With the exception of pulling my boost signal from the last charge section, post IC & just before my TB...I'd been running the external WG control configuration (NC) shown below (left). But I recently changed to the internal WG (NO) config shown below (right) d/t it's greater simplicity, i.e. It eliminates two hoses and a "T". I'm a big proponent of "K.I.S.S." to minimize potential failures. Though the diag indicates that the NC is for external WG, which I have, and the NO config is for an internal WG config.; both work fine on my external WG setup.

Questions:

1. Other than the obvious fact that an internal WG does not have a top nipple...is there any other reason that the NC s/b run on an external, & the NO run on internal WGs?
2. For anyone who's run both...what are the pros / cons of each config.?

As I said I prefer the simplicity of the NO config, but both work fine on my external WG.
v
v

- Left: NC WG Control
- Right: NO WG Control

 

Found this helpful info

Boost Control Plumbing - Get It Right, Save Money

https://www.onpointdyno.com/boost-co...ht-save-money/

Excerpt:
"The tee method is the preferred method to plumb external wastegates, and while I haven’t tested the response and characteristics of the two boost control methods back to back on the same setup, ...to show the differences, if any. In my experience, the simple method works just fine in most cases, and may be preferred if you value simplicity (I know I do)."

 

I've run the simple one line method a lot and it worked fine .Haven't tried it the other way.
These days I run a 4 port valve and that works well also... main reason is that allows me to run a small spring in the wastegate. If there is a line failure I believe it wont overboost nearly as much that way , although I haven't tested this.
The reason you can run such a small spring is that the top port gets fed boost (from about 1psi) as the turbo is spooling up which helps hold the WG shut.

 

Thanks, Brett, As quoted above and at another site I read...the dual line control model is preferred for external WGs... particularly on systems w/ high back-pressure. But I'd bet at the boost & back-pressure levels we're running on our systems...either is fine. Both configs c/b wired to revert to WG spring pressure as a failsafe, i.e. on de-energizing of the solenoid. The NO config is just simpler.

So, I'll run this config a while and compare functionality and boost profiles from both configs... If there are no discernible differences... I'll continue to run the simpler config as I prefer having the solenoid mounted high in the relative security of the engine bay, and the simplicity of only needing to run & protect a single line into the undercarriage environment near the turbine & DP heat.

 

Yeah ...that reminds me of the other reason I like having a small WG spring.

 

Yep...small WG spring for safety... and the valet..., then govern higher boost profiles via EBC.

 

That's the way I do it too. If I want slower response time and only 6psi I just turn off EBC. Turn it on and we rocking 9psi and noticeable spool-up difference.

 

Yeah...I'm actually wanting to fine tune my "throttle angle to load" response thru the 3 - 4.5k rpm range to more finely control boost/torque onset. Right now it's a bit ...aggressive. During normal driving I love the torque response, but want more control w/in that range.

I could reduce "START / SET GAIN" on my EBC, which controls when my WG begins to crack open, but then I sacrifice spool-up when I go WOT. Conversely, tuning the throttle angle gets me finer control thru boost onset for the normal daily...w/out sacrificing spool-up on WOT.

 

Update:

Recall a while back I'd planned to use SteelStik to create a "band" around the curved end of the below charge section to achieve a more reliable seal. Well... SteelStik didn't work. It didn't form & adhere to the section as I thought.

So, I got another idea for a interim fix ......a modified version of a vid I saw online...

- installed a 1" rubber "band" under the coupler (on the end farthest from the TB)
- installed the coupler as normal (over the 1" band)
- installed a ~3" section of heat shrink over the coupler
- installed the clamps as normal ...(w/ the outer clamp over & sealing the band underneath.)
- finally, the heat shrink is sealed via the outer clamp and a zip tie.

Objective here is simply to implement a reliable fix to avoid the nuisance of recurring actual or imagined leaks here ...until I determine if I need / want to modify the charge section itself.

The reinforced coupler is sealing like a champ so far.
v
v


Difficult curved section to seal at the TB
v

1" wide band & heat shrink...
v

Reinforced coupler completed.
v

Reinforced coupler completed.
v

 

You wouldn't be saying that if knew how fragile these things are under boost!

 

Yeah ... I knew you were joking ...... with a hint of baiting !

 

I think the smartest thing to do is keep turning it up until the engine blows, then on the rebuild just set the boost 2 psi lower than the blow point and you should be good to go

 

Team, Appreciate your sharing my joy in my project progress ..., even if a bit devilishly.

Me thinks too many succumb to fatal Icarus syndrome...
v

Icarus..... boosted w/ excitement d/t his new wings..... couldn't resist the temptation of flying too close to the sun...

 

Yes, most logical..........

 

On holiday w/fam in Cancun atm...


.

 

Update:

I’ve been experiencing a boost drop at ~6k rpm. Not a gradual decline normally seen w/ an overwhelmed WG (edit; "turbine", not WG), but an incremental drop from 10 to ~ 5psi. I’d experienced this to a lesser degree while running the NC config, but nothing like I’m seeing now. It happens intermittently… and I’ve not been able to identify a trigger.

The issue doesn’t appear to be SSV related as my SSV is set to open ~ 3k rpm and h/b cleaned. So, my thoughts at this point are to investigate:
- all WG plumbed vac lines
- Will likely revert back to the NC WG config …to eliminate any potential contribution d/t the recent WG control model change.
- If still not resolved…I’ll investigate my APV, i.e. vac line, solenoid, & switch, which opens at ~6k rpm. This c/b the cause as it opens at the same rpm as the issue and has never been cleaned. That said… my intake runs very clean, i.e. I get virtually zero oil in my catch can, intake, etc.

Thoughts?

Clearly blue line below is displaying the issue....

 

Overwhelmed wastegate would result in boost creep. Restricted exhaust/choked turbine would see a gradual decrease. It looks to me like your boost controller is turning off as I assume your wastegate pressure is 5 psi? How do you control boost?

 

Stroker, Thanks. My mistake...you're right re: boost creep, not drop on an overwhelmed WG.

Hmm... hadn't considered the possibility of my EBC turning off. Generally, not watching the EBC when driving as it's mounted low in the ashtray. I'll take a spin and glance at it. I am running a 6# WG spring. I'm controlling boost via the WG (NO) config shown below. I'd recently changed from the "External WG" config shown on the left side of the diag in post #386.

 

Evidently, the Greddy Profec B2 &/or it's solenoid are prone to these type issues. A quick search turned up similar cases: the WG intermittently dropping to spring pressure. Unfortunately, none indicate whether the root cause was a faulty controller or solenoid. So, I'll need to do some testing…
.

• "I've been having all kinds of boost control issues for over a year now …and the problem revealed itself on the dyno. The controller is failing on occasion and dropping back to stock boost for a few seconds and then back to normal. We checked all connections and tested for a power drop. Nothing. All connections and lines check out fine."

• "So my profec B spec 2 decided to act up today. Everything was fine then all of a sudden i only had wastegate pressure... I did a boost leak and there’s none to be found. Everything is hooked up right, it just stopped allowing me able to control boost…"

Edit: After more investigation...it m/b a matter of EBC settings, specifically the GAIN set too high. I had it set at 30% w/in its range of only 0-35%. Perhaps over modulating the solenoid. So, I'll start there...re-tuning the controller at a decreased GAIN setting.

 

“Primum non nocere.”- Latin This episode of changing up my WG control appears to h/b...at least in part... an abject lesson in "First, do no harm".

Did the following.... and initial testing indicates that boost control is rock solid again.

1. Confirmed there were no WG control vac line leaks
2. Reverted back to NC WG control model (shown below)
3. Retuned EBC w/ reduced GAIN.....(Greddy manual indicates that "inconsistent boost" c/b caused by "Too high GAIN")

So, she's blasting about again w/ smooth summoned power. I'll continue to monitor to confirm consistent performance.

NC WG control model:

.
.

Initial testing... 3rd & partial 4th gear boost profile
.

WG w/ NC control lines
.

 

Interesting find. Hard for me to say for sure because I'm using the stock GReddy turbo and boost fall off is just a product of the undersized turbo; but I'm pretty sure my gain setting is around that 35%.

 

Hmmm... that is interesting...b/c if your GAIN is at 35%, i.e. maxed out...the manual states that's a reason for "Inconsistent boost" issues. Check the t-shooting section of the manual.

My boost issues appear resolved, but b/c I changed both simultaneously... I can't say for sure if my root cause was a) GAIN set too high, b) changing to the NO WG control model, or both.

Didn't have the patience to test them independently...just wanted to fix it.

 

Never seen that symptom ...but never had gain over about 25% either ...

 

Backed down GAIN to 20% as you initially recommended last year ..., and increased SET ...until boost returned to my target level...along w/ reverting back to the NC WG control model seemed to resolve it.

 

Good to know ...learning all the time