turbo boost

nurkov · Post by **nurkov** » 22 Oct 2006, 17:40

I've checked turbo boost on my 2.0 petrol and it's 0.4 bar max. It should be 0.6. Is there anything I could do about that? All air hoses look ok. Maybe adjust the wastegate a bit?

jeremy · Post by **jeremy** » 22 Oct 2006, 20:01

Some turbos are electronically controlled from the engine ECU. I suppose the easiest way to determine this is to have a good look at the turbo unit and see if there are any wires going to it.

Turbo boost gauges can be misleading - as the engine will only produce full boost at reasonable revs when it is pulling very hard for some time - eg for a diesel - up along hill at 70 in 5th. I should inagine your car will be flying by this time. Seriously it can take some time before full boost is reached.

nurkov · Post by **nurkov** » 22 Oct 2006, 21:16

I've checked it quite good today I think and 0.4 is max, hole turbocharger looks like that and there is no any wires with it :

wheeler · Post by **wheeler** » 22 Oct 2006, 23:19

There is an electrovalve (no 1 in the 1st picture) that is controlled by the engine ECU that opens & closes to allow vaccum to the wastegate,check that all these pipes are clear by blowing through them with compressed air,also check for splits in these pipes.

nurkov · Post by **nurkov** » 23 Oct 2006, 18:18

So I've disconnected pipes from electrovalve and boost is 0.5 on all gears, before that was 0.4 and not on every gear. Car drives faster and is accelerating smoother. What does it say?

BonceChops · Post by **BonceChops** » 23 Oct 2006, 21:26

nurkov wrote:So I've disconnected pipes from electrovalve and boost is 0.5 on all gears, before that was 0.4 and not on every gear. Car drives faster and is accelerating smoother. What does it say?

It says that either the turbo is knackered or you have a leak somewhere. I think you have been lucky to not damage something from over pressure.
If I disconnected the waste gate on my 2.1TD I would expect to burst the intercooler or pipework as the pressure would rise uncontrolablly. I would have expected the same thing to happen on a petrol.

nurkov · Post by **nurkov** » 23 Oct 2006, 23:26

I'm watching boost gauge very carefully.

KevMayer · Post by **KevMayer** » 24 Oct 2006, 09:10

With the pipes to your waste gate actuator disconnected your waste gate will remain shut which should give you a very high boost pressure at full throttle when on heavy load, say going up a hill.

If you're only getting 0.5 bar then you could have an air leak on your pipework or intercooler.

The other possibility is that your waste gate is 'sooted up' (carbon build up) and its stuck partially open (i.e. it can't close properly). I had this happen on a turbo diesel a few years ago. I couldn't get more than 0.2 bar out of that one. I had a refurb turbo fitted and it restored the 0.8 bar max boost.

I have a 2.0 turbo engine on my Activa. I've tried fitting a manual boost controller and my boost level goes pretty high. The manual boost controller fits onto the pipe which supplies the waste gate actuator. You set a spring tension to determine what boost you like. But the ECU on these engines cuts the fuel supply if it sees 1.0 bar or more as a protection against engine damage.

It is possible to remove your turbo and clean it up. You can get refurb kits for them. I think it's a Garret unit on your car.

If it were mine, i'd take it off and check for carbon build up around the waste gate.

Cheers, Kev

nurkov · Post by **nurkov** » 24 Oct 2006, 16:48

It's garrett TB2567 and about wastegate I can move that metal rod quite easly to easy for me really. I've never done it before so don't know how it should be. Problem with getting turbo out of xantia is that I would have to get the engine out first and that is a problem.

nurkov · Post by **nurkov** » 24 Oct 2006, 16:50

It's garrett TB2567 and about wastegate I can move that metal rod quite easly to easy for me really. I've never done it before so don't know how it should be. Problem with getting turbo out of xantia is that I would have to get the engine out first and that is a problem.

BonceChops · Post by **BonceChops** » 24 Oct 2006, 17:26

It was fun removing the cat on my 2.1TD so I think removing the turbo would be very difficult if not impossible with the engine in the car.

nurkov · Post by **nurkov** » 24 Oct 2006, 18:38

I've just checked all again all pipes etc. There is no difference between wastegate connected or not. It's always 0.5 bar. Car is driving fast but it's pissing me off really.

KevMayer · Post by **KevMayer** » 24 Oct 2006, 22:53

The waste gate actuator rod should be difficult to move. It should be held tightly in position by the spring tension in the diaphragm unit. A pair of pliers and considerable effort should be needed to move it against the spring.

If you can move the rod easily then the rod could have become disconnected from the diaphragm and a new actuator is the answer. You should be able to get a new actuator fairly easily. I replaced one on an Audi turbo diesel.

The actuator consisted of the capsule containing the spring loaded diaphragm with the actuator rod sticking out of the hole in the middle. I purchased it from a diesel tuning specialist. Can't remember who, but Garret dealers should be easy to find.

It was replaced because the connection of the rod to the diaphragm had broken causing the diaphragm to leak and so my waste gate stuck closed. The Audi had an overpressure relief valve on the inlet manifold which saved the day.

nurkov · Post by **nurkov** » 25 Oct 2006, 07:17

It costs about 50 so it's not bad. Does anyone know if it possible to exchange actuator with the turbo and the engine of course in a car?.
With mine rod can be moved easly with one hand without any efford. It comes back to previous position.

KevMayer · Post by **KevMayer** » 25 Oct 2006, 22:57

I've had the actuator off on my 2.0 turbo engine.

Jack the front up, support it on axle stands as high as possible then crawl underneath and you can get to the actuator ok.

You will need to remove the turbo oil return pipe to get to the actuator fixing bolts. It should come off quite easily.

Don't forget to chock the rear wheels solidly because the handbrake is on the fron wheels on the Xantia.

Cheers, Kev