It was stock... Garrett Powermax Stage 3 GT3788R Ball Bearing Turbo

[WarWagon]

The Garrett Powermax Stage 3 GT3788R Ball Bearing Turbo might be fun to try on a 6.5. It's long discontinued and is for the 5.9 diesels. Few still around out there. The 2nd gen turbo's have the compressor housing that would work better than the 3rd gen HPCR design below. The ball bearing takes less HP (friction loss via heating the oil in a JB) and spools up quicker than the same sized journal bearing (JB) turbo. Rumor is you can run a slightly larger BB turbo and have the same performance as a smaller JB turbo. Sound is supposed to be like the Knight Rider car... The drive pressure is documented to be lower than the stock turbo and that sold me to find one of these. They generally cost more than JB turbo's.

Anyway is there any reason the 5.9 Cummins turbo should survive 3 engine rebuilds? Yeah, turbo time as it's starting to rub the housing. I suspect it's blowing oil out the exhaust seal as well. Nevermind later 5.9's have a better turbo and, well, towing the 6.5 killer grade this turbo falls over some in high RPM.

Stock photo starting to rub:



So we pickup the last discontinued turbo available from a Garrett distributor, rebuilt, with 1 year warranty. (I made 1 phone call to check stock and the company I called did all the calling around for me and found some outfit with one in the back room.) It has a ball bearings and has a coolant cooled center section as the oil flow is way down. The oil feed is like an AC orface tube restricted as the ball bearings don't need much oil. Thus the need for coolant. Of course stage 1 is simply too small, Stage 2 is highly recommended and Stage 3 is for high RPM lovers like me. It's also the only stage that was available to me... ( All three stages are also known as GT3782R , but, stage 3 is a true GT3788R.)



The install is going to be a PIA as the two 5/8" to 1" heater hose adapters are missing. I already emailed Evans about turbo heat coking their coolant. They assure me it will be ok.

Of course this needs all the trimmings to take full advantage of "Stage 3" like a Smarty Touch tuner and EGT probe as Cummins will s#it a valve seat out of the head if you run EGT too high. I have to limit the HP to 425 and torque to 900 as that's all the South Bend Clutch I have will hold.

Now taking the 305 HO engine to 395 HP and raising the RPM defuel to 3400 from 3200 already is fun on the stock turbo. We have the 110# valve springs and Hamilton cam from the rebuild already in so time to take advantage of that.

Just got to be careful of the surge area and barking it...



Description- 2002.5 - 2007 5.9L Cummins Engine
- The GT37R dual ball-bearing turbo
- A Garrett exclusive ball bearing cartridge for unbeatable response, efficiency, and durability. Elimination of the thrust bearing eliminates Failures at elevated boost levels
- The upgrade results in lower intake and exhaust gas temperatures as well as reduced backpressure for more efficient air flow
- Water-cooled center section with a patented dual ball-bearing center section results in higher durability and longer turbo life
- Oil inlet fitting features a built in restrictor for worry-free operation
- High flow compressor wheels move air quickly and powerfully
- Maximum recommended boost is 40 psi

Garrett Stage 1 Horsepower 475*
Garrett Stage 2 Horsepower 510*
Garrett Stage 3 Horsepower 560*

* Estimated. Performance results of this product are highly dependent upon your vehicle's modifications and tuning/calibration. The horsepower numbers represented above are calculated based strictly on choke flow of the compressor map (total turbo capability), which represents the potential flywheel horsepower.

 

[FellowTraveler]

The Garrett Powermax Stage 3 GT3788R Ball Bearing Turbo might be fun to try on a 6.5. It's long discontinued and is for the 5.9 diesels. Few still around out there. The 2nd gen turbo's have the compressor housing that would work better than the 3rd gen HPCR design below. The ball bearing takes less HP (friction loss via heating the oil in a JB) and spools up quicker than the same sized journal bearing (JB) turbo. Rumor is you can run a slightly larger BB turbo and have the same performance as a smaller JB turbo. Sound is supposed to be like the Knight Rider car... The drive pressure is documented to be lower than the stock turbo and that sold me to find one of these. They generally cost more than JB turbo's.

Anyway is there any reason the 5.9 Cummins turbo should survive 3 engine rebuilds? Yeah, turbo time as it's starting to rub the housing. I suspect it's blowing oil out the exhaust seal as well. Nevermind later 5.9's have a better turbo and, well, towing the 6.5 killer grade this turbo falls over some in high RPM.

Stock photo starting to rub:

View attachment 50097

So we pickup the last discontinued turbo available from a Garrett distributor, rebuilt, with 1 year warranty. (I made 1 phone call to check stock and the company I called did all the calling around for me and found some outfit with one in the back room.) It has a ball bearings and has a coolant cooled center section as the oil flow is way down. The oil feed is like an AC orface tube restricted as the ball bearings don't need much oil. Thus the need for coolant. Of course stage 1 is simply too small, Stage 2 is highly recommended and Stage 3 is for high RPM lovers like me. It's also the only stage that was available to me... ( All three stages are also known as GT3782R , but, stage 3 is a true GT3788R.)

View attachment 50098
View attachment 50099
The install is going to be a PIA as the two 5/8" to 1" heater hose adapters are missing. I already emailed Evans about turbo heat coking their coolant. They assure me it will be ok.

Of course this needs all the trimmings to take full advantage of "Stage 3" like a Smarty Touch tuner and EGT probe as Cummins will s#it a valve seat out of the head if you run EGT too high. I have to limit the HP to 425 and torque to 900 as that's all the South Bend Clutch I have will hold.

Now taking the 305 HO engine to 395 HP and raising the RPM defuel to 3400 from 3200 already is fun on the stock turbo. We have the 110# valve springs and Hamilton cam from the rebuild already in so time to take advantage of that.

Just got to be careful of the surge area and barking it...

View attachment 50100

Description- 2002.5 - 2007 5.9L Cummins Engine
- The GT37R dual ball-bearing turbo
- A Garrett exclusive ball bearing cartridge for unbeatable response, efficiency, and durability. Elimination of the thrust bearing eliminates Failures at elevated boost levels
- The upgrade results in lower intake and exhaust gas temperatures as well as reduced backpressure for more efficient air flow
- Water-cooled center section with a patented dual ball-bearing center section results in higher durability and longer turbo life
- Oil inlet fitting features a built in restrictor for worry-free operation
- High flow compressor wheels move air quickly and powerfully
- Maximum recommended boost is 40 psi

Garrett Stage 1 Horsepower 475*
Garrett Stage 2 Horsepower 510*
Garrett Stage 3 Horsepower 560*

* Estimated. Performance results of this product are highly dependent upon your vehicle's modifications and tuning/calibration. The horsepower numbers represented above are calculated based strictly on choke flow of the compressor map (total turbo capability), which represents the potential flywheel horsepower.

Interesting how that stage 3 surge line swings out then back in, sounds like a nice upgrade..........

 

[WarWagon]

This install has ATT written all over it, but way worse. Like the ATT it's a massive turbo compared to the stock turbo. Granted the 5.9 runs well except when you toss a large 5th wheel on it and try 6.5 Killer Grade: You know you are out of turbo... Not as bad as a 6.5 GMx, but, the hard pull to redline isn't there.

Like the ATT: Hacksaw required for install. The install instructions simply SUCK!!! Some online installs are helpful but leave out 1 coolant pipe routing and the oil drain mod.

So I figure it's just a drop in oil return to the block with the OEM drain. WRONG! After fighting to get the larger turbo in with all three pipes attached... No wait. Uninstall was fun. Oh yeah the PacBrake is also in the way to add even more quality "Fun". The brake assy extends to the middle of the turbo compressor housing. I threaded the studs out of the turbo manifold on the engine side and the turbo to get the turbo out without removing the manifold. There are two studs on the manifold engine side and two outboard studs threaded into the turbo. The penetrating oil I used made the studs finger tight - History will record the only luck I have ever had on a Diesel.

So fighting to get the turbo in place took 2 people and a large crowbar to pry the exhaust out of the way. And it's 1/16" too big to clear the exhaust manifold. (Hits while trying to "rotate" the turbo in place. Hitting on the frame as well.) So I have to pull the bottom bolts and loosen the top manifold bolts.

Then I notice the oil return hose is in a "Z" kinked shape. So at 4AM we remove the oil drain tube with the turbo in place, apply a hacksaw, and add another hose section with 2 dangerous worm clamps. Worked out very well, but, could have reduced the fight on the way in if I had known it needed modification and left it off.

So the oil return line is on, oil feed is on, 2 studs threaded in by hand with the turbo in place on engine side only, 2 bolts outboard side. Need to put the vband clamp on all the way exhaust side to the brake down pipe, plumb the cooling lines, and put the intake on. Simple plan: It will run enough to get back into the garage for the second night of finishing up.

The cooling plumbing will be another "work of art". At least one line is clear as day and second luck I found two hoses with different in/out diameters. parts store turned me loose in their hose selection and said "Have fun!" Recall I am going from 5/8" to like 3/4" in two separate locations. IMO they should have done this on the metal tubes supplied.

Oh yeah 4 AM... It was like 106 out during the day (110 predicted today) and way too hot to be working in the garage on this even with the AC pointed at me because I can't close the door with the long crew cab long bed. I lasted all of 30 min trying. It was a pleasant 80 degrees at 4AM.

The old turbo is rubbing the compressor housing and has oil in the elbow of the compressor housing. Pretty sure I found the oil consumption of 1 quart every 1K miles.

Interesting to note the Dodge alternators have a "hot" bolt that sits in the middle of a plastic backing. The charge wire is lower and covered. Left a nasty burn mark on my favorite tool. I did not expect it.

 

[WarWagon]

So the results are in.

I put some Fender covers down on the hot pavement to change the turbo oil drain hose that was made into a "Z". This was after noting an oil leak and with the 5th wheel attached. The hose had torn from the "Z" shape experience. It was easy to replace from the bottom.

Then on to the South Rim Grand Canyon avoiding roads closed from a wildfire. After that up the 87 and 6.5 killer hill (8600') camping along the 260 where the fire restrictions weren't so bad due to yet another wildfire. 13000# GVW 5th wheel with tall bug splattering aerodynamics of a brick.

Officially found the limits of the 2003 cooling system and EGT's would cheerfully go high enough to scare even me. Plenty of power, but, at 3000 RPM with the fan screaming at 50 MPH the cooling system is getting really close to 240 degrees. EVANS or not that's damn hot. Will try some other not so hot tunes. The EGT and ECT were controlled with the right foot. First time I have down shifted on grades by EGT's.

The turbo itself simply howls like a firetruck siren winding down around 3-5 PSI then shuts up at higher boost with a roar of air topping out over 30 PSI. (40 PSI is the known limit of the turbo.) Enough noise to put a grin on your face. It's not an annoying screech of nails on a chalkboard whistle like some turbo's have.

Combined with the tuner the turbo hits hard and pulls past the redline. It also is boosting around 1500 RPM. I just have to make sure I don't get under the turbo RPM with smoke although the tune smoked with the OEM turbo as well. Unloaded you need at least 3rd gear to be able to wind it up and out and feel it lean you back. 1-2 wind out too fast.

I feel the MPG has gone up as it's now double digits towing where it was 9 or less MPG before to the campgrounds on the 260. But I am not really watching MPG that close anymore.