C or D turbo?

[dirtyfingernails]

Perhaps a silly question, but I may buy a truck this weekend and need to know. The truck I'm looking at has a placard on the passenger side of the block with LDT-465-1C. But the truck doesn't "whistle" as I've heard on other trucks. Is the D version actually the whislter or is this one broken or damaged? Which leads to another question. Would a turbo truck run without the turbo functioning? Thanks.
DFN (aka The NOVICE)

 

[Hookin1]

It may have had the turbo changed to d model....i would pull yhe boot off of the intake side and make sure the fins turn freely inside the turbo...if they turn with no binding then it probably has had a d turbo put on it...also while you have it open check to make sure there is not excessive oil in the intake which would show that the seals are going out..

It will run without the turbo but it will be a read dog due to the timig is different betwen turbo's and non turbo's and since the turbo is not spinning it becomes a air and exhaust restriction....

 

[cranetruck]

I have the "D" turbo and can hear it spool down when the truck is shut down. Of course, if you have an insulated/hard top it may not be that easy to hear it. I can hear it for about ten seconds after the engine is off.

As a side note, the boost gauge is a perfect way to keep an eye on the workings of the turbo.

 

[Stretch44875]

When I bought my truck, it didn't whistle at first. Took about 30 miles of driving before it would spool up and whistle. The motor is tagged as a D turbo, but at some point it received a C turbo.

 

[houdel]

Same thing here. My engine tag states LDT465-1D, but I definitely have a "C" turbo. I'm not really sure that the -1C or -1D suffix refers to the turbo, it may be a difference in the engineering level of engine itself. FYI, I have attached a photo of my "C" turbo. The "D" turbo has a wider, flatter and more "square" exhaust side, and the clamp between the exhaust and intake sides is different. Sorry I don't have a picture of the "D" turbo, but if yours looks like the attached pic it is a "C" turbo. If it looks significantly different (the difference is quite plain) then you have a "D" turbo.

If you have a "D" turbo, maybe good, maybe not. The "D" turbos put out about twice the boost (approx 12-14 psi for a "D" vs 6-7 PSI for a "C"), but the "C"s sure sound COOL!

Horsepowerwise I'm not sure of the difference, a "D" might give you 5-10 more HP, but I doubt it's not enough difference to feel in the seat of your pants. You'd be better off installing a pyrometer and cranking up you fuel rate to give you an EGT of about 1100F-1150F on a hard pull. The "C" will smoke a bit more, but that is as good as you are going to get without running into turbo overheating problems, which you want to avoid at ALL costs!