Hi! Thought I'd ask about this here as you US-based guys seem to have done more with TD05-based turbos than here in Aus.

I've recently fitted a TD05H-16G turbo to my MY02 STi which is an otherwise stock EJ257 save for an AVO silicon turbo intake and 3" TBE with open-mouth collector.

I've recently taken it to fairly well-known tuner here in Sydney to have a custom Ecutek tune done. The car now feels great and managed 227kW on a Dynapack but apparently there are issues with boost control which need more tuning time to clear up. Which leads me to my Q.

Should I persevere with the factory 2-port solenoid, try getting the boost sorted with something like a turbosmart 3-port solenoid or go for an aftermarket electronic boost controller?

I'd prefer not to use an EBC as I do lots of track work and I like the additional safety of having the stock ECU which can cut boost if bad knock is detected.

Any advice is greatly appreciated.

Cheers,
Ben

i would go three port, run in interrupt mode, and have the oem ecu control it. if your tuner knows what he's doing he will have no issues tuning the boost control system with the three port and it will be more responsive than the oem bleed based system.

unless you spend like $500 usd there is no better EBC than the oem ecu.

Thanks for the reply.

Sorry if this is a silly question but can you please fill me in on this "interrupt mode"? It's not a common term over here.

...Ben

Typically, the 2-port solenoids use a "T" connector to plug into the boost control hoses.

A 3-port solenoid would be installed where the "T" currently resides in your boost control hoses (logically, not physically*), allowing it to completely "interrupt" the boost signal to the wastegate.

* Do not install the solenoid in the exact same physical position as the "T". Buy some longer hose to position the solenoid off to the side, just like your current factory solenoid.

Just used the search button. :banana:

Looks to me like the term "interrupt mode" is used to describe what I understand to be the normal operation of a 3-port solenoid. One line from the compressor to the solenoid, one line back to the actuator and the 3rd line plumbing the bleed back to the intake.

Interrupt mode is precisely why I'm considering going to a 3-port solenoid. I'm hoping to bring boost on faster (I assume that having abolutely no boost pressure going to the wastegate actuator until target boost is almost reached will help in this regard) and most importantly keep it consistent through the rest of the rev range.

Is there a 3-port solenoid available that will bolt up to the stock location and use the stock harness? The authorities are a bit picky over here and anything that looks non-standard will often result in a defect notice.

Thanks,
Ben

ben, i'm going way out on a limb here, but if i remember correctly there might have been an actual subaru oem part that had three ports.

i'm pretty sure i had read about it over on scoobynet.com--you might want to check out some old threads by those smarmy brits.

the only ones we have in common use on this side of the pond are the grainger, the perrin (rebrand grainger), and the gm syclone/typhoon oem part. none of them look really at home under the hood, although the gm part can be ordered with a pigtail/harness and could probably be made to look pretty sano.

Great thinking Ride. If I remember rightly my old Liberty (Legacy to you guys) RS Turbo had a 3-port solenoid. I'll look into getting a new one from Subaru Oz. Thanks for twigging my memory!

As for those smarmy Brits, they're only good for beating in sport! Hehehe :p

Cheers,
Ben