Turbo lag?

[UltraObamaX]

Can anyone help please?

I have noticed an increase in turbo lag since having a new radiator last week.

When it's running fine I can be in 3rd at 2000 rpm, put my foot down and it pulls pretty much instantly. When in 6th at 50 mph on the motorway I can floor it and it gets to 70 pretty quick.

However, when I'm noticing turbo lag I can be in 3rd at 2000 rpm and it will build slowly to 3000 rpm then pull hard from there. In 6th at 50 mph I can put my foot flat to the floor and nothing happens, it tells me to shift down to 5th. It's like the turbo isn't doing anything.

It seems to happen more when engine is at full operating temperature.

Does anyone have any idea what it could be?

Hope it's not a new turbo.

Thanks.

 

[R3k1355]

Check the actuator diaphragm isn't failing and check for boost leaks.

 

[UltraObamaX]

I'm a bit of a noob when it comes to cars. I have no idea how to check that myself.

Would VCDS show any boost leaks?

 

[R3k1355]

Nah, needs manual inspection.

Best take it to a garage

 

[UltraObamaX]

Thanks ive got it booked in at a turbo specialist with free inspection so hopefully they find out what it is.

Any idea what vacuum/boost should be?

Car has 200 bhp, remapped from previous owner.

 

[R3k1355]

Sorry can't say, especially if it's been mapped already.

Testing vacuum on the actuator is simple, you hook a little vac tester to the actuator line, give it a few pumps and wait.
The vacuum gauge should not move as the diaphragm should be sealed. If it does leak vacuum the diaphragm is shot and the actuator is junk.