I'm starting to do my research early and gather information so I'll make an informed decision when the time comes. Current setup in my signature but if the font is too small:

P.I.S. 160cc/80% single shot injectors (Stage 2), T-500 HPOP, stock turbo with billet wheel, Banks Big Head wastegate controller, FRx, deleted EBPV, Overboost Code Regulator, S&B intake, 4" MBRP exhaust, and a Hydra with way too many tunes. I'm still running the stock 4R100 with a modified valve body. Before you lecture me about transmission BEFORE sticks, an oil leak forced my hand to make the injector investment first. My body, my choice!

The truck has 308K miles on it (2K miles on the new injectors). I've got some driveline refresh/updating to do (u-joints, carrier bearing, springs, traction bars, and Detroit locker) and I have my sights set on an HD4R100 in the future as well. The last piece of the power puzzle is going to be the turbo. After that I'm done with power and will tweak/live with what I have. I have passed my PMS threshhold and crossed over from fun (and expensive) hobby to (even more expensive) money pit. I'm not looking for a pavement-ripper that pegs the boost gage every shift (I'm long past 22 years old) but would like to balance out the air with the fuel (new injectors). Not as much performance as balanced power (strong powerplant, manageable EGTs, etc.) that will make the truck happy as well as me (cruising at 65mph on the freeway suits us both).

FIrst let me give you the parameters, which is a choice of two options. I am either going to rebuild my stock GTP38 in some way, shape, or form (wheels, housings, port, polish, spit shine, etc.) or get a GTP38R. You can lecture me on practicality, show me graphs and pie charts, and talk numbers all you want but in the end I will only do one of those two things. I had a bear of a time getting past my smog inspection a week ago and I'm too old for those games. In my younger years I would gladly store everything in my garage, take 2 days to tear down the truck, install the OEM stuff, pass my smog test, then take another 2 days to put all the goodies back on to enjoy almost 2 years of fun in the sun. Nowadays not so much.

Sure a KC or BW turbo would be great but there is no way I pass smog with one of those, especially with a T4 mount glaring at the inspector. It needs to be drop-in AND have GARRETT stamped on the housing. I also need to retain the OEM style wastegate controller to connect the red line to.

The 38R is an attractive choice as it's ready to go out of the box. It has more airflow and can go upwards of 40 psi of boost. The downside is the non-rebuildable cartridge which pretty much makes it a disposable turbo.

There are plenty of options for rebuilding the stock turbo but is it worth investing in a unit that may not be able to deliver the goods to take advantage of the aftermarket injectors and only good for 25-30 psi of boost?

I'm leaning towards the 38R but not knowledgeable enough on the parts options for the 38 (and how they affect it) to completely discount what's already mounted to the truck.

Decisions, decisions.

Looking forward to personal experiences, recommendations, and witty banter!

 

Needing the Garrett logo leaves you with the 38r being your best bet most likely. I had a stock turbo with a 1.0 wastegated exhaust housing and spturboost compressor wheel. I never had a 38r to compare to but wish I would have tried one as I feel I had modified a stock turbo about as much as you can while still having the stock compressor housing.

I vote for a sxe turbo with a well placed Garrett sticker. but seriously I don't know if a 38r would have been any better than what I was running with my modified stock turbo and never really got a good answer when I asked.

 

Brian, if I were in your shoes I would probably go with the GTP38R and call it a day. I would get the original wheel with it, not a billet wheel.

Now, if you decide to go the other route and want a built GTP38 turbo (high flow outlet, RR 4/4 billet wheel, 360 degree bearing, stepped oil seal, painted) then I may have one coming up for sale soon if I go with the T4 mount. I am going to wait until we sell our current 5th wheel and get a new one to see how it does with that before jumping on the T4 band wagon.

That said, with the turbo I have I have a steady 25-30 PSI climbing grades while towing heavy. Peak boost is ~32 PSI. EGT's are not a problem using heavy tow. This could serve as a bit of a baseline of what you might be looking at if you modify your current turbo.

 

Mine is a similar setup: Garrett rebuild kit (270º bearing), RR 4/4 billet wheel, high flow outlet, and non-EBPV pedestal. I've had to go to the Banks Big Head wastegate controller. Either I have a solenoid issue or the 4 turns of preload in the instructions is a bit much. I can hit 30psi with no issue and set off my filterminder's dash light any time I want. EGTs are not a problem (I haven't towed anything of merit with the new sticks but I don't tow much anyway) but I know the stock turbo degrades past 25 psi and isn't happy past 30psi.

I'm just not sure if there are any viable housing/wheel options that might fit the bill for 30 psi max.

I haven't done much research as I thought I was stuck with the stock turbo regardless. At my smog check I learned that they don't care about the intake any more as long as there is a filter attached to the turbo inlet somehow. Up until recently you had to have the original intake tube attached to the turbo inlet (or have a CARB-certified exemption). This ruled out the 38R because of the adapter inlet tube. Now that it doesn't matter the 38R option is on the table.

I just don't know if there is a GTP38 combination that will rival the improved airflow and 40 psi of the 38R and allow me to keep the rebuildability. The disposable nature of the 38R is the only detractor in its equation.

 

 

Thanks for the link!

 

Scrap my last post... vote goes to the GTP38R with original wheel... vote placed.

 

The GTP38R is considerably louder, keep that in mind. Sounds cool for about a week then it's kind of annoying.

I still like mine though.

 

Brian, I have P.I.S. 160/30's, T500, S&B, HD4R100 and a few other things. I had a stock turbo with the WW gen 1 and the bearing went a few months after the addition of the injectors.That 38R gave me the biggest permagrin since I first got the truck tuned. You will REALLY like it.

 

He has an S&B intake. It won't be loud with that.

 

Noise doesn't bother me. I don't realize how loud the S&B and single shots are until I get to the top of a hill and ease off the throttle. Definitely not for everybody. But I do love the permagrin.

 

38R is the best way to go for a stock appearance. Plus to many guys love them. Riches isn't noisey with that set up. And I rode in a friends with thte AIS set up and you couldn't even hear it. There was a time to that Gale Banks also said that was the best stock replacement turbo on the market. He also sells them, I wouldn't buy from him, to expensive, but you will really like it with your set up.

 

I also have the S&B intake/GTP38R and turbo whine is definitely still way louder than stock. I keep the clear plastic cover on and have never run without it.

I will say, with the new single-shots, the turbo isn't as noticeable (because the injectors are now so much damn louder).

I guess if I wanted quiet I picked the wrong vehicle.

 

I have the plexiglass cover off to let it breath a little better so I'm not resetting the filterminder every time I park.

With the cover on, though, once the boost needle starts climbing it sounds like a vacuum cleaner in the quarter panel that echoes into the cab.

 

Mine really doesn't sound loud to me. But like BT said, if I wanted a quiet truck, I definitely went the wrong way.