I'm getting ready to install a GT40R turbo. I currently run a -3AN line for my plain bearing Mitsubishi.

I guess the question is, do I run say a 2AN line with no restriction or a common 4AN or 3AN line with a restrictor on these units? I've heard that the seals will blow out quite quickly without a restrictor and that they need just a splash of oil. What's a good source for restrictors? Any feedback greatly appreciated!

 

Call ATP, they have many customers running these turbos.

 

I checked the ATP site, go to GTBB install accessories, they have a oil restrictor fitting(.035") specifically for the "R" turbos.
Carl
http://www.atpturbo.com/root/releases/release112403.htm

 

There is no need for a restriction on the GTBB series turbo's if you wanna pay money for something not needed that's fine, the center sections on GTBB series are restricted internally. I have had long discussions about this with numerious people at Garrett as well. Every single person both at Garrett US. and AU. say the same thing "if you wanna restrict it you can, BUT I WOULDN'T, it is restricted internally." also I have yet to have a single turbo out of the tons I've sold blow a seal of any kind.

-Sean

 

Nevermind

-Sean

 

I've confirmed this through other sources. Sean's right, no need for a restrictor on the 40R.

 

Yup, Sean is right. Confirmed by doing a pressure test at the CHRA inlet to outlet. It restricts "air" about the same rate as a .030 fitting. My lips still tast like turbo flange.

 

I'm not going to touch that one Tony :-)

 

Hey Sean, I was just poking around asking questions just to confirm what has been said about the GT series turbos is true, and I emailed ATP to see if the gt35R / gt 35/40 needs to be restricted or not. The response I finally got was that they are internally restricted, but not enough. This guy is full of SH*T right? What should this turbo actually be seeing in Psi?
Also wont the pressure at the turbo be dependent on the pressure coming out of the engine if it has had oil mods to boost its pressure? And then could require a pressure restrictor placed in line?

Most importantly what should this turbo be seeing in terms of Psi??

 

Rule of thumb for most BB turbos, <35 psi oil pressure.

 

First the guys at ATP are pretty knowledgeable I've talked to them a couple of times, they know there stuff.

Here is a piece taken right out of the book from garrett.

" oil pressure at turbocharger oil inlet to be 2.17kg/sq cm minimum at peak torque speed and above and no lower than .70kg/sq cm at idle.

So no lower than 30.8psi at peak torque speed no lower than 9.95 psi at idle. I hope that helps.
From my experience I have never needed one from what garrett has told me directly, If you want to you can, but there is no need, it is restricted internally.

-Sean

 

I could see the "restriction" on the inlet side of the CHRA on my GT35/40 turbo.

Going from -4 to -3 won't really help restrict it as the inlet side is pressurized and a small decrease in size is relatively ineffective.

For my old T04B turbo on my FC, I tapped the oil inlet side and used a Holley carb jet (#60 from what I recall; i still have the package for reference).

Garrett GT series is nice and they considered many factors during in their design.

J