Anyone changed the dump valve ont he CRD yet?
I was in stop start traffic the other day and could hear the dump valve releasing but wondered about say? a forge unit? AKA Saab or similar.

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06 Cherokee CRD Limited Automatic
97 BMW 750i

If I understand your question - and I'm not sure I do - I think you were either hearing the guy next over, or were imagining things.

"waste gates" that dispose of excess exhaust gases are not used on diesels with variable vane turbochargers like the CRD Libby. "pop-off valves" that dispose of excess intake air are not used on diesels, with or without variable vane turbos, because diesels also have no throttle-plates.

"waste gates" would not generally be audible, since they would operate under heavy load when the engine is too loud to hear 'em anyway. "pop-off valves" would be heard if you rev up the engine at a traffic light and then let the throttle slap closed. they would thus be audible, and in fact, a lot of folks with turbo-charged gassers love the sounds they make.

From time to time I see posts of people wanting to put a "pop-off" on a turbo-diesel, not realizing that there is simply no way to make one actually work on a diesel engine. The best solution to this dilemma is to make a recording of such a valve on a really cool car, and play it through your stereo when you want to hear it.

So by "dump valve," which of these do you mean, or have I completely lost your meaning?

Hmmm,,,,
Well on my CRD in the UK I have got a dump valve mounted right on the hybrid Turbo to prevent the turbo stalling on throttle open / close. Operated by a vac assisted arm.
I am perplexed that they are not fitted on US ones as my Ford car with a diesel has a manually (vacuum) operated recirc one as well and has a variable vane technology Garrett unit
I was able to produce the sound by sharp acceleration then sharply releasing the throttle at which time a noise from the (as viewed from the driver seat) lower right footwell was produced that sounded like,,,well the dump valve,,,, actually.
On Saab's and Scoobies/Skylines they have trumpet items or twin trumpet items by Greddy or Forge so I assumed that one of these could be grafted inplace of the factory which sounds like a full recirc rather than atmos type.

But if its not fitted on US I will do some UK research as I am sure there will be one around. There is a huge VW TDi tuning scene been developing so will scrounge around there.

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06 Cherokee CRD Limited Automatic
97 BMW 750i

I recall some of the European Liberty CRD owners, pre 05, stating that their engines had a fixed vane turbo, with a wastegate. The wastgate label is still on our 05 CRDs, but it looks like all its showing is the vacuum line to the variable vane acutator... VM Motori's site, lists the R428 2.8 CRD as available with or without the variable geometry turbo. The VGT has about 15% more power iirc.

I also found a reference to VGT's sometimes having a condition called "turbo bark", on a Ford PSD forum. A few members described the condition, which I have on occasion experienced on my Liberty CRD, where after full throttle acceleration, sudden letup on the pedal produces a rattle-like sound from the engine bay near the turbo location. The rattle sound varies in intensity and some PSD owners were quite annoyed by it and even more annoyed by the fact that not all PSD owners had it. A Ford diesel engineer described this noise as occuring because of a high level of boost in the intake system, then the sudden reduction in pedal leaves all that boost with nowhere to go for a second or so. It apparently is common enough to have a nick-name for it.

Ahh now it makes sense it must be the VGT actuator and the Turbo sound was this "Bark" it was very very similar to the wastegate sound if none of you have had cause to hear it when you do it will be surprised as I was and assumed the pipework shrouded by heat shield was for a wastegate / dumpvalve unit

The spec on the R428 in Europe is 161Hp and 295 Lb ft torque I assume it is the same as US Spec?

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06 Cherokee CRD Limited Automatic
97 BMW 750i

163 hp, 295 ft-lbs torque. Pretty close.

ah, now indeed it all does make sense.

Thanks Naturist in re-reading the thread it does seem a bit vague, but I think,,,, (famous last words!) I know what the noise is and such associated parts to cause it

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06 Cherokee CRD Limited Automatic
97 BMW 750i