iain atkins

Hello

I put some 300v in on the last oil service (MY97 turbo) 1600 miles ago and someone told me today that it's a race oil and should not really be used for normal road use.

Can someone help me with this.

Bob Rawle maybe????

Cheers



Iain

Caronte

Hi Iain,

The multigrade consists in two values. The first one is the viscosity when cold and the second is the viscosity when hot. Therefore the lower the first value the better for cold starts ( especially at low outside temperatures. The higher the second value the better resistance at high temperatures. When starting the engine from cold the oil is so thick that it does not circulate in the system, with higher frictions on internals. Therefore a lower first value diminishes the time for the oil to circulate. Opposite when the engine is hot oil can reach temperatures os 120-130 C which causes a deterioration of the oil mechanic properties (ie. less lubricant effect). Therefore the higher the second value , the better lubrication at higher temperatures.

Racing oil tend to have the the second value very low (in these last years) to dimish the friction of the moving components (crankshaft, etc) with the oil. This gives an advantage in terms of hp ( that in normal "road conditions" is absolutely marginal). However race engines are rebuilt often ( f course depending on the budget).
For road cars it is better to look for an oil that covers as much as possible all the temperature ranges. Therefore a good 5-50 would be ideal for both low temperatures and performing engines under termal stresses.
Also a 10-50 can cope with temperature in the order of -5 C approx.
A 15 -50 if used in summertime is perfect, bearing in mind that could be too thick for winter time.

Hope this help

C./

Bob Rawle

Hi, I use it all year round, recommended for the turbo Impreza as the best Motul grade by Motul themselves.

iain atkins

Cheers Bob Top man!!

Thanks for your explination as well Caronte

Cheers



Iain