Low boost after turbo swap

[ToLows10]

Beings this is my first post on this forum I figured I'd introduce myself first. My name Mike. I frequent S10forum and S10racer. I build and race S10's and blazers and do all my own engine and chassis work as a hobby. I also own a 24' enclosed trailer to haul my 9sec S10 Blazer, and of course I use a 2005 F350 4X4 6.0L (harley edition if it matters) to pull this 10,000 lb combo .

Now onto to problem. My F350 has 142,000 miles on it, coming home from work I had the first ever problem out of this truck... the turbo stopped spooling. No big deal just install a new one. I've been looking for a reason to fool around with the tow pig. Well now here's the problem. After Installing the new turbo I lost 10psi of boost. The old turbo was a stock Garrett (P/N 1832255C91) and I replaced it with another Garrett (P/N GT3788VA) (which my research found to be a slightly better then stock upgrade). Well after the install I discovered it will not make nearly the amount of boost the old turbo. The stock turbo made 28-29 psi while the new one can only produce around 22-23 max. I know the turbo was installed correctly as I was there helping while it was installed buy an ASE tech in a professional shop environment. I checked the obvious...couplings, clamps, joints, exhaust leaks, and what not. The turbo spools fine, it has a little more lag but once she gets goin it will actually make boost with less pedal but it just won't make the boost like the old one when I got her floored! I know my way around a motor and a toolbox for that mater but this is my first step into the world of diesel. Thanks in advance hopefully it will be an easy fix!

Oh... one more thing. Do our motors have waste gates? Internal on turbo? Just wondering. That was my first thought but a friend said my truck doesnt use a waste gate. I thought for sure it would be a nessity. ???

Thanks again

[ToLows10]

Nobody?????

[Jeckstine]

If you went up to a power max it may be programing.

[BeXtreme04]

Common problem is a leak from the y-pipe to turbo... Your new turbo is what is known as a powermax and our trucks do not use a waste gate at all.. Instead it is what is known as a variable geometry turbo where it has moveable vanes that direct the exhaust gases onto the exhaust turbine blades. These vanes get clogged up with soot or rust and can cause boost issues... Chances are that is what happened to your old turbo, common fix is to remove it and clean it and then reinstall it.


Sent from my Autoguide iPhone app

[TerraScaper]

The powermax turbos don't boost as high unless you get a custom tune from an SCT. Look into the livewire and that will give you some guages too. Sorry for the unexpected down grade but with the stock tune it will be real laggy. Maybe the new whistle will cheer ya up

[ToLows10]

Well I went ahead and reprogrammed it with a preditor sport. Truck has some seriouse power now! Think I'm gonna tune it back a little