Robo, given that a cai is not required for turbocharging, wouldnt some form of upgraded intake be necessary on a 2.4L?? also what engine upgrades are required to add when going from an n/a to a turbo? im sorry if im sounding elementary, but im very interested in learning how to work on and improve my car (and i can see from your account you have credible experience with this), what would you suggest i add to prep for a turbo in the future but also maybe increase performance now??
i really appreciate all the good info
The good news is you have an 07 Sky. the 2006-7 LE5 engines came from the factory with forged connecting rods making them more tolerant of boost. 2008 and up have different rods which really limit their power before you need to strengthen the block. I've been told the 2006-7 LE5 is good to about 450 WHP while the 2008+ is only good to about 250 WHP. After those levels you need to work on the internals.
While a CAI isn't required for Turbocharging, an intake...of some kind...is. It can be a cone filter attached to the turbo inlet or it can be 20' of plumbing but whatever it is, you need to have it on a street car. And really, a CAI isn't necessary on ANY car. They run with the factory airbox on them just fine. Some cars get improvements from aftermarket intakes, others don't. Ours see very little return as our factory intakes are more than enough for our factory setups.
The reason a NA intake won't work when you go turbo is the nature of the intake of the two systems. On the NA setup, you're picking up air from the front of the car and directing it (via the intake) to the driver's side of the car where the throttle body is located. When you go turbo, you're now directing the air from the front to the passenger side of the car where the turbo inlet is located. From here, the turbo compresses the air, sends it through the intercooler in the front of the car, then from there it is directed to the throttle body still on the driver's side of the car. About the only thing that is similar on the two setups is the air filter on the intake and the clamps on the CAI itself.
Here is a list of things you need to change on your car to go turbo other than what parts you'd need to add as part of the turbo installation (like turbo, manifold, intercooler and that plumbing):
Injectors. You need bigger injectors. How big is determined by how much power you need. For stock Redline power levels, 42# injectors will work. For my 400 whp power level, I went with 60# injectors, a DDM fuel rail converted to a return system, and a boost referenced fuel pressure regulator. While not necessary, I'd seriously consider a DDM center feed fuel rail too. You'll have the stock fuel rail off to swap your injectors anyway, quick and easy to swap this out at the time. The Center Feed rail gives you more consistent pressure across the injectors.
2-bar MAP. This is just to read boost. Right now you have a 1-Bar MAP and that only reads vacuum. A 2-bar will read from -14.7 psi (full vacuum) to +14.7 psi of boost.
Water pipe and thermostat housing for a Redline. While some kits may not need the thermostat housing, having it will let you do a more factory like installation of turbos that use water cooling. You need the 2.0 water tube to clear turbo exhaust manifolds.
Catalytic Converter. Again, most kits will come with a solution for this since your 2.4 cat will not work with a turbo.
Spark plugs. I would drop a temp range cooler on your plugs. Just go to your local auto parts store, ask for plugs for your car one step colder than recommended. Can't remember the gap right now but it is smaller than stock to prevent spark blowout under boost.
If you're going for higher levels of power and a manual, throw in a clutch too.
Finally, I HIGHLY recommend a Wide Band 02 kit. This will help your tunner really dial in the tune on the turbo setup. Some kits come with a canned tune for the kit and for these kits a wide band isn't completely necessary.