I have been researching the 60mm comp. wheel upgrade for our trucks and found an interesting bit of information. On the early intercooled trucks '91.5 only, the turbos had a 54mm comp wheel, but in the '92 model year that changed to a 56mm wheel. Has anyone else heard of this?

 

The non i/c trucks had the 50 mm wheel, the intercooled had the 56mm and the 1 ton cab and chassis intercooled had the 54mm. Slap me if I am wrong.

 

i dont understand teh 54mm wheel thing on chassis cab trucks

 

It may have not been just the cab and chassis but I know I read on a turbo shops web site that some of the 1 tons had the smaller 54mm wheel. Can't remember the companys name. It was Htt or some similar company that offers upgrade turbo parts. Can't always believe what you read. I have never measured any myself.

 

Yes, and everything you see on the internet is true

 

how much is that upgrade and where can i find it? i have a hx40 but i still have to wait awhile till i can get everything else to put it on

 

I believe I read it on the GDS website. They didn't say 1 tons only, they said all '91.5 trucks.

NO SPRK, I'll see if I can find a link for you.

 

http://www.gdsdieselparts.com/1991_5...o_upgrades.htm

NO SPRK, you will want part # GDS CH-05

At the top paragraph is where they say these turbos have the 54mm wheel.

 

I read that some where too but I do not recall where.

I was wondering myself if it was an error or whether they really did that.

 

I didnt see any prices there. Do you know what they charge. HTTurbo.com is asking 400 ($50 core) for theirs. Thats just the compressor upgrade. The exhaust housings start at about $195 i think.

 

I read the GDS link above and they just say 50mm for non i/c and 54mm for i/c. That may be true, but I am sure I read about the difference of 54 and 56 mm on the later factory i/c trucks. As I said above, who knows.

 

Here is where I read it. this is from HTT website


For H1C, WH1C model Holset turbos
This upgrade will convert your stock H1C or WH1C turbo into a H1C/H1E or WH1C/WH1E/40 hybrid turbo. (This upgrade utilizes an 6-blade wheel and requires no machine work ... backplate comes with kit)
This housing and wheel mounts to your stock 12 valve 1992-1994 (It only bolts directly to the 91 trucks that came equipped with air-to-air charge air cooler.) Your stock compressor wheel measures 56mm unless your truck is a one ton. This upgrade wheel measures 60mm.
No internal turbocharger modifications to your turbo are required.
Note: Some 1994 WH1C turbos have been replaced in the field with HX35W turbos so verify your turbo part number with us).

 

I think, personally, since the various engine parts are determined by CPL, and not the weight rating of the truck in question, it makes sense the turbos would be the same within a given CPL. I'm just sayin'......

 

sounds like a pain for my factory non IC turbo. i think ill just wait for my hx40

 

From what others have told me, they are in the $200 range, and require no core.

NO SPRK, waiting for the HX-40 sounds like a good idea.