Ph4tty

I think drive pressure is the biggest hp killer with the stock turbos. If the new holsets turbines flow more than the one on the hx35's then they should make more power on either truck.

The 3rd gens do have a couple advantages such as a better head and FI system

tlse1

You are looking for a drive pressure of 1to1 is optimum 10 psi over on drive pressure isn't to bad at max boost wide open throttle.

Big Blue24

I'm with you WVAussie, I think that the 3rd gen hotside flows more than an HX-35. I think some of the bench racers on this forum will be surprised when I finish my project and strap her down to the dyno.

And all of those Jammer 5 Naysayers, true they are cheap, smokey, and hot, but they do make power and with the Adrenaline, I have no doubt that they spray enough fuel for 500 HP!

Now as far as this turbo getting me there, who knows, it might be worse than stock! But I'm gonna try it and see!

HOHN

I thought they were basically the same, too--- HE351s, no?

WVAussie

Is there a way to put a boost gauge on the hot side without melting it?

Big Blue24

I think if you run the first few feet in copper, you can run a temporary drive pressure gauge. I think I'm going to test my HX's drive pressure before the switch to compare. I have a cheap 20 dollar sunpro oil pressure gauge that goes to 100 psi that I have been running as a cheap boost gauge to verify the Adrenaline's map sensor based boost readings. If it gets sooted up and stops working, no big deal. I'm just not sure if my egt probe hole is the right size. I'm not going to drill and tap it again!

Anyway, I think that if I can maintain drive pressure at identical boost, the HE 351 will out perform the HX-35 due to cooler boost from larger compressor.

It is going to be really hard to compare egt's as there are so many factors and the fact that the weather is rapidly changing around here. I would just dyno the two setups back to back but there is no way that I can swap out a turbo that fast when the two are so different in terms of down pipe, and cold pipe.

kas83

It's the same with any turbo. The 3rd Gens have a better flowing head, a timing curve that's infinitely adjustable, and all around more efficient design. Ever see a 12 valve and CR spool identical 66mm turbos? The CR will do it alot better than a 12 valve, and at lower power levels to boot.

They're not bad turbos, it's just that a 12 valve, and even the 24 valves, need more air at comparable power levels than the new Common Rail motors, the 12 v's needing alot more obviously.

Hammer

Doesn't the 3rd generation trucks turbos have a very small(9cm) exhaust housing on them?????.How does anyone feel that they will make better power with one of those over a HX35/12 combo?.With how tight the 3rd gen exhaust housing is drive pressures would go through the roof and heat would build very quickly,alot faster than any HX35 combo would......Andy

Big Blue24

No one knows for sure cause no one has done the swap on a 24 valve and posted their results. I am going to do the swap regardless of what others say can and cannot be done. I am going to ensure that I can easily go back to stock if this doesn't work, but no crime in trying something new.

I just need a dang v clamp about 5" to connect downpipe to cast elbow flange. Can 409 Stainless be welded to Cast? I don't have easy access to a torch to braze either, so I might just pop rivet the two together with some high temp red copper glue to give it a test drive. Hopefully saturday I'll get this all done.

JDGnut

I guess that was more of a Question.. than a statement... I knew there was a change in the 4.5's.. didn't know what the change was.. Looked on here for specs.. seem to get everything from 57-62 on the compressor side.. but like others have stated looks like everything I have seen on here is a 9cm... Any way you can miss match the parts.. use the compressor wheel and housing.. Never looked close at a 3rd gen turbo..

XLR8R

'03 - '04 used HE341, '04.5+ 5.9L used HE351 turbos.

351s had a larger compressor and the solenoid-enhanced wastgate actuator... hot side is the same, AFAIK.

One of the reasons HPCRs spool so quickly with the big compressor is the pilot injection event and the fuel map's dynamic timing. The solenoid's duty cycle combines driveability with high boost potential.

No free lunch though - 1600*F EGT & 75psi drive pressure (boost 45+psi) are common with 500HP worth of fueling... good news is that the 351 takes that abuse pretty well and the engine, of course, has features such as under-crown oil cooling jets, high-temp aluminum alloy slugs and excellent stock HG sealing.

That's a good mod you did for the wastegate - what is your regulation scheme?
Incidentally, radiusing the wastegate's entrance won't have a negative impact on the exhaust gas's laminar flow when it's closed, and can only improve the efficiency of excess drive pressure release.

Big Blue24

I'm going to cap the hose barb on the solenoid and place a bung on the new cold piping that I am creating. I am not going to reclock the compressor but just allow the outlet to remain @11-12 o clock. That way I dont change the geometry of the wastegate actuator and I don't rely on drive pressure alone to open the gate. I still haven't decided if I'm going to put a standard adjustable boost elbow in the bung, or rig up something different. I think to begin with, I'm going to use my edge supplied wastegate elbow and tune/ make changes from there.

Does anyone know much copper tubing is required to run a drive pressure gauge? I have 14", just wondering if that is enough to get away from the heat and transition into nylon? I have a cheap gauge that I don't care about sooting up, just want it to work for a while.

Big Blue24

Couple more pictures. Just cleaned up a few of the burs on the inlet to the turbine housing. I'll port match it when I get the old HX off this Sat hopefully.

Also a pic of my parts to fab up a cold pipe.

Big Blue24

Close up of compressor and turbine wheels. Does the turbine wheel look like it will flow more than an HX 35 turbine? I have no idea what an HX wheel looks like.

XLR8R

Here's a permanent drive pressure gauge kit (TIP) that works with any boost gauge (0-100psi is best) without drilling & tapping an extra hole in the exhaust manifold:



Stainless steel, of course...