On the back of the plenum there is a 1/4" or so vacuum hose with check valve that feeds the HVAC, Cruise and Vac canister. Should I re-run this vacuum source from the plenum to the turbo intake pipe? I already have the fitting installed so it wont be a big deal... just asking if it'll work properly.

 

No, put a good check-valve on the hose instead. You don't get any vacuum before the turbo.

 

If you dont get any vacuum before the turbo then how is one supposed to run PCV?

 

You can use a vacuum pump, or you can use the vacuum you have in the plenum during low throttle (like stock).

It is important that you move the hose between the other valve cover and the TB, the one without PCV-valve. That valve cover hose should connect to before the turbo.

If you get vacuum before the turbo, then you should have replaced the air filter a loooong time ago.

 

Yes, i would leave it in the stock location and put a checkvalve on it. Also make sure to have a vac reserve canister still hooked up or else once your in the boost you wont have HVAC, Cruise or power brakes once that little bit of vac in the line is gone!

 

Two of your three answers are false.

..How often do you use your brakes under boost? when you let off the gas pedal and move it to the break pedal the engine is pulling vacuum therefore power brakes will function normal and the canister is not needed....I never even had a problem if I power braked the car....actually the car didn't need powerbraked to turn them over anyways

When the car is in cruise the throttle will not open far enough to pull boost, therefore the engine will still be pulling vacuum. therefore cruise will be fine without the canister.

I would put a check valve on the line to the Hvac controls tho....so under pressure you don't blow off a vacuum line under the dash.

The best reason to eliminate the vacuum canister in a turbo'd car is....
Mainly to eliminate the large mass of potential boost leaks. and it is a waste of space.


Other than that leave the line alone with the exception of putting a checkvalve before the HVAC.

 

In cruise the thing has the ability to pull as much throttle as it wants. But since it can only pull enough throttle to the point it looses vac you probably wont be making it up any hills...

Im not sure you catch my drift on the vac reserve canister. Im talking about the small 'orb of death' that is down inside the fender that stores a small reserve of vaccume. Not the big ugly coffee can looking piece of emissions garbage that fills up half the engine bay, grab that thing and throw it as far as possible!

 

I know your talking about the globe....get rid of it....his turbo kit without the globe will be fine trust me I had the exact kit on my car.

Best point of all....what is the fun in going up a hill with the cruise control on?

The whole turbo on a V8 thing pretty much throws that out the window, mashing the pedal down and roasting tires up a hill....that's priceless.


With all of the vacuum line associated with the globe, it is not worth the headache of tracing down vacuum leaks that really don't need to exhist

 

A single line going to a little ball hidden within the fender. Not really a complicated or ugly looking system...

Im sure not everyone likes to cruise a longazz trip roasting the tires up every little hill on the road... Some people like to set the cruise and relax for the trip!

It would kind of suck if your going up a very long gradual slope and the cruise is pulling just enough throttle to get you into the boost then after a second falls flat on its face because of no vac. Then the throttle blades close, the car has slowed down a bit then the bloody cruise mashes the gas and repeats the cycle. Theirs been a few stories of that happening floating around here!


Also im sure its possible to stab the brakes in an emergency when your pulling some boost, before their is enough vac to properly operate the booster. Its probably unlikely, but im sure its still possible!


For what its worth just keep the dang thing. One small vac line is not the end of the world!

 

I don't ever take my car on looooong boring cruises. I dont need the mileage on it and its not the best on gas. I think I'll just dump the cruise control.

 

So basically you guys are telling him to get rid of his cruise controll and charcol canister. What about us who want them .

 

as the manifold vacuum decreases the cruise control will stop opening the throttle with a few inchs of vacuum still in the manifold, it will never boost because the cruise control will reduce the throttle position, maintaining a vacuum in the intake manifold. The cruise control is vacuum operated, so as the vacuum gets too low to hold the throttle open, the throttle will begin to close. All of this happens fairly smoothly. The crappy part about 3rd gen cruise control is the crappy electronic controler that monitors speed and opens the vacuum solenoid accordingly. It acts like it has no PID control and a simple 5mph hysterisis switch (I never looked into the circuitry of the box).

From experience, the cruise control works exactly the same as without a turbo.

 

^^^

From what other memebers have posted the problem is that when it regains vac it will open the throttle way too much and loose vac and close the throttle, regain vac open the throttle wide open again then loose vac and slam the throttle shut. then just conitnue the cycle till you either shut it off or get whiplash! Haha, catch my drift? Other members have had some serious issues with the cruise doing this, not just with forced induction but big cams also!


But, if the cruise doesnt have to pull much throttle to keep the set speed all of this is not a problem. Just dont try to set the cruise @ 100mph!