1997 2.5 D boost pressure?

From memory 0.9bar at anything over ~2700rpm.

I would be hooking up a gauge and not only checking peak boost is attained and held through the rev range, but also how it builds.

If it is slow to build as well as down, then either tighten or preferably replace the wastegate. Heat weakens the spring in time.

Tim..

Hi Tim,

Thanks for the quick reply - I will see if I can do this at the weekend...

As an aside, if all is well, is it possible to tweak the boost pressure a little ? I know that without fuelling adjustments which I guess I can't adjust, there will be no power gain, but if there is fuel not being burnt then I guess adding a little more air will give a bit more power and reduce pollution - or will too much air have an adverse effect ?

Thanks, Nick

It will self compensate for a mild increase in boost- upto a point.

The only way to increase boost is with a boost controller, or more elementary a bleed valve type. This wont help a tired actuator, which should be replaced first.

I would try for 1.0, perhaps 1.1 bar, and see how it goes. Any more, and you will need a chip to help with the fuelling too.

I assume your MAF and injectors and engine innards are now in rude health??

Tim..

Well, I am at the moment just collecting parts and info as it is slightly possible that I will be changing the car for a later model, or even going down to one car as wife doesn't drive anymore.... but I need a work car as well as a "nice" car, so may still happen yet..

However, I like "fiddling" and I like this car, so not sure...

I found a brand spanking new MAF unit, the injectors are still about to be done ( now definitely do need doing as I am sure seals have gone on one/some as I get a bit of diesel smoke on start up after rest so I assume they are leaking fuel into the cylinders when stopped) new brake discs and pads all round just fitted, and generally the car is good ....

Years ago I bought an adjustable turbo boost controller for another car and never fitted it, but essentially it is an adjustable pressure valve which goes between the inlet manifold and the waste gate - at the allotted pressure ( say 1.1 bar) the valve opens and activates the waste gate, so both controlling the max boost but also preventing partial opening as you near the pressure - not sure if the waste gate on these is directly operated by manifold pressure or via a pressure sensor / switch and a solenoid, but I guess it could still be used.

So, over the break I might get to do these things

Thanks again,

Nick