I am trying to identify the turbo on my father in laws 1992 350 dually. When he bought it he was told it was an aftermarket turbo. The only markings on the turbo is the name Holset and a funny looking H and a small 3. I am curious as to which one he has as he runs substantially higher EGT's than me but shows to be making 40 psi boost. Also there is no wastegate!

 

Ok from looking at pictures I have found I think it is going to be an H1C. How can I tell if it has been upgraded?

 

measure the inducer and exducer of the compressor wheel.

 

A pic would help tons. The h1c is the stock unit for a 92. It may have a smaller exhaust housing (thus the "upgrade") which could explain the higher EGTs. Or it may have been hybridized.

 

Sorry it took so long. Got a couple more if needed. Sorry if the quality is poor. All I had was my cell phone.

 

appears stock to me. i know the '92 models came stock with a 22cm exhaust housing. possibility of an 18.5cm h1c exhaust housing was mated to the center section? but even with an 18.5cm housing, egts shouldn't be too high should they?

 

Possibly has an upgraded compressor housing.

 

He says at cruising speeds he runs around 10 and sees 1200+ when pulling.

I am just curious because we are wanting to do some upgrades but are not sure what is actually already done.