Wednesday, March 7, 2012
Mitsubishi FTO with 6A12 Engine
Mitsubishi 6A12 engine is commonly use in Malaysia local Proton Perdana 2.0 V6 model, so sometime the Mitsubishi FTO owner looking for some engine gasket or even timing belt, when they quoted that is 6A12 engine, they might get the wrong item.
The FTO 24V V6 Engine AKA 6A12
The FTO engine comes in several guises, but the most interesting is the 24valve V6 found in the GR, GP, GPR and GPX versions. The main difference between the GR and GP/X/R is the additional of variable valve timing to allow the engine to run different cam profiles at different revs. The MIVEC system is very similar to the honda VTEC system in that it adjusts timing on both inlet and outlet ports. Many cars that offer variable valve timing only control the inlet ports timing and do this electonically rather than using two cam settings. The FTO has two sets of cam lobes (giving it 4 cams in total), one for low-down torque response and the other for top-end power. These are electronically controlled and hydraulically actuated. The transition between low and high cam settings is not as abrupt as the VTEC system which can feel like a turbo kicking in, but it is noticable and the car does seem to "dig-in" more when this happens. The point at which the cams switch is about 5500rpm, but by use of a MIVEC controller it is possible to alter this. This can simply be a case of dropping the rpm point, but the more sophisticated controllers also allow you to specify the lift for different RPMs.
6 cylinders in a V shape with a 60° angle with double overhead camshafts.
Combustion is carried out in a pentroof type combustion chamber
Cylinder bore of 78.4mm, piston stroke or 69.0mm and a compression ration of 10.0
There are three ignition coils controlling the spark plugins in pairs (1+4), (2+5), (3+6)
The valve timing at low speed is at 15° (Intake opening), 41° (Intake closing), 41° (Exhaust opening), 15° (Exhaust closing) and at high speed is 37.5°, 82.5° for the intake and 75°, 30° for the exhaust.