Actuator maybe?

[greeleyt5]

Hi all, just thought I would post this see if any of you guys had a solution to my problem, I have just changed the turbo on my t5 for a 15g turbo off a t5r I believe these are the same unit, anyway it has a mbc fitted to it that is now wound right out but I seem to be getting boost cut but here's the weird thing if I set off from traffic lights and floor it it's auto by the way she sets off like no bodys business and pulls like a train all the way up 100mph plus no probs just as it used to, but if I am traveling along say 40mph in sport mode and then I floor it the boost comes on the gauge and slowly creeps up right off the boost gauge then I get boost cut and it's the same if I turn the mbc up to where its always been it's just a more aggressive cut out, at the moment it's turned right down below standard I reckon but if you keep it floored as I said from rolling start I hardly get any boost and the little gauge just keeps creeping up until i get boost cut, does the size of boost pipes from mbc to actuator make any difference or could it be a faulty actuator any help guys would be much appreciated.

[T5frankie]

you need to take the mbc off and start from scratch by adjusting the actuator so boost is around half way into the white at full boost, then connect your mbc again and adjust it until it reaches the end of the white on the boost gauge, anymore and you will hit boost cut unless you have a remapped ecu and then it will go way off gauge

[greeleyt5]

Yeh that's what I was thinking but the old actuator was wound right out ie lots of thread showing and the new one is wound right in with no thread showing at all I'm I right in thinking less thread on actuator means less boost.

[cherry1809]

And check the spring. I bought a cheap one off ebay a couple of years back, And the spring was under slight load even when the screw was right out. Ended up cutting a couple of coils off.

[Yorkshiresxi]

you checked al your pipes etc for leaks? also why you change your turbo in the first place?
mine kinda does the same but i am getting 12 psi on a 15g and will be fitting the 16t next week, but mines onlu splutters if i am easy...if i floor it its ok, but i have found 2 or or 3 places my vac pipes are leaking, so waiting for a manifold gasket to come, take off the pcv system and replace it all with a catch tank and renew all vac pipes. This then should fix the slutter i hope.
You need to check yours and go back to standard though with the actuator arm and fit the bcs again..then re fit the MBC and go from there..u got a after market boost gauge?

[claymore]

more thread showing = less boost

[greeleyt5]

Cheers guys, the actuator is genuine Volvo so I'm sure this should be ok but can you please tell me if the thread on my actuator bar has lots thread showing is this less boost or more boost.

[claymore]

Cheers guys, the actuator is genuine Volvo so I'm sure this should be ok but can you please tell me if the thread on my actuator bar has lots thread showing is this less boost or more boost.
As I've just said, the more thread showing the less boost you will have

[Yorkshiresxi]

Doesnt having a MBC mean you dont have touch the actuator arm? hence leave it as standard?

[claymore]

Doesnt having a MBC mean you dont have touch the actuator arm? hence leave it as standard?
but the actuator arm needs setting right first, sounds like its set much to tight at the moment

[greeleyt5]

Cheers guys I think that is now the problem as the new actuator is wound right in with no thread showing, I changed the turbo as I was getting blue smoke out the back and oil blowing out the dump valve and I also fitted a new pcv and all vac pipes why I was at it I will take the actuator rod off and wind it out with out the mbc removed and set the boost, thanks again.

[cherry1809]

I heard a good bit of advice on here.
Wind out the actuator arm until when you look through the hole, You have a sort of half moon shape from the wastegate arm it attaches to. This should give around 6-7 psi base boost.