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    Great SR20DET Upgrade Setups


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    Great SR20DET Upgrade Setups Empty Great SR20DET Upgrade Setups

    Post by PurpleTop240 on Mon May 21, 2012 1:34 am

    SR20DET Power Upgrade Walkthrough
    Hi guys. Lately I've been getting a lot of the same question from people that are new to the 240 and SR20 community. Being busy at the shop I often don't have the time to fully explain all of the turbo options and fueling/tuning options, and what is best for what power goals. The goal of this thread is to let you know what you need to do to get X horsepower for minimum dollars, without sacrificing reliability.

    The first modifications that should be done to any SR20 looking for over 250whp include:

    Turbo elbow, downpipe and full 3" exhaust
    Front mount intercooler
    Walbro fuel pump
    Adequate cooling modifications, suited to the driving you're doing (but that discussion is beyond the scope of this discussion)
    An aftermarket clutch, especially if you're going to be drifting or drag racing will be required above 250whp

    Let's quickly look at the limitations of the factory computer, air flow sensor and injectors:

    The factory ECU can be tricked with an MAF signal interpreter up to around ~310whp
    The stock 370cc injectors max out around 240-250whp, or typically anything above 9-10psi on upgraded turbos.
    The factory SR20 MAF maxes out around the same area, and the fueling can become sparatic and a boost spike will result in almost sure detonation and engine damage.

    We offer the following ECU options, sorted by cost:

    A'PEXi S-AFC - This allows you to upgrade to a 300zx MAF and 550cc injectors (but we suggest no bigger), to support roughly 310whp-330whp.

    A'PEXi Power FC - MAF Sensor based - This is a replacement ECU with commander that allows you to upgrade to the 300zx MAF and run just about any injector you want. It allows for ignition table and fuel table tuning and can be fine tuned by the hand held commander. This is a great solution for anything under 450whp.

    A'PEXi Power FC - MAP Sensor - The same as the above, except it eliminates the flow sensor and uses a pressure sensor. Included with the kit are a MAP sensor and intake air temperature sensor. This is a great solution for anything under and around 450whp.

    ViPEC Replacement ECU - Similar to an A'PEXi MAP Power FC, except a real full standalone that can be fully tuned through a laptop. Installation is more costly but this system has the capability to support basically unlimited power.

    AEM EMS - An alternative to the ViPEC ecu, this is a plug and play ems from AEM that allows tuning of just about any setup out there, just like the ViPEC. The EMS can handle MAF or MAP sensor inputs.

    The pros of MAP are they return to idle better and don't display the problems associated with atmospheric blow off valves, and they don't require a MAF - so your intake can be relatively simple.

    The pros of MAF based systems is that they are less costly to setup and tune, and they don't require a full re-tune (just a fine checkover) whenever you change engine or turbo components, unlike MAP based systems.

    The next upgrade required are injectors, the following sizes are roughly the ones you want for target power levels:

    Keep in mind that the larger the injector, the worse the idle and low speed fuel efficiency - buy the smallest injector that will meet your long term goals.

    350whp and less - 550cc
    420whp and less - 740cc
    480whp and less - 850cc

    When it comes to flow sensors, the Z32 maf is a great upgrade with mild idle response issues due to its size, but by far the best option out there for 90% of people. A custom intake with a recirculated blow off valve is the way to go if you want to avoid the MAP sensor route, to save money on dyno tuning down the road.

    Turbo sizing:

    The factory T25/T28s obviously run out of steam around 240whp. There are a lot of different turbos out there but we have had best success with the GT2871R 0.64 A/R exhaust side, with the 56 trim compressor housing that allows you to literally bolt the turbo right in to an S14 SR, or with the use of re-clocking adapters with an S13 SR. We recommend replacement coolant and oil feed lines as the factory ones are known to crack at the solder if they've been used.

    The GT2871R 0.64 A/R starts to build boost as early as 3000rpm and offers incredible response. On most setups we see 14psi by 3600-3800rpm, which leads to an incredible 280-300ft lbs of torque almost across the board. The turbo is capable of 360whp with the proper supporting modifications, which is more than anyone on this board should likely have under their right foot. Unless it is a track only drag car, but that is not the purpose of this article.

    Let me conclude the article with some coles notes:

    If your long term goal is 300whp (which is the perfect power for a lapping day car, amateur drift car, or street car) I suggest:

    550cc Injectors
    GT2871 0.64
    A'PEXi S-AFCII w/ Z32 MAFS

    If your long term goal is 350-400whp, and if you want a bit more control than the SAFC offers I suggest:

    740cc Injectors
    GT2871 0.64
    A'PEXi Power FC MAF w/ Z32

    If your long term goal is over 400whp, be prepared to spend over 5000 to do it properly, otherwise consider the more realistic options above, which will be incredibly fun and reliable, which is way more satisfying than trying to chase a number and being left with blown motors or ticking time bombs.

    Finally, other components that require change:

    Above 300whp the factory headgasket starts to leak cylinder pressure into the coolant, so we recommend the APEX'i head gasket and ARP studs.

    Above 7000rpm the water pump starts to spin a little too fast and a larger water pump pulley is suggested to slow it down.

    New turbo hardware including locking tabs, nuts, and gaskets are suggested or required depending on the type of driving you're doing. We suggest safety wiring the manifold and turbo elbow hardware in racing applications.

    I hope this post helps some of you that are considering a large power upgrade for your SR20, please keep in mind that we sell and install all the parts listed above, and can supply you with a start to finish solution all under one roof, all orchestrated by one person, tuned on the dyno by yours truly.
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