Turbo Vacuum lines

[Fox1486]

Changing out the turbos today and i just wanted to know ahead of time where the vacuum lines from the T25 should go on the 16g.

I know the line from the wastegate actuator should transfer other to the other one. But what about the vacuum line that attaches to the T25 near the compressor outlet elbow? I don't believe there is anywhere to hook this on the 16g. I've read on a few other posts that you need to hook the vacuum line to the J-pipe nipple for the correct amount of pressure. I don't have an nipple that comes off the J-pipe I am using since it is aftermarket. However on my hard IC piping that I will be installing, there is a nipple to hook a vacuum line that is close to where the pipe ends and where the SMIC Inlet starts. Is this where that line should go? I wasn't sure since I thought it may be a little too far away from the actual compressor outlet.

It should also be mentioned there is no boost controller setup at this time. Thanks.

 

[kqodprez]

If I'm not mistaken that's the vacuum line that goes to the stock boost controller. I just capped it off.

 

[Fox1486]

I have two lines coming off the stock boost controller. Both can be capped off? What will that do for me running the 16g with stock injectors/pump? I know it only raises psi up 1-2psi if I remember correctly, but will that put me in fuel cut or another damaging situation?

 

[Mr Peepers]

I've never seen a nipple on the LICP near the SMIC to be honest.

You want the pressure source as close to the compressor outlet as possible, but the LICP will work alright IMO if there is a nipple there. Otherwise tap into the aftermarket J-pipe or even the compressor cover(be careful here).

You want the stock BCS setup correct? Everything will be the same as with your t25 but the pressure source(J-pipe or perhaps the LICP instead of the compressor cover). A line from the pressure source to the WGA, then a T off that line leading to the boost control solenoid(BCS). The other side of the BCS will lead into the intake pipe.

Or, you could just run a line directly from the pressure source to WGA although you'll only run 8-10ish psi. I'm not sure what stock boost is with a 2g BCS setup and 16g.

Be sure to install an aftermarket boost gauge to keep an eye on your freshly ported 16g

 

[demografik]

your WGA needs a boost source to function, the nipple on the LICP is fine. bypass the BCS (stock boost controller) by just running a vacuum line from the the WGA to the nipple on the LICP. just pull the lines off the BCS and leave it alone, it needs to stay in the car as it plugs into the harness and will throw a CEL if unplugged.

to run more boost than wastegate pressure, you'll put an MBC in the line from the WGA to the nipple on the LICP. i strongly recommend you don't install an MBC until you upgrade fuel. i wouldn't even get in boost on that turbo until you at least install a better fuel pump and rewire it.

edit: whoops! peepers beat me to it.

 

[Fox1486]

Hmmm. I believe when I installed my Dejon Hard Intake Pipe that I was unable to use one side of the vacuum lines that came off the BCS. I know the other side of the BCS lines has a "T" off on it. One part of the "T" goes to the WGA nipple and the other to a boost source (Jpipe/compressor housing). Strange enough the J-pipe does not have a nipple to tap into. I'll go get some pics of this piping setup in a little bit.

As far as running 8-10psi by hooking the WGA directly to the nipple on the LICP, that would be okay for a testing the car once it's put back together. I agree with you demo, I am not going to up the boost until I get some fuel upgrades. Although searching around I find that this won't be a problem in the 12-15psi range. Obviously anything above that fuel is a necessity.

I'll try to use MSPaint in a second in order to make sure I know my options (inspired by Mr. Peepers earlier porting graphics )

 

[Fox1486]

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Is this right? Also the "T" goes to the WGA but what about the other end?

 

[wishnfor4g63T]

I'm pretty sure i know what your talking about on the T-25 right next to the waste gate it has a T. You can just cap it off on the t-25. As for the 16g you won't need to T it. Just run a line from the pipeing like you have to the stock bcs then to the wastegate no problem.

You can build a Lowes or Home Depot boost controller for around 20$ or under if you have the parts. a couple ball bearings and springs out of a pen. it's a lil bit of a task but it gets the job done. Then you won't have to worry about anything over 12 psi when you turn it.

I did this install about 5 months ago. go to www.vfaq.com and print the 16g install and go by it. You won't regret it!

 

[Fox1486]

So I'm guessing it should be this then?

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[Mr Peepers]

The stock setup is a bleeder style, but almost reverse.

The default position of the solenoid is closed. When the car is ON the solenoid is opened and air can freely pass between the pressure source and nipple on the intake pipe. When you start to hit boost it stays open, bleeding off pressure before it can act upon the WGA. Once stock boost is achieved, the BCS will close; allowing the WGA to be pressurized and open the WG. It will continue to open/close/open/close to maintain a steady boost pressure.

More info here: http://www.dsmtuners.com/forums/new...l-turbosmart-tee-style-bleeder-style-mbc.html

 

[Fox1486]

I did this:

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almost WOT it held at 10 maybe a little higher.

 

[Mr Peepers]

You want the other side of the BCS going to the intake tube since it's essentially a boost leak.

 

[Fox1486]

Its a Dejon Hard Intake.....there is no nipple for a vacuum line.

The following picture (yes this is an actual picture, my camera is -37 Megapixels ) is the stock 2g vacuum setup. This is pretty much what Mr. Peepers posted above.

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Now the next picture is currently where I'm at:

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Now I do not have the resources right now to go out and get a MBC. I was reading about the taboo diagram, but that shows tapping into the BOV line which I thought was a big no-no .

I know the BCS has to be plugged in, in order not to throw a CEL. Is there a way to bypass this and just connect one line from the LICP to the WGA and call it good? Now Mr. Peepers, you're saying that the actual resistrictor is inside the vacuum hose? I was always under the impression in order to raise boost 1-2psi without an MBC is to disconnect all vacuum lines from the BCS entirely. 1-2psi is not going to kill me without upgraded fuel system (I don't think), but my main concern is not creating new boost leaks as you have stated above.

I drove the car into school today and noticed it takes a while for boost to build. I know this is a larger turbo but it seems like around 2,800rpm is still trying to build and doesn't really "kick" when in boost. I'm assuming this could be due to boost leaks

Also the other "Mystery Line" labeled above......where does that lead to and would that cause boost leaks?

 

[Boost92awd]

http://www.dsmtuners.com/forums/art...-speed-shop-vacuum-diagram-removal-1g-2g.html

 

[Fox1486]

Yes I've seen that. But it does not help without an MBC. Plus they say to "T" off into the BOV line, which I've read takes the pressure away from letting the BOV open properly.

 

[Mr Peepers]

As long as the BCS is still plugged in (the electrical plug), you won't throw a CEL. Then you can run a line directly from the pressure source (LICP in your case) to the WGA. Worry more about boost later when you have the fuel system and tuning to handle it.

The mystery line should be two mystery lines/fittings, unless you removed emissions. With removed emissions, that line would go to your valve cover breather. If you still have emissions, you should have another intake fitting that leads to a solenoid for the charcoal canister as well.

 

[demografik]

the restrictor is actually inside one of the ports on the BCS. there's no reason to keep the BCS in the loop, that's why dejon didn't put the nipple there. you can pull the hoses off of it and be fine. the reason you need to leave it in the car is because it plugs into the harness and will throw a CEL if you unplug it there. do it like you did in the image below.

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that extra line you're seeing is going to be coming off the valve cover. the purpose is to relieve excess crankcase pressure. since you don't have a nipple for it on your intake pipe, you have 2 options. put a small breather filter on the nipple at the valve cover or install a catch can and run the line to that.

edit: damnit, you beat me to it again.

 

[Mr Peepers]

If you use a catch can, route it back into the intake pipe through a closed system. During idle and cruise, the PCV valve and sucks air in through the crankcase from the breather. With the breather VTA, it will suck in unmetered air. Do not use a breather filter.

the restrictor is actually inside one of the ports on the BCS.

In the other link I was seeing that there was also a restrictor in one of the vacuum lines from the T. I've never had the luxury of dissecting the stock BCS setup on a 1g or 2g(if any different as far as restrictors go so I'm not 100% sure. You are right about the restrictor in the BCS being removed to increase boost, not the T. Either way I need sleep

 

[Fox1486]

Awesome. You guys always come through for me. Ill take the BCS out of the vacuum loop, but keep it "plugged in".

I know that I have the vacuum line off the valve cover going to a catchcan. I believe this is the other line that peepers says goes to the charcoal canister. Ill have to look into it a little more. I would like to keep "emissions" if it will help me pass inspection and not throw a CEL. I just was unsure if the line was left open if it would create some sort of boost leak.

 

[demografik]

If you use a catch can, route it back into the intake pipe through a closed system. During idle and cruise, the PCV valve and sucks air in through the crankcase from the breather. With the breather VTA, it will suck in unmetered air. Do not use a breather filter.

this is widely preached but with my breather filter off that nipple still sees positive pressure at idle, i do have quite a bit of blow-by though. granted there's nothing scientific about my method so i'm not going to claim it's accurate. only that it's good enough for me

 

[Fox1486]

Awesome. You guys always come through for me. Ill take the BCS out of the vacuum loop, but keep it "plugged in".

I know that I have the vacuum line off the valve cover going to a catchcan. I believe this is the other line that peepers says goes to the charcoal canister. Ill have to look into it a little more. I would like to keep "emissions" if it will help me pass inspection and not throw a CEL. I just was unsure if the line was left open if it would create some sort of boost leak.



Is there any other place I can reroute the exit end of the catch can to since I don't have a location to route it into the intake pipe?

 

[demografik]

most people just let it dump into the engine bay. if you're a stickler, you'd have to tap the intake pipe and put in a nipple.

 

[Fox1486]

I'll just leave the exit of the catch can open in the engine bay.

Now do I need to cap off the holes on the BCS, or can I leave the nipples that come off it open if I bypass the BCS?

 

[MrBoxx]

All the lovely MS Paint diagrams.... very nice.

I'll just leave the exit of the catch can open in the engine bay.

In that case, why bother using a catch can in the first place? Why not just have the hose stick out the bottom of the car? The system works best in a closed state: The ECU is counting on that air to be there. Recirculate it, use an inline fuel filter (Fram G2-style), or leave it alone.

Now do I need to cap off the holes on the BCS, or can I leave the nipples that come off it open if I bypass the BCS?

You can leave them uncapped, or you can cap them, it's up to you. At this point, the BCS is a vestigial organ.

 

[KrazyRob]

I know this is an old tread. But I have a similar situation I am swapping out the t25 for a evo III 16g.. i do not have a vacuum line nipple on my jpipe or on my licp. Where is the best place to hook a vaccum line to my wastegate? Right now i have it hooked to my stock 2g air intake tunnel using all the availble ports like stock.. the only difference is that im not using the "T" at the wastegate to feed the T25 as the 16g doesnt have a nipple, i have a vacuum line going from the sbc straight to the wastegate.. will this work? Im getting ready for smog here in CA and trying to go stock as much as i can for the test..

I also have fuel cut.. but i found a huge leak at the bottom of my TB housing gasket.. going to fix the leak today and see if that helps the fuel cut...