Why pay hundreds for a turbo charger when everyday hundreds are sent to the shredder? Typically junkyard turbos run between $30 and $50 and many people simply pull one from a junker and install it in their car without any problems.
Selecting / finding the correct turbo is your greatest dilemma. From what I've gleamed from others a 2.5 liter engine
should at a minimum run a Garrett T03 turbo with a 0.63 A/R exhaust scroll and a 60 series (largest stock) compression
wheel.
When considering a junkyard turbo a turbo expert (with a land speed record) has informed me that water-cooled cartridge is not
required. Use of modern motor oil combined with a cool down interval after spirited driving will eliminate all coking
problems.
| Vehicle | Displacement (cc) | Compressor Trim | Compressor Scroll A/R | Turbine | Exhaust Scroll A/R |
|---|---|---|---|---|---|
| 86 Thunderbird (auto) | 2300 | 60 late carbon seal rebuild kit |
0.60 I've never seen this A/R on any other turbo. Unfortunately it is a bolted flange design instead of a hose clamp. |
T03 std Inconel alloy |
0.63 |
| 82 Nissan 280ZX (auto) | 2800 | 60 | 0.42 | T03 std GMR alloy see side note |
0.63 the flange on this unit is not perpendicular to the scroll As a result you may not be able to swap between this and any of the other units unless you have planned ahead. Also note that this turbine is a GMR alloy that has a thermal resistance that is 150 degrees F less than that of Inconel! |
| 900 Saab 16 valve (lots of years) | 2000 | 50 | 0.42 | T03 std Inconel alloy |
0.48 |
| 900 Saab 8 valve (lots of years) | 2000 | 45 | 0.42 | T03 std Inconel alloy |
0.48 |
| Volvo 240 (year unknown) | 2400 | 45 | 0.42 | T03 std Inconel alloy |
0.48 this has a funky exhaust flange that would be a pain to work with |
Notice the differences in the ends of these turbines. The end of the left wheel is roughly triangular has extensive grind marks and is made from Inconel. The end of the right wheel has a bolt pattern is made from GMR alloy. Inconel has a 150 degree F higher thermal resistance and is the preferred turbine. This can be inspected at the junkyard once the turbo is pulled from the car. All Garrett T03 turbine wheels are interchangeable so if you don't like a turbine from one, simply find another car and pull another. Since new turbine wheels cost $190 so you might as well take your time and select the one you like.
Turbo disassembly - The hard part of disassembly is removing the turbine housing from the cartridge. Soak the assembly in penetrating oil and back off the exhaust scroll bolts (don't remove them yet). I use the 'Fred Flintstone' technique where I insert a chisel between one of the bolts and the cartridge and not so gently tap. As much as possible work with opposing bolts to ensure the housing comes off straight. As you slowly move the housing off you need to back the bolts off and periodically rotate the shaft to ensure that the turbine is not binding. Hopefully you have resisted the temptation to remove the compressor scroll first since it is much easier to bend the compressor wheel with the inlet scroll off (and trust me they bend VERY easily).
Once both scrolls are off place the very end of the turbine in a vice (preferably with plastic jaws) and use a T handled wrench to remove the retaining nut. It is important to note that Garrett used both left and right handed nuts on the end of the shaft so make sure you know which one you have before twisting! Do not apply any side load or you will bend the shaft. Bent shafts can be trued but it simply adds to the cost of refurbishment.
Turbo Rebuilding - Before ordering a rebuild kit you should inspect the seal that is behind the compressor flange. There are three types of seals:
Warning: sales people will tell you that if you have this year and model it will be a certain type of seal. Don't believe
it, the ONLY way to get the correct rebuild kit is to physically examine the internals of the turbo. Sales people don't know
beans!
Rebuild kits run about $90 from Turbonetics or a little cheaper from your local dealer. When ordering remember to order the
correctly threaded nut - both left and right hand threads were used!
Notice the differences in the center sections of the two shafts. The left center section is smooth which indicates that it has been reground and is most likely 10 thousands undersize. The right center section is thicker where the bearings ride and is stock. A stock shaft should be 0.399 inches thick. At this point I usually take the turbine wheel and shaft to a professional to have them rebalance the wheel, check the shaft for thickness, ensure it is true, and check the ring seal width. The time I had this work performed by a local shop it ran $50 for the entire operation.
This photo shows the back of a newly balanced turbine. Notice that a significant amount of metal has been removed from this turbine.
This photo shows the side of a newly balanced turbine. Although it is difficult to see there is some light grinding marks on the end of the shaft. Just to the right of the turbine you can see the installed oil ring. It is important to note that the tolerance of the oil ring grove is very important.
Reassembly - There are a number of web sites that go through the assembly process so I won't duplicate the instructions here. However the installation of the final bolt is typically glossed over. There is a LOT of contradictory information so read a lot before trusting anyone's recommendations (including my own). From what I have been told by a local rebuilder the nut should be tightened so the shaft stretches by 0.006 to 0.009 inches (one web site quotes 0.0055 to 0.0065 inches). Another commonly set of numbers is torque to 18-20 inch pounds and then rotate an additional 90 to 110 degrees. I found that it required more than 110 degrees of rotation to achieve the desired amount of stretch. Just like disassembly use a T handled wrench and don't bend the shaft! Personally I found that this was a pretty hefty torque. A new nut is mandatory, and use of blue locking compound is optional.
This is a photo of a completely rebuild cartridge ready for installation.
This gargantuan turbo must have come from either a locomotive or a ship. We are still trying to figure out how to get it to fit under the hood.
