D24Tic 940 Turbo testing and intercooler questions

[ukvolvo]

Hi Everyone,

I think my 940 is literally running no boost. It smokes a little on start but no other time so no tell tale failed turbo signs for such low performance.


That said, it is very dirty around the turbo area and caked.
So could the turbo be kaput but smoke free? It has years of grime on it to wash off.

Or are they really that slow standard and flat ? It does not feel boost assisted really. Acceleration increases at 3k but no noticeable kick at all or boost noise etc.

Should I run a t piece and test boost? What should it be if so?

The car has done 256k miles so far on standard everything major i suspect. Its got good service history but its soldiered on it seems beyond a water pump, thermostat and small bits.

The previous long term owner told me he had not cleaned the engine bay in 19 years and it shows

Also on the intercooler piping etc front and cooler itself, are they the same as petrol turbo units?

Thanks
Mick

[ngoma]

Originally Posted by ukvolvo

So could the turbo be kaput but smoke free?

Best to test it with a boost gauge as discussed below.

Originally Posted by ukvolvo

Or are they really that slow standard and flat ? It does not feel boost assisted really. Acceleration increases at 3k but no noticeable kick at all or boost noise etc.

There is a moderate power increase felt that starts between 2500 - 3000 RPM, but not a neck-snapping explosion that you would feel in a modern hi-performance car. Sometimes I can hear the turbo whine on mine but not always. Depends on ambient conditions, and never when the radio is on.

Originally Posted by ukvolvo

Should I run a t piece and test boost? What should it be if so?

Yes, good idea, and not hard to implement. Tee it into the small tubing running from the rear of the intake manifold to the boost diaphragm (the "flying saucer") on top of the injection pump. IIRC, D24T stock boost should be around 10 - 13 PSI, D24TIC may be higher.

Originally Posted by ukvolvo

The car has done 256k miles so far on standard everything major i suspect. Its got good service history but its soldiered on it seems beyond a water pump, thermostat and small bits.

You will want to get on the TB situation as addressed in your other post.

Originally Posted by ukvolvo

Also on the intercooler piping etc front and cooler itself, are they the same as petrol turbo units?

Sorry, IDK, not so familiar with the IC as unfortunately we didn't get the IC version here.

[ukvolvo]

Originally Posted by ngoma

Best to test it with a boost gauge as discussed below.


There is a moderate power increase felt that starts between 2500 - 3000 RPM, but not a neck-snapping explosion that you would feel in a modern hi-performance car. Sometimes I can hear the turbo whine on mine but not always. Depends on ambient conditions, and never when the radio is on.


Yes, good idea, and not hard to implement. Tee it into the small tubing running from the rear of the intake manifold to the boost diaphragm (the "flying saucer") on top of the injection pump. IIRC, D24T stock boost should be around 10 - 13 PSI, D24TIC may be higher.


You will want to get on the TB situation as addressed in your other post.


Sorry, IDK, not so familiar with the IC as unfortunately we didn't get the IC version here.

Thanks Buddy, Belts aa said in other post are top priority i know.

I have noticed the yellow pipe on the boost diaphragm goes to a sensor, is that a regulatory sensor like a n95 valve on other vw engines or mere boost low or high warning?

Mick

[ngoma]

Originally Posted by ukvolvo

I have noticed the yellow pipe on the boost diaphragm goes to a sensor, is that a regulatory sensor like a n95 valve on other vw engines or mere boost low or high warning?

Not sure, can you post a photo?

[ukvolvo]

Originally Posted by ngoma

Not sure, can you post a photo?

I will get one today Thanks

[ukvolvo]

Originally Posted by ngoma

Not sure, can you post a photo?

As requested, pics of sensor

I should have took some more later, I really went at the engine bay today with some cleaner and it looks alot better. I can actually see hose ends and jubilee clips again haha

[ngoma]

The boost compensator is the very tiptop of the injection pump. To measure turbo boost, you want to tee your gauge into the black tubing that I have circled in red.

With a long enough tube, you should be able to run it into the cabin so you can view it while driving. The engine will not generate much boost when not under load.

bay-resized.JPG