The engine code broken down is

RB from the RB family of engines
25  over all engine size (2498cc)
D   Dual camshaft
E   Electronic Fuel Injection
T Turbo

The Engine is an inline six cylinder block, with 24 valves featuring Unisia Jecs variable valve timing on the intake camshaft and has a bore of 86mm and a stroke of 71mm.

How the Internal Combustion Engine works, explained, with a glossary.

The ICB engine works on a four stroke cycle (it also works as a two stroke cycle but is not the case here).

Induction, Compression, Power & Exhaust - or suck squeeze bang blow if you prefer.

1. Induction Stroke

The piston will start moving down the bore, from TDC (top dead center) with the 2 air intake valves open.

At the same time the Air Flow Meter (AFM) is recording the amount of air passing through, and the temperature, and passing it on to the ECU (Electronic Control Unit - the brains of the car) so as to prepare the injextors to add the correct amount of fuel necesary for optimum air & fuel ratio.

As the piston reaches BDC (bottom dead center) the intake valves close, sealing the combustion chamber.

2. Compression Stroke

With all valves now shut, the piston travels upward, compressing the drawn in air.

3. Power Stroke

All valves remain shut, and at around 10 - 12 degrees BTDC (before top dead center) the injectors squirt the fuel into the chamber, and the spark plug fires, igniting the air & fuel mix at TDC.

4. Exhaust stroke

Once the exploson has talen place, it effectively pushes the puiston back down the bore, while opening the exhaust valves to allow burned gasses to escape.

Except in the case of the RB25DET, which is a turbo engine, that uses exhaust gasses and turbines to compress larger amounts of air into the cylinder.

Important notes for the RB25DET and fuel.

use 99Ron or above as a standard car, if you have it remapped be sure to always use the same fuel, as a lower Octane Number fuel may burn up to early. With ;pwer RON Fuel detonation may occur which will result

Although the engine has knock sensors fitted, which then send the information to the ECU which will advance or retard the timing accordingly. Constant detonation can result in engine failure.

Cyliner Numbe & Firing Order

Locating cylinder No.1 is simple enough, its the one closest to the camshaft pulley cover, Cylinder No. 2 is next on the right and so on (for most engines except some french engines, which Cylinder No.1 is the one nearest to the clutch)

The Firing order is Cylinders 1&6 ; 3&4 ; 2&5. So when 1&6 are at TDC, the next two are 3 or 4 and then 2 and 5.

So what goes on when i turn the key?

The ECU switches on and does a check for faults within its serving components - ie road speed sensor, air flow sensor, engine speed sensor and knock / detonation sensors, and sometimes you can hear the fuel pump primeing up.

Once the "start / cranking point is reached it sends a live feed to the starter motor, which flngs out the shaft to turn the flywheel, which athe same time turns the crankshaft, which controls the upward and downward movement of the pistons for each cycle.

There are plenty of components i need to add, but for now this should give a good idea on how it all worls.