Another Dummie

[shoot4fun]

OK. Here comes another dumbass question. On my '92 D250 4WD, what size is the stock turbo? I'm reading all these posts about 12s, 14s, 16s and now I've read one about a 18.5! I'd like to make mine run decent without a lot of expense, and I've been reading up on the VE pump tuning. I understand all of that (ok, some of it anyway) I'm just curious and want to learn all of this. All my years around the Cummins have been bone stock. The old man didn't let us monkey with them. (We've had 6 since our first in 1989)Now that I have one of my own that I can tinker with, and I have the shop to do it in, and the time, I want to do all I can to make it run like it should. The serious upgrades can be done later, after this project is actually able to be driven.

Thanks!
Brad

[JD730]

Most 92's should have the lag master 21cm exhaust housing on it. Although I have seen some with 18.5cm housings on them.

[shoot4fun]

That helps a little JD. Thanks! I guess I need to take mine off and measure it? What part do I measure? Is it the opening, or the turbine itself? I'm not sure what I'm looking for so it'll be dang hard to find it!

Brad

[Philip]

My orginal exhaust housing was marked with the size. It was located on the bottom of the housing by the mounting flange. It was cast numbers.

My 16cm housing wasn't marked that I can remember.

[shoot4fun]

Thanks Philip! I'll look on mine when I get home.

[cummins king]

21 came with the automatics and the 18.5 came with the std.

if you have a std get a 12 or 14cm

if you have a auto get a 16 or maby a 14

depend on what you do with it, play, tow, ext.

[shoot4fun]

Mine has the 5 speed. I'm not going to play hard with the truck. It'll be a daily driver, may pull one of my stock trailers a week, or a flatbed trailer once a month. Mostly, it's just a regular truck. Thanks for the advice guys!

[cummins king]

a 16cm will make you happy but if its not enogh you arnt wasting much money and they can be easly resold on here or bay

[Ace]

I ran a 16 for awhile and it was a nice improvement over the stock 21cm. I later went to a 12cm, and like it even better. Almost instant boost, really fun to drive. I have the wastegate bolted shut and EGT is not an issue. I don't think the stock I/C injectors flow enough fuel to ever make EGT and issue. 12cm with the 60mm impeller upgrade and the wastegate bolted shut makes 28lb max boost and 1100 max EGT on my rig. Feels like it'll run that all day long, but I haven't towed heavy up into the mountains with it yet.

[GLHS]

Non-intercooled engines (89-early 91) and 93's had the 18.5.
Early intercooled engines (91.5 and 92) had a 21 housing. That's what mine had.
A cheap upgrade is the 16 cm ($160 new) like cumminsking said.
Other options would be a used 12 cm wastegated ($40-$120?) or a 14 cm non-wastegated ($175 new).
The most expensive is the wastegated 14 cm housing ($425 new; $250 used).

[shoot4fun]

Thanks for all the help guys! It'll help!

[75Dodge]

How do you measure the size of the exhaust turbine housing?

[cummins king]

were the exhaust flange is going to the manifold on the inside it tells you a number