TARManiAC

My rallydriving Subarudealer who also does crosskarting in a vehicle with an Impreza turbo engine tells me he had two engines go bang during enduranceraces (8 hours non stop). He is quite experinced in this kind of motorsport and has also won a race. The problem is he says this happened using Castrol RS. This makes me confused cos everybody (almost) on here says to use this oil. My service is up soon so I would like to know what oil is best. My dealer says he is using Duckhams semi in both the rallycar (Impreza turbo) and the crosskart. Which is also what he is selling
in his shop. He said yes that I could bring my own oil.

What to do?

SD_GR

The lubrication requirements for a road car that will go 5000-1000 km between oil changes and an endurance racing motor are quite distinct, since the road car will be concerned with viscosity stability, shearing, thermal breakdown, cold starting, cold pumping pressures, temperature extremes, hygroscopy, fuel contamination, motor seal conditioning over the car's lifetime etc.. Since your vehicle is newer, it is probably still under warranty, right? I'd go with an ACEA A3-02 rated oil in the weight recommended by your owner's manual for your climate, and a works filter and sump bolt crush washer. I'd also adhere to the manual's recommended change intervals strictly. I'd prefer a Group IV/V polyalphaolefin/ester mix type oil, as these seem to respond best to high stress environments and last the longest - providing the best safety margin. I'm not in your geographic area and oil formulations vary greatly from place to place for a variety of economic/political/strange reasons, so I can't recommend a specific make.

My US MY02 WRX is getting Mobil 1 10W-30, largely for warranty spec reasons. If I could use M1 0W-40 or 15W-50 under warranty, I would, but that's just my opinion.

The best way to go about this kind of decision is boring and tedious: get an oil analysis done on a virgin oil sample, then a sample pulled out of the sump at 5,000 km, then another later and so on and monitor wear metals in the chemical analysis results. A simpler solution is to get an oil rated for the toughest specs existing at the time that still meets your manual's requirements for grade, weight etc. ACEA A3-02 is the toughest spec in Europe right now, and always an indicator of a good oil. Individual manufacturers also have stringent requirements; it takes a good oil to meet Merc's MB 229.3, for example, or BMW's long-life. So check your manual, check the oil container, and have fun...

TARManiAC

Others??