External wastegate w/ manual boost controller
 

Tial wastegate- "use 1/4" minimum vac line from pressure source to wastegate."
No problem. I sourced a 1/4" barb and 1/4 vac line.
Problem-- I go to tee in my turbosmart boost tee, and the barbs are 1/8"
I know I can control boost with different springs in the wastegate but I wanted quicker spool and more precise control with the MBC.
Will it work to reduce the vac line down to 1/8" right at the boost controller?

yes

This does not work. The EWG needs to get ALLTHEPRESSURE. Running a 1/4" line from comp housing directly to the WG is the only way I can get it to not creep. Is there any way I can control boost (besides swapping springs) and gain some spool? Different mbc? Ebc?

Check out the picture of my turbosmart mbc. I know its supposed to restrict pressure that the gate sees but damn that hole is tiny


Attachment 177002

That's weird because I've been running external gates on dozens of different cars, turbos, setups and none needed a bigger line or anything special

Ill try it without the "ball and spring" but I think its still just too much of a restriction in the line

Small lines only restrict pressure when you're trying to flow a lot of air through it. The EWG itself should be sealed, so the only flow should be the gas necessary to move the diaphragm. That would make it lazy to respond, but shouldn't cause steady state boost creep. Does the MBC leak? If so, then that would increase the pressure flow.

Why are you using an MBC on an EWG anyway? The main reason I usually see people running MBC instead of EBC is because they don't want the complexity of setting up the PID parameters, but EWGs are so much better at regulating boost that they're really easy to set up. Why not just run EBC?

--Ian

My external gate installation was to cure some nasty boost creep on my old FM setup. I plan on using EBC in the future, but first I need to make sure this setup is capable of controlling boost without issue. So for "testing purposes only" I want to use a mbc. In short-- its a very simple, easy, mechanical way to get the car back on the road for now

I take that back, it wasn't creeping with the mbc. It just wasn't opening. Or it would open barely. It would flutter really bad. Not like they flutter on subarus either. It was really fast. Barely on the throttle and it would hit 10psi+

You said when you hooked up a direct 1/4" hose it was capable, right? That means the problem is your MBC. Does that not qualify for "getting the car back on the road"? What's the problem?

Is it that the EWG spring gives you too-high of a base pressure? An MBC can't fix that, all it does is restrict flow and potentially bleed air in order to reduce the pressure at the diaphragm. To lower the base pressure, you would need to do the opposite -- increase the pressure at the diaphragm above that available in the manifold, and an MBC can't do that (nor can EBC for that matter). If the spring base pressure is too high, you need to swap the spring. I haven't done it on a Tial, but on my TurboSmart valve the springs are cheap and it's a 30 minute job.

--Ian

Lol i understand how everything works dont worry. I have all the springs that came with the ewg when I bought it (new) a few weeks ago.

I reposted in my thread to show that the setup in the first post does not work. The mbc is too restrictive. So my options are

1) run no boost controller and use only the springs to control boost
2) try a different mbc with 1/4" barbs that might not be too restrictive
3) ebc

run just a vacuum line to the ewg without anything else. if you still have a problem then it's your ewg
2 minutes to diagnose