legacycentral bbs

Already have 06 wrx top mount currently running a vf8... Stock injectors stock fuel pump. Boost controller and FCD. Wideband O2. I am gonna pick this turbo up monday. I can't decide if its too big for my touring wagon with stock management basically? Its either put it on the touring wagon or the rally car. But I think it would be too big for rally. Is it gonna overboost? Or will it get really good gas milage because it will stay outta boost? Your opinions appreciated. If no one knows this is the 07 sti turbo.

You mean VF43. The VF 34 was a JDM turbo on the 01-02 STI's.

I have a super 16G on the Legacy, but I am no where near stock injectors.

As for better gas mileage, SURE- YEAH- with more power, you put your foot into it more- which means WORSE gas mileage. I lost 3-4 MPG with the bigger turbo.

If you are going this route, I would go with the 440's ad hope the computer will learn to keep it within a safe range. Unless you did a bigger exhaust, this will be worthless, as you will feel the restriction.

And you'll need a higher flow fuel pump to keep up w/ the larger injectors.

What kind of AFRs do you see w/ the VF8?

You will probably only be able to run 12 psi or so unless you do some piggybacking or whatnot.

the guy says its a VF34 from his 07 sti... And I do have full 3".
My vf8 at about 14psi sometimes makes the car run lean if i'm at high speeds in low gears at high rpm. It doesn't like to do 80 in 3rd with the vf8 thats for sure. Its normally in the 10-12 afr at full boost but sometimes it overboosts and goes to like 17psi for a sec and thats when it throws the CEL and runs like GASP 14AFR .

The 07 STI had a VF-43. He must be mistaken.

I would keep the boost under 11 until you have better injectors and engine management.

ya ur right its a vf43. I typoed it on my pm to him lol.

So i got the turbo yesterday and wasn't thinking about it... Before the turbo the inlet pipe for the cold side isn't there! D'oh! What has been done to fix this? Just a 90* pipe and a couple silicone hose fittings? Basically on the sti turbo you can see directly into the compressor wheel and on the turbo legacy there is a aluminum piece bolted to the cold side that goes 90* up towards the top of the engine.

That is why the td05-16g is so popular, it has the 90* inlet that the vf-11 has. When I used my td04, I had to use a radiator hose that had a 90 in it, I just clamped it right on, and used a metal tube to connect that to the stock 90 in the intake tract.

Thats kinda what I figured I would have to do. So that worked for ya pretty well?

07 STi injectors are what, 550cc? For a turbo that was originally matched with those, you're going to want injectors closer to that size. Then you need to properly control them and so on...

I know for my dinky td04, I only 10 psi, and the hose never collapsed under vacuum. depending on how much boost you plan on running, silicone might be the better option. You can get good quality silicone and clamps from siliconeintakes.com. The sti yellows drop in dont they? and those are 550 aren't they?

Arctic Assassian wrote:The sti yellows drop in dont they? and those are 550 aren't they?

They only drop into the 92-94 n/a fuel rails, and yes they are 550 cc/min

They're 550 cc/min at 3-bar fuel pressure. Our stock fuel pressure is 2.5 bars, which would reduce flow down to around 500 cc/min.

vrg3 wrote:They're 550 cc/min at 3-bar fuel pressure. Our stock fuel pressure is 2.5 bars, which would reduce flow down to around 500 cc/min.

The FSM states that the pressure of the pump for the n/a cars is 36.3 psi, while the pressure of the pump for the turbo cars is 43.4 psi.

Is this just for the pump output? It looks like the regulator is the same for n/a & turbo models, which would indicate, they should have the same fuel system pressure.

I'd think the fuel pressure regulators would be different between NA (no boost rise nec.) & turbo cars (1:1 boost rise).

Whats the correct base fuel pressure for a SS (2.5 or 3 bar)?
I assumed it was 3 bar (43.5ish psi) as it is on just about every fuel injected car except some Mopars (neon SRT4).

vrg3 has me scratching my head...

Turbo and non-turbo 1st-gen Legacy fuel pressure regulators are identical. They both regulate fuel pressure to 2.5 bars above manifold pressure.