Motul 300V (5W30) vs Motul X-clean 8100C3 (5W30) in a streetcar

Aug 24, 2020
I thought I'd make a dedicated thread to discuss 300V vs the X-clean.

And the winner is: Motul X-clean 8100 C3 5W30

The basic conclusion is that Motul X-clean 8100 C3 is a very good oil and exceeds all my requirements for a lubricant. Motul 300V is also a very good oil but, even though it is made from the best base group V producs to the highest spec, it is not optimal for a street application because it is meant to operate at a high temperature, in an engine that will be rebuilt after let's say.. a Le Mans 24h race. Bear in mind, Motul has upgraded the formula since my first few tests with better street application in mind and I heard they were testing it.

If we consider, what is the requirement for a good lubricant in a street car? It needs to keep wear to a minimum at a reasonable cost for a reasonable oil change interval.

Than how did the 300V do? It did good on the wear part but I think an OCI of 10k with considerable cost per liter (my V8 takes almost 9L) makes it very expensive. Also, it could be detrimental to gaskets and there is the question of significanly lower flashpoint. Is the latter a problem? It could quite well be. If the oil gets hot enough and the flashpoint is low enough, burning of oil could result in carbon deposits, oil 'consumption' and perhaps other unwanted effectes. When would this happen? Flashpoint drops due to fuel contamination. I think, a race car engine does not contaminate oil as much as a street car engine. So a race car running 300V will probably not have this flashpoint issue. A road car however, after 10k, could.

Than how did the X-clean do? I think it did very well. Again, the wear numbers indicate nearly no wear at all, even after a oil change interval of 19,5k. The properties show that it still has nearly the factory spec viscosity, VI and base number and it does not seem to be detrimental to gaskets. We cannot compare or even see the flash-point levels so this will remain a mystery. Considering the significantly lower cost as opposed to the 300V oil, I would say the X-clean is to be considered the most optimal oil in my application. Which is a high performance street car. If I change this oil once a year after no more than 20k I am quite sure it will keep the engine in the best possible condition an oil can do.

See the whole project and testing:
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To clarify, the oil referred to as X-clean 8100 C3 5W30 (oil C) is the 'X-Clean+ 5w30 for
  • VW 504 00 / 507 00
  • MB-Approval 229.51
  • BMW LL-04
by Motul.