Lets be clear first off, a Tial wastegate should never see vacuum. I only added it in the title to help people searching in the future.

So this thread might not really go anywhere...Seems there is only 4-5 of us that keep this place alive. However I'm trying to decide where I want to get my source from for the wastegate. From countless searching I've come with the following notes:

1. Quote:

   Originally Posted by Tony the Tiger

   Most wastegates have slight leakage at the stem of the valve either from its design or regular wear and tear. Having it under vacuum will actually pull exhaust gases into the engine, as you can see traces of carbon at the vacuum lines over a period of time.
   
   The most ideal spot to take the pressure source is after the intercooler and right before the throttlebody for maximum spool.
   
   If the turbo setup is prone to spiking, then taking it off the compressor housing is more ideal.
2. A lot of people suggest running it off the compressor housing however that has a lot of turbulence and I question how ideal that could be.
3. 9 second GM turbo guy said the following: "I ran mine from the turbo housing and was getting about 9#to the engine with a 10 spring so I added a port after my intercooler but before the throttle body.and that got me back to 10 lbs."
4. Just about everyone with success has run their source AFTER the intercooler
5. I spoke with Tial about this very issue and below is their response to my question here and they also directly comment on Tony's post above.....

“Most wastegates have slight leakage at the stem of the valve either from its design or regular wear and tear. Having it under vacuum will actually pull exhaust gases into the engine, as you can see traces of carbon at the vacuum lines over a period of time. This statement is 100% accurate. No external WG, and no TiAL WG design of any type, is intended to be connected to negative manifold pressure under any circumstance. As noted, not only will the WG not function correctly, but you will be ingesting exhaust gas into the intake tract, and eventually, you will cause the diaphragm to fail prematurely.

The most ideal spot to take the pressure source is after the intercooler and right before the throttlebody for maximum spool.

This is somewhat subjective, and would be dependent on the control strategy. We recommend using the boost signal port typically machined into the compressor cover on the turbocharger for the signal, as it's typically located close to the WG anyhow, but more importantly, is not subject to intercooler pressure drop, and serves as a more 'pure' signal. Regardless of where that signal is taken, though, it would have very little or no effect on how quickly the turbocharger responds. And, when all is said and done, the ECU will self-correct for boost pressure versus atmospheric pressure based upon your command anyhow.



But if you are also employing a "dome pressure" sensor into your strategy, you really should pull that signal directly from the turbocharger, as shown in Holley's instructions.

If the turbo setup is prone to spiking, then taking it off the compressor housing is more ideal. “ My question to Tial>>> Is it true that a vacuum port welded into the intake pipe right before the throttle body would be more ideal than the area on the turbo compressor section? I would honestly much rather weld on a bung to the replaceable intake pipe versus the turbo housing, however the vacuum line would be much longer…

If your turbocharger doesn't already have a boost signal port machined into it, you could absolutely weld a small bung into the charge tube, just downstream of the compressor housing, and have the same signal. But in most cases, it's much easier to just remove the housing and drill/tap it for your signal.


The shorter that signal hose or line path is, the more responsive the ECU will be in regards to making changes to boost pressure, as air travels far more slowly than electrons, so the shorter the paths of all of the WG control hoses or lines is what we would always recommend, keeping safety in mind, of course. "

So.....Opinions here?

I was thinking of having a bung welded one in 1 of 2 places, and that is below.

 

Like Tial has already indicated, it doesn't ultimately matter too much. Either location you marked, or of course tapping the housing directly, would work safely and efficiently. I agree with Tial's point about the pressure drop post-intercooler, but again ultimately moot when it comes to results.

I'd just drill the housing and run a thread tapper myself.

Me, Highschooler, JRCivic, DaX, Pepe, Goldie, 93h2beg, AZ Civic... That's basically the whole crew now I think lol

 

Where did Justin go?

 

Justin is Shodan right? He still comes around once in awhile but nowhere near as active as he once was. As far as I'm aware STC is still in business, and I think Shodan is around his mid 40s now.

 

The shodan name was mac i believe. Im on here multiple times a day reading seeing whats new or just to go over stuff.

Me, myself personally, i had my reference off of the compressor housing couple years ago. Due to the turbulence, i never had a steady boost reference. For that spur the moment of trying out a different boost reference. I dont even remember why i even decided to switch at the time anyway, from a vacuum manifold to the compressor housing. Needless to say, while on a tuning session, i reverted by to the vacuum manifold. Due to its erractic behavior.

That being said, if and when i have a diaphram issue, ill just replace it. And continue to run from a vacuum manifold.


Now..., if i had to pick of your locations, i would drill and tap the housing after center punching its location of course

 

For your set up, I recommend right after the Intercooler. I’d be a little worried about drilling into a turbo and tapping it just because of the cost of turbochargers.
I didn’t know that if a wastegate source sees vacuum, it pulls in exhaust. I thought it was more sealed than that, but I’ve used a vacuum manifold before for my turbos and had no issues. I guess it’s kind of like EGR (exhaust gas recirculation) which lots of cars have…
This time, I have a fitting on my Precision turbo as it is new, so I’ll be using that source. Like you said though, it might not see as many PSI per wastegate spring. It also might have more issues with boost spike, but I don’t mind that for myself since I’m using a small turbo.
Sourcing it right near the throttle body would work also, but it could be a tiny bit less responsive than right after the intercooler. But then you’d get the most PSI per wastegate spring.
Really like ChanceEG says and Tial, it doesn’t matter that much, but for convenience I’d do right after the intercooler for your set up.
There’s at least 3 or 4 dozen people who are active in the forced induction sub-forum regularly, just not every day though.
I’ve in the last year turned Honda-tech into a daily thing for a few reasons, but I might get off again when I “finish” my build…I’ve actually met some real people, sold and bought parts/tools, got some good advice, and I think I’ve shared info with new people who need help.
I think he means the guy with the copper/gold colored B18C1 turbo CRX mynameisjustin.
As for that member, I think he stopped getting on here after he “competed” his build, but then updates his thread when he makes other changes to parts/has issues. Which is what I might do also.

 

Ah yeah, that's right.

And I left you off my list, which is unacceptable
Definitely glad you're still around. It's a small subforum here now but it's always nice discussion. It is crazy to think how much forums in general have downsized (or just closed) over the last several years.

 

FB really killed these forums, however it seems impossible to get real info from FB. I posted about my mopar 4 speed and got answers from dumb to normal to ludacis. Guys saying my trans can hold 1000 HP no problem... their buddies car did this and that.

But yea, there is nice discussion here. I may not lways post, but i try to keep up on the builds that are going on.

I just got back from vegas. Did the race car thing there. Drove a porsche GT3 RS on a track for 10 laps. Lots of fun. Makes me really want to buid that kind of track car

 

I lurk. I post occasionally. There's not a lot to post that's new info. And for the most part I don't have time for GD stuff, so much stuff to do.

I'm glad you wrote this up, I have been trying to tell my friend for a couple weeks to change his pressure source on his wastegate from post throttle body to pre-throttle. Maybe this can convince him lol

 

That sounds awesome, I really need to try that sometime when I have cash to spare. The body style of the 80s and 90s Porsches are really cool looking, classic design.

I work a desk job and type 120wpm, so it's easy for me to check the forums a few times during the day and make a couple posts. I actually spend less time here on the weekends because I'm outside doing stuff lol.

And yeah, the one thing we all agree on regardless of anything else is that the WG source shouldn't be post-throttle body or off the intake manifold.

 

Well....lol. I've been running my WG source off the intake manifold on my Civic. Maybe that's not the best practice, but it's worked for me.

And we can't forget about turboLScrx - he's still a regular in here too!

 

I only have time to lurk every now and then, but certainly glad this forum is still around as I've gotten a lot of solid advice from people on here. Maybe someday I'll go back to regularly updating my build thread

 

Idk what this post is about but ive had my wastegate source come from the manifold for yearsssss. Not one issue. I got logs of rock solid boost lines. I probably drive my car the most at wot than anyone here posting.

Im almost postive you have vacuum in the charge pipes under slight load

 

Fugg it, tap your oil drain line for WG source

 

I've ran the vacuum source from either the turbo compressor and I/M...one of the two should work.

 

I think I'm going to meet in the middle and do right after the intercooler on the cold side.

 

Yeah, I'm still around. Just into a few different areas other than cars as of late.. Having a good friend working on the other side of things to get at least a few things working before I call it a wrap. I just realized how long I have been on here. SO, yeah, I'm now like about a handful of people on here left. OG-Triple-Triple.. I'm to a point of just finishing the last of my projects (that I shouldn't have gone so deep into) and just enjoy watching everybody else do dirt.

I mean ****, I was cleaning out my garage to reorganize and I found THIS...



But I digress.. *sigh* Back to the topic at hand..

I would still say to use the Intake manifold as the best vacuum source for the wastegate as opposed to the compressor cover. I've never liked that as a vacuum source, i don't care what the Internet lore suggests.

There's still a sticky up top discussing intake manifold vs. Vacuum block, and IIRC, It still referenced vacuum sources for wastegates

 

It'll be interesting, I'll give ya that much...

 

So go completely against what the manufacturer says you should or shouldn't do.

 

More stable, potentionally better boost reference, with a cheap and easy source to change out vs potentially unstable boost reference.

you be the judge. Try it out and see for yourself. Ive never once had an issue with my diapharm running off the vacuum manifold. When i tried the compressor route, just didnt workout for my setup atleast.

 

I'm also not planning on using the compressor housing nor do I think it's an ideal point. But I also think going against what the manufacturer requires is idiotic.

 

You can go against what a manufacturer wants, it might just not last as long.
Kind of like the coolant to the wastegate- the manufacturer wants it to keep it lasting longer, but you can choose not to use coolant to the wastegate and it will still work for a while.

 

Tial states the coolant to the wastegate is an option. They do not say you can take either positive pressure or vacuum for the wastegate. This is my question about this to Tial and their response below

3.A lot of people incorrectly plumb the external wastegate and give it vacuum when it should see positive boost pressure according to your site. It is my understanding that you can use anywhere from the turbo compressor side to the throttle body. Another more knowledgeable than me person stated the below. “Most wastegates have slight leakage at the stem of the valve either from its design or regular wear and tear. Having it under vacuum will actually pull exhaust gases into the engine, as you can see traces of carbon at the vacuum lines over a period of time.

This statement is 100% accurate. No external WG, and no TiAL WG design of any type, is intended to be connected to negative manifold pressure under any circumstance. As noted, not only will the WG not function correctly, but you will be ingesting exhaust gas into the intake tract, and eventually, you will cause the diaphragm to fail prematurely.

 

I agree, but a wastegate should last for at least 5,000-10,000 miles hooked up to the intake manifold. It might pull in a little exhaust. But it’s not terrible for the engine. There’s something called EGR - exhaust gas recirculation on lots of cars, so a little exhaust won’t hurt the engine.

 

I've known Greg (owner)at TiAL for years. Even he doesn't complete go with that premise. Think about ALL of the Garrett turbochargers that don't have vacuum reference nipples. They know people are running wastegates, and TiAL still works along with Garrett. I mean it's up to you.
I've have these systems since before 1998, and the only time that diagram about using the compressor housing as a boost reference only started coming up around 2009. Next thing you know, people were having boost creep issues. I run Vacuum manifolds with strong boost reference points and the brake booster as the main source of vacuum. NEVER have I run a vacuum line off of the compressor cover. The amount of vacuum is just a bit more inconsistent.

But, again, do as you feel best. I'm not gonna stop you. I'll say this.. you'll be the 1st I've yet to see ever to run a wastegate vacuum off of an intercooler pipe. So, I'll be routing for ya.