That's phenomenal information and detail! Thank you so much I really appreciate it. I think I'll wait until you get the numbers back on the new rpm kit (which will hopefully be released in the somewhat near future). It sounds like yours would be the correct footsteps to follow in on this. Thanks again for all your help! I hope the big wheel K04 goes as awesome as hoped for. I'll be anxiously awaiting your final analysis!
Glad to help!
Keep in mind that his kit and where I'm going with it may be very different.
Here is what I currently have on mine and what may be different in his kit:
K04 "big wheel" turbo. It is believed these add flow to increase power by 30-50 whp. The standard K04 from the LNF (2.0 turbo Sky engine) on the 2.4 though sucks a lot of air up top compared to the 2.0 so while I have max boost at 10 psi, that's at 3K RPM. By 6K RPM, that's dropped to 5 or 6. The Big Wheel K04 should reduce that drop and that's my biggest hope. This is an option you can get on his current turbo kit so no need to wait for it to be released.
Charge pipes. You'll get the RPM 3" cold pipe I have but his intake and hot side pipe in the kit are different from mine. Size wise though they are identical and his intake looks a lot nicer. LOL
Intercooler. I have a Hahn Racecraft intercooler while RPM goes with the factory unit. I had the factory unit on mine originally and install of the factory unit is much nicer. With the Hahn though, that's going to work better for my future goals.
Fuel injectors. I have 60# now but may go to 80#. See the next item as to why it's a maybe. His kit offers different options based on your needs.
Boost referenced return fuel system. This is something that you currently don't have. You have the standard returnless style fuel system. Let me explain why this is important. With the stock system, your fuel pressure is set to about 55 psi. Because you're Normally Aspirated (NA), you are always spraying that fuel into a compartment that is at the same pressure as the air outside (0 psi) or in vacuum (up to -14.7 psi). This means your working fuel pressure is between 55 psi (at 0 psi manifold pressure) or up to 69.7 psi (at full vacuum). Now with fuel, the more pressure you have behind the injector the more fuel you're going to be pushing into the engine for a given injector duty cycle. This means an injector at 5% duty cycle being fed by 60 psi of fuel is spraying more fuel than if it was at 5% duty cycle and 50 psi of fuel.
Now, when you boost a car, you're going to see different pressure in the manifold. At 10 psi of boost, that 55 psi of fuel pressure is now like 45 psi of fuel pressure because you're no longer spraying it into a 0 psi manifold, that manifold is now at 10 psi. Thus your injector will spray less fuel at the same duty cycle as before and thus has to work harder (be at a higher duty cycle) to deliver the right amount of fuel. To get the right amount of fuel, you may need to go to bigger injectors. Stock 2.4 injectors are REALLY small...25 lbs or something. Going to 45 lb injectors will work for a small turbo on 5-6 psi. 60 lbs will work on 10 psi. 80s will work for 12+ psi. This is done because you need that bigger injector to overcome the lower fuel pressures with the stock return system.
HOWEVER, at some point even bigger injectors won't help as you go way up in boost. Also, trying to get even the 60 lb injectors to idle smoothly at 69.7 psi of fuel pressure (stock) is near impossible and the 80s get even worse. At that pressure, they just flow too much fuel even at low duty cycles to get a smooth idle.
This is where the boost referenced return system comes in to play. This system regulates fuel pressure at the fuel rail in the engine bay rather than in the gas tank like the stock system. This means the fuel pressure is not significantly affected by acceleration and braking of the car (our stock returnless systems can lose or gain about 3 psi of pressure under heavy braking (3 psi gain) or acceleration (3 psi loss). By moving regulation to the engine bay at the rail, this effect is nullified. The other benefit is that the fuel pressure regulator can now be hooked up to the manifold to read what the pressure is in the manifold. This regulator is set to about 50 psi fuel pressure at 0 psi of manifold pressure. As the pressure in the manifold drops, so too does the fuel pressure. This makes getting the engine to idle smoothly with larger injectors possible as the fuel pressure is below 50 psi under vacuum. More importantly, as the pressure in the manifold rises, the regulator raises the fuel pressure too at a 1:1 ratio. So if you run 10 psi of boost, the regulator increases the fuel pressure from the initial setting of 50 psi up to 60 psi thus maintaining the effective fuel pressure of 50 psi and thus allowing your larger injectors to deliver more fuel under boost than they would on the stock returnless fuel system.
Thus, with this system, I may not need to go to 80lb injectors with the new turbo because my fuel system is going to continue to increase fuel pressure with boost. Now the only question is can the 60lb injectors with this fuel pressure deliver enough fuel without having to work too hard (almost being always on...a duty cycle of 100%) to do so. If they can, no need for bigger injectors. If they can't, I'll need 80s.
The thing is there though, depending on what happens with my dyno run, you may have to run larger injectors to get the same results if you stay with the stock fuel system. My return system had cost about $800 to build because there was a lot of trial and error involved. RPM may be able to do it for FAR less. I used DDM's center feed fuel rail but capped the center feed and had them ship it without the two end plugs in it then got AN and NPT fittings (as necessary...rail plugs are NPT thread, everything else was AN thread) to attach the regulator and fuel lines plus you need about a 12 foot long return fuel line going back to the fuel tank from the regulator. This needs to be a braided line and braided line runs about $9/foot. For more information on how I built it, check out these threads:
How to: Le5 fuel return system.
This is the first thread but the author welded a stock fuel rail. Everything he did at the fuel tank applies to my version.
How To: LE5 Fuel Return System Ver 2 (no welding required)
This is my version and is all done with DDM's fuel rail and AN fittings.
Wide Band O2 sensor. The LE5 comes with a narrow band O2 sensor. The LNF (Lucky bastards) comes with a Wide Band O2 sensor. To really know what air fuel ratio (AFR) you're running, you need a wide band. Why worry about your Air Fuel Ratio? Because if you run too lean, you blow stuff up with boost real quick. I like it because it tells me real quick if something is way off. When I ran my stock fuel system, you could see the AFR jump all over the place while the ECM "hunted" for a good fueling option with the 60 lb injectors at idle. After going to the return system, the Wide Band showed much more consistent AFR readings and thus the smoother idle. At Wide Open Throttle (WOT) you should see much richer AFR numbers and if they're leaner than they should be, you wouldn't know it without the Wide Band reading...and too lean is bad. If the tune is right and the engine is running right, the AFR isn't important but if something goes wrong, it may be the only way you know it's gone wrong. I think of it as a good security blanket.
Boost controller. I have a mechanical under the hood. The stage 2 RPM kit comes with something similar. I've also added a boost gauge (since I needed a 2 gauge pod for the Wide Band gauge anyway) but eventually want to go to the AEM True-Boost gauge and electronic boost controller in that same spot. It's good for detecting problems with the turbo since our boost isn't read or controlled by the ECM like the LNF.
Valve springs. I've been told by RPM I NEED valve springs for valve float at higher that 12 psi boost levels and then been told by DDM I DON'T need them because the LNF uses the same springs and they have no issues with 24 psi of boost. We'll see what happens on the dyno for a definitive answer for this turbo and this setup. Again, RPM does offer the harder valve springs if we find it is necessary.
Many of these items (larger injectors, Wide Band O2, boost referenced fuel system, valve springs) will all increase the cost of the kit he currently offers so it may still swell the cost of the upgrade to 300 WHP to more than your $4K budget. Just be aware of what you may be getting into.
Hope this helps.