Comma Motorsport 5w-50 5w50 Fully Synthetic Racing Car Engine Oil - 5 Litres 5L. This fully synthetic, high-performance 5W-50 oil is ideal for motorsport and track day use, and is suitable for replacing SAE 5W-40, 10W-40, and 15W-40 oils in motorsport applications. Comma Motorsport 5W50 Fully Synthetic 5 Litre Motor Oil Race Road Rally.