Tomei Engine: SR20

Tomei Engine: SR20
 
 

SETUP GUIDE

■BOOST SETTINGS
M7960
1.6㎏/cm² (22.8psi) Boost Controller Recommended 
M8270

The ARMS M7960 turbo is capable of over 400ps with 1.6k of boost. It is recommended to upgrade the head gasket to increase the engine strength and to minimise the chances of leakages. The stock engine is capable of producing around 300-330ps at best. In this case, the boost is usaully at around 1.1-1.2k. When making changes to the boost setting, please do it when you are in 4th/5th gear. If you make changes whilst in a lower gear, the load will then be greater at a higher gear, and therefore the boost will be higher than the initial setting. (After setting the boost might drop as the rpm rises to peak boost. But don't be alarmed as this is normal.)
 
■ACTUATOR SETTINGS
M7960
Not Required [ Initial Setting 0.9kg/cm² 12.8psi]
M8270

The actuator is already pre-set for optimum efficiency. However in order to stabilize boost at a higher loads, it is best to use a boost controller to make the required adjustments. By adjusting the actuator and stabilizing the boost you can change the characteristics to suit your needs. If required, the use of a boost controller is highly recommended if you want to adjust the actuator settings. 
 
■TARGET POWER
M7960
400-420ps
M8270
430-450ps

The stock engine weakpoint is with the head gasket. So at stock condition, the SR20 is capable of around 330ps at best. That is the max limit with a max boost setting of 1.0 to 1.1 kg / cm² (14.2-15.6psi) when taking reliability into account. Boost of 1.3 kg / cm² (18.49psi) is possible after upgrading the head gasket to a metal head gasket. And boost seetings of 1.5 to 1.6 kg / cm² (21.3-22.8psi) is possible when running Forged Pistons. 
 
■PISTONS
M7960
Forged Pistons  Recommended: TOMEI Forged Piston Kit
M8270

The stock SR20DET pistons are another weak point that has to be addressed when aiming for more than 330ps. When running either M7960, M8270 turbos with 1.6kg/cm² boost, the higher the combustion pressure, the higher the risk of the stock Pistons failing. {1.3 kg/cm² (18.49psi) boost is the max limit of the stock Pistons. There has been cases of the engine lasting about a year with the stock pistons.} When running higher boost, together with the upgraded Head Gasket, Forged Pistons are highly recommended. 
 
■HEAD GASKETS
M7960
Upgrading to Metal Type
Recommened: TOMEI Metal Head Gasket
M8270

Raising the boost also increases combustion pressure. In that case the standard head gasket will just no do. By changing to a Metal Head Gasket, reliability is increased and you can then run more boost. The head gasket thickness will also change the compression ratio and thus more power gain is also possible.
 
■INJECTOR SIZES
M7960
680cc or higher  Recommended: TOMEI 740cc 
M8270

This is an easy formula to use to calculate what you need.?
Cylinder horsepower objective×5.9÷ = discharge per minute required per cylinder?
To ensure stable atomization conditions, the injector(s) need to run at 80 to 90 percent capacity to be ideal and to maintain safe conditions. 
 
■FUEL PUMP
M7960
182L/h or more (when fuel pressure is at 3kg/cm²) Recommended: TOMEI 248L/h (when fuel pressure is at 3kg/cm²)
M8270

Injector size × number of cylinders × 0.06 = discharge rate (Fuel capacity)?
Considerating the fuel pump efficiency, please select one that will be suitable whilst running at 80-90% efficiency to allow a safety buffer.
 
■FUEL PRESSURE REGULATOR
M7960
Required for adjusting the fuel system changes. Recommended TOMEI Type-S
M8270

Due to changes with the fuel pump, the fuel pressure will have to be adjusted to suit the new setup.
The initial fuel pressure is set to atmospheric pressure of 3kg/cm².
■AIR CLEANER
M7960
High Flow Type
M8270

If you have upgraded the Air Flow Meter, upgrading the Air Cleaner is also highly recommended. 
 
■AIR FLOW
M7960
Z32 Genuine, or Air Flow Less Recommened: TOMEI Airflow Conversion Kits, TOMEI Air Flow Less Intake Kit
M8270

The stock Airflow diameter is too small and restrictive. So a common upgrade is the Nissan Z32 Airflow meter. With the Z32 AFM it is possible to reach 450ps. In that case, an aftermarket ECU like the REYTEC must be used, or alternatively to go with the airflow less setup.
■SUCTION PIPE
M7960
High Flow Type
M8270

If you run high boost with the stock suction pipe, deformation of the pipe can occur and cause unwanted flow restrictions. By replacing it you can gain improved air flow.
 
■INTERCOOLER
M7960
Large Capacity and High Flow Type
M8270

The turbine forces compressed air through the intake which will expand with heat. When the air is hotter, density is reduced and performance drops as combustion efficiency becomes poor. When the intercooler is larger it will allow higher flow and improved cooling. This will allow higher density compressed air to be fed into the engine delivering optimum combustion efficiency for best performance results. 
 
■BLOW OFF VALVE
M7960
Non Vent to Atmospher Types for S14/15 Recirculation Intake Relief like Stock.
M8270

When the Blow Off Valve relieves pressure by venting to the atmosphere, the turbo will work the same as the re-circulation method. But when the throttle is suddenly closed, air will still continue to flow through the AFM which will confuse the ECU to allow more fuel to be injected into the engine even when there is insufficient air flowing into the engine. This will cause the mixture to run rich and cause the engine to stall. This fouls the plugs and drops engine performance. So when using a blow off valve that re-circulates like standard, this eliminates the problem and allows the ECU to accurately control the correct air/fuel mixture at all times.?

*The S14/15 comes with the Re-circulation Valve for intake relief function. This is when the pressure is higher than the supercharger, and so it acts as a safety device to allow the excess pressure to vent back into the intake system. This usually happens when the excess pressure reaches 0.1 ~ 0.4kg/cm².
 
■EXHAUST MANIFOLD
M7960
TOMEI EXPREME Equivalent
M8270

Upgrading the camshaft will improve the exhaust pressure to turn the turbine wheel more efficiently, however the exhaust manifold will also need to suit the new cams for optimum connditions. A good smooth exhaust pressure flow will maximise the turbine wheels efficiency and this will deliver a more responsive sharper boost.
■OUTLET PIPE
M7960
TOMEI EXPREME Equivalent
M8270

The stock outlet pipe is restrictive, and hinders the exhaust gas flow. High engine speeds and high boost conditions will cause the boost to be unstable. This will cause performance problems with the turbo and engine performance. By changing the size of the pipe to a larger size, this allows stable boost control and conditions with reduced backpressure from the exhaust.
■FRONT PIPE
M7960
Recommendation: The main equivalent pipe diameter Φ80
M8270

As with the outlet, smooth air flow will improve response pickup and performance gains to suit with the outlet pipe increased sized. 
 
■CATALYTIC CONVERTER
M7960
Recommended: Metal Sports Catalysts
M8270

To allow high exhaust flow efficiency whilst still being able to reduce smog emmissions. 
 
■MUFFLER
M7960
Recommendation: The main pipe diameter Φ80mm or equivalent
M8270

As with the outlet, smooth air flow will improve response pickup and performance gains. 
 
■ENGINE MANAGEMENT SYSTEM
M7960
To suit the cars setup requirements.
M8270

The Engine Management System will need to be remapped to suit the new setup. 
 
■PLUGS
M7960
Recommended Heat Rating 8-9 - Please change to suit.
M8270

With increased horsepower the higher combustion temperatures will need to be adjusted to suit. The heat value of the stock plugs will not be sufficient for the extreme conditions and can melt.
Spark plug heat value of 8's is common, but 9's is also possible depending on your setup, please choose the right ones for your needs. 
 

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