Do I have a "D" turbo or a "C" turbo?

[houdel]

My truck data plate states my engine is a LDT465-1D. I assume that means I have a "D" turbo. However, it does have a very noticeable whistle. (Don't mind the slight oil drip in the engine plate photo, I power washed it after taking the picture).

Over the weekend, someone posted a photo of a "D" turbo and the exhaust section looked a lot fatter than mine (I think the thread got lost in the server crash). I've attached some photos of my turbo. Can anyone tell from the photos if it is a "C" or "D" turbo? The last pic is some numbers cast into the intake side, I had hoped it would be a part number but instead is a date (8/22/83).

 

[TacticalTruck]

RE: Do I have a "D" turbo or a "C" turbo

It's a "C" turbo. The exhaust housing on Cs are held on by a clamp Ds are bolted.
Jeff

 

[houdel]

COOL! I always wanted a "C" Turbo! Gotta go change my signature line. Thanks

 

[Djfreema]

I just swapped a C turbo on my truck this morning. God I love the way they sound!! Even with the muffler they whistle very loud.

 

[motorolanut]

Go Super C!!!

 

[rdixiemiller]

Sick puppies.
Just send me those quiet old D turbos. I'll give them good homes.

 

[houdel]

I just LOVE that turbo whistle! if you look real closely at my exhaust stack in the first picture of my posting http://www.steelsoldiers.com/index.php?name=PNphpBB2&file=viewtopic&t=6546, you can see a slight discoloration of the stack and three barely noticeable fasteners just above the joint between the J pipe and exhaust stack.

I have an internal race car collector insert mounted within the stack to tame the exhaust stack noise (without much reduction in the turbo whistle). I'm figuiring it gives me a 5-7 dBa noise reduction from the stack. Once I get some instrumention installed (EGT, Boost Pressure and back pressure gauuges) I'll list another post wih some hard numbers.

I'd like to reduce the exhaust noise 10-20 dBa, but I need to get the instrumention installed to make sure I'm not screwing my performance! Keep tuned for more data with hard numbers to see what I get. If the insert doesn't get me to where I want to be, next step is an Edelbrock 4" ID x 9" OD chambered high performance muffler. Gotta get that exhaust down to about 80 dBA, then work on cabin insulation to reduce the background mechanical noise for a reasonable quiet ride, I.E. be able to converse without shouting in the cab!

 

[Lax]

Great posts guys! Could you help me? I am going to pick up my first duce next week from Ft. Drum NY. Can you tell me what turbo this is? Is the "C" the whistler? Thanks for your help.

 

[Recovry4x4]

LAX, its a "D" turbo Sir!

 

[Lax]

Recovry4x4<
Thank you very much. Can you tell me anything about it? I was kind of hoping for a whistler when I bought the truck because I like the sound. No bid deal though. As long as it works forever I'm happy! Thanks again.

 

[Recovry4x4]

D turbos are regrded as being worthy of a tad more boost. The deeper throaty sound is preferred by many. Either will do you just fine and those who prefer the D tubo will tell you that the C sound can get irritating.

 

[Lax]

Recovry4x4,
Thanks for all your help. Like I said, as long as it works every time the way it was designed to I'm happy.

Houdel,
Sorry for jumping in on your post. I hope it is okay. Thank you.

 

[houdel]

Not a problem Lax. Maybe rdixiemiller has a C turbo he wants to trade.

 

[mangus580]

What I wonder... is if you had your truck running, how could you NOT know what turbo it is?

 

[houdel]

Mike - Nothing to compare it to, there are no others in my area. Dave Allen is the closest, about 1-1/2 hours away, the one time I went to his shop he wasn't around. I assumed from the LDT465-1D on the engine plate that it was a "D" turbo (which is also what the mechanic at Selfrige ANG base, where I got it, told me). Glad it is a "C" turbo, I just LOVE that sound!

 

[mangus580]

From what I understand.. the D's dont whistle at all...

 

[Flatlander]

What causes the whistle? Is it a difference in housing size? Fan design?

 

[Djfreema]

OK, I swapped my D turbo out yesterday for a C turbo but didnt do a test drive until just now and the butt dyno results are in. The D spools up quicker and gives the truck a better power band. There is a definate difference in power but nothing drastic. With my D turbo I was getting 15 lbs of boost earlier on, with the C, I am getting 13 lbs of boost and you really have to wind the motor out to get those numbers. With that said , I am still glad I did it since these things arent made for acceleration. When I had the turbos set side by side, I could see the C compressor wheel had a different design and I think I remember counting 1 less turbine blade on the C turbo. I already have my D sealed up for storage so I cant go back and count but I remember one had 12 blades and I think the other had 11 unless I miscounted.

 

[dmetalmiki]

Just read all these comments..as I HAVE THREE spare turbos..2(two) HAVE clamps AND thinner "snails" AND DONT MAKE A SOUND!!! quiet as u like! THE one remailning one LOOKS EXACTLY THE SAME "small sails" CLAMP...whistles AND shreiks like a beuty! MY 5 ton has BIG SNAILS (and) BOLTS again..NO WHISTLE till U start pulling..THEN it whistles!!!??? so...I remaim TOTALLY PUZZLED still.. and dont think there IS A DEFINING WAY to tell a whistler from a NON whistler...ERRRRRR..CEPT MY deuce (which screams like a banshee and whistles great!!) HAS A TAG ON IT STAMPED C1308 ..NOW THATS whaT I call a DEFINING I.D. good luck all those seeking the differences..IF it HAS "C" on the tag...your IN. (else its try it and see!!)

 

[alphadeltaromeo]

I don't notice the whistle on my D turbo if I'm not wearing ear protection, but I can notice it if I have hearing protection (either plugs or the full covering) during the shifting and then when I take my foot off the "go button".