Build Your Own Turbo Kit

I am always thinking of just buying some cheap car that runs OK and throwing a turbo on it to make it a sleeper.  Of course Honda’s come to mind but eBay turbo kits are available and super cheap.  Then I think about Corolla’s, maybe a V6 Camaro or firebird, a V6 Mustang, anything that would be fairly cheap to obtain and easy to throw some boost on. 

Let’s start with the obvious, the turbocharger.  Depending on what your end goal is, will determine what kind of turbo you are looking for.  Reading up on some specs and looking for max boost levels on the turbo you are looking at would probably be wise.  Most turbos will be able to put out 5-6 psi, so for a mild build you can pretty much get anything.  If your plans are to go a little more powerful, you will need to read up on some specs.  You can get all kinds of granular with boost maps and such, but that is up to you.

You need to mount it.  The turbocharger is using exhaust gases to spin so the most efficient designs have and exhaust manifold that you mount the turbo to.  There are other options as well, there are rear mount turbos and other mounting solutions that you can look into, but the most common is right off the exhaust manifold.  Which leads into the next problem, getting a manifold that can connect to the turbo, the easiest solution would be to see if there is anything out there that would work for your desired application.  If it already exists, don’t re-invent the wheel.  If it doesn’t exist, you will need to fabricate your own or have someone else do it for you.  This will most likely require some kind of welding, so pick your poison.

Plumbing!  You will need to get the compressed air into the motor somehow.  This is where all that piping comes in.  You can use any kind of hoses that you want, but remember that the rubber hoses will be expanding with the pressure so are not recommended.  Using exhaust piping will work, or you can get some universal aluminum piping.  You will need to get the inlet side of the compressed air to connect to the throttle body, and the exhaust side will need to connect to your existing exhaust.  If this is a custom application, you will be mostly on your own.  Some welding skills may be beneficial.

Depending on the turbo that you ended up with, you may need a Wastegate.  Some turbochargers come with internal wastegates and some will need an external one.  This is usually mounted either to the exhaust manifold or the turbine side of the turbo.  What this does is regulate boost pressure, there is a spring in the wastegate that is set for a certain psi, and when the pressure in the manifold is exceeding that psi, the wastegate will open and relieve some of that pressure.  This saves your turbo and your engine by not over revving the turbo and not overboosting the motor.

You will need a blow off valve, or a pressure relief valve.  This valve releases pressure in the intake system when the throttle is shut.  There is a vacuum line that is connected to the intake manifold that will apply vacuum to the BOV and open it when the throttle is closed.  This prevents a condition known as turbo flutter where the blades in the turbo make a fluttering sound as it chops through the compressed air that is being built up in the intake system.

You will need to run oil lines to the turbo.  An oil feed line will be needed to supply oil to the turbo, this is typically accomplished by a “T” fitting that is installed where the oil pressure sender unit is installed.  The “T” will go between the sender and the block, then the turbo supply line goes to the turbo.  You are looking to get positive oil pressure to the turbo. 

Once you are supplying the turbo with oil, you need to return the oil into the system.  This is typically accomplished by tapping an AN fitting into the oil pan and letting the oil gravity feed to the pan. 

An intercooler, although it is not really needed, will cool the intake charge before it gets to the throttle body.  Cooler air is denser and will supply more oxygen to the engine which will produce more power.  You will need additional plumbing to install the intercooler, since it is typically installed in front of the radiator for maximum efficiency. 

Another optional component that you may want would be a boost controller.  This will allow you to control the amount of boost that is actually getting to the engine.  There are a few options here, but the easiest way to go would be to get a manual boost controller.  This would be mounted under the hood and connected to both the intake side of the system and the wastegate.  What this will do is hold the wastegate closed until the desired boost level is hit, then allow it to open.  The manual one would be a turn knob that would control the boost level.  An electronic one would allow you to make those changes from the driver’s seat.  Depending on how you want it setup, would determine which one you would purchase.  I’m thinking an electronic one, that you can adjust from the driver’s seat at a stop light……

Depending on the car you have and the boost you plan on running, you may need a fuel pump or some bigger injectors, or both.  You will most likely need a fuel pump with a better flow rate than the stock unit.  With more air, you will need more fuel to ignite it.  Modern fuel injected cars will most likely be able to deal with the added air coming into the engine by just adding more fuel.  With the upgraded fuel pump, you may get away with the stock fuel injectors.  If you start to run lean or want more boost, you may need to upgrade your fuel injectors as well.

That should be it, those are the components that you will need to get a turbo onto something that doesn’t already have it.  If you do it yourself, it’s possible that you can do it pretty cheap and create some pretty nice gains for not a lot of money.  Check out the D-Series posts to see what I mean.

Leave a Reply