59 replies to this topic

[LukeFranky]

Bought some circlips from AutoBarn. Good timing too, the rod had almost rattled its way off. Readjusted the ECV as per Jimbo's directions on the TT guide. Two full turns away from the rattle feels like a lot but the turbo does switch over well.

 

Secondary definitely spools faster and boosts harder. Primary hits 8 psi and secondary 14 psi. 8psi seems a bit low to me. So far so good for starts but the erratic boosting on primary when cold is still there.

 

Not sure what to make of it. Maybe the primary has issues too, but the secondary was definitely the source of oil in the intercooler. Could the ECV still need more adjustment? Will try Rob's suggested ECV diagnostics next.

 

I also noticed that my intercooler gaskets are leaking fraction. They were made using gasket paper. Oil was managing to slowly seep through the material. Is there a better material or do I have to buy genuine?

[duncanm]

I also noticed that my intercooler gaskets are leaking fraction. They were made using gasket paper. Oil was managing to slowly seep through the material. Is there a better material or do I have to buy genuine?

RTV silicone or Anaerobic gasket maker? Either should do fine as both surfaces are machined.

8psi sounds like wastegate pressure - though it doesn't sound right that you'd get significantly more on secondary if that was the issue. Try plugging your (primary) wastegate solenoid and see if the boost stays the same.

[natho]

boost targets in the stock tune are 14psi primary, 12psi when the secondary is added. low boost on the primary could be due to the ecv not being tight enough. however, running non-stock turbos will also likely affect this. for example. my tune currently is targeting 19psi (both pri & twin). swapping my primary turbo (ported p16 housing including ported wastegate, vf32 centre, vf31 comp cover) for a stock vf25 resulted in significant overboosting to 21psi.

 

perhaps try tightening up the ECV, but without replacing the boost controller (or a custom tune), you may not be able to do a lot about it.

[LukeFranky]

boost targets in the stock tune are 14psi primary, 12psi when the secondary is added. low boost on the primary could be due to the ecv not being tight enough. however, running non-stock turbos will also likely affect this.

- Keep in mind my primary is stock (although rebuilt). Secondary is the oddball turbo so only once the ECV starts opening I'd expect to see non-stock behaviour, right?

 

I have ecuTek and judging by the stickers it was likely tuned by... erkk, MRT. I think I've seen 'Stage 2' mentioned, anyone know the boost targets?

 

Thanks for the advice guys. I'll play with the ECV tonight.

[LukeFranky]

So I had some success.

There wasn't a lot of thread left to begin with so tightened the ECV rod all the way. Primary got to 10 psi and secondary was still getting 14psi sometimes dipping to 13psi.

Next I blocked the top port of the ECV. Primary managed to make 14-15 psi. Given this result I think I need to tighten the ECV a little more.

Is it unusual to need to tighten the ECV rod so much? I foresee someone asking if I have mixed and matched the turbo, ECV and actuator, but I haven't and this turbo is paired with its matching ECV and actuator.

[Robbks]

That's normal when there is too much flow through the vac lines feeding the ECV Positive Pressure Port
check for a missing retrictor pill or blocked Duty Solenoid.
(or just leave the ECV PPP blocked)

[natho]

if it's not overboosting on the primary with the ecv positive pressure disconnected, it should be safe to leave it that way. it'd be interesting to see a datalog of full throttle run in 2nd or 3rd gear, with both wastegate duty cycle values logged along with the ECV pos/neg and ias solenoids.

 

bit of a tangent, but some people may be interested...

 

The B4 ECU has 3 distinct boost control modes, each with their own maps for controlling the boost with the wastegate or ECV:

1. primary turbo, with wastegate on the primary turbo only
2. primary turbo, with ECV positive pressure activated. stock tune will switch to this mode as low as 2000rpm, dependent on load!
3. twin turbo, with wastegate on the primary turbo only (ECV now opened fully with negative pressure)

with a completely stock tune, boost seems to gradually build to a 14psi peak before changeover, with both ECV positive pressure and the primary wastegate used.

 

however, if you set a higher boost target, the ecu will end up closing the primary wastegate as much as possible (e.g duty cycle shows 100%) if it can't reach boost targets when attempting to control boost with ECV positive pressure activated. I'm not quite sure on the logic the ECU uses here, but it seems to 'ramp up' the duty cycle on the primary wastegate a fixed amount when ECV positive pressure is activated - which is why some people may find that simply disconnecting it causes an overboost.

 

at this point i've kept ECV positive pressure disabled on my car (in the tune, not physically). at 18-19psi it didn't really improve the VOD at all.

[LukeFranky]

I suspect oil from dodgy secondary turbo may have worked its way into something but I'm cautious about cleaning the BBoD given my history with it (killed some solenoids).

Instead of risking at overboost by totally blocking the top port on the ECV could I add a restrictor pill to the line?

[natho]

i've cleaned bbod's a few times with no issues... probably at least worth cleaning the lines to the ecv solenoids.

 

there should be a restrictor pill in one of the ecv positive hoses already, check the diagrams in the your guide to TT thread.

[LukeFranky]

I do have inline fuel filters before the BBoD. They had fair bit of oil in them that I've already drained. Not sure if anything could get past the filters.


Will pull the box off tonight. What's the safest cleaner to use?

[LukeFranky]

Cleaned the BBoD and it didn't make a lot of difference.

Stock ECV: 10psi primary. 14-15 psi secondary.
Top of ECV plugged: 14-15 psi primary and secondary.

I does feel like it pulls a little harder with the ECV plugged. What problems does a Rev D face with the ECV setup like this?

Something I have totally forgotten to take into account is my altitude. Armidale is pretty high above sea level. When I go down the coast I generally see about 2psi more boost. Car loves the dense moist air.

What is a safe amount of boost to run? Anything below 20psi? Haven't seen anything over 15psi so I guess the ECU bleeds it off after that.

I generally go for 2nd or 3rd pulls to test. Tried a few in 4th too. Similar results.

[LukeFranky]

Well, yes. I'm assuming you think they might be a possibility so I will remove them. I'm doubtful they restrict the air flow to be a problem but happy to be proven wrong. They did prevent a lot of oil getting into the BBoD.

[Robbks]

Instead of risking at overboost by totally blocking the top port on the ECV could I add a restrictor pill to the line?

Not a bad solution.

This car still needs a re-tune.

[natho]

Not a bad solution.

This car still needs a re-tune.

 

there is a restrictor pill already in the ecv positive circut, not sure if adding another would help unless it's smaller. i believe the one in there is the smallest one available from subaru. would be interested to hear if this works.

[LukeFranky]

This car still needs a re-tune.

- Are you offering?

It has ecuTek so likely locked down by the previous tuner. I suspect it might be costly to retune.

Would some data logging show up an issue with the tune?