Schister66

Hey guys,

I asked this question on NASIOC, but it seems most Subaru owners are quite clueless...so i thought i'd see what you all have to say.


I was driving about 6hrs on the interstate the other day and after stopping at a rest area for ~5 min, I re-entered the interstate only to hear that the turbo on my 06 STi sounded like it was working much harder than it typically does. I pulled over, noticed the Grimmspeed 3port was not grounded and grounded it.

Since then i have had odd rattling sounds coming from the turbo (or surrounding area) when i'm in boost. It doesn't boost fully either, but feels like it wants to. I'm unsure what to check and would appreaciate any suggestions you guys may have. Tonight, I will be cleaning the BOV and inspecting for torn couplers, but neither of those options deal with the rattle i've been hearing. I checked the wastegate actuator arm and it isn't loose and the diaphragm still has resistance against it when i tried to move it. My initial thought was that the wastegate was seeing strange boost readings (due to the 3port being disconnected) and flapping around all crazy-like. All of these modifications (apart from the Tial) have been on the car for 4+ years, Tial has been on since last spring.

-06 STi 120k miles
-Grimmspeed 3port, tuned on 18-19psi reflash
-Gimmick inlet, SPT intake
-4" bellmouth dp, 3" invidia turbo back
-Tial 50mm bov

TheShodan

iTrader: (14)

even with boost fluxuations, the wastegate flapper wouldn't make rattling noises. Any audio /video recordings of it occurring at speed? that may be the best way to display your description better.

That is an interesting puzzle, however.

wantboost

iTrader: (2)

Check all of the heat shielding around the manifold, up pipe, and turbo. they use so much heat shielding from the factory that if one comes loose it will rattle like crazy.

as far as the boost issue, make sure the solenoid is operating properly. also check the signal lines for any punctures. Given the install location most companies use for their solenoid the hoses pass through rub and pinch points.

wantboost

iTrader: (2)

Try iwsti.com or whatever it's called. their members seem to be leaps and bounds more knowledgeable and helpful than NASIOC members

Schister66

Good to know i can eliminate the wastegate flapper from the possible candidates. I will try to get a video of it, but i dont know how well my phone will pick up the sound. Its odd though, the car runs just fine, but falls flat in boost and this issue came on so suddenly...

Wantboost, i'm going to disconnect the 3port boost controller and run straight off the wastegate to see if that has any effect. My only other thought is my Tial 50mm bov is loose/sticking. I checked it last night and it seemed secure, but i can't hear any bov sounds when i'm on the throttle.

Unless I figure it out beforehand, the car is going to Subaru for a check-up on Friday. I would have brought it in sooner, but they didnt have any loaner cars until then...now I get to bump around in a 2014 Forester

boosted94gsr

All that rattling is probably causing false knock and the ecu is pulling timing. On my wrx I have a random slight exhaust rattle at a lower rpm and my ecu will pull timing.
After checking the learning view it will have knocked around 3000 rpm and not anywhere else and my ignition advance will be pulled back to 14 instead of 16. These damn subarus seem to be really sensitive to random rattles lol.

Have you checked the learning view or you ignition advance? Not saying that's the cause of the problem but maybe that's part of the reason why its falling on its face under boost. Good luck man.

sirtef9

iTrader: (4)

Have you pulled the downpipe to check the turbo?

Schister66

I haven't...i dont have the time to work on it after work lately. With a 1yr old and my fiancee's work schedule, it simply hasn't happened. I did realize I was a little low on oil...i dont know if that would cause catastrophic issues like this, but I have since topped it off. Its scheduled to go into Subaru on Monday. Part of me is contemplating trading it in on a new XV Crosstrek

sirtef9

iTrader: (4)

Would be a hell of a downgrade power wise for the XV.
The turbos do go, I work at a Subaru dealership and would quote maybe 1.5 to pull the down pipe and inspect. But not all techs are the same, I couldn't see you paying much more then that if you wanted it checked out.

viper_boy403

iTrader: (1)

With an aftermarket DP minus the OEM heatshield, you could drop the DP in 30-45 mins easy. Those studs really like to strip though.

A really common issue on turbo subarus is, like you mentioned, oil consumption (shitty PCV system). Which snowballs into a gradual buildup of metal shavings in the turbo feed oil screen, followed by turbo starvation and eventually failure. I don't even work at a dealership and I've done plenty of WRX/Forester XT turbo replacements

Schister66

So, funny story....

Brought the car to Subaru on Monday night. They gave it an oil change and cleared the CELs (i have a TGV that gets crabby and throws a CEL...will be gutting them soon enough). Anyway, they proceed to check over it and can't figure out what the sound is. I urged them to drive it and put some load on it to see if they hear the sound, but they report nothing. The service tech keeps telling me they're only hearing the "boost dump valve" and "blow off solenoid" and all these not-word word combinations...basically it sounded like they had no idea. I was told that they could order a new boost dump for me but it would be $300. I thought they meant to replace my GrimmSpeed 3port, but they were referring to the Tial Q bov and replacing it with a stock bypass valve

When i picked the car up, the service tech explained that the sound was my atmospheric boost dump (aka bov) and to fix it, i would need a new downpipe...no idea what the correlation is, but i'm sure he thought i had an EWG and open dump. Since they didnt solve the issue, i wasn't charged for service.

When i drove it home, the rattle was entirely gone and hasn't reappeared. The only sound the dealer ever heard was my Tial Q.... The car is getting retuned at RS Motors in Burnsville, MN on June 24th to ensure everything is still ok and that its not overboosting/underboosting/whatever.

Cliffs: Subaru fixed it, but didnt realize they fixed it...and didnt charge me for it

Schister66

The apparent trouble-maker


And some shameless self-promotion since i got a car wash

LightningTeg

Hmm, Evo wheels on an STi lol. Looks good

Schister66

They're my winter rims with Dunlop WinterMaxx tires, which i kind of regret. If i could do it over again, i would switch them with my BBS rims with Star Specs and use them for summer rims because I love the look of the Enkeis on the STi (and it confuses Subaru/Mitsu people).

BBS's are going back on this weekend, weather permitting

ballistic1350

iTrader: (7)

I always like the way the 06-07s looked

wantboost

iTrader: (2)

You know what it could've been, I didn't realize the bov was so close to the intake manifold. the top mount does move around a bit since it's on rubber mounts, the valve could have contacted the intake manifold causing the rattle.

do you see any signs of contact/rubbing?

and you just reinforced why I don't do dealership service... most of the people there are a little "off" and don't really know what's going on most of the time. however you can't argue with a free maybe they fixed it job lol.

Schister66

I dont see any signs of it rubbing anywhere that i can see, no...i'll have to look at the intake manifold to see if the bov is rubbing it. The fitment is almost too tight for it to move...as you can probably tell from the unbolted hard line across the top of the bov. I had to coerce it out of the way to get the bov mounted. As for the rattle, i have no idea...it could have been bad gas or the car might have been in some strange limp mode. At any rate, they "fixed" it and didnt make me pay. I'll take it

I'm counting my blessings on this one, but getting it retuned just to make 100% sure this little hiccup doesn't return

wantboost

iTrader: (2)

Yea I don't blame you.

we are about to start modifying our 2015 Launch Edition STI here soon once we get a few sessions in at AMP and see what it needs. probably a downpipe, exhaust, methanol injection, braided brake lines and decent pads, harness bar, possibly adjustable arms, and a boost increase and a tune once Cobb cracks the new ecu.

should make one fun circuit car. the goal is to keep up with our friends built lotus exige (ohlins coilovers, ap brakes, Quaife sequential transmission, methanol injection, vipec standalone, aero, etc)