X25XE

Infobox Automobile engine


name = X25XE
aka =
manufacturer = General Motors Europe
type = V6 petrol engine
production =
predecessor = C25XE
successor = Y26SE
bore = auto mm|81.6|3
stroke = auto mm|79.6|3
displacement = auto cc|2498|1
length =
diameter =
width =
height =
weight =
block = cast iron
head = aluminium alloy
valvetrain = 2x DOHC
fuelsystem =
fueltype = unleaded petrol
oilsystem = wet sump
coolingsystem = water/antifreeze
power = convert|125|kW|hp
specpower =
torque = auto Nm|227|0
compression = 10.8:1
fuelcon =
specfuelcon =
oilcon =Infobox Automobile engine


name = X30XE
aka =
manufacturer = General Motors Europe
type = V6 petrol engine
production =
predecessor =
successor = Y32SE
bore = auto mm|86|3
stroke = auto mm|85|3
displacement = auto cc|2960|1
length =
diameter =
width =
height =
weight =
block = cast iron
head = aluminium alloy
valvetrain = 2x DOHC
fuelsystem =
fueltype = unleaded petrol
oilsystem = wet sump
coolingsystem = water/antifreeze
power = convert|155|kW|hp
specpower =
torque = auto Nm|270|0
compression = 10.8:1
fuelcon =
specfuelcon =
oilcon =The X25XE is a General Motors Europe (GM) petrol engine. It is a 2498 cc (2.5L) 24 valve, DOHC V6 engine, producing, in standard form convert|125|kW|hp (170 PS).

The breakdown of the engine name [Topbuzz, "Engine Codes Explained", "Topbuzz Website", 2002. Accessed 9 Dec 2006 [http://topbuzz.co.uk/info/engine_codes/engine_codes.htm] ] is as follows:

X - Exhaust Emissions Level: 94/12/EC, stage 2
25 - 2.5 Litre displacement
X - Compression Ratio - 10.0-11.5:1
E - Mixture System - Injection

In the early 1990s, GM identified the need for a modern, lightweight and compact power plant to replace its ageing straight-6 engine range. This engine needed to be compact, to allow its use in front-wheel drive applications, as well as rear-wheel drive cars.

The first version arrived in the Opel Vectra / Vauxhall Cavalier (both codenamed "Vectra-A") and Opel/Vauxhall Calibra in the C25XE form, and was later followed by the X25XE in the Opel/Vauxhall Omega and Vectra-B, with the Omega gaining a variant with increased displacement in the form of the X30XE.

This power plant was a modern 4 valve per cylinder, quad cam arrangement, with an oil to water heat exchanger mounted within the V of the engine block. The cylinder heads were constructed from aluminium alloy, and the block from cast iron.

An unusual feature of the engine was its 54 degree cylinder angle, as opposed to the more conventional 60 degree setup used on many V6 units, this added to the setups' compactness.

A Bosch Motronic engine management system is used to control the unit, with full sequential fuel injection, knock control on each bank, distributorless ignition system (DIS), and closed loop lambda control.

Technical data

The "X" variant of the engine had the addition of secondary air injection, and EGR to meet later and more stringent emission requirements.

The air injection blew air via a large blower into the exhaust manifolds to ignite un-burnt fuel in the downpipes during the engine warm up phase, in order to get the catalytic converters up to temperature faster. The EGR setup re-cycled exhaust gases (which are in theory inert to the combustion cycle) in order to reduce the production of NOx.

History

Minor changes were made to the unit during its production, including an uprated oil pump around mid 1997, with the addition of larger oilways in the head machining (T-Vents), and modified valve lifters to reduce top-end valve noise, at which point the cam belt arrangement also changed with the lower idler moving.

Around 1998, the spin-on metal canister oil filter was changed to a disposable paper element.

2000 saw a complete revision of the power plant in order to meet increasing emission requirements, with the 2.5 and 3.0 being replaced by lower compression 2.6 (Y26SE) and 3.2 (Y32SE) units.

These later power plants had a revised engine management system setup, which utilised quad lambda sensor control, coil per plug ignition system and drive by wire throttles. The 3.2 also received a stronger steel crankshaft. As a result of these changes the EGR and secondary air injection system were removed.

References