piehole1983

iTrader: (7)

Yeah I suppose that's a possibility, I use a Turbosmart Supersonic BOV at the moment and will be switching back to an OE plastic recirculating valve as the other is just too loud for me. It'll be interesting to see if that affects me too. I wonder what sort of pressure the OE valve can hold? I had to buy one from eBay, not sure what way round it's supposed to be but it actually looks like the positive pressure will hold the valve shut and it's opened only by vacuum rather than the possibility of it being pushed open by too much boost. I could be wrong though.

Welloilbeefhooked

iTrader: (3)

A stuck open dump valve would cause problems. Looks like a week one opening at 1.3 bar to me.

My oe dump valve, the plastic one is fine at 1.4 bar.

piehole1983

iTrader: (7)

Looking at it again, my OE BOV should be held shut by boost pressure until you lift off and shouldn't really be able to leak. Mine is the older type with a pipe in and and a pipe out, not connected directly to the intercooler like the newer ones.

Jaysz

Own my v3 with vf23 the boost duty is from 35 to 68% makes about 1.4 bar and throttle log graph looks close to boost graph

alessio

iTrader: (3)

Good evening,

Thanks for the input again. It seems then that the recirc valve is not the obvious culprit - with it being fine at 1.4 bar and with me never having issues with it and all.

Checked the plumbing, and no eureka! moment here, unfortunately. Everything was connected as it should be. I also decided to put the 2-port back in to see what the car does with it controlling the boost. Attached are a few graphs and the only conclusion I can make from these is that the boost comes in very late compared to others. Why that is I'm at a loss.

Started with the 3-port BCS on WG pressure, then having increased the target boost lower in the rev range to 1.6 bar and then decreasing the target boost to 1.2 across all the relevant sections. Here are the respective screenshots

alessio

iTrader: (3)

I then put the 2-port back in with the pill that came with the VF34. The first run was on WG pressure, then with conservative BCS DC numbers and the last one with the BCS DC set at 100% before boost. I'd say that there is no noticeable improvement compared to the previous days, the boost arrives very late.

Should I be worried there is something mechanically wrong with the turbo or something? Visually it looked great and everything moved as it should.

Compared to the time when the car ran fantastically on a TD04 with a 3-port at 1.2 bar (falling off by 6000, as expected), I have installed the VF34, replaced the intercooler with a somewhat larger ARC one, including the much better flowing Y-pipe, and the stock injectors were replaced with 800cc ones. The turbo and the DP were also wrapped/covered with a blanket.

Thoughts and ideas are very welcome

Cheers,
Alex

piehole1983

iTrader: (7)

I honestly don't know why it's slow to build boost other than its bigger than the TD04 or perhaps the up pipe isn't best suited to it. Is the compressor wheel damaged at all?

alessio

iTrader: (3)

Nope, no damage that I could see at all.

I've seen people hit full boost at 3700 on this turbo and I was really hoping for something similar.

Welloilbeefhooked

iTrader: (3)

Out of curiosity what other mods do you have fitted?

piehole1983

iTrader: (7)

Looks like it's a characteristic of the turbo, doesn't it?

alessio

iTrader: (3)

It is but on mine it gets there noticeably later than that, at a out 4500.

Welloilbeefhooked

iTrader: (3)

For the op. The thing that stands out for me is having 90% or thereabouts boost duty at 1.3 bar ish. On mine that would equal boost of about 1.5 bar or above due to nearly all the air being bled away from the actuator.

Welloilbeefhooked

iTrader: (3)

Did you test the boost pressure with the turbo nipple connected directly to the actuator? Just wondering if the wastegate is opening under less pressure than it should.

I think the wastegate is opening before it should or is stuck open.

alessio

iTrader: (3)

Haven't tried it like that, only turned the BCS DC down to zero to make it work at WG pressure, hopefully. But I can try that next.

Welloilbeefhooked

iTrader: (3)

What was the wastegate pressure?

The Rig

iTrader: (13)

Agree with Wayne, if your duty cycle is at 90% to get 1.3 bar, your actuator is very weak or preload is way of, 90% duty cycle is alot of pressure to be relieving the actuator of to get 1.3bar

You can adjust the preload on the actuator easily.

As an example,To get 1.3 bar from 4000+ my Duty starts at around 62 and only increases to 63.1 to maintain 1.3ish at full load

Get that turbo hose on the actuator and tell us what the actuator pressure is, hopefully its low and that will be your problem

Welloilbeefhooked

iTrader: (3)

Rig, it opens under pressure not vacuum ��

The Rig

iTrader: (13)

LOL, corrected, was written before lunch and brain not working well

Jaysz

The main mods are
Hks high power exhaust
hks downpipe which modded by drilling hole in flange and welding pipe into then to pipe
Walbro with 440's and adjustable fpr, parellel fuel lines
k&n with trumpet
I have ported standard headers
Hybrid gt2 fmic with reversed inlet
3 port boost solenoid
Esl
V7 sti short block
Did make 346 with standard v3 block but didn't last long lol
Standard v3 recirce as a vta with washer to restrict air released