Turbochargers & Choices:
There are MANY options out there for what kinds of turbos you can use. Some people like Garretts as I do, and others like IHI, Holset, and Borg Warner. They all serve the same purpose and work the same way, just some have better oil flow and bearings. I personally like the Garrett turbos since they seem to last a little longer than most others. Many people ask me what size turbo I think is the best. There are two different routes to go. Small turbos have serious low end torque and big turbos are all top end. Im still having problems spooling too soon and getting no traction with a large T3. So after 3 different turbos I have come to the decision that the perfect turbo for my application is a T3/T4 hybrid. Here's what I believe will suit the needs of turbocharged 2.5L V6's. If you don't understand the fundamentals of how a turbo works CLICK HERE.

T3 exhaust side & T4 compressor side
T3 .63 A/R exhaust housing with standard or stage2 turbine
T4 .60 A/R compressor w/ 54 or 57 trim T04E compressor wheel
also T04B 60-1 Compressor wheels are very efficient for less than 10psi

Using a turbo that meets those specs will absolutely dominate if used properly on a probe gt, 626, millenia, or MX6. For the 2.0L engine I recommend going with a .48 A/R T3 exhaust housing instead of a .63 but everything else the same. The T04E compressor wheels are the most efficient for our engines and they wont run out of breath past 5k RPMs. My latest turbo was a 54trim (T5/6 Turbonetics) and it was strong enough for anyone looking for 260whp but I am going far beyond that now so I have moved up. This is my new monster...

This is a hybrid T3 (.48 stg3 turbine) T4 60 A/R compressor & 78trim wheel.
This little bad boy should be 72-78% efficient at 11-13psi.

Fuel Management Units:
These are pretty darn simple for their design and how they work. They are pretty cheap for a fuel system and they work like a charm with some tuning. Basically its got a flat round diaphragm inside of the housing almost like a fuel pressure regulator and it is boost sensitive. So you hook a hose up from the fuel filter into the FMU then back to the oem FPR and fuel rail. When the engine starts to get positive manifold pressure (boost) the vacuum port on the FMU senses this and the diaphragm will make the fuel pressure raise to compensate for the extra amount of air being forced thru the motor. I have a 12:1 FMU and it h as work great so far using stock injectors and stock FPR. SO when the engine sees 1 psi of boost the pressure it forces onthe FMU makes the fuel pressure raise 12 psi for each 1 psi the engine boosts. Its not quite as exact as 12:1 but it does make the fuel pressure go much much higher.

I have upgraded from my stock FPR to an aeromotive and would recommend it strongly as the base fuel pressure gets a little higher once you add that big fuel pump. And if you get into any kind of engine management electronics fuel pressure becomes increasingly important to tune the correct duty cycle for your injectors
CLICK HERE FOR MORE FUEL MANAGEMENT INFO!

Fuel Pump Upgrade:
There are really only 2 different fuel pumps you can use on the V6 while boosting. The stock fuel pump will fail at about 1-2 psi of boost and your engine will melt from the inside out as it runs very lean. So accompanied by the FMU the high pressure fuel pumps will allow you to run rich while boosting so your motor is stoich or rich. You can use the 190L/Hr Walbro pump for smaller turbos like T3's but once you start pumping serious power with hybrids or T4's you need a 255L/Hr HP fuel pump to compensate for the extra volume of air going into the motor. With smaller turbos like T3's the compressor wheels are much smaller and will push the same amount of boost as in PSI but with a T4 compressor the actual volume and speed (CFM) of the boost going into the motor is nearly double what a T3 wheel produces. You can never have too much fuel while boosting so the 255 pump is the ideal choice. You can get them here: www.autoperformanceengineering.com
CLICK HERE FOR MORE FUEL MANAGEMENT INFO!

Iintercoolers:
There are so many styles of intercoolers that it gets confusing and can give you a headache when picking one out. I built my own but I am a sick sick person and have too much free time. There are also 2 main theories in intercoolers. The two core styles are tube/fin AND bar/plate. They will perform about the same but they work differently. The cores with flat square looking runners will flow faster and smoother so they have less pressure loss after the turbo pushes air through it but they don't cool air quite as much as the tubed cores do because the boosting air passes by so fast that it wont release as much heat. The tube/fin design will have rounded looking tubes for the runners and are thinner. They are more restrictive (as much as 3 psi in the worst cases) and will release more of the hot air because the boosting air does not pass as fast through the core so it has more surface contact time with the metal and can release more heat to the atmosphere. So its a trade of because if its restrictive you have to run more boost on the turbo to make the motor see the same amount of psi as before but that will also heat up the air more. So they end up about the same place but I like the bar/plate style better because fast cars usually have them in their front bumpers :D
Here are a couple pics that show both core styles:


BAR / PLATE STYLE

TUBE / FIN CORE

End tanks come in to play a little bit as well. Basically you want to avoid using IC's where the inlets are pointing in the same direction because the intercooler will have to do a U-turn inside the core which slows the flow speed down about 25%. The general rule of thumb is to make sure you minimize the amount of intercooler piping you use while making the air flow into the core in one direction and make sure it flows out the exact same direction having inlets going opposite directions from the core. If buying an OEM used IC from a different car make sure the car its coming off of was at least a 2.6L engine or bigger with a fairly big turbo stock. Some good oem IC's are NPR Isuzu, Starion Conquest, Mk4 Supra TT, MK3 Supra (late 80's), and most of the high end cars like Porsche have good intercoolers. Also try to find cores that are thicker than 2.5" and have inlets 2.25" or larger as those will be able to flow 300 hp or more. These are just what I have learned and are some good guidelines to follow. 

Turbo Piping:
There aren't very many people making turbo piping for the V6's. I made my own pipes after bugging and bothering many turbo probe owners for about 6 months to get the best design. For that reason I am making this page so I don't have to answer the same questions 20 times a month like they did. There are a few different ways to have turbo pipes. None of the different setups are any easier since they all require you to do the same things. We'll start with collector piping. This is the piping that goes from the exhaust manifolds to the turbo. This is what spools the exhaust turbines in turn making the compressor spin and push air into the motor. I wanted to get full boost fast so I made my collector tubing slightly smaller than most others did. That way you can get a bigger turbo and still spool somewhat fast. Here is a picture of my piping:
 
I used the stock exhaust down pipes and chopped everything off after the o2 sensor bungs that way I didnt have to remake that part and my flanges were already done for hte manifolds. From where they bolt to the exhaust manifolds till they merge into the Y the pipes is 1.75" OD tubing. After they merge (3" - 2.5" adapter) the uppipe is 2.5" from there to the turbo. That completes the collectors!

The the 2.5" OD downpipe goes from the turbo's internal wastegate (round flange) back down to the exhaust by the catalytic converter. So your pushing the exhaust gasses into the turbo (thru square flange on collectors) and it spins the exhaust turbine which makes the blower side spin at the same speed forcing air through the intercooler and back into the engine like ram air. Then the exhaust gasses pass thr the wastegate until the engine reaches whatever boost your actuator opens then it releseases everything out the downpipe and thru the exhaust. Its common sense that the combustion in the motor revolves around...well combustion and fire. So what happens when you push a large volumes of oxygen into a fire??....MORE FIRE! So its goes Vrrrooooomm as the engine goes faster, then ssssssssssss as the turbo starts winding up, the psshhhhhh from the BOV!!!! FUN FUN =)

As for intercooler piping here are some pictures of how my pipes were welded together and how they sit on the car. Everything was made from summit racing steel mandrel U bends. I used (2) 2.25" U bends, (1) 2.5" U bend, 2" silicon coupler, 2.25" silicon coupler and a 2.25-2.5" reducer coupler. I just cut pieces and welded them together on the car and so far so good. I would like to have had more room to run my intercooler pipe around the turbo instead of over it but oh well. This gives me an excuse to get water injection. As you can see there is a 1st generation DSM blow off valve on the intercooler pipe. So far it has done its job well and its very loud.!

At first I never thought my pipes were on caliber with some of the true professionally made kits out there but at 6 psi on a T3 turbo I made over 230 whp and that's definitely on par with most other kits out there. So I wouldn't hesitate to tell people to try making a kit like mine. If you got some free time (LOTS OF IT) and a nice mig welder knock your socks off!

I hope this will help some of you guys understand a little more about some of the basic things in a turbo system on a KL03 or KLZE - Dan