Help me get full boost earlier

[Lith]

Fivebob:

Ah ok, I see what you are saying though I'm not sure that'd work... at least any better than the current setup. Its not bleeding from a system isolated from the other side of the actuator - and I'm not sure that a solenoid bleeding boost off a hose off a T-piece is going to make that much of a dent. I suspect if it would work better, Apexi (or others) would use it. Or did you consider that?

Cheers, eitherway - can definitely see where you are coming from.

going from your diagram, you would want the avcr to be pulsing quite quickly to keep the valve closed then open up after boost case come on then slowly close up again as it gets up to the top of the rev range to compensate for the turbo starting to boost outside its preferred limits. And going from what has been said previously about the avcr you can only set the target boost level and not the duty cycle of the solenoid directly.

Sorry do you mean let less air through the solenoid when its spooling, more air through when boost is reached and then less air through at the top end?!

[gasman]

Fivebob:

Ah ok, I see what you are saying though I'm not sure that'd work... at least any better than the current setup. Its not bleeding from a system isolated from the other side of the actuator - and I'm not sure that a solenoid bleeding boost off a hose off a T-piece is going to make that much of a dent. I suspect if it would work better, Apexi (or others) would use it. Or did you consider that?

Cheers, eitherway - can definitely see where you are coming from.

going from your diagram, you would want the avcr to be pulsing quite quickly to keep the valve closed then open up after boost case come on then slowly close up again as it gets up to the top of the rev range to compensate for the turbo starting to boost outside its preferred limits. And going from what has been said previously about the avcr you can only set the target boost level and not the duty cycle of the solenoid directly.

Sorry do you mean let less air through the solenoid when its spooling, more air through when boost is reached and then less air through at the top end?!

flip what you said: so more when its spooling, less when boost level is reached, and eventually more at the top end to keep the boost up at the top end.

your problem only seems to be the first part and its not leting any pressure reach the bottom hlaf of the diaphragm to keep the valve shut

[fivebob]

Ah ok, I see what you are saying though I'm not sure that'd work... at least any better than the current setup. Its not bleeding from a system isolated from the other side of the actuator - and I'm not sure that a solenoid bleeding boost off a hose off a T-piece is going to make that much of a dent. I suspect if it would work better, Apexi (or others) would use it. Or did you consider that?

It should work better because the wastegate would see less of a pressure differential across the diaphragm so it should open slower.

I think a lot of your problem is because the wastegate is being opened to fast.

Is it possible to change the duty cycle of the solenoid?

[Lith]

flip what you said: so more when its spooling, less when boost level is reached, and eventually more at the top end to keep the boost up at the top end.

your problem only seems to be the first part and its not leting any pressure reach the bottom hlaf of the diaphragm to keep the valve shut

OK, just making sure you were getting it correctly Thats pretty much how it is supposed to be doing it at the moment and yeah you are correct, the AVC-R is completely failing at doing its job for whatever reason

Its why I came on hoping someone could come up with a reason it might do so, one of the tests I did was feed the boost directly to both ports while bypassing the AVCR to make sure the actuator is working correctly, and there wasn't some kind of restriction in my T'd feed but it basically free boosted.

I think a lot of your problem is because the wastegate is being opened to fast.

Is it possible to change the duty cycle of the solenoid?

It would work better IF it was able to do what you want it to do, but I don't think it would work..

Of course the wastegate is being opened too fast, thats the reason I bought the AVCR, and posted the information I have so far on trying to diagnose the issue. I have maxed out the duty of the solenoid, and maxed out the amount of preload I can run with the wastegate actuator.

The previous setup with a single port actuator actually seemed to work a little better than my joy with this dual port setup, so to try something new...

I have ordered a Norgren pressure relief valve with a .7bar spring and will switch back to a single port wastegate setup use that with the AVC-R activing as an active regulator so I can completely block the feed to the wastegate until 1bar (relief valve is adjustable) and then let the AVCR take over from there, as it controls the boost fine once my target boost is reached.

Any thoughts on that hair brained idea?

[fivebob]

I have maxed out the duty of the solenoid.

Are you sure that's the right way to go

I would've thought you'd want minimum duty cycle with that arrangement not max.

[Lith]

Pretty sure, to let as much air through as possible!?

I suppose I should have explained how I believe the AVCR works (I am pretty sure it is, I could be wrong of course haha), to make sure we're on the same page.

The AVC-R solenoid has two "output" ports - if I understand it correctly one is the one you'd use with a standard single port internal wastegate actuator and by default lets pressure straight through, when the solenoid goes that feed is "disrupted".

The other port is one used for dual port internals (like mine) and external wastegates, and its default mode is to not flow any air through unless the solenoid is goes...

[fivebob]

The AVC-R solenoid has two "output" ports - if I understand it correctly one is the one you'd use with a standard single port internal wastegate actuator and by default lets pressure straight through, when the solenoid goes that feed is "disrupted".

The other port is one used for dual port internals (like mine) and external wastegates, and its default mode is to not flow any air through unless the solenoid is goes...

Unless you're meaning as a fail safe setup i.e. power off will cause the wastegate to open then that's the wrong way around. On a single port actuator you want it normally closed, on a dual port you want it normally open. That way when the EBC is doing nothing until target boost is reached and then the control algorithm takes over increasing the duty cycle until the boost is controlled.

I'll have to do some reading on the AVCR. It may be that the solenoid is set up for failsafe but the normally open/closed position of the valve is the default with power supplied. In which case the duty cycle should be low to get softer control around the target boost.

[Lith]

That way when the EBC is doing nothing until target boost is reached and then the control algorithm takes over increasing the duty cycle until the boost is controlled.

Nah you've actually got it around the wrong way, the AVC-R actively blocks the feed to the actuator until target boost is reached and then lets the actuator receive the full pressure flow until (or if) the boost drops down below target again at which point it will start actuating again. The solenoid starts operating as soon as the AVC-R senses pressure...

[fivebob]

I've just read the manual, what an arse backwards way of doing things

Does the wastegate actuator have an internal spring?

[Lith]

Yeah, its basically identical to the one in the pic I posted.

So you agree with all my conclusions about whats going on after looking at the AVC-R documentation? Did you read my idea in regards to the pressure relief valve I am getting on Monday?

[fivebob]

I think that it should work but you'll probably end up with boost creep. If it was my car I'd be more inclinded to go to a single port actuator and bleed off pressure using the AVCR, much the same way stock 3S-GTE boost is controlled.

I note in the instructions for the AVCR there are two duty cycle settings but there's seems to be little explanation of the start duty setting

BTW I assume you reset the AVCR and made it re-learn it's boost control strategy whenever you've changed anything

[Lith]

Yes, I have been there and done that with everything you mentioned - I was previously running a single port actuator and it didn't work acceptably.

In regards to the pressure relief valve, I am not going to set it to the target boost - I am just going to use it to get up to 14psi quickly, I actually want to run around 16psi and once 14psi is passed the relief valve will be fully open and the ball with be in the AVCRs ball course. Since the AVCR is proven to be able to maintain a stable boost curve once reached, I think it shouldn't be too bad but either way - unless anyone convinces me its a bad idea or suggests a better idae I will be able to report the results next week

[steve murch]

block the wastegate off totally and hold actuator hard closed
take for a run but be very carefull and see where the threshold point is.you cant improve over the set point as the turbine hsg desides what that is.
and its not the first time ive seen this on gt turbos as much as they are ball bearing it only makes them 5-7% more responcive over plain.
remember your only checking threshold so dont push it past 3-4k or itll hurt something.

[Lith]

Hi Steve,

Thats one of the first things I did, as per my first post in the thread. 1.1kg/cm2 by 3600rpm with the wastegate hose removed or 3800rpm with the wastegate connected and the boost control post on the actuator fed directly by the pressure feed to make sure it can hold the flap shut.

Cheers
Dan

[steve murch]

im also believe in running the spring pressure to the level you want rather than rely on boost controllers or bleed offs to which they can put you into over boost.
just in-case the valve is dropping too much energy try restricting the outlet size in the dump pipe,you need to put a boost gauge off the turbine hsg and see what the back pressure does when the gate opens

[Lith]

Cheers, hadn't really thought of the wastegate dump pipe size but had worried that the oversized wastegate port in my internal housing was dropping manifold pressure too quickly when the actuator starts reacting. In theory the actuator I had was a 1bar one, which had me thinking the opening at 11psi thing was to do with turbine pressure until I was able to rule that out. I understand that the actuator can start opening a little before target pressure, and have treated it that the problem could be as you say - and that the port just drops the pressure too quickly even at slight opening.

I am going to set the pressure relief valve to 14psi as all my target boost levels (15psi - 17psi) are higher than that, I just want to have it building to something more sensible than 11psi (the extra 3/4psi make a real noticeable difference) before it starts opening.

So you think its not that good an idea? The AVCR has proven to hold 15 or 17psi flat once that boost level is reached, its just bringing it up to that level which is proving to be a challenge

Here is the turbine housing I am using:

[Lith]

I had some fun during a gap in the weather today, so here is the new pressure relief valve I got from Norgren:


I took advantage of the opportunity of doing these changes under the supervision of Tomei:



I did my first tests with the twin port wastegate as I need to remodify the setup to suit the old wastegate (changes were needed for the twin port) as my relief valve is best suited to a single port actuator... and the dual port actuator seems to be rated to 7psi vs my old actuator's 12psi. As a result of this I had some boost level oscillation, but that was no surprise.

My flatmate is going to reweld up my old actuator setup so I can re-install that - and going by tonights testing I suspect its going to finally have the type of boost control I have been hoping for:


I was a little weary of it potentially boost spiking, but no issue with that at all - with the soft spring it hits 1bar and drops back a couple psi and then rebuilds it in reducing swings but I expect the harder spring and a bit of tuning to sort it out.

[Lith]

OK, put the original wastegate actuator back in - made a few adjustments to actuator preload, the pressure relief valve and the AVC-R and took it out for a thrash tonight and it seems much much much better.

1bar seems to kick in by 3500rpm, wavers slightly and is acceptably steady at around 1.1bar by 4000rpm which is where I would have been happy with it reaching full boost by anyway!

The bits for the Norgren relief valve cost me $70 and have really made quite a difference in terms of spool and response, quite pleased with the results of this hair brained idea.

[~SlideWays~]

OK, put the original wastegate actuator back in - made a few adjustments to actuator preload, the pressure relief valve and the AVC-R and took it out for a thrash tonight and it seems much much much better.

1bar seems to kick in by 3500rpm, wavers slightly and is acceptably steady at around 1.1bar by 4000rpm which is where I would have been happy with it reaching full boost by anyway!

The bits for the Norgren relief valve cost me $70 and have really made quite a difference in terms of spool and response, quite pleased with the results of this hair brained idea.

I used one of the Norgren valves after having issues with the Link G1 boost control and I'd never go back!

[Lith]

I assume you used the regulator valve? They make heaps of sense, they are designed for industrial pressure control - they HAVE to work. Seeing as I have the AVCR anyway, I can adjust it from in cabin and it regulates boost fine once full boost is reached I won't mess with it but the Norgren valve is doing a great job of bringing the boost up to full fast