Adjusting non adjustable boost on turbo

[ollyc98]

I don't know if this applies to the superturbo or any other turbo'd car but I thought I'd share my experience with you. We're always saying we need more hands on information on the forum so here goes.

My dad was complaining that his turbo didn't seem to be doing much and his car was generally slow and crap.

We checked the wastegate actuator and that was fully adjusted as high as possible (on the nuts on the rod that goes to the wastegate)

All I know about turbos is what I've read. Anyway I decided to unbolt the mounts to move the rod separately to see if maybe the wastegate was jammed open (bypassing turbo) as the car had been sat for 6 months previously.

It was fine but it was here I noticed that you could lift the actuator about another 10mm. I decided to stick a washer under the mounting plate to lift the actuator up and close the wastegate. took it for a run, slight improvement but still not great. Came back, added another washer lifting the whole unit up around 3mm. Now it runs perfect, acceleration is much better and the turbo still cuts out at the higher RPM.

I may have got some of the terms wrong here, I'm not a turbo mechanic just thought this may help someone.

However I will not be held responsible for any damage caused to your engine, run a boost gauge to make sure you're not gunna blow your rings or melt anything.

 

[Alienfish360]

The turbo will open the wastegate to control boost levels, the turbo may also be on the limit of how much air it can flow.

The better way of doing this, is to get a new actuator with a stiffer spring in it.

 

[ollyc98]

If I had any money to spend on it I would've got a stiffer spring but the washers were free

 

[Bombardier]

Would be an idea to find out how much boost pressure you are supposed to run standard and then measure to see what your mods have resulted in.
It may feel good but if the ecu and fuel system is not up to supplying enough fuel etc damage is a real possibility.
Holes pistons will make the new spring seem very cheap.

 

[ollyc98]

It's a diesel so no risk of damage

 

[Bombardier]

There is a risk.
If the ecu thinks that it is getting x amount of boost and supplying enough fuel to allow this boost then you risk cooking the engine from too much fuel.

As to too much boost then there is also an upper limit for each engine. If there were no risk of damage to a diesel by overboosting then we would all be driving 1.5 litre 4 cylinder diesel turbo cars and towing 40 foot boats as well whilst on the autobarn at 300kmhr.

More boost equates to higher cylinder pressure and there is only so much bang in each cylinder that an engine will sustain before the pressure finds a way to relieve itself from the engine.

If you could supply which engine type it would make the help easier. Just a thought.

 

[ollyc98]

2.5 TD I turned the pump timing up, the pump is belt driven so no electronics to worry about upsetting. Still going strong, and getting 25mpg


In the factory they set boost for economy etc, you can push them a lot harder with no problems

 

[Bombardier]

How black and thin is the oil getting?
25mpg sounds like you are overfuelling a tad.
Bore wash is a problem without setting pump advance without meters/gauges.

 

[ollyc98]

Oil is fine, it's about as fast as his old 3 litre v6, wasn't expecting much fuel economy, it does weigh over 2 tonnes