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Home > Help Needed / General Tech Chat > No boost

Ryan22lgm

8 Posts
Member #: 11857
Junior Member

My turbo set up is all fitted and engine running well. Booked the car in to be rolling roaded to be told itís not boosting at all until itís basically to late high up the Rev range. I had only driven the car gently before hand as Iím very cautious of running lean/rich. Standard metro t3 setup with rebuilt carb.
Triple checked all vacuum lines
Checked wastegate pre-load set about 6mm
Bleed valve piped in correctly as per diagram.
Chap at rolling road checked for boost leaks found one and sorted this for me.
He seemed to think I could have an issue with the wastegate not shutting correctly. Is there anything else I should check before I start stripping it right back down???


wil_h

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9240 Posts
Member #: 123
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Betwix Harrogate and York

How about the poppet valve on the plenum not being fitted or not sealing?

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

On 2nd Jan, 2013 fastcarl said:

the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


Turbo Phil

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4418 Posts
Member #: 20
My sister is so fit I won't show anyone her picture

Lake District

The actuator could be weak allowing the wastegate to creep, hence the boost only at high RPM. Or the WG is sticking open. If you disconnect the actuator from the WG does the WG arm move smoothly/freely ?

Phil.

WWW.TURBO-MINI.COM


stevieturbo

3389 Posts
Member #: 655
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Northern Ireland

Shouldnt take long to check the actuator etc to see if it is closing/closed ok.

Is it ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


Ryan22lgm

8 Posts
Member #: 11857
Junior Member

Cheers Guys havenít had a chance to try anything yet broke my ribs on the mx bike!!!
The popper valve has been blanked with modified plenum chamber for intercooler pipe takeoff. New gasket put on when carb rebuilt.
I have tried running up the road with the actuator vacuum line disconnected this made no difference. Should I swap it out for a standard actuator as the one fitted is a red aftermarket one? Or should I disconnect it altogether and try to hold the wastegate shut with cable ties to see if I get boost that way?

Thanks again

Edited by Ryan22lgm on 14th Jun, 2019.


stevieturbo

3389 Posts
Member #: 655
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Northern Ireland

No, as already said you need to check the w/g is actually closed.

A decent start would be about half a hole tension on the rod

Edited by stevieturbo on 16th Jun, 2019.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


Ryan22lgm

8 Posts
Member #: 11857
Junior Member

Had a little play with the car tonight. Took carb off and checked the preload on actuator seemed to be around 3-5mm so upped it to about 8mm. Took it for a test drive and seems to be Ďboostingí but still doesnít have that turbo car feel. Seems to come in too high up the Rev range. I donít have a tachometer so can only judge by how loud it is in the car 🤣


metroturbo

764 Posts
Member #: 989
Post Whore

North Yorkshire

Boost from an old school T3 should have arrived by 3000rpm and be obvious, as it isn't very progressive.

Have you got a boost gauge fitted? You really need a boost gauge and a tacho or it's all just guess work.


Ryan22lgm

8 Posts
Member #: 11857
Junior Member

I do have a boost gauge fitted and it was showing boost but as I say when itís far to late.
I have had a thought about something that could not be right on my turbo. When I stripped it I noticed no gasket between the wastegate flapper and the housing part. So I used some exhaust paste between the two when rebuilding. Could this be enough to not let the flapper seal??

Edited by Ryan22lgm on 6th Jul, 2019.


stevieturbo

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Northern Ireland

There isnt supposed to be a gasket there, nor any other crap.

And what do you mean you stripped the turbo.....exactly what did you do to the turbo ? This sounds a more likely cause of problems ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


Turbo Phil

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4418 Posts
Member #: 20
My sister is so fit I won't show anyone her picture

Lake District

As Stevie says thereís no gasket or anything else to seal the wastegate flap against the turbine housing, it simply relies on the pull of the actuator to hold it against the machined surface in the housing.
Sticking a load of paste on there will stop it seating properly and allow it to leak. Itís most likely why youíre not seeing any boost until high RPM.

Phil.

WWW.TURBO-MINI.COM


Ryan22lgm

8 Posts
Member #: 11857
Junior Member

So took the car apart again tonight and think I have sussed out the problem! Seems like the actuator has far to much play in it preventing a full seal over the hole (see pictures) You can also see the sealer I used which I will remove. Is there a way to tighten up the actuator/flapper rod? Or do I need to source a new part? Seems like mostly up and down play not side to side.


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shane

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Lowestoft, Suffolk.

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Edited by shane on 10th Jul, 2019.


stevieturbo

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Northern Ireland

What do you mean it has far too much play ?

It's a simple flap, and you were asked ages ago to ensure it was actually closed, and ideally with maybe half a hole pre-load on the actuator arm.

Which from the black marks....seems it was nowhere near closed, and doesnt even look as if it is aligned over the hole ?

Is something fucked with the arm/flap ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


wil_h

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9240 Posts
Member #: 123
Post Whore

Betwix Harrogate and York

It looks fooked to me too.

Usually when there is play in the wastegate shaft or it's not sealing it's new turbo time. These aren't parts you can get.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

On 2nd Jan, 2013 fastcarl said:

the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


Ryan22lgm

8 Posts
Member #: 11857
Junior Member




On 12th Jul, 2019 stevieturbo said:
What do you mean it has far too much play ?

It's a simple flap, and you were asked ages ago to ensure it was actually closed, and ideally with maybe half a hole pre-load on the actuator arm.

Which from the black marks....seems it was nowhere near closed, and doesnt even look as if it is aligned over the hole ?

Is something fucked with the arm/flap ?


I fully understand how the flap should work and reset the preload several times before stripping it apart. As I just said the shaft has to much play up and down as shown in the black marks. This is allowing it to leak at the top.

I am not going to scrap my turbo just because this part is not available. I plan on removing the weld from the top of the shaft then moving it up and re-welding to cure the up and down play. This will then make a full seal over the hole and solve the problem.

I want to say thanks to everyone that has commented nothing has been ignored!


stevieturbo

3389 Posts
Member #: 655
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Northern Ireland

Anything is fixable, and many parts are available.

But until you recognise what is wrong....it will appear unfixable.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

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