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Carb preparation requires that you know how a carburetor works and be able to service your particular model of carburetor. If you want to learn how a carburetor works, check out the sites that I have listed on the links page. I also have listed a few books/websites on there about how to service specific brands of carburetors; you should get your hands on these or other service manuals specific to your carb if you are unfamiliar with servicing it.
At this point, I recommend that you buy a rebuild kit for your particular carb, complete with new seals, gasket, accelerator pump diaphragm, etc. and rebuild the carb since it needs to be disassembled anyway. Avoid using liquid gasket makers such as the various Permatex brands unless you are absolutely sure that they are compatible with gasoline. These gasket makers have been known to degrade under exposure to gasoline for extended periods, and little bits of them break off and end up clogging your jets, making the engine run lean and possibly cause detonation under boost. Your safest bet is to use brand new gaskets, or at least cut some gaskets out of fuel compatible gasket sheets by tracing the pattern of the old gaskets.
If your carb has hollow floats with flat sides, you may want to fill them with minimal-expansion polyurethane foam and re-seal them with solder or epoxy to prevent them from collapsing under high fuel pressure required in turbocharging. I have heard of people getting away with skipping this step without problems, but if your as cautious as I am, you will want to fill your floats. Those with solid floats or have semi-spherical or cylindrical shaped hollow floats need not worry about filling them. To fill hollow floats I recommend that you cut a section or corner off of them carefully with a Dremel tool or other precision cutting tool to make a fine, straight, sectional cut leaving a fair sized hole or cross section. Proceed to inject the polyurethane foam into the float (use a very small squirt, it does not take much foam to fill a float) and replace the cut-off section temporarily as a cap and set the float down with the capped section upwards overnight. After the foam cures, there is a good chance that the foam has expanded enough to push the cap off the seat and have excess foam in between the gap formed. At this time you can separate the cap by cutting the foam in the gap with a razor blade. You then can cut the excess foam off the cap end and the float end so that the cap section sits tightly flush against the float. At this point, use the razor blade to carefully scrape off any excess foam that may have leaked on the surface of the float. When satisfied with the fit, use a small amount of glue or silicone adhesive to stick the two foam surfaces together to hold the cap in place while you seal the cap and the rest of the float back together (after the glue has set). If your floats are made of brass, use plumbing solder to seal the gap, otherwise use an adhesive fuel resistant epoxy like QuckSteel or fuel tank repair adhesive available from auto parts stores. After the solder has cooled or epoxy has cured, dip the now filled floats in a bucket of water to ensure that they still float and have no leaks. There may not be much in the way of bubbles to look for to spot leaks, so look carefully and/or submerge them for a few hours to be sure. Any leaks will have to be filled with solder (after you are sure there is no water in the float) and if it does not float anymore (and the float has no leaks) you will have to melt the solder/cut the epoxy, remove the cap section and drill out a small amount of foam from the center of the core, or as close to center as possible, before resealing and testing again.
The next thing to do while your carb is apart, is to make provisions to seal the throttle shaft. I have heard Dellorto carbs are sealed from factory and do not require this hassle (do not hold me to this, I am not at all certain), but carbs are not designed to flow pressurized air through the throats, so the throttle shafts are not sealed and will leak a little air/fuel mixture into your hot engine bay. Not a good idea. The easiest way to seal the throttle shaft is to carefully drill a 3.5 mm bore that intersects the throttle shaft bore (with the throttle shaft already removed) with a precision rotary tool, like a Dremel. Then, deburr the drilled bore where it intersects the throttle shaft bore with a precision fine file to prevent the throttle from binding or being stuck open. Then, epoxy a small hose barb to the inlet of the bore you just drilled, and run a section of 3.5 mm vacuum hose from the plenum to the throttle shaft. What this does is push air with a higher pressure from the plenum against the lower pressured air/fuel charge that would otherwise leak out the throttle shaft, forcing it back into the carb throat. Alternatively, you could seal the whole carb in an airtight box that can be disassembled to allow access to the carb and allow for periodical cleaning of fuel stains from the seeping. You will have to make sealed openings for the throat inlet and outlet and run the throttle and choke cables out through grommet holes.
Now, its time to setup the baseline fuel jetting for turbocharging. It was recommended to me by knowledgeable people on the blow-thru turbo discussion board that a good baseline setting to begin fine tuning from is to size up all main jets as well the power valve orifice by 30% in orifice area. This assumes that the carb was initially tuned to give an air/fuel ratio of around 13:1 at wide open throttle when it was set up for non-turbo. This is a safe baseline when running a conservative 5-7 PSI of boost, which I recommend as a good initial boost setting to fine tune the fuel from. This is where the EGT gauge comes in handy, as it can help you tune your fuel curve. Refer to this page for how to tune via EGTs. In tuning for off-boost and mid-RPM ranges, drivability and fuel consumption are the key factors. Use your sparkplugs as indicators of fuel mixtures (if you do now know what I mean, look into a Haynes service manual on sparkplug reading) and do some research on how best to tune the lower end of the fuel curve. When you have the fuel fine tuned and know a thing a two about carb tuning, you can then increase boost levels if desired and re-tune. Carb tuning is an art and science; to learn more about it you will need to do some homework in the sources, particularly the books and message boards, that I have listed in the links page,
Note that there are other methods of enriching the fuel mixture under boost. These alternatives are usually in the form of electronically controlled auxiliary fuel injectors. You could buy effective systems such as the Tim Systems fuel controller (info is available at the bottom of this page) rather inexpensively, but this set up greatly complicates your fuel system. You could also design your own auxiliary injection system with a Hobbs pressure switch (which activates at a pre-set PSI) and a cold start injector (out of most any fuel injected car) wired to the pressure switch. This alternative is cheap and simple, however is not the best means of fuel enrichment as this system has no way knowing airflow and thus cannot meter fuel accordingly; it will only blindly inject fuel at a certain PSI of boost pressure. If you are an electrical engineering whiz, I am sure you could make your own system that mimics fuel injection (similar to the Tim Systems unit) by using parts from fuel injected vehicles.
Upon reassembly of the carb, you are going to have to ensure that any plugs or screws that could be pushed out by either fuel or boost pressure are secured against loosening. You should also secure and fasteners in the airstream that could fall out and get ingested into the engine. You can secure these by method of staking, meaning that you put a series of 4 or more punch marks around the head of the plug or screw; the idea being that the deformation of metal around the edge of the plug or screw will bind and resist against the plug/screw from coming out. Many throttle plate screws are staked from the factory. Be sure to firmly support the backside of whatever you are staking and that you use no more force than necessary to slightly dent the metal, otherwise you may warp or damage the part you are staking. If you cannot fit a punch in the space available to secure a fastener/plug, try covering the plug/fastener using a thin coat (practically a smear) of fuel-proof epoxy, making sure that you clean out the tool contacts of the screw heads before the epoxy cures so that you may be able to apply a tool to the fastener to remove it if needed in the future.
This is basically a box to blow pressurized charge into as a buffer tank before it enters the carb, thus is usually designed to mount onto the carb and seal against the old airbox/air filter sealing surface. This site will give you a good idea of what a plenum looks like (its the aluminum box attached to the carb). The volume of it should be 1.1-1.2 times your engine's displacement, and can be made from sheet steel or aluminum that is no thinner than 3 mm. A suggestion on design would be to try and incorporate a velocity stack into the carb inlet (a trumpet mouth design). Also, ensure that the inlet into the plenum does not blow the pressurized charge across the carb inlet. Make sure you have epoxied, welded or bolted on all the hose barbs/fittings that you will need for various things that need to reference boost pressure and that you have made arrangements to attach the blow off valve to the plenum. You also need to drill a hole and attach a small hose fitting in the intake manifold downstream from the throttle plate to attach the BOV vacuum signal line to if no such vacuum signal exists that you could tee off of. The barbs/fittings you need to have that come to mind are the pressure references for the float bowl, the boost gauge, and the throttle shaft seals (if this is the method you use to seal the shafts). Your plenum inlet tube and your hose barbs must all have raised beads circling their edges to prevent the tubes attached to them from blowing off under pressure.
If you have experience working with fiberglass, you could make your plenum out of that (or expensive carbon fiber if you wish and know how to work with it). You would have to carve a Styrofoam plug representing the inside volume of your plenum, coat it in flooring wax or other release agent, then coat it in fiberglass resin and wrap the fiberglass mat or cloth around it with a firm tightness after the resin has semi-cured. Coat it again and repeat, using a de-airing brush in between layers to get rid of air bubbles until the fiberglass is around 5-10 mm thick. You will then need to drill a hole and pour in some acetone to melt the Styrofoam out after the fiberglass has fully cured (dispose of this melted Styrofoam in an environmentally responsible way!). Thoroughly clean out the inside of the plenum, then finish it by attaching hose fittings , inlet tube (unless you masterfully carved a plenum inlet at the plug stage), cutouts for the carb throat, drill mounting holes, etc. You can then paint it or polish/gel coat it if you, for some reason, like fiberglass' natural color.
This is one of the simpler parts of the fabrication process if you have established a good idea of the intake path from the planning stage. All you need to do is to cut the straight and curved tube sections into pieces that will route from the air filter to the turbo, and then from the turbo to the intercooler (if applicable) and then to the plenum. The diameter of the tubing between the turbo and the plenum should not be much larger than the discharge outlet of the turbo; likewise the tubing between the air filter and the turbo should not be much larger than the inlet of the turbo compressor housing. At the very least, you will need couplers/reducers to join the piping to the turbo, the intercooler (if applicable) and the plenum. Make sure the cuts are straight and avoid cuts that yield an elliptical cross-section of the tubing (called a cheater bend) if at all possible. The air filter should be located in a place that draws cooler air from outside the engine bay, yet not be exposed to rain or snow. The intake path should be as free of bends as possible, and where there are bends, try to make them as large radius as possible as tight turns hurts airflow. You should weld as many tube sections together as possible to create long, solid sections while still allowing for easy removal of intake for maintenance. Then, join these super-sections with couplers to ensure flexibility to counteract engine flexing and vibration. When welding, tack weld the tubes in place and ensure that the routing of the whole tract is correct before fully welding every joint. Joints to be welded together should have very little gap between them. If there is too much of a gap at a joint and you do not want to cut another piece of pipe, then use a coupler to join the pipes, as welding across wide gaps creates a flow restriction along the wall of the pipe at the join. One final note is that you must have a raised bead circling the circumference the ends of the pipes (like radiator inlets/outlet tubes) that carry pressurized charge to prevent the couplers from blowing off them under pressure. This can be done with a specialty bead roller for pipes that you may be able to rent from an industrial tool rental business, or have a so- equipped radiator shop do this for you. You could also run a smooth, thick bead of weld near the edge of the pipe end if you are a good welder, just be sure you have the welder on the right setting so as not to melt through the thin-walled tubing.
Exhaust manifold/downpipe/tailpipe fabrication
This step requires excellent welding and metalworking skills. If you do not posses these skills, then here is where the machinist friend who owes you favors that I mentioned earlier will come in handy. If you do not have such a friend and lack metalworking skill, then this part could easily be the most expensive portion of the project. I will start at the most difficult and sometimes necessary method of connecting the turbo to your engine: Fabricating an exhaust manifold. I mentioned in the choosing components section that there were both log type and equal-length manifold designs. Both are constructed with the same methodology; however the equal-length manifold's difficulty is in the complex angle cuts, pipe fitting and tight-angle welding necessary to form an efficient merging point (collector) right before the turbo, like the one pictured in the equal-length to log manifold comparison. A not-so-efficient but simpler collector could also be made by dumping the primaries into a collector box. This is not as optimal for flow as the smooth, angled merges are, but is simpler to fabricate. A log manifold is generally simpler to build than an equal-length manifold because the pipe intersections are separate, thus do not require cutting, fitting and welding as complex as the equal-length version. If you are going for the efficient merge collector, I highly recommend that you make a mock collector out of thin walled steel, plastic or even rigid cardboard tubing of a similar diameter in order to devise a way to set the angles, cuts and fitting of the pipes to form the collector. From this, you can devise a methodology and jigs that you can use to ease the creation of the real collector. For and excellent write-up on header construction tips, see this article. For a step-by-step guide of how an equal-length manifold is fabricated from weld-els, see this wonderful article. Note that the header constructed here has the box-style collector which you can substitute with your merge collector if you so feel the need for challenge. One last tip that you may want to consider is to make cuts on the cylinder head flange between each primary tube (after all the welding and final fitting is done) to allow for heat expansion of the flange, or fabricate the manifold to have separate small flanges for each primary like the manifolds often seen on sportbike motorcycles. Otherwise, the heat expansion could warp the flange enough to cause leaks or even break off manifold studs. This is especially important on longer manifolds such as those found on an inline 6 cylinder engines. If you plan on running an exhaust gas temperature gauge, drill a hole ready for the thermocouple probe at the collector. You may need to weld a threaded bung on the hole if your thermocouple is of the bolt-in type.
Modifying an existing manifold to work with the turbo is much easier. One option is to cut the manifold at the collection point and weld on a box or conical collector with a flange matching your turbo. Make arrangements for the thermocouple probe at the collection point if you have an EGT. Be sure that the type of welding rod/wire that you are using is compatible with cast iron (assuming your manifold is cast iron, as most factory manifolds are). I have heard conflicting stories about the weldability of cast iron and I do not have experience in this matter, so you will have to be the judge.
If you have the space to fit one, you could fabricate an adaptor that mounts between the turbo and the stock manifold. This would be the easiest and cleanest solution; all it involves is the fabrication of 2 flanges, one for the turbo and one for the manifold outlet, and a section of weld-el in between that could be a reducer if the turbine inlet is smaller than the manifold outlet (this is better than having the turbo inlet significantly bigger than the manifold outlet for flow velocity reasons). It would then simply bolt between the manifold and the turbo. You would then have the EGT temperature probe mount to the adaptor if you have an EGT gauge.
The downpipe is equally as simple; how trendy name brands manage to charge $300 or more for these things blows my mind. It essentially requires 2 flanges, one for the turbine exit and one for where the downpipe meets the exhaust system under the car and some weld-els in between these flanges to form the bends you need to meet the exhaust pipe. Ensure that the turbo-end flange does not interfere with the opening of the wastegate or you will over-boost. Also, it is recommended by guru Corky Bell that you weld 360 degrees around the internal edge where the downpipe and the turbo exit flange join but leave 1/2" gaps in the welds around the outside. He claims that welding weakens the metal, so gapping the outside welds will make the weak area discontinuous. Where downpipes could get complicated is if you make a dedicated exit tube for the wastegate to achieve a tiny performance gain that is negligible in budget applications. Going this route, your flange for the turbo-end needs to separate the wastegate exit and the turbine exit. Then you have to weld a small exhaust pipe for the wastegate side, and a separate main downpipe for the turbine side. You could either dump the wastegate pipe into open air in a race car application, or rejoin it to the main pipe further down the exhaust stream in a street car. When rejoining the wastegate pipe to the main exhaust, be sure to have a slip-joint (female-ended tube pointing upstream) or bellows (raised, consecutive beads around the circumference) on the wastegate pipe to allow for heat expansion. Also, join it to the main pipe at a shallow angle (as close to parallel as possible).
The rest of the exhaust system is up to you. Add/remove/upgrade mufflers, catalytic converters, resonators and piping as you (and your local laws) see fit. Three things to note are: Turbo cars run quieter than NA cars as the turbo itself dissipates some sound. I read somewhere once that it can account for around 1/3 of a muffler's sound absorption ability, so keep this in mind when removing, adding or changing your muffler. Also, catalytic converters often do not fare well when situated close to turbochargers. Although the closer the cat is to the engine, the faster the cat will reach operational temperature, high performance systems could produce exhaust temperatures at the turbine discharge hot enough to to melt and clog cats in close proximity. If your local laws allow, you might want to relocate and/or run a high flow cat. Finally, turbocharged cars need high flow exhaust systems as turbo engines simply flow more air through them under boost than their NA equivalents. I strongly recommend that you at least upsize your exhaust piping 1/4"-1/2" from the stock NA size and change exhaust components accordingly.
Routing turbo coolant and oil lines
This is a simple aspect of the installation that you need be careful about. Though they are simple, the coolant and oil lines going to the turbo are vital for its operation and longevity.
For the coolant feed line (assuming that your turbo is water-cooled, if not skip to the oil line write-up), use a suitable tee-fitting to tee the feed line off the coolant hose going toward the heater core. Alternatively, you could tee the coolant feed off any other convenient source of hot (having already been through the engine) coolant such as the engine temperature sending unit. Turbos should have hot coolant feed to them to so that the bearing will reach operational temperatures, and thus proper bearing tolerances, faster. Colder (nor hotter) is not always better as turbos are designed for an ideal operational temperature range. The coolant return hose should run from the turbo and tee into the hose running to the radiator. Use high quality tees made preferably out of brass as well as high quality coolant or heater hose in the same diameter as the factory hoses that were used in the donor car. Also use secure hose clamps to attach the hose to the tees. Route the coolant line well away from the exhaust manifold or exhaust side of the turbo. When in doubt, fabricate a heat shield for the coolant lines from aluminum flashing or thin sheet metal available from hardware stores; just be sure to fold any sharp edges that could end up cutting the coolant lines.
The oil lines should receive greater attention to quality still. Get oil from the oil pressure sender unit for the oil pressure light or gauge using a high quality metal tee and the required NPT fitting and barbs. If possible, get a tee with a threaded male-end that bolts into the block where the oil pressure sender used to bolt to, and a threaded female-end perpendicular to the male that you can bolt the sender unit to. The end of the tee that is inline and opposite with the male end that bolts into the block would then hook up, with the required fitting, to the oil line running to the turbo. If you cannot find a threaded tee that will work with your bock and sender, then you could use threaded barb fittings and a barbed tee, however I recommend avoiding this if at all possible as more joints in the system introduces more chances to develop a leak. If you are running an aftermarket oil pressure gauge as well, you made need to get a 4-way tee to tee in the pressure gauge sender or run another tee right after the tee for the OEM sender. Alternatively, you could just replace the OEM sender with the aftermarket one and use the oil pressure gauge as your sole warning device. You could get oil from other places such as the oil filter by using an adaptor plate (that you can buy from performance shops, or get one fabricated) at the base of the oil filter to tee off clean oil to the turbo. However, running the tee from the oil pressure sending unit is easy and offers the side benefit of having the oil pressure warning system warn for low pressure right at the feeding point of your turbo. As for the oil return, you will first want to take the oil pan out, drill a hole and attach a hose barb that fits a minimum 1/2" diameter oil hose (if the turbo's drain outlet permits). You can attach this barb by means of soldering, welding (be sure not to melt the thin pan or barb), epoxy, bolted-and-gasketed flange or bolted via a bulkhead-style fitting. Be sure to have to hose barb dump oil into the pan above the oil level or else the oil will not drain properly from the turbo and build up in the center section, causing it to leak past the seals and into your intake. For this reason also, you may want to check/replace your PCV valve; if stuck shut, the crankcase could pressurize enough to not allow the oil to drain properly from the turbo. The barb should also be angled upward toward the turbo as much as possible (not usually possible if using a bulkhead barb). When angling a barb, do not cut the barb at an angle, rather ream out the hole into an oval that will set the barb at the angle you want when inserted in. If the barb were to be cut at an angle, then the oil pan hole would have to match the cross section very accurately, which is hard to do, as to avoid ridges that inhibit flow or gaps that could potentially leak. You could use a file or a rotary power tool to clean up ridges on the backside if you want cut the barb at an angle, but I would imagine that this would be more time consuming then just having the oil pan hole set the barb angle. When the barb is installed, thoroughly clean the pan to ensure no metal filings are left in it and reinstall it. Run a high quality line made for oil (a stainless steel braided one would be nice) from the turbo oil drain to the oil pan barb in a path that is straight as possible, well away from anything that could rub against it. If the line is long and needs support along the way to avoid obstacles, fabricate a mount that firmly clamps the hose (do not let it chaff the hose) and attach the other end to a point that flexes with the engine. If for some reason you turbo is lower to the ground than the oil pan drain barb, you will need to drain the turbo's oil into a custom reservoir and have a low-volume scavenge pump, usually electric, to pump the oil from the reservoir back to the oil pan. You may need to have a reservoir level switch, perhaps from a windshield washer tank (be sure the float is compatible with oil), to switch the pump off when oil levels in the reservoir are too low to avoid burning out the pump.
For fuel requirements, you are going to have to mount (using rubber insulated mounts) and wire up a fuel injection fuel pump that either replaces your existing pump or runs in series with it. If running in series, be sure that your existing pump (be it mechanical or electric) comes upstream (ie. feeds) the high flow pump, or else the original pump will become a flow restriction and fuel pressure will not be adequate. The high flow fuel pump should preferably be an inline, external tank unit (for ease of installation) like those found (I was told) in 80's Fords such as Aerostar vans and and 4 cylinder Mustangs, or Bosch units out of many older or late model German vehicles. Wire the pump to a 12v power source and the ignition switch "on" position so that it begins to pump when the ignition is switched to the on position, unless it is in series with a mechanical pump. In that case, you would want to wire it to the "start" position. Route new feed and return lines if your factory lines are too small, along with installing the new fuel filter if you choose/need to replace it. I mentioned in the list of parts that 3/8" for the return line and 5/16" for the feed line are good sizes, so you should be able to judge if your lines will restrict flow. Be sure to protect any fuel lines running under the car with adequate casing made of rigid plastic or metal heat shields if the lines absolutely have to run near the exhaust system. The safest bet is to go along the same route as the factory lines did, however do not assume that the factory lines have adequate protection or went along the best route to begin with. Be very careful with fuel line routing, after all they are carrying flammable fluid under pressure and often near heat sources.
The boost referenced fuel pressure regulator needs to be mounted just upstream from the carb float bowl feed. If you took my recommendation and decided to fabricate your own rather than buy one, the refer to the bottom half of this page for excellent instructions on how to fabricate one from the Bosch regulator I specified. Now, run a tee-block in the fuel line between the pressure regulator and the float bowl to attach the fuel pressure gauge. Do not run this gauge into the cockpit unless you have an isolator or pressure sending unit as running a pressurized fuel line into the cabin is a bad idea in the event of an accident that could snap the line and spay fuel all over the interior. Leaving the gauge in the engine bay is fine; all you need it for is to verify that fuel pressure is always equal to boost pressure plus the stock fuel pressure when it was NA. For example, if stock fuel pressure was 3 PSI, make sure that fuel pressure is 3 PSI at vacuum, and [boost +3] under boost. This is to allow for 3 PSI of relative-to-boost fuel pressure in order to fill the float bowl, otherwise when boost exceeds 3 PSI, it would push the fuel out of the float and back into the fuel tank. The Bosch unit mentioned above (as well as any other unit worth buying) allows for the adjustment of base fuels pressure via the adjustment screw at the top.
Most carbureted cars will have the archaic distributor and points-and-condenser style ignition. If you took my recommendation and bought an upgraded ignition coil, wires, distributor and new spark plugs, go ahead and install them now. One thing to note is that it is recommended to gap the plugs 0.025 inch less then the factory specs for the NA engine to ease the spark bridging of the gap under dense charges, especially if your ignition system remains stock. You can experiment with wider gaps later, which in essence tests the strength of your ignition system. Like the fuel curve, the ignition curve is something that has to be tuned for each individual engine, and re-tuned when an aspect to the engine's induction is modified. High boost and advanced timing generally do not get along together as it may lead to detonation. The most simplest solution that I was told to establish a safe baseline ignition curve to tune from is to cut out or hinder the factory ignition advancing at high engine speeds. This involves jamming the centrifugal advancing weights in the distributor or disconnecting the vacuum advance diaphragm if it is negatively affected by positive pressure. You can then use various devices such as check valves, vacuum advance and pressure retard diagram actuators to try and achieve the perfect ignition curve that offers retard at start up, advance off-boost and only as much retard as necessary under boost to prevent detonation. Good sources on information on setups needed to achieve a good spark curve would be the book Turbochargers by Hugh MacInnes and the carbureted turbo message boards (see links page)
This involves running a boost gauge, fuel pressure gauge and water temperature and oil pressure gauges if you so decided to have them. Simply follow the manufacturer's instructions to mount and run the signal lines/electrical wires for these gauges, keeping in mind that the boost pressure gauge should be referenced to the intake plenum that you built, and that the fuel pressure gauge be outside the cockpit and referenced in between the fuel regulator and the float bowl (as I have mentioned above), and that the oil pressure gauge should reference from the tee to the turbo oil line (as I have also mention in the oil line install above). Install the thermocouple for the exhaust gas temperature gauge (if you have one) at the collector point of the exhaust manifold by either bolt-in or clamp-on, depending on the thermocouple design, then route the signal line into the car to attach to the gauge. Be sure the gauges are in a spot that are easy to read and neither block your vision nor divert your attention away while driving. As for your boost controller, you will have to run it in between where the wastegate takes the boost signal (usually the compressor outlet) and the wastegate actuator, and extend the signal hose long enough so that you may mount the controller in a spot where it can be adjusted easily. I recommend setting the boost to the absolute lowest setting or leaving the controller out completely for the initial test runs until the fuel and ignition curves are worked out. Be sure the signal lines are secured tightly to the fittings either with tie-straps or small hose clamps, otherwise boost pressure may pop the hoses off and cause over-boosting.
Engine systems that were once designed for an intake system to be under constant vacuum must now be altered to work with boost conditions.
Firstly, the PCV must be vented upstream from the turbo (between the air filter and the turbo), or if legalities allow, be filtered and vented to open atmosphere. In either setup, you may want to run a catch can (this may be required by rules in racing), which essentially is a drainable can that with two hose barbs in the top and some stainless steel dish scrubbers in it. The idea is that the crankcase air will go in at one end and the oil vapors will condense out once in contact with the cooler surface of the scrubbers, allowing for the other end of the can to draw out dry air to the atmosphere or the intake.
Next, the charcoal canister that catches fuel vapors must have a check valve installed in the vacuum line to close against boost pressure, otherwise this pressure would pressurize the fuel tank.
Finally, other systems such as the brake power booster and air conditioning systems, etc. must have a check valve to close against boost pressure in the vacuum lines if not already so-equipped from factory.
Now that the system components have been fabricated and are in place, it is time to top up the oil and coolant, fill the tank with premium high octane fuel, make a final check over everything and start it up. From here on, its all about testing and fine tuning your system. This is where you need to do more research, especially from the sources I have listed on the links page, to make the car run like it did (or better) when it was not turbo, but only with more power! When the testing bugs are out of the system, you can, and I am sure you will, go for more power.