hellotbone

Here is a question I have always wondered. Say accellerating lightly up a large hill when my truck its od and is lugging say I get a really loud woosh sound from the turbo not the usual screm like when accellerating hard and it really sounds like its sucking like crazy however when the turbo does this the truck feels lazy. Anyone explain this to me?

Lary Ellis (Top)

What you are describing sounds more like the when Clutch Fan kicks in.

hellotbone

It has that roar sound buts its not the fan the turbo makes a similar sound.

Scotty

Check your intercooler hoses and clamps...real close.
Clamps might appear to be tight but not.
Hoses can creep out from under the clamps too.
Hoses can have splits in them too.

How is the boost?

hellotbone

Boost is normal scotty. Thats what gets me its a totally differnet sound it has always done it so its odd

Stamey

I'm no expert here, but I'm gonna throw something out there. When the engine is "lugging", it is not able to consume all of the boost you are trying to put in there and the woosh you hear is the air being churned as the turbo tries to push it in but the engine can't take it all. At higher RPM the engine is able to absorb the additional air from the higher boost. This is less likely to happen, if at all, with a stock truck because it is not able to put enough fuel in there to get the turbo spinning fast enough to raise boost pressure higher than the engine can consume, even when lugging.
:
OK experts, what do you think?

Chris

hellotbone

Sounds logical to me.

Diesel Freak

The high boost/low rpm condition you are describing when lugging causes the turbo to run very close to surge. This is easier to do with your -40 than the stock HX35.

Running a turbo this close to surge won't hurt it, that is untill you quickly back out of the throttle....and then it starts Barking at you..then you run the risk of a broken turbo shaft.

I have heard this every time I do this on my truck, or Rips truck when out on a diagnostic run through the neighborhood.