Low Speed Pre-Ignition (LSPI) is a frequently asked about issue among technicians, according to Millers Oils which is today outlining what it is and how it can be solved.
LSPI is more commonly known as ‘super knock’ and relates to uncontrolled combustion, according to Millers Oils.
A spokesperson said: “It occurs when oil on the cylinder wall mixes with freshly injected fuel and atomises.
“These two substances create a mixture that spontaneously ignites when compressed by the rising piston, before the spark plug fires.
“The resulting rapid, uncontrolled rise in pressure can cause irreparable damage to pistons, rings, cylinder heads and con rods, even leading to complete engine failure.
“LSPI takes place at large throttle openings and low to moderate engine speeds, such as when accelerating in a high gear but at a low rev count.”
Downsized turbocharged engines
The vehicle manufacturer trend for downsized turbocharged engines has led to increasing cases of LSPI, due to the high combustion pressures involved in some vehicles.
Millers Oils add that LSPI is only a problem for petrol engines due to the different methods of ignition.
Petrol engines are designed with a spark plug for ignition to give controlled combustion while diesels rely on gas compression for ignition, so are not affected by LSPI.
Newly developed engine oil
Millers Oils has developed a new engine oil, XF Longlife LSPI 5w30, that uses the latest additive chemistry to compensate for the shortfall in engine design.
It means drivers can avoid the problem of LSPI and costly engine damage simply by using the correct oil.
XF Longlife LSPI 5w30 performance profile lists API SN, ILSAC GF5/API SN-resource conserving, GM Dexos 1 Gen 2 and Ford WSS-M2C946-A.
Millers Oils adds that XF Longlife LSPI 5w30 is not backward compatible with the GM Dexos 2 5w30 specification.
To find out more about Millers Oils’ offering please call 01484 713201 or click the ‘more details’ link.