Easy wastegate line question

[S13Koop]

Just went with a FMIC, where does my wastegate line connect to now? Do I T it off something?
tia

[g6civcx]

There should be a nipple on the intercooler piping for the wastegate line. If your kit is specifically for an SR, there should be one. Look for it. It may be hidden somewhere.

If your kit is universal, you'll have to fabricate and tap into the line.

[S13Koop]

I have the Hybrid kit hot pipe only has one other outlet (pic here (http://nissaninfiniticlub.net/photopost/data/500/65IMG_1035-med.jpg)
not my kit, but similar

[g6civcx]

The cold pipe nipple is for the idle air injection. The flange on the hot pipe is for the BOV.

[NemeGuero]

actually, the cold pipe nipple is NOT for the wastegate.

The wastegate needs to draw from the charged pipe.. or the compressor housing. Find or make one.

[S13Koop]

strange, i thought that nipple connects to that pipe that leads under the intake manifold.
edit, ok thats what I thought, I need to drill, tap, and install a nipple for my WG

[NemeGuero]

You are correct, the nipple on the cold pipe does go to the pipe under the intake manifold. (IACV)

[g6civcx]

Are you absolutely sure?

The wastegate gets its signal from the nipple on the intercooler piping. The Apexi boost controller stepping motors go in between the IC piping and the wastegate actuator.
The wastegate needs a pressure signal to activate. Meaning, it needs pressure to push the diaphram inside the actuator in order to open the wastegate valve thus regulating boost. The intake pipe is VACUUM. You will need to hook up the wastegate somewhere in the intercooler piping. If not you can T it from your BOV line. Best way to do it is after the intercooler before the intake manifold.

The turbo's wastegate vacuum runs from the wastegate to a nipple that is on the stock intercooler piping. Located on the cold pipe. If you do not have stock piping then have it routed to some place on the cold pipe between the intercooler and the throttle body. It may be able to be tapped into other vacuums, but im not sure which (possible hotpipe).

You can see it in this picture below. This is how the factory routes the wastegate vacuum line. Follow the blue line to that nipple there on the cold pipe (car has stock sidemount IC).

http://g6civcx.angryhosting.com/S13/noturbo.JPG


It's also said that "The wastegate gets it's signal off of the charge piping (aka Intercooler Piping). The stock piping has has a nipple on the cold side for the wastegate. Blitz and HKS front mount kits have a nipple on the hot side, and GReddy or custom intercooler kit will need to have a nipple welded in on the hotpipe (or somewhere else on the charge piping)."

http://www.sillbeer.com/vaccum.php

Please please tell me why it's better to run that vacuum line on the hot pipe because the picture is how I am running it now, and that's how it was on the front clip. If I need to change my vacuum line to the hot pipe, please let me know why and I'll have it moved. It's running perfectly right now, and I also had 2 shops look over it.

Thanks for the help.

[Angel]

Or you could just grab a reference off the intake manifold and be done with it. No need to make things more difficult.

[NemeGuero]

If you have more than 1 nipple on the cold pipe, then its fine to have the wastegate vacuum line there.

The wastegate vacuum line needs to be in the piping AFTER the turbo.

The reason he says its better to have it after the intercooler is that some intercoolers have pressure drops across them slightly altering the pressure sent to the wastegate.

The closer to the throttle body, the more it is related to the pressure actually entering the engine.

Its a slight discrepency.

But it appears that they didn't leave him enough nipples on his piping for all the lines he needed. Mine is on the compressor housing itself but I'm KA.

So to answer your question, anywhere on the IC piping is still "charged."

[NemeGuero]

Or you could just grab a reference off the intake manifold and be done with it. No need to make things more difficult.

NO! You can't use a vacuum source from the intake manifold. Once the throttle plate is closed, you won't be reading pressure anymore.

[Angel]

NO! You can't use a vacuum source from the intake manifold. Once the throttle plate is closed, you won't be reading pressure anymore.


WRONG!. Don't tell my car that, or the hundreds if not thousands of cars running around that way. Plus there is at least one source on the sr20 that is on the tb that only sees pressure and not vac. I am very curious to read your reasoning as to why that's a NO! Many ways to skin a cat. Closer to the source (comp housing, hot pipe) would have the wg opening earlier relatively speaking and not taking into account the pressure drop through the ic core, versus post ic or intake mani giving a little more boost for the opposite reasons.

[Angel]

NO! You can't use a vacuum source from the intake manifold. Once the throttle plate is closed, you won't be reading pressure anymore.

Nor will you be making boost anymore....

forgot to write that earlier.

[S13Koop]

One last dumb question!If the BOV goes to that side of the hot pipe, where does the other end go to?

[shift_knob]

On my S13 SR's throttle body there is a port just before the throttle plate and its ported into a nipple just underneath the TB. On the heavythrottle walkthrough it says to block off this port. I have thought about using this for my wastegate reference, but it seems like it might be an inaccurate source due to possible venturi effects through the TB, or vaccum on part throttle. I don't know how many of you guys were exposed to carburetors, but ports are placed in stages relating to the position of the throttle plates and are exposed to different levels of vaccum. Am I overthinking this? Is anyone using this port for their wastegate? Someone please shine some light on this nipple.

Edit - BOV is connected to the hotpipe using a flange. The vaccum hose nipple goes to manifold vaccum - tee into the fuel pressure regulator.

[Angel]

On my S13 SR's throttle body there is a port just before the throttle plate and its ported into a nipple just underneath the TB. On the heavythrottle walkthrough it says to block off this port. I have thought about using this for my wastegate reference, but it seems like it might be an inaccurate source due to possible venturi effects through the TB, or vaccum on part throttle. I don't know how many of you guys were exposed to carburetors, but ports are placed in stages relating to the position of the throttle plates and are exposed to different levels of vaccum. Am I overthinking this? Is anyone using this port for their wastegate? Someone please shine some light on this nipple.

Edit - BOV is connected to the hotpipe using a flange. The vaccum hose nipple goes to manifold vaccum - tee into the fuel pressure regulator.

I'm using the port on the bottom of the tb before the plate on mine. Works fine, I have stable and quick boost response.

[NemeGuero]

Nor will you be making boost anymore....

forgot to write that earlier.

But you will feel vacuum and not boost pressure.

As long as the source is BEFORE the throttle plate you can use it. Otherwise, don't.

If you don't understand why, read Corkey Bell.

[g6civcx]

Edit - BOV is connected to the hotpipe using a flange. The vaccum hose nipple goes to manifold vaccum - tee into the fuel pressure regulator.

Oh no no. The BOV vacuum is on the right side of the TB. It goes straight to the BOV. Doesn't tee off with anything.

The vacuum lines are simple: 3 lines start at the throttle body. The bottom one goes to the canister, block it off unless you are using the canister. The larger one on top runs to the bypass valve (BOV), there should be no tee's or branches - go directly to the BOV. The smaller top line splits to the fuel pressure regulator, and runs across the front of the engine to your boost gauge and/or the boost pressure port on your boost controller.

Hope that clears it up.

[g6civcx]

If you have more than 1 nipple on the cold pipe, then its fine to have the wastegate vacuum line there.

The wastegate vacuum line needs to be in the piping AFTER the turbo.

The reason he says its better to have it after the intercooler is that some intercoolers have pressure drops across them slightly altering the pressure sent to the wastegate.

The closer to the throttle body, the more it is related to the pressure actually entering the engine.

Its a slight discrepency.

But it appears that they didn't leave him enough nipples on his piping for all the lines he needed. Mine is on the compressor housing itself but I'm KA.

So to answer your question, anywhere on the IC piping is still "charged."


Okay, so the short version is anywhere between the turbo and the throttle body is acceptable, and being closer to the throttle body is better, but if you have plumbing issues it's still acceptable to go from the hot pipe.

That clears it up. Thanks.

[NemeGuero]

I'm feeling nice.. so here is why you don't put it AFTER the throttle plate:

http://www.holset.co.uk/files/2_5_1_2-wastegate.php
http://auto.howstuffworks.com/turbo6.htm

Or the cliff notes version:
"The wastegate bypasses exhaust gas around the turbine using a valve in the turbine inlet controlled by compressor outlet pressure. This serves to limit turbocharger speed at high engine speeds and loads. In doing this, it reduces the boost pressure attained at full speed full load."

After the throttle plate, you don't experience proper compressor outlet pressure.

Okay, so the short version is anywhere between the turbo and the throttle body is acceptable, and being closer to the throttle body is better, but if you have plumbing issues it's still acceptable to go from the hot pipe.

That clears it up. Thanks.
Yes, correct.

[g6civcx]

I'm feeling nice.. so here is why you don't put it AFTER the throttle plate:

http://www.holset.co.uk/files/2_5_1_2-wastegate.php
http://auto.howstuffworks.com/turbo6.htm

Or the cliff notes version:
"The wastegate bypasses exhaust gas around the turbine using a valve in the turbine inlet controlled by compressor outlet pressure. This serves to limit turbocharger speed at high engine speeds and loads. In doing this, it reduces the boost pressure attained at full speed full load."

After the throttle plate, you don't experience proper compressor outlet pressure.


That makes perfect sense. The pressure is affected by throttle position if you hook it up after the throttle plate, i.e. the plate closes and blocks off pressure from the compressor outlet.

[sean350z]

just put it on the hotpipe :)

[S13Koop]

just put it on the hotpipe :)
I am :D
and here I thought this was an easy question.

[NemeGuero]

Also, the reason it is on the cold pipe on stock SR is because it IS a side mount. This means you only need a short vacuum line to reach the wastegate.

While with a front mount, you'd have to run a line all the way across the bay to the cold pipe.

Shorter vacuum lines are better.

[Angel]

But you will feel vacuum and not boost pressure.

As long as the source is BEFORE the throttle plate you can use it. Otherwise, don't.

If you don't understand why, read Corkey Bell.


Haha, read corkey bell.... He may even teach me how to limit my boost via exhaust back pressure, intake restrictions, or maybe a pop off valve... You still aren't explaining the bad that will result. Tell me what will happen, I know how it all works, even without consulting a website or a book. I have built, tuned and owned cars that make over 300rwhp per liter good sir, I didn't just stumble into this. Tell what bad side effect I am experiencing in my car right now.... I simply must know. The 2 links you provided did nothing but explain in the most simplistic way the basic function and reasoning behind having a wastegate in the system. Now I am not saying that one way is better or worse, I know the tradeoffs that will normally result from any given method. Also worth note, I currently run the US operations for a company that makes bovs, recirc valves, actuators, boost controllers, intercoolers etc. etc. so I am immersed in this stuff daily. How many cars are out there right now running a silicon hose from the intake manifold to the wastegate port?? What's gonna happen when you close the throttle and your refference is behind the plate and sees vac? Keeping in mind that you are closing the plate and will either have a bypass valve to open and relieve pressure or if you don't run one, nice shock waves bouncing back as a matter of choice.

I'm not trying to be an ass, but if you are going to tell me I'm wrong, not "that's not ideal" or "that's not how most sr's are setup" then you need to explain it to me. I may not agree with you or your sources for that matter, but that's because I am basing my stance on not only my understanding of the systems involved as a whole but also on a large amount of observed real world experience.

[S14DB]

What about the Vac line on external WG's? I've heard arguments both ways whether to have it hooked up to the intake pipe or to have it open to the atmosphere.

[NemeGuero]

I don't need to explain anything to you.
If you look closely, the vacuum source under the throttle body is still BEFORE the throttle plate.

If "I've heard" and "I've done it this way without problems for this long" works for you, that's fine. I however would like things to function the way they were designed to.

Boost pressure is boost pressure. If you want it accurate you read from what feels boost.

I don't really care what would happen if you sourced it from an incorrect location. Put your FPR vacuum in front of the throttle plate and tell me what bad happens. Not gonna do it, are you?

I'm using an external wastegate and my source is the compressor housing. The only external wastegates that I've heard you leave the nipple open is the wastegates that have 2 vacuum nipples. In which case, one of them is left open. I don't see how leaving the vacuum open to atmosphere would be able to read the pressure, and then know when to open without at least one source.

Have a nice day.
And please stop congesting this guy's thread. If you want to talk with me personally, PM me and we can continue. However, this guys question was answered and this thread doesn't need to continue.

Thanks
-Evan

[S14DB]

I'm using an external wastegate and my source is the compressor housing. The only external wastegates that I've heard you leave the nipple open is the wastegates that have 2 vacuum nipples. In which case, one of them is left open. I don't see how leaving the vacuum open to atmosphere would be able to read the pressure, and then know when to open without at least one source.
I was talking about the WG's with to nipples. One Pressure, one Vac(reference). Some people say to hook up the reference line to the intake pipe and some say atmosphere to get better results.

[Angel]

S14DB- No real difference either way in terms of function, mainly to keep crap out of the other port

NemeGuero-I don't need to explain anything to you.
If you look closely, the vacuum source under the throttle body is still BEFORE the throttle plate. * you need to be prepared to if you are going to tell people that they are wrong*

If "I've heard" and "I've done it this way without problems for this long" works for you, that's fine. I however would like things to function the way they were designed to. *It works under far more extreme conditions than an sr running a T2 turbo and maybe 14-18 psi, obsevred data is far more valuable than your superstitions. And as far as the intended design, how many different layouts do you think can be observed across different models, different manufacturers and in the aftermarket? Not to mention end user setups. Oem is not the only way to go.*

Boost pressure is boost pressure. If you want it accurate you read from what feels boost.*the intake mani "feels" boost as well*

I don't really care what would happen if you sourced it from an incorrect location. Put your FPR vacuum in front of the throttle plate and tell me what bad happens. Not gonna do it, are you? * "incorrect", not quite and you haven't proven it to be. Of course I wouldn't source it from before the plate, it NEEDS both vac and press, different animal altogether*

I'm using an external wastegate and my source is the compressor housing. The only external wastegates that I've heard you leave the nipple open is the wastegates that have 2 vacuum nipples. In which case, one of them is left open. I don't see how leaving the vacuum open to atmosphere would be able to read the pressure, and then know when to open without at least one source.

Have a nice day.
And please stop congesting this guy's thread. If you want to talk with me personally, PM me and we can continue. However, this guys question was answered and this thread doesn't need to continue.* I hope you have a nice one too. I have no desire nor reason to talk with you directly at this time, you called bs on something I wrote, plain and simple, and I was looking for you to elaborate as to why. Simple really.*

Thanks
-Evan

*Basically, as stated, I know which ways will and won't work, and why. You claim that my statement was incorrect and then give 2 links that show rudementary turbo terminology to prove your point... didn't work. No matter what, to disprove what I wrote you would have to provide proof that it doesn't work or your just blowing hot air.

Regards,

Angel *

[NemeGuero]

I was talking about the WG's with to nipples. One Pressure, one Vac(reference). Some people say to hook up the reference line to the intake pipe and some say atmosphere to get better results.

Right, the reference line is there because there IS a difference between vacuum behind the throttle plate and boost pressure in front of it. Otherwise it'd be pointless to have 2 vacuum lines. I haven't dealt with them so I don't really know why leaving it open to atmosphere would be better. Probably for calibration purposes.


Angel:
And please stop congesting this guy's thread. If you want to talk with me personally, PM me and we can continue. However, this guys question was answered and this thread doesn't need to continue.

Thanks
-Evan

Read much??

Or are you trying to show off?

Private message me if you want to continue arguing. There is a little button when you click on my username that gives you that option.

[Angel]

I was talking about the WG's with to nipples. One Pressure, one Vac(reference). Some people say to hook up the reference line to the intake pipe and some say atmosphere to get better results.


Supposedly a small advantage in spool because of the vac helping to keep the wg closed, but in reality, next to no difference since most properly sized intakes won't have much vac.

** This is actually wrong. It would be the other way around, in my haste to make the post and leave I had it backwards. So in other words, if anything it will help to open the gate.....**

[S14DB]

Right, the reference line is there because there IS a difference between vacuum behind the throttle plate and boost pressure in front of it. Otherwise it'd be pointless to have 2 vacuum lines. I haven't dealt with them so I don't really know why leaving it open to atmosphere would be better. Probably for calibration purposes.
:wtf: Did you just try to make your point with my totally unrelated question to your point?