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FAQ  :   Turbo Swap Guide

for the Mitsubishi 3000GT VR4 / Dodge Stealth RT/TT

VERSION 1.0,  05. 21.2000

Primer by Errin Humphrey

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SPECIAL THANKS to everyone who promptly offered me advice and information when I did my first turbo swap.  I wouldn't have made it this far without your help!  In particular, I want to thank the following people for their contributions and inspiration:

Mike Mahaffey
John T. Christian
Jeff Lucius
Mikael Akesson
Barry E. King
John Adams
Matt Bompani
Jack (Xwing) Tertadian
Hank Orsel
David Brown

(I’m still digging through my old emails trying to find out who else helped me on it...)

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So you’ve got a 3000GT/Stealth and a pair of new turbos, and you think you’ve got what it takes to do a turbo swap yourself?  You’re not going to be a pansy and pay somebody else to do it for you?  You’re not going to run home crying for your mommy at the sight of your mangled hands as you try to remove the rear heat shield?  Well, we’ll see about that.

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[Each step denotes removal of the specified part unless otherwise noted].
[Many (but not all) terms correspond to terms used in the Service Manual].
[Several of these steps are not entirely necessary, depending on your level of skill and how quickly you want to finish the job].
[O2 Housing == O2 Sensor Housing == Precat Housing (rear only) == Exhaust Fitting. I will refer to these two parts as "O2 Housing" exclusively].
["Left" and "Right" generally refer to said direction while standing in front of the vehicle and facing the engine].

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Preliminary Steps

   01)   Drain engine oil (dispose of properly!)

   02)   Drain coolant (dispose of properly!)
   03)   Exhaust System (all of it including catalytic converter)
   04)   Air Filter
   05)   MAF Sensor Unit
   06)   Battery and Battery Tray
   07)   Winshield Washer Reservoir
   08)   Air Intake Hose A (connects to MAF Sensor Unit)
   09)   Y-Pipe (connects to Throttle Body)
   10)   IC Pipe A (connects directly to rear turbo)
   11)   Intake Plenum (with Throttle Body connected; see T&T 4 and 5)

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Front Turbo Removal

   01)   IC Hose B (connects to Y-Pipe).

   02)   Air Intake Hose B (connects to turbo inlet).
   03)   IC Hose D (connects to turbo outlet).
   04)   IC Hose E (above exhaust manifold).
   05)   IC Hose C (above alternator).
   06)   Radiator:
              a)   2 brackets.
              b)   Remove upper hose.
              c)   Disconnect lower hose.
              d)   3 electrical connectors.
   07)   Front Heat Shield.
   08)   Unbolt exhaust manifold Heat Shield.
   09)   IC Pipe B.
   10)   Engine hoist bracket (L-shaped).
   11)   Front cam gear cover.
   12)   Disconnect O2 Sensor (electrical connection).
   13)   Remove O2 Sensor.
   14)   Unbolt O2 Housing from the Turbo (4 nuts).
   15)   Unbolt Turbo Stay (big metal bracket) from engine (3 big bolts).
   16)   Slide this bracket to the right (off the 4 turbo studs).
   17)   Remove O2 Housing.
   18)   Unbolt Turbo Oil Return Line from Oil Pan.
   19)   Turbo:
              a)   2 Coolant Line Eye Bolts (on the sides).
              b)   1 Oil Feed Line Eye Bolt (on top).
              c)   Disconnect Wastegate Actuator Hose (vacuum hose).
              d)   3 Turbo-Manifold Bolts (remove these last).
              e)   Turbocharger.
   20)   Optional:  In order to remove the Turbo Oil Feed Line you must remove the drive belt, alternator, dipstick guide, AC compressor, tensioner bracket, and AC compressor bracket.

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Rear Turbo Removal

01) Air Intake Hose C (connects to turbo inlet).
02) Clutch Booster Vacuum Hose.
03) Throttle Cable Guide:
    a)   Disconnect from firewall (2 bolts).
    b)   Disconnect cable from accelerator pedal.
    c)   Move cable guide out of the way.
04) Unbolt Rear Heat Shield (3 bolts).
    --> Use stubby swivel ratchet.
05) O2 Sensor.
06) Remove Rear Heat Shield.
    --> Take off shoes; climb up on top of engine; reach way down with right arm; grab lowest edge of heat shield; give repeated violent upward yanks until heat shield comes out.  (This procedure might not be necessary for you).
07) EGR Pipe.
08) O2 Housing (4 nuts + 1 nut/washer on lower mount).
    --> Pull it off turbo studs and let it drop down out of the way.
09) Unbolt upper bolt on Front Heat Shield.
    --> The lower bolt is awfully tricky to remove, but it is now possible to "rotate" the heat shield to the right in order to gain better access to the turbo coolant line bolt.
10) Unbolt Turbo Oil Return Line from Oil Pan.
11) Turbo:
    a)   Turbo-Manifold Nuts (3 total; 2 from below).
    --> Use LONG extension + wobble extension for lower 2.
    b)   Disconnect Oil Feed Line from Turbo (on top) & Plenum Stay.
    c)   2 Coolant Line Eye Bolts (on the sides).
    --> Don’t drop the washers! (2 for each eye bolt).
    d) Disconnect Wastegate Actuator Hose (vacuum hose).
    e) Oil Return Line must be unbolted from the Turbo.
    --> Helps if you (or an assistant) lift the turbo to access the bolts, but make SURE that they don’t drop into the exhaust manifold (same for the gasket)! Helps if you lift the turbo and cover the manifold hole with a rag.
    f) Turbocharger.
    --> Lift oil feed line and rear coolant line out of the way. Move turbo carefully towards firewall until oil feed line clears the compressor housing. Point the compressor housing downwards to gain clearance for wastegate actuator. Lift turbo out turbine-side first. (Note: Please let me know if you discover an easier way to remove this turbo.)

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Re-Installation Notes

01) Almost all steps are the reverse of the above.
02) Don’t overtorque the oil/coolant eye bolts!  They break easily!
03) Don’t overtorque the O2 sensor!  You’ll never get it off again!
04) You ~might~ need to cut a chunk off of the rear heat shield in order to reinstall it.  It wasn’t necessary for me, but it has been necessary for others.

* [under construction] Much more to be added to this section later.

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Tips and Tricks  (T&T)


Organization!!!  –  This is the key to making installation of the turbos as headache free as possible.  Keep all parts in an isolated area of the garage so everything can be found easily.  More importantly, it’s a very good idea to extensively organize all the nuts, bolts, washers, etc.  For the front and rear turbos, use a 3x5 card and neatly line up ~all~ the related bolts, eye bolts, washers, etc., and put abbreviated labels next to everything.  I also used another 3x5 card for other miscellaneous small parts.  You might not be reusing all these things, but you will probably refer to it often when you get ready to put the new turbos in.


Put bolts in their places!  –  This is a simple tip which for some reason is not followed by everyone.  Whenever possible, after removing something from the car, take the bolts-washers-nuts, etc., which held it on and screw them in where they were originally threaded.  This might not always be possible (they might be in the way of removing some other part), but it is much better than throwing all the bolts/washers/nuts in a plastic cup (or on the floor) and spending hours later trying to find the one you need.  And whenever this is not possible, put them into a small sealable plastic baggie along with an appropriately labeled 3x5 card.


Use Liquid Wrench!  –  The night before you’ll actually be removing the turbos themselves, douse all the nuts and bolts with Liquid Wrench.  This will make them much easier to remove and reduce the likelihood of breaking them during removal.


Cover up them holes!  –  Make sure that you have a pile of rags handy to cover up all holes in which dropping a small part into the hole would be a bad thing.  During the course of a turbo swap, many of these holes will pop up.  One of them (and probably the most critical) is the set of 6 holes which go into the intake manifold; these are exposed after removing the intake plenum.  Fold a shop rag over a couple times, and lay it across these 6 holes.  A few other holes you’ll want to cover up: various IC hoses;  rear turbo outlet;  rear exhaust manifold (after turbo removed).


Support that fuel rail!  –  After you remove the intake plenum, the fuel rail (actually the rail for the fuel injector connectors) will be hanging suspended over the holes into the intake manifold (which should be covered up with a rag, right?!).  I found myself accidentally leaning on this with my hand on occasion, so I figured out a way to support this rail.  Take a cardboard center from a used paper towel roll, and flatten it slightly.  Place it below the plastic rail piece and use a few zipties to keep it in place securely.  This will support the rail when you set your hand on it.


Towel Magic!  –  After you have mounted up your new turbo and you begin to connect the fuel/oil lines, the dexterity of your fingers will surely be tested as you attempt to thread in bolts (sometimes blindly) along with washers (or gasket) without dropping anything.  The coolant lines and the rear oil return line are the big trouble-makers.  Dropping something while doing the front turbo is usually not a big deal since you won’t have any trouble finding it, but on the rear turbo it can become a major problem, especially if the part somehow makes its way into the exhaust manifold. 

So here’s how I made the job a bit easier for the rear turbo:  I took an old bath towel and did my best job to "blanket" the entire area which lay below the exhaust manifold.  The towel wrapped tightly around the hole into the exhaust manifold and was pulled up loosely towards the sides.  I also had to leave a crack which I used to pre-setup the oil return line (which you don’t want to bolt to the oil pan yet!).  So basically, if you looked at the rear of my engine, you saw only a pink blanket with the exhaust manifold and oil return line peeking through, ready for the turbo to be bolted up.  If and when you drop an oil return line bolt or coolant line washer, it will be within easy reach rather than down in the dark recesses of the engine bay or stuck in your exhaust manifold.

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Necessary Parts List

Part Name
Part Number
Price ($)
Turbo-Manifold Gasket
Turbo-Manifold Seal Ring
Turbo-O2Housing Gasket
Studs: Front Turbo-O2Housing
Studs: Rear Turbo-Manifold
Studs: Rear Turbo-O2Housing
Exhaust Gaskets: Front
Exhaust Gaskets: Rear
Coolant Line Gasket
Oil Feed Line EyeBolt: Front
Oil Feed Line Gasket: Front
Oil Feed Line Gasket: Rear
Oil Return Line: Front
Oil Return Line: Rear
Oil Return Line Gasket
Oil Return Line Bolt: Turbo
Oil Return Line Bolt: Oil Pan
Plenum-Manifold Bolts: Short
Plenum-Manifold Bolts: Long
Plenum-Manifold Gasket
Rear IC Pipe O-Ring
EGR Pipe Gasket
AC Line O-Ring

Note: You’ll need extra gaskets if you plan to remove/replace the oil feed lines.

Note Legend:

(1) = Might not be 100% necessary to replace; reuse old parts at your own risk!
(2) = Good idea to buy extra of these!
(3) = Only necessary if you want to remove the front exhaust manifold heat shield!

Prices are those given by Tallahassee Mitsubishi, taking advantage of their 3/S discount.

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Necessary Tools List

I’m still working on this section.  Here’s a short list of some important things needed.  This list is in NO way comprehensive, and not all things listed are 100% necessary.

01) 14mm sockets (1/4 and 3/8 drive; 6 point; short/med/long).
02) Quite a few different 10mm and 12mm sockets.
03) Open and boxed-end 14mm, 17mm, 22mm.
04) Stubby handle swivel ratchet wrench.
05) Antiseize.
06) Extendable magnet.
07) Flashlight.
08) Liquid Wrench.
09) BFH.
10) Old Blanket.
11) Latex Gloves.
12) Bandaids.
13) Neosporin.
14) Tourniquet (j/k)!
15) 10mm x 1.25 nuts to remove/install turbo studs.

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[section under construction]

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...and a comment from one of our members...

I just removed my rear turbo and have found some steps in the 3S guide not necessary.  First, I didn't remove the intake Plenum, that saves a bunch of time.  I found that I was able to remove the rear turbo with the waste gate air house still on but disconected from the top side.  I also had no problem removing the turbo with the oil return pipe still connected, a much improved method over trying to disconnect while in the engine area; same for the front.  I also didn't bother removing the O2 sensor front or rear, although I did disconnect the electric plug to get more play in the rear.

The Stealth manual recomends removing the battery tray and washer bottle but that is not going to help at all - it has nothing to do with the rear turbo.  The book also shows that you should remove the EGR valve - nope, don't bother.  It adds nothing to removing the rear turbo.  The Turbo came right out with me standing at the fender on the driver's side.  Now one major problem I didn't catch and I do have some question about this, the air intake hose "A" when I disconnected it...  I didn't think it would be full of oil but it was and made a mess on my driveway.  It had about a 1/4 to 1/2 a quart of oil in it and I can't but be worried about where that oil came from.  There was oil in all the pipes leaving the turbo, but I didn't expect oil in the hose leading into the turbo-- the manifold exhust was dry.  The turbo was full of oil.  Is there anyway oil can get into the intake Hose "A" other then maybe backing up from the turbo?  Is there anything down towards the air filter that could be a problem with throwing oil into the intake air lines?  I see several smaller hoses conecting into the air hose but don't have any idea if they could be the source of oil, any help!?!

--- Peter

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...further comment and reply...

Sounds like you already found the problem, which i was thinking...a bad turbo.  The rear turbo most likely spewed all that oil into the pipes.  The reason it's also in the intake side, is because it passed through the blow off valve.

You might want to remove the driver's side intercooler and drain the oil out of it too, rather than letting the new turbo blow it into your engine.  If you had that much oil in the hose, you probably have as much, if not more in the intercooler.

I removed an intercooler from a car that had a blown rear turbo, and there was about 2 quarts in the I/C.  All this oil in the intake caused the motor to hydraulically lock, and break 2 rods.

--- Wayne

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Turbo Swap Guide ©2000-2004 Errin Humphrey, All Rights Reserved.
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