Txwelder

Anybody have detailed specific instructions on how to modify the HX35 turbo? I thought I read something about milling out the turbo to allow all six cylinders to flow and increase efficiency of this turbo. Thanks.

WideOpenThrottl

You can drill out the divider in the exhuast housing to allow it to wastegate all six cylinders and not just the rear three, also a few people take and port out the stock exhaust housing to get some better flow out of it, do some searches to see what you find. Here is some pics of my housing that I drilled out. Tim.

12valve

ported turbine housing:
https://www.dieseltruckresource.com/...=porting+turbo

drilled through divider:
https://www.dieseltruckresource.com/...threadid=57304

40 mm internal wastegate:
http://www.cumminsforum.com/forum/showthread.php?t=1854

SHARPMACHINE

sweet attachment 12 valve

thanks

Txwelder

Thanks for the info. What are the noticeable improvements from this modification?

got...DIESEL?

mine's working sweet!!

Txwelder

Do I have to take the turbo apart to do this? I saw where people have said to drill through the wastegate hole but Im not tracking on that one because it is so small. How would you get a 13/16" drill bit through there? If I do take it apart what needs to be done to ensure proper re-assembly of the turbo? Just looking for step by step instructions I guess. Thanks for anything you have.

HOHN

I didn't take mine apart at all. I carved on it with the die grinder, then just vac'd the shavings out with the shop-vac.

15K miles later and no problems at all. It's a good idea to "port match" the housing to the manifold and the manifold to the exhaust port on the head. You don't want the flow to enounter a lip from a mismatch-- if anything, you want things EXPANDING as you go downstream..
jh

jasonjones

I was kinda wondering that myself...... Could someone elaborate on the reason for this mod?

HOHN

The biggest reason is to prevent turbo overspeeding. The factory setup only vents 3 of 6 cylinders, and a severely overfueled truck can push the turbo to the moon (explosion) on the 3 cylinders that aren't wastegated.


The next reason is correcting factory flaws. The overall precision with which the head, manifold, and turbo are matched at the mating points is TERRIBLE. Some carving here can eliminate mismatches that disturb flow and restrict it.

jh

WideOpenThrottl

If anyone is wondering what it may look like before and after here is a pic of my 14cm2 before and after I matched it to the exhuast manifold. Tim.



AFTER,

Txwelder

So if I can get the exhaust housing on the mill and just completely remove the center divider then that would be better than just drilling the hole from the wastegate port? Then port match everything and put it all back together? Does this mod allow you to achieve more boost out of the HX35 or does boost go down a bit but the turbo runs more efficiently?

HOHN

You don't need to remove the divider, just notch it so there's a 3/4 sq in or so.

Of there's about a Quarter's worth of surface area joining the two sides (i.e. removed from divider), then you've done enough.

jh

TxDiesel007

What is the reason behind this?

Ive already seen the photos for this setup and im understanding that it will better flow exhaust and gate all six cylinders instead, so Im gettin this, that the complete removal is not needed,

But wouldnt it be more efficient to just remove the whole area instead of the 3/4 square inch? if i wanna remove just the 3/4 square, can i cut it at the center of the lip with a dremel or something?

THanks guys!

Reason im askin, is twins are comin up and fast...

Rick

Forrest Nearing

I'd just cut the entire wall back with a die grinder or equiv. open up the
wastegate hole a bit too while you're in there