Proper Vta Dump Valve Setup

[Big 'D']

I just spoke to the supplier and the wastegate is indeed ported at the current diameter, there is scope for further porting though. It's the actuator supplied with the turbo and it is set to 1.2bar which I've been told will equate to approx 1bar on the road. Can't post any pics just now as don't have my PC lead here.

I need to remove the exhaust and check to see if the problem is still there. He also wanted me to leave the wastegate arm disconnected and fully open and see what boost I get then.

I'll report back my findings - probably not today though!

I am now thinking that the wastegate actuator spring is way too tight for your setup mate, I would defo try a weaker spring rate, running the car with the actuato rarm disconnected will simply not allow the turbo to spool, with the arm connected the wastgate port is only opened a fraction of its full range of movement and this is very much governed again by the spring rate, my next step would be to fit the next spring down if that is possible mate and take it from there, if the wastegate is ported and you are still getting boost creep I would be looking at the setup of the actuator.

Cheers Iain

[badbaz]

Iain, clarify we are NOW talking about wastegate actuator as opposed to dump valve earlier - not able to change any springs in actuator - rod is adjustable but not any springs? Adjustment is currently correct on wastegate actuator rod, i.e. just need to pull rod a fraction to latch onto wastegate arm.

Out of curiosity, in real world, how far does the wastegate actually open?

Edited February 23, 2010 by badbaz

[Big 'D']

Iain, clarify we are NOW talking about wastegate actuator as opposed to dump valve earlier - not able to change any springs in actuator - rod is adjustable but not any springs? Adjustment is currently correct on wastegate arm.

Out of curiosity, in real world, how far does the wastegate actually open?

Yes I am talking now about the actuator mate, (the DV seems too tight too though, thats a differents issue), the wastegate plate only moves by a few mm really mate. If the adjustment is correct of the wastegate arm ie just nipping the wastegate closed then it must be the spring rate of the actuator or there is a leak across the actuator itself not allowing it to open. The spring rate being too tight will have the same effect as the wastegate port being too small if you see what I am saying.

Disconnecting the actuator arm should defo result in zero boost or very close to it ie like running a 2.0 or 2.5 Sport

What turbo is it that you have fitted mate? (sorry I should have asked earlier)

Cheers Iain

[badbaz]

MD321T, brand new. Nothing out of the ordinary in my set up and this is first boost creep supplier has seen. We checked the actuator is the correct one by part number and it was. I'm gonna try some tests when I get time to be sure. Thanks for your help.

[Big 'D']

I just spotted the Turbo on your sig

Cheers Iain

[Big 'D']

Well all I can say mate is that if it is creeping with the compressor outlet connected directly to the actuator (boost controller 'OFF') then it will be down to one of the following. (in no particular order)

1. Split hose between the compressor outlet and the actuator, this removes the pressure required to open the actuator and the turbo will spool past wastegate pressure.

2. The wastegate port is too small, basically the exhaust gas cannot get through the port whist on boost it then chokes and the exhaust gas then passes through the turbine again causing boost creep.

3. Spring rate of the acuator is too high basically which can cause the same effect as the wastegate port being too small.

4. You have a restrictor in the boost control system that should not be there?

5. The wastegate actuator is faulty/leaking which will also allow uncontrolled boost beyond wastegate pressure.

Edit to add :

6. Boost control solenoid stuck open?

Cheers Iain

Edited February 23, 2010 by Big 'D'

[badbaz]

1. Split hose between the compressor outlet and the actuator, this removes the pressure required to open the actuator and the turbo will spool past wastegate pressure. - this could be so, got to admit that these hoses haven't been checked nor actually physically disconnected, direct connection was achieved electronically by the controller - will check these out.

2. The wastegate port is too small, basically the exhaust gas cannot get through the port whist on boost it then chokes and the exhaust gas then passes through the turbine again causing boost creep. - is ported, is it ported enough - we shall find out

3. Spring rate of the acuator is too high basically which can cause the same effect as the wastegate port being too small. - this 'should' not be the case as it's fitted to countless versions

4. You have a restrictor in the boost control system that should not be there? - pipes are without pill

5. The wastegate actuator is faulty/leaking which will also allow uncontrolled boost beyond wastegate pressure. - could be!!!

Edited to add - the boost controller isn't brand new and the solenoid could be faulty - I'll need to check that too! Somehow.

Edited February 23, 2010 by badbaz

[Big 'D']

It was just a generic list to aid your diagnosis mate

Cheers Iain

[badbaz]

Thanks Iain, I'm just thinking aloud. Will need to get testing.

[Big 'D']

Thanks Iain, I'm just thinking aloud. Will need to get testing.

Keep us updated mate and good luck, it should be fairly straight forward.

Prob best to connect a pipe direct to the actuator from the compressor housing that will take the boost solenoid and related pipework out of the loop and leave just the actuator and wastegate port

Cheers Iain

[badbaz]

Got a spare half hour this afternoon and stuck the downpipe back on. Removed the boost controller pipework and connected the compressor to the wastegate actuator with a short bit of pipe.

Just had time for one run to check what would happen.

1.7 bar and backed off

No more time so wasn't able to open the wastegate fully and try that - maybes tomorrow . . .

[Big 'D']

Got a spare half hour this afternoon and stuck the downpipe back on. Removed the boost controller pipework and connected the compressor to the wastegate actuator with a short bit of pipe.

Just had time for one run to check what would happen.

1.7 bar and backed off

No more time so wasn't able to open the wastegate fully and try that - maybes tomorrow . . .

Hi mate

Ok mate, in that case either your wastegate actuator is leaking (not allowing the wastegate to open), the port is too small or the spring is too strong, I would suggest at this stage that it is likely to be the actuator that is leaking.

I am working in Canada at the mo so I dont have alot of time on my hands to reply

Fully opening the wastegate by removing the link arm should result in zero boost.

Cheers Iain

[badbaz]

Iain, how much importance do you place on the boost pipes being clamped to the turbo and what do you use if not just hose clips?

[badbaz]

Forget the hose clip question for the moment.

Came into work and disconnected the wastegate actuator and tied the wastegate FULLY open. And away we go, no boost, 0.1, 0.2 bar dead as a door nail. Turned around and thought the revs never really got high enough. Into 2nd, foot to the floor, no boost, no boost, oh oh: 1.5 bar!!!!!!!!!!!

It's the turbo alright - can't be anything else now. I'll report on the next step!

Edited March 1, 2010 by badbaz

[Big 'D']

Forget the hose clip question for the moment.

Came into work and disconnected the wastegate actuator and tied the wastegate FULLY open. And away we go, no boost, 0.1, 0.2 bar dead as a door nail. Turned around and thought the revs never really got high enough. Into 2nd, foot to the floor, no boost, no boost, oh oh: 1.5 bar!!!!!!!!!!!

It's the turbo alright - can't be anything else now. I'll report on the next step!

Well that is odd mate, it can only be the wastegate port is too small then especially as you have tried it with the port fully open, you should never see any real boost in that situation, the wastegate port is choking evenm when fully open which is not good

Cheers Iain

[dipsy]

Baz any more joy on solving your boost creep.Kev

[badbaz]

Turbo coming off and going back for work on Saturday morning - not very happy!

[badbaz]

Well, last gasp - under instruction from the supplier, exhaust system off and one last chance. I turned the boost controller down to 1.3bar and away I went. What a f**ckin racket!!! Anyway, 1.6bar and climbing. I hate turbos.

Away to burn my fingers taking it off now.

Updates after it returns from the turbo to$$ers.

[StrikE]

You having to send it back Barry? I wouldn't be a happy chappy either

[badbaz]

Yes Derek, it's off back doon sooth. I'm going home now - fed up. A few bolts to take off and I'll box it up tomorrow. It's unfortunate but modding rarely goes to plan!

[Big 'D']

Well, last gasp - under instruction from the supplier, exhaust system off and one last chance. I turned the boost controller down to 1.3bar and away I went. What a f**ckin racket!!! Anyway, 1.6bar and climbing. I hate turbos.

Away to burn my fingers taking it off now.

Updates after it returns from the turbo to$$ers.

They advised you to run the car with the exhaust system off???????????

What did they hope to gain from doing that?

If the exhaust was restrictive the boost would be low any increase in the freedom of gas flow would increase the likelyhood of boost creep.

As you have run the car with the wastegate port fully open and you still got boost creep the wastegate port is not big enough, the turbo sounds like it is working as it produces plenty of pressure you just have no control over it.

I would like to think that a turbo dealer/company would have a better idea of simple fault diagnosis

I hope you get it sorted mate.

Cheers Iain

[badbaz]

They advised you to run the car with the exhaust system off???????????

What did they hope to gain from doing that?

If the exhaust was restrictive the boost would be low any increase in the freedom of gas flow would increase the likelyhood of boost creep.

It didn't really make sense to me either Iain but I wasn't going to refuse to try and do what they asked and find them telling me it was my fault at the end. They say that they have had a damaged baffle cause a restriction in the exhaust and this caused boost creep. Who am I to argue?

As you have run the car with the wastegate port fully open and you still got boost creep the wastegate port is not big enough, the turbo sounds like it is working as it produces plenty of pressure you just have no control over it.

I would like to think that a turbo dealer/company would have a better idea of simple fault diagnosis

I hope you get it sorted mate.

Cheers Iain

I'm sure we have covered every eventuality. My worry is that it comes back and still has the same problem!!

Here's hoping!

[Big 'D']

They say that they have had a damaged baffle cause a restriction in the exhaust and this caused boost creep. Who am I to argue?

An exhaust restriction caused boost creep, I would love to hear the explanation behind that one.

Any restriction in the exhaust would cause a boost restriction as it is restricting the engine/exhaust gas flow, you certainly should not see boost creep as a result. Adding/having a restriction to your exhaust you reduce your boost output but this has the knock on effect of reducing your overall performance, an example would be running with or without a bung in my backbox, without it fitted my car will boost to 1.35 BAR with ease, with the bung fitted I would be lucky to see 1.2 BAR, I have seen a car local to me with a failed CAT which caused a restriction it resulted in zero boost, but the car still started and ran fine off boost etc.

Cheers Iain

[badbaz]

An exhaust restriction caused boost creep, I would love to hear the explanation behind that one.

Any restriction in the exhaust would cause a boost restriction as it is restricting the engine/exhaust gas flow, you certainly should not see boost creep as a result. Adding/having a restriction to your exhaust you reduce your boost output but this has the knock on effect of reducing your overall performance, an example would be running with or without a bung in my backbox, without it fitted my car will boost to 1.35 BAR with ease, with the bung fitted I would be lucky to see 1.2 BAR, I have seen a car local to me with a failed CAT which caused a restriction it resulted in zero boost, but the car still started and ran fine off boost etc.

Cheers Iain

My thinking too but he insisted I tried it. Even today when I rang to enquire on the progress he commented on the fact that I had tried it.

The bottom line is with the wastegate wide open we saw big boost: turbo fault - we'll see what comes back - it better work correctly this time

Edited March 10, 2010 by badbaz

[Big 'D']

My thinking too but he insisted I tried it. Even today when I rang to enquire on the progress he commented on the fact that I had tried it.

The bottom line is with the wastegate wide open we saw big boost: turbo fault - we'll see what comes back - it better work correctly this time

Well it makes no sence to me mate, I just hope they sort it for you.

Cheers Iain