I saw this on another forum (http://www.dieseltechtalk.com/forums/showthread.php?70-Stock-turbo-Mod) and figured I would give it a shot since I am sooo close to having EGT's completely controlled. I think this will set me over the edge and I will be able to do whatever I want with the truck.

The thread states that a stock HX35 has only the back 3 cylinders wastegated because of the divider between them. They carry on to say that this design raises EGT's under full boost (wastegate open) conditions. By drilling the wastegate port through to the other side of the exhaust (through the divider), all 6 cylinders are wastegated and provide more flow through the turbo, lowering EGT's. Of course I like to test everything myself so that I can say it worked on my specific truck as well

They said a 3/4" works good but since I have a mill here, I set it all up dead center and drilled it to 15/16". I might go back with a 1" end mill later, still deciding if I should or not. It has to be dead center for it to be that tight as the wastegate valve thing that covers the hole is 1 1/8" diameter, so you don't want it to be off any if you use a big drill bit.

I still need to test it and put the turbo back together, and finish wiring the truck and, yeah it will never run again lol. Maybe friday.

Here's a video I made showing the planning process.

http-~~-//www.youtube.com/watch?v=kyhHRPUF7NA

Here is a pic of my turbo when I got done.

Got it done today. Only the water temp gauge, RPM, A/C compressor don't work. I put 15 miles on it and I really can't tell a difference with that hole in the wastegate. I think my wastegate actuator is a little stuck because I was hitting 45psi or so. I think my 35psi gauge tachs out around 40-45 and I was still going when it just stopped so it might have hit 50 for all I know. I will check the actuator out and see what the deal is. I have a pressure relief setup that lets the wastegate see pressure and that little thing that does it is what is sticking. I have a 12V air solenoid that I want to make work one of these days. The turbo does have a little more whistle to it, though I haven't heard it in months so maybe thats why it sounds louder.

Bump to the top.................any updates ISX?????

Why do I keep forgetting about this. I have pulled the trailer several times and I can say that.....I can't tell a difference. My wastegate opens instantly when I get to 35psi and stays shut any time before then because of a special overflow valve I put in and I haven't got enough boost to tell if it is working or not. But as for drilling the hole in the turbo, during nonwastegate opened conditions, I can't tell any difference at all. My EGT's are really low but they were low before so I can't say the crossported hole did it. Pulling our trailer at a constant 70mph I cannot break 900F egt even at 85F ambient up 7% grade hills, nothing will make it break that temp. Passing people with the trailer I can get above it but driving sane at a constant 70 will just not go over it. Got 17mpg pulling it the constant 70mph for 300 miles so it's still on top of it's game This trailer.. http://forum.mopar1973man.com/attachment.php?attachmentid=210&d=1259508018

Figured it out. They are split off because of a thing called pulse turbocharging which uses the kinetic energy of the pressure pulsations caused by the expulsion of the exhaust gas from the cylinder. It achieves higher torque at lower engine speeds. This is why the exhaust manifold is split into the front 3 and back 3 and why my turbo was split as well. So no clue why the HY isn't split. I didn't notice much of a difference if any but I guess the principle is there

The HE's found on CR's aren't divided either. I wonder if the housing is so small that it's not needed for low end flow. My Garrett is divided.

I thought those were variable so they wouldn't really need any kind of fancy pulsations?

The HE's found in 5.9 are not variable, HE341 and HE351CW. The HE351VE found on the 6.7 is variable.

You're telling me those trucks just have a regular turbo with a 9cm tiny housing?

You're telling me those trucks just have a regular turbo with a 9cm tiny housing?

And now you see why I wanted to ditch it! According to Hoslet a 9cm undivided flows about the same as a 12cm divided... but???? Anything with a fixed housing size is not variable, the HE351VE is something like 3-26cm3.

Hmmmm, wonder if whoever tested that is the same one giving all this other inconsistent data I keep finding lol. I'm gonna win the lottery and start buying my own test equipment. Fix the world's data consistency issues

Hmmmm, wonder if whoever tested that is the same one giving all this other inconsistent data I keep finding lol. I'm gonna win the lottery and start buying my own test equipment. Fix the world's data consistency issues

Good luck with that one!