VF35 on 2003 WRX PPP
 

Hi all, first post and new to the forum so apologies if this isn't in the right place. Been doing modifications for a very long time indeed, however, totally new to the Subaru boxer and looking for guidance.

In the process of replacing my Brother's turbo on his 2003 WRX which I believe is a PPP model (not sure how to confirm however).

The turbo extracted is a TD04, and certainly has thrust bearing play and needs attention so won't be going back on.

We have to go on in it's place a good condition VF35. Simple enough swap, however, I have some concerns with regards to fuelling, especially as I have no idea what the WRX PPP stock injectors or pump are, or capable of. Looks like the injectors (380 or 420?) will be OK to around 300 BHP as will the fuel pump, however I want some real world advice and feedback from people who have done this, or similar.

Fuelling upgrades and a map will come at a later date, but for now this need to be 'safe' (word used cautiously) on stock pump and injectors. What's the score here?

The current plan is to bolt on and pipe in as the TD04 was and run on stock map. I appreciate that the turbo will flow more air due to size, however expecting the lambda to trim the fuelling. Not sure how it will react AFR wise at WOT.

Thoughts/experiences appreciated.

Why not just upgrade to TD04 Hybrid. I'd be alot happily running one of those without mapping right away. Wouldn't be happy running VF35 your planning to run. You can pick them up for around £450 refurbed and trade in old turbo.

Just running something like a dump valve on an Impreza causes over fuelling.

Thanks for your reply :-). Not sure exactly what you were meaning to say there, excepting for the TD04 hybrid piece, as it looks like auto correct went a bit mental? The reason it's going to be running a VF35 is I have a spare which used to be run top mounted on a 1.8T VAG engine, it's in excellent condition and has done about 600 miles from new. Whilst I appreciate a TD04 hybrid may be better for a number of reasons, it's also £450 quid more expensive than the current plan.

Any answers to the original question appreciated, other than why don't you do some thing else such as *insert option here*.

Sorry sorted out typo errors, phones been going mental, no better using scoobynet app.

Basically i wouldn't go running around on a VF35 with no remap.

No problem, thought that was the case. Fair enough, and duly noted. I'm going to get the tubby fitted and log the AFR on a friends 4WD dyno to see what's what. Any further decision will be based on the outcome.

I see there are some Subaru specific logging softwares kicking about which a capable of doing AFR logging from the lambda. Do these motors use wideband lambda?

Obviously the ECU runs closed loop on part throttle etc, however does it remain closed loop under WOT? This will define how useful the logging software would be, hence why I ask.