theNeanderthol

iTrader: (1)

Hey guys, I was thinking abot the blow through turbo setup that I am in the process of building for my 12a. How will I find a vacuum sourch for the power brakes. The whole intake system will be pressurized, with vacuum a little of the time. I thought of setting up a vacuum reservior that they sell at the local speed shop that will work when there is vacuum in the manifold and the check valve in it will keep it from pressurizing during boost.

Or maybe I can rig a little thingy between the inlet on the turbo and the air filter. Will this provide enough vacuum?

Will either of these 2 ideas work?

How are you guys doing it?

Alex-7

You have to run the power brake booster hose into the cabin and suck on it when you want to stop.


Unfortunatly, that's the only way.


Rotaryshack sells cheese flavored vacume hose, for turbo setups.

mazdaspeedrex

But I wanted ranch flavored. Remember, ranch goes with everything.

theNeanderthol

iTrader: (1)

Ha ha. Very funny guys. Seriously, what will work with this setup? I don't think that boost pressure be good for a brake booster. Any ideas?

I'm leaning toward the 'between the filter and turbo inlet' idea, but I'm not sure.

REVHED

Just run it to manifold vacuum like you normally would. As soon as you're off the throttle and on the brakes there will be vacuum. All you have to do is put a one way valve in the line.

trochoid

iTrader: (6)

If you can find a TII at the wreckers, pickup the oneway valve from it.

theNeanderthol

iTrader: (1)

wow simpler than I thought. Why do people even use vacuum reservoirs then? Would there be a point where you would have brake fade from lack of vacuum? (The crane cams reservoir ad said that THAT is what it was supposed to correct.)

perfect_circle

what about whe your heel-toeing, or if you were brake boosting? would it cause brake fade then?

FB II

ok guys, there is no need to worry about this issue. on 3 different turbo FB's i've driven it's all been FINE. never needed to change ANYTHING in the brakebooster lines..... and i loooove to brake boost it works great.

just hook everything in that area up as normal.

steve84GS TII

You are correct.

The brake booster is a vacuum resevior.It holds enough vacuum to apply the brakes several times.Unless you plan on holding the throttle down and keeping the turbo spooled,while you pump the brakes,your not gonna have a problem.Just run a standard one-way valve before the booster and dont worry.

On a street driven car,the intake system is only pressurized a small percentage of the time.And even if you boost like a madman and try to make pressure all the time,you still have to let off the throttle to shift,and thats when the booster will recharge itself..... if you happen to be on the brakes at the same time.....which is unlikely.

crispeed

I believe there is a check valve built into the hose already. Just connect it to the manifold.

FB II

^^^ correct ^^^

theNeanderthol

iTrader: (1)

sweet thanks guys. (too bad I threw away the original booster hose and used fuel line as a quick fix) Oh well. I'll find something.

But that still makes me curious. Why would they sell a separate vacuum reservior at the local v8 shop? It's cool looking, but why would a cirle track car or a drag car need one?