eckseleven

The Totally Stainless bolts actually give just a hair more clearance than the stock studs IIRC.

I was under the impression that the TS bolts could have been the source of my problems initially. The OEM studs have the shoulder area to help locate the whole DP assembly to the turbine housing and that shoulder area is just a tiny bit smaller than the TS bolts.

So can these ARP bolts be used in some other location (bolt on turbo, headers) or are they pretty much 40 bucks in the garbage?

Most likely garbage/paper weight. I'll probably be using them to put my OEM DP back on when I inevitably part out this car.

So I asked nameless for input and this is what I got ekcselevn did u try this

 

There is a very simple resolution - just loosen up the bolts and shift the downpipe forward relative to the car and bolt it back on. It was probably installed pushed all the way to the back of the range of tolerance and was hitting due to that. I don't believe we had a single customer that actually had a part altered at all. The only people with issues were able to be resolved by simply adjusting the location of the downpipe flange relative to the turbine housing. We make the bolt holes oversized a bit to prevent shearing of the turbine housing studs during heat cycling. If the downpipe was even installed centered on the bolt holes it should have no issues.

Absolutely. Everything that can be tried with this DP, has. There are no clearance issues with the DP and the wastegate door. This was confirmed with a hand pump hooked to the actuator.

A couple exhaust phases for me. Organize how you'd like. I'm at sea level.

Originally: Nameless DP + AVO CBE. Easily hit boost cut below ~30F. Would see ~18-19 psi around 40F.

Next: Nameless DP + AVO front pipe + Grimmspeed DP adapter + stock everything else. With this configuration could still exceed WG spring pressure by a fair amount at 40F but did not hit boost cut. I think it peaked at about ~16.5 psi.

Currently: Nameless DP + AVO front pipe + Grimmspeed DP adapter + stock mid pipe + AVO muffflers. Did not get to test this in the cold but would expect it to be somewhere in between the other two.

In all three configurations: stock BCS, stock non-ported turbo, tune set to 0% WGDC.

I went out last night for a pull in the 25 degree weather. Hit about 18.5 psi. So I don't think things are as bad as they were but I would expect an overboost situation could still occur if the temps dropped a bit further. At this point I'm guessing it's just as good as it's going to be without porting the IWG.

Did a little research last night on this forum and it sounds like some of these cars are just finicky when you go stage 2. Some overboost, some don't. Catted or catless DP, any CBE set up. Porting solves the problem in most cases. Mine apparently is one that's going to be problematic.

Not sure what the plan is next. I'll probably throw my AVO mufflers back on because I miss the noise. Get it retuned in the spring / early summer. Add a boost gauge so I can keep an eye on things. When it gets cold I'll just have to be careful.

I'm going to check with the local Subaru communities and see if there is a semi local place that does porting. If it can be done for a reasonable price I might consider that.

No, setup is:

Nameless DP -> AVO front pipe -> Grimmspeed adapter -> stock everything else.

Stock mid + mufflers back on. Unfortunately it's been too warm to be able to test to see if the problem is gone. Hope it gets cold again otherwise we won't have an answer until next winter.

Performance seems to have suffered. The tune is still the temporary 0% WGDC tune so I suppose that makes sense. I would need to visit the tuner to get things back to where they should be.

Kinda miss the exhaust noise...

Elekseven did u ever find/fix your over boosting problem ?

Not yet. As far as I've gotten is pulling the stock exhaust out of my attic. Hopefully I'll get a chance to put it on in the next week or so. Hard to believe I haven't gone WOT in 2 months...

I do not have an aftermarket BCS. WG actuator and the rest of the boost control system has tested out fine. All signs point to the exhaust being too free flowing. I have the AVO CBE which connects directly to the Nameless DP. It is 3" up to where it splits at the Y. It narrows down to somewhere between 2.5" and 2.75" from there to the mufflers which are straight through.

I'm willing to bet that anyone that has a full turbo back would get more than wastegate spring pressure boost if they had their tune set to 0% WGDC. Would be very helpful if Fischbach, Swannee, or anyone else that has had "success" could test this theory out but I understand that may be a hassle. If they did this and saw more that ~11psi than they could overboost given the right conditions I would think.

EDIT: In response to some of the discussion above: I am on stock mid pipe and cans and currently am over boosting too.

This concerns me. I was hoping switching out the exhaust would fix my problem. Perhaps you have some sort of mechanical issue? Maybe the flapper can't open? That was my first problem.

Honestly, even though the concept makes sense, I'm still pretty skeptical. In all the reading I've done on here (and it has been copious), I haven't really stumbled upon any other stories of such severe overboost. Lots of folks missing by maybe 5 or 6 PSI, but I don't even know what the ceiling would be for me right now. I've had it sneak to beyond 25 and based on how fast that happened, I would not be surprised it if could hit 30. Just seems hard to believe that everything else in my setup is working right and all the overboost is coming purely from such a free-flowing exhaust.

I had no issues until I went from a CBE to a TBE using the Nameless DP. My tune is set to 0% WGDC and when it gets cold enough boost will shoot right up to 21 psi and then Christmas tree the dash. It happens extremely quickly, within 1k RPM of going WOT in a 3rd gear pull.

The warmest temps I've tested in are about 65 and even then boost will hover around 16.5-17; still far above waste gate spring pressure. Everything I've tested/tried points to the exhaust being too free flowing. When I get time and it warms up a bit I'm going to put the stock mid pipe back on and see what happens.

As for you being able to hit 25 psi, I'm guessing it can be configured in the tune where boost cut is triggered.

I would next try, to disconnect the flap so its flopping and open. See if it persists or give you no boost. Sorry if you have already tired this I didn't go back and read all the posts.

Can that be done easily with out removing a bunch of stuff?

Do you have a stand alone boost gauge to cross-check the AP reading from the ECU?

I do not but this experience may be the push to finally get one. I have been wanting one for years.

Log it and post the actual boost curve.

Here's the log. First 40 lines or so.

https://drive.google.com/file/d/0BwoQtejdZCJmQXVsb1RqWlUyNnNEcG1KYmpBS2J4YTU0U0Vr/view?pref=2&pli=1

So would both stock midpipe & mufflers be needed? Or can it be one without the other?

I'm giving my options some thought. I may put my stock mid on and keep the AVO mufflers and see what happens.

Perhaps a longshot, but has your turbo ever been rebuilt maybe before you bought the car or did you buy it new?

Bought new.

So is this indeed pointing more towards creep?

That's what I'm thinking and what was suggested by my reputable tuner after checking the car top to bottom. The problem only gets serious around 30F though so some people may never see this. But since we can have stretches of -10F for weeks here, I just don't think it could be a problem I'd feel comfortable living with. The one time I hit boost cut in 3rd, I had started at 3000 RPM and was at 21 psi before 4000 RPM. That's nuts. I'd have to drive around never exceeding half throttle when it gets cold.

I'd be surprised if the flapper was still touching that tube. With the switch from bolts to studs like everyone else has used and considering the good wack with a hammer I gave that tube, it just doesn't seem possible to me. There would have to be a serious manufacturing defect to cause things to be off still. Perhaps there could be an actuator issue but since I've never had a problem in 38k miles and my tuner has never pointed out any odd behaviors in the past it just doesn't seem possible to me.

fahr_side, I know you've mentioned this in the past, what do people typically gain with a CBE? I'm curious what I'd loose if I were to go back to that. Maybe I'd loose some peak HP but gain TQ when compared to stock DP plus 3" CBE? I need to consider my options. It sounds like you'd just port the WG but unfortunately I don't have the resources in my area to do that. Switching exhaust components is the only thing I'm willing to do.

Ah ha. With the stock actuator you should only be seeing 11~12psi. Mechanical problem.

What do you think it could be? The rod moves all the way when I pressurize the actuator by hand. I would think that rules out the flapper being stuck, correct?

Show your appreciation by doing what I suggest and not second-guessing me. A pump test is not the same as actually testing in boost with the BCS connected. You have backpressure in the exhaust to overcome and we aren't sure if your BCS lines are good etc. Take the factory T-hose off, with the pill still in there, and connect a new short length of vacuum hose directly from compressor to actuator. If you see more than about 11psi then you have a problem with either the wastegate flapper still hitting something, the actuator not holding pressure, the BCS being faulty, a line leaking... lots of possibilities. If you do hold a steady 11psi or so we have eliminated the WG flapper, the actuator, the downpipe design, the exhaust system etc. Just get back under the car and do it. It takes less time to actually do this than thinking up arguments and excuses not to.

Did as suggested. Bypassed BCS with no pill. Hit 17.8 psi in a 3rd gear pull.

I read some Cobb documentation about testing the wastegate and in it they use a pump just as I did. That's what I used to come to the conclusion that I did. Your experience tells you this isn't a sufficient test. That's fine. I'm not second guessing or doubting you so don't take offense. I'm just trying to learn.

I'll try what you suggest. Thanks.