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DIY Turbo Installation Tips

Hairdryer hints

by Julian Edgar

Click on pics to view larger images

At a glance...

  • Turbo plumbing fittings
  • Reorientating compressor covers and turbines
  • Apportioning the work
  • Turbo plumbing layout
  • Heat shields
  • Unexpected extra costs
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This article was first published in 2005.

Upgrading a turbo or installing a turbo on a previously naturally aspirated engine? Here are some do-it-yourself tips to help you on the way.

Turbo Connections

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If you’re buying a secondhand turbo, it’s important to try to source one that has all its oil and water fittings still in place. Doing so can save literally hours and lots of dollars.

In a wrecker-sourced turbo, the fittings will either have been removed completely (bad), or the hoses and pipes cut off (much better). If the hoses and pipes are still in place, it’s a lot easier to make the connections. For example, a banjo fitting is often fitted to the oil inlet, a flange and large diameter metal tube to the oil exit, and barbed metal pipes to the water inlet and outlet connections. If all the fittings are missing, you’ll have to source new ones – an expense that can quickly add up.

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Another reason for sourcing a turbo with its fittings still intact is they show the manufacturer's preferred sizing. So it gives you a guide for the required size of the oil return fitting for the sump, the oil supply line and the water connections. In roller bearing turbos, the inlet oil fitting can also include a restrictor.

Spinning Around

In nearly all turbos, one end or the other (or in some cases both) can be rotated relative to the position of the centre bearing. The centre bearing normally has to stay in the one orientation (ie it has an ‘up’ direction) but often the compressor cover lugs can be unbolted and the cover rotated, allowing the outlet to come out at a new position. However, other turbos have bolted-on compressor covers, where the cover may be able to be attached only in the one position. Still other turbos have the turbine housing connected to the centre bearing by a V-band – loosen-off the V-band and the turbine can be spun around as well.

But while there is often plenty of flexibility, it is far better if the turbo can be used as it was sold off the shelf, or as it was configured in another car. Rotating the turbine housing can cause interference between mounting bolts and the centre bearing housing fittings (eg the water fittings) and rotating either the compressor cover or the turbine housing can cause wastegate actuator mounting problems. As in, a whole new mount for the wastegate may need to be made!

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That was what was required in this fitment, where one of the turbos from a Liberty twin turbo was being fitted to a Toyota four cylinder engine. Rotating the turbine housing was required, but as a result, the wastegate actuator (which normally bolts to cast-in threaded bosses on the compressor cover) lost its mounts. To replace them was quite an involved procedure.

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A lathe was used to turn-up a thick aluminium ring (arrow). This is sized so that it is a snug fit over the top of the compressor cover, and is sectioned to allow for the compressor exit. The ring is held in place by longer-than-standard stainless steel cap bolts that also hold the compressor cover in place. Spacers (nuts drilled out) were used to distance the ring from the compressor lugs – without these, the ring would have had to be a very complex shape to provide sufficient ‘meat’ around the bolt-holes. The wastegate actuator bolts to the ring.

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The wastegate actuator rod (arrowed) already had a kink in it but the rod needed to be bent just a little more so that the wastegate operated smoothly. Its operation was tested with a large syringe on the wastegate actuator hose.

All in all, it was a lot of hassle to remount the wastegate actuator – so if at all possible, avoid this sort of fiddling.

How Much Work?

It’s not something that people will normally tell you, but in the home installation of a turbo, the organising of the oil and water systems and the making of a stainless steel heatshield can total as much time as making the exhaust manifold!

How come? Well, the oil supply line and oil return fitting both need to be made-up by an industrial hose supplier, the water supply and drain and the oil drain pipes may all need to be modified and then silver soldered back together by a welder, and despite looking quite simple, heat shields can be absolute bastards to shape so that they clear the turbo, block and all the connections.

In short, by the time the cutting and trial fitting of heatshield pieces is complete, and all the running around to suppliers and the welder is done, it can take days to put together these bits and pieces... longer than it takes to make the manifold!

Laying Out the Plumbing

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Installing a turbo on a previously naturally aspirated engine comes down to nearly one thing: plumbing. Think about all the pipes: the exhaust manifold (after all, just an arrangement of plumbing that connects the exhaust ports to the turbine), the inlet from the airfilter, the outlet to the intercooler, the exhaust pipe out of the turbine, cooling water in and water out, the oil pressure feed and oil drain...

When you start to throw in ideas like keeping the intake air plumbing as far apart from the exhaust plumbing as possible (to prevent the combustion air being overly heated), making sure that hoses cannot rub against hot bits or heat shields, and keeping the oil drain to the sump as close to vertical as possible, it can all start getting quite complex.

That’s why it’s important to mock-up where all these pipes are going before starting to weld them.

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This view shows just such a mock-up, with the lower heat shield removed. A single turbo from a Liberty twin turbo was being installed on a Toyota four cylinder engine. Two inch copper plumbing fittings were being used together with copper tube for the air plumbing (see Copper Intercooler Plumbing for more on this approach) while the exhaust was also two inch, this time in steel mandrel bends. The configuration of the turbo prevented the exhaust and intake ends being nearest the on-car exhaust and air filter locations, necessitating the use of lots of bends.

(1) The exhaust pipe, comprising one mandrel 180-degree bend and two mandrel 45-degree bends. (2) The turbo air outlet plumbing. Here the adaptor from the turbo outlet’s relatively small hose to the 2-inch intercooler plumbing has yet to be made – just a temporary one is doing service. (3) The inlet plumbing connecting the airflow meter to the compressor inlet. Note how the bends are held together at this stage with electrical tape. (4) The water hoses. (5) The braided oil pressure feed hose. Missing from this view, because it was yet to be completed, is the oil drain hose from the turbo.

Note that with this engine, the turbo is mounted on the rear of the transverse engine (ie nearest the firewall) where access is difficult. The ability in this case to lay out the plumbing on a second engine being suspended from an engine crane was absolutely invaluable.

Heat Shields

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Heat shields tend to be overlooked in aftermarket turbo installations and upgrades – but are near universal in factory systems. Heat shielding of the exhaust manifold, turbine and exhaust off the turbo are all extremely important. But first, how does this shielding work?

The shields prevent the radiation of heat. If you imagine watching the red-hot exhaust manifold of a hard-worked turbo engine on the dyno, placing even a thin sheet of metal between the glowing manifold and your face will cut down a lot on the amount of heat you’re subjected to. So long as the heat shield itself doesn’t start to get red-hot, far less heat will be radiated from the manifold to the surroundings, even if only a thin shield is used.

Because they’re primarily radiant heat barriers, heat shields don’t have to be made from insulators, so explaining the use of factory pressed metal shields.

Without heat shields being fitted, two things happen. Firstly, any object under the bonnet that is close to a hot bit - and is in direct line of sight to it - will also get very hot. Depending on where the turbo is mounted, that could include wiring, the radiator, the firewall, the bonnet, air con hoses, and so on. Wiring, for example, can easily have its insulation melted, and bonnet paint can bubble. Secondly, once the radiant heat has escaped from its source, the whole underbonnet environment will get hotter, resulting in increased intake air temps.

Theoretically, the hotter the exhaust manifold is kept, the more heat that gets to the turbo, resulting in better turbo performance. However, improved performance from heat-shielded turbo engines is normally the result of the decreased intake air temps.

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If a turbo is being fitted to a previously naturally aspirated engine, and the new turbo manifold is shaped somewhat like the original exhaust manifold, the original heat shield may be able to be modified to fit in its new application.

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That’s what’s been done for the top heat shield here. The lower flat one has been formed from scratch from stainless steel sheet (you can easily buy small stainless offcuts like this from scrap metal dealers and also manufacturers of stainless steel products... like urinals!)

Extra Dollars

Finally, don’t forget that installing a turbo will result in plenty of expenses that you might not have catered for. These include coolant (you may need to remove the radiator to get enough clearance for the installation of the turbo), engine oil (best to remove the sump when installing the turbo oil drain), and transmission fluid (in the Toyota modification described here, one driveshaft had to be removed to give sufficient room for the turbo and exhaust manifold to be fitted past the lower part of the engine).

And those costs aren’t including the more obvious extras like hoses, clamps, spray paint and so on!

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