Engine/Transmission (1994 - 1998) Turbo warble?

[Ram-Man Cummins]

I have a pdr hx35 with 14cm wastegated housing.

My issue is that at low boost, useally at decelerate, I experience a warble in the turbo whistle or whoosh. . whoosh... whoosh... . whoosh... ..... whoosh... ... ... ..... whoosh... ... ... ... ..... whoosh... ... ... ... ... ... ... ... ... whoosh... ... ... ... ... ... ... ... ... ... ... ... ... . whoosh. It will do the same at low boost or cruise speeds. During aceleration it will do the same but it reverse order. Kinda like it winds up then winds down.

I thought it may be the new pdr hx35 but after I installed the stock back on it it did the same thing so I dont believe its the turbo.

My thoughts are exhaust leak but I can't find any signs of leaks.

Maybe Intercooler leak or hoses. All are tight and look good but I dont know how to do a pressure test.

Maybe its the new EGT probe that I installed. It isnt exactly center in the rear exhaust its kinda to one side but not touching, maybe it flutters or does some kinda whirling vortex in there.

Everything else seems ok and it runs fine, I can get as much boost as I want from it and it doesnt do it when I give it some good pedal or higher boost just around cruise or low boost of 1-5 lbs.

Maybe its just the way it is.

Odd thing is that it didnt start to do it until about 200 miles after I installed the new pdr hx35. Then it didnt seem to get more apparent after that.

I talked to Piers and he said he had never heard that situation before at low boosts but maybe at higher and it doesnt do it at higher boosts.

I was going to return the PDR hx35 but since the original does it too I need to look elsewhere or nowhere. AAArrrrggg!





Any thoughts or answers would be greatly appreciated.



Thanks

 

[WDimig]

you may be experiencing what is known as turbo bark, but generally that is with higher boost pressures, and at wot and the foot is sudenly taken off the pedal, and the compresed air seeks the lowest point of pressure, which is now the compressor, and tries to spin the turbo backwards, creating a whoosh, whoosh sound. as far as you egt probe, it is in the correct location, for in the center of that neck of the ehxaust manifold, there is a metal divider between the two passages, and you would have ruined the manifold if you had drilled there. i doubt if there is a vortex that is created by that probe being where it is, other than that i have never head of the low boost surging that you are describing. good luck with you problem.



wes

 

[Forrest Nearing]

if it's doing it at steady speed, it sounds like compressor stall or surge... shouldn't have any problems w/ that turbo... look for a torn intercooler boot?? (major shot in the dark)



Forrest

 

[McDowra]

If its compressor stall or surge I would also be looking for an exhaust restriction somewhere probably after the turbo, I cant imagine how that would happen just swapping the turbo out though



-Good Luck

 

[Ram-Man Cummins]

I checked all the intercooler boots, removed and reinstalled all the boots and made sure everything lined up and was tight.

Still no different.

A surgeing is what it sounds like but from what?

The exhaust is a new 4" no cat so there is no restriction there, no apparent exhaust leaks also.

I will replace the square intake gasket on the intake tube and see if there is a leak there.

Maybe intercooler.

I'm stumped, I also talked to Piers alot and we still can't figure it out.

The turbo whistle just surges at lower boosts or cruise speeds, winding up and down with throttle.

 

[McDowra]

What else has changed on the truck, we know you changed the turbocharger, but thats obviously not it since your stock turbo does the same thing. We know you changed the pyrometer thermocouple,-is it pre turbo or post turbo? If those are the only two things that have been changed I would take the new thermocouple out just to see if that straightens it out. Just a shot in the dark but if your thermocouple is post turbo and its in a different position than before it could be causing an exhaust restriction which would contribute to compressor surge.



Jason

 

[SEmerson]

I get a little fluttering sound on my hx40 when it is starting to come to life.

 

[Ram-Man Cummins]

Pre turbo thermocoupler and its not exactly center in the rear exhuast port. It is kinda towards the center of the divided exhaust port but not touching the inside center of the rear exhaust port. I will remove and cap it to see if that is it.

I havent replaced the intake square gasket yet.

This condition slowly developed since I installed the thermocoupler, turbo, cam 10 plate and GSK 3000 all at once.