Switchable boost?

[91dsmtalon]

This is probably a really silly question, I was intrested in doing this , but when I go to do the vacuum line eliminationelimination
do i need an aftermarket Fuel pressure regulator?

 

[vr6chris]

Either way, you need a vaccum source going to the fuel pressure regulator, aftermarket or stock. As far as doing a scramble boost or a dual boost controller, you need an electronic boost controller or a dual stage to be able to switch boost levels

 

[91dsmtalon]

So that idea for a switchable boost setting wouldn't work?

 

[jackalopeTsi]

you do not need a after market FPR, just the vacuum line going to your stock one, like chris said. and yes the switchable boost mod will work. i havent had time to wire mine up but it will work as long as your solenoid works and you get proper voltage to your solenoid.

 

[Goodguy162000]

Probably a dumb question, but what would happen if that vacuum line didn't connect to the FPR. What exactly does it do?

 

[jackalopeTsi]

i think it raises the fuel pressure with how much boost you run, i think it raises it 1psi of fuel pressure for overy 1psi of boost you run.

if i am wrong someone correct me. but you have to have it hooked up.

 

[LaN-]

That setup does not work 100% the way the guy made it (i tried it)

when you have it bypassing the MBC it loops around and leaks out the small hole in the MBC causing you to run at like 12 - 13 psi IF more depending on your setup.

Now there is a possible fix, and a 100% fix (bare with me)

You can put a PVC valve on the line comming off the MBC so air cant leak out of then MBC hole, BUT my boost dropped off at higher RPM's.

Reason for this is at lower RPM's the air going through the PVC valve is restricted (due to the spring/ball design) and it gives me the boost i want but when i get to higher RPM's more pressure is going in the PCV and it lets more air by causing my boost to drop off.

NOW if you want it to work 100% this is really the only way i can see it happening

You need 2 solenoids and a toggle switch.

(I believe you can take off 2 solenoids and have your car run fine. Not completely sure which ones but i know you can do it)

All you gotta do is leave the 1 solenoid where it is and put the other one where the PCV valve was, then wire them up on a 2 way switch but make sure you wire it so only one is on at a time. This way you have complete control over how the air flows.

Cliff notes:

2 solenoids + toggle switch = 100% workage


first off I'm gonna have to say sorry for how crappy these pictures are but I'm at work and don't have much time SOOO this should help

 

[jackalopeTsi]

i am setting mine up a little different. one of the solenoids has two outlets, when the solenoid is switched off the air goes through one of the outlets, when it is switched on the air goes through the other outlet(this outlet is capped off from the factory). so i am going to use this as a T. when the switch is off the boost will go straight to the wastegate, when the switch is on it will reroute through the MBC.
here is a basic diagram, its not too good:

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PS: even with your setup LAN, couldnt the boost go back to the mbc and still leak out.

i dont think it will cause that much of a problem since even with a normal boost setup with just a mbc air leaks out a little bit.
here is a diagram of this theory:

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[LaN-]

yes it leaks out both sides but it only leaks out the one side IF you have enough pressure to make the spring collapse

and it doesnt make THAT much of a difference i think having it setup like that i got 12 - 13 psi , but when i'm only pushing 15 psi it was sort of pointless on higher applications i can see it working alot better

 

[91-gsx]

this would really work great for those FWD guys. launch at low boost and then flip the switch.