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Discussion Starter #1
Alright so i'm noob to boost, and not really thinking too much about it, but this question just popped into my head;

How do vacuum operated items work if there is no vacuum because theres boost? Especially superchargers because you're seeing boost (even a small amount) at low rpms. Things like the brake master cylinder for example.

:)
 

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Discussion Starter #3
But wouldnt the boost cause a positive pressure forcing air back into the vacuum lines? The motor doesnt just gobble up all the positive air...
 

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At idle or off boost there is a vacuum, when you are boosting it is allowing your motor to run more than 100 percent v.e. and you are also forcing more air into the system thanks to the turbo
 

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think of it this way, A vacuum cleaner sucks in right. well so does your engine only through you intake mani, your boost gauge it attached to your intake mani and sees no air being blown in to the lines only sucked out in the the engine. When the turbo starts blowing air in to the engine it starts to blowing air in the the boost gauge line there for reading boost. take a straw and suck on it you are creating vacuum, there for your mouth is the engine and the straw is the boost/vac gauge. now blow on it and you have positive pressure AKA BOOST.
 

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Discussion Starter #8
Huh, i see. But what about supercharger setups? Superchargers supply continuous boost, even at idle because the pulley is still spinning at engine rpm. no?
 

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Discussion Starter #11
I let this thread die by accident.

So therefore, booster wouldnt work in boost then? But it doesnt see positive pressure.. So i guess it'd be like hitting the brakes with the car off..

Oh, and i haven't put the ECU in yet, i need fundage for tuning first. x_x
 

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cruise control works because of engine vacuum so theoretically cruise control wouldnt work under boost but thats not the case. i can even accelerate (with the cruise control accel button) and still retain proper cruise control operation.
 

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the artist formerly known as drexelstudent11
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dude, how often are you gonna be on the gas enough to build boost AND on the brakes?

on a FWD car it should be never
 

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cruise control works because of engine vacuum so theoretically cruise control wouldnt work under boost but thats not the case. i can even accelerate (with the cruise control accel button) and still retain proper cruise control operation.
from what i understand, cc uses map and vss signal to determine holding speed. but when under accelleration, it just pulls the throttle cable till you let off the accel button. then resets itself by the above parameters. i could be wrong though.
 
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