....

Eg, what happens when your running 7psi and tap the brake... does the pedel come back out or what happens?

i dont know of any differences in the lines, id imagine there arnt any, since even the honda boys just stick turbos on, without any modifications to brakes / M / S cylinders.

[vvega]

it has no relevance
normally when you hit the brake your foot is off the gas so the booster has vacume anyway

so in the real world whenever you hit the brake the booster is boosting

there is no different between the 2 regardless

v

[CozmoNz]

it has no relevance
normally when you hit the brake your foot is off the gas so the booster has vacume anyway

so in the real world whenever you hit the brake the booster is boosting

there is no different between the 2 regardless

v

Rally cars do it, left foot braking... Full throttle, press the brakes, keeping weight over the front wheels to promote turn in.... far less understeer without losing boost. Works in fwds well ^_^.

But i havnt tryed it in a turbo car yet... will have to give it a go in the future.... .

[MetalupYoAss]

even if you are boosting and trying to brake at the same time you'll still have 2 pumps before the brakes go stiff

[Dr-X]

even if you are boosting and trying to brake at the same time you'll still have 2 pumps before the brakes go stiff

That's right. Coz - the brake vacuum is just used to assist braking, not to help return the pedal or anything. If you wanna know what difference it makes, do this: (CAREFULLY!!!!)

Park on the verge of a big hill (with no or little traffic). Turn off ignition. Pump your brakes twice. Push the car down the hill with the ignition still off, and try to brake.

Yet another good resource from Howstuffworks.com (I assume, havent read this one) http://auto.howstuffworks.com/power-brake.htm

[CozmoNz]

even if you are boosting and trying to brake at the same time you'll still have 2 pumps before the brakes go stiff

That's right. Coz - the brake vacuum is just used to assist braking, not to help return the pedal or anything. If you wanna know what difference it makes, do this: (CAREFULLY!!!!)

Park on the verge of a big hill (with no or little traffic). Turn off ignition. Pump your brakes twice. Push the car down the hill with the ignition still off, and try to brake.

Yet another good resource from Howstuffworks.com (I assume, havent read this one) http://auto.howstuffworks.com/power-brake.htm

nah fk off, already tryed braking when the ignition dies on you (driving gfs car and dizzy died... while i was mid brake, so i let off and pushed again, felt stronger and wasnt braking strong.... so i let off and did it again, NO assistance... argh! horrid feeling.

car died, no brakes... horrid.

i suppose, if your left foot braking while on boost, you dont repetitively press it do you, you would let off boost between braking and get assistance again.

So in short, answer to this thread - No problemo!

[Corona]

Cool, well thats that problem sorted then. I would not have been happy if I went to go down the road on the maden voyage and couldnt stop

[vvega]

please remeber that abs plays a bit part in no engine feel

fact is all you have to do is stick the engine in gear while tring to slow down and you will have all the vacum you need


v

[TrouserFxGt]

most cars have a one way valve on the vacuum line to the booster.

[GT4 20]

As above. A PCV (Pressure Control Valve) sits in the line between booster and manifold. When on boost, valve closes to prevent the booster becoming pressurised.
Many competition cars do away with a brake booster (not sure about WRC cars) so it's not an issue with them.
Gary

[spencer]

most cars have a one way valve on the vacuum line to the booster.

that pretty much sums it up, and non boosted brakeing is sweet feels ok boosters just for grannys

[craigt]

You could run an electric vacuum pump. The Yanks love them, quite a few on the market over there. Otherwise get a good check valve to install in the vacuum line, you could also put a vacuum reservoir between the check valve and the booster, just make sure its of solid construction.
The other extreme is a belt driven pump, most diesels have them.
But they would be a slut to mount.

[TrouserFxGt]

The other extreme is a belt driven pump, most diesels have them.
But they would be a slut to mount.

most light duty diesels have them integrated with the alternator.