Originally Posted by AuthorEditor
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There's no proof that the money spent on premium products in normal applications gives a decent ROI.
From what we read on BITOG people advocating non-premium products often aren't really saving money. For example, using standard dino oil and changing the filter every 5000 miles does not save you any money over using synthetic oil and a better filter while only changing the oil every 10,000 miles, assuming that synthetics and better filters are about twice the price. If you count your time as worth something you get the same results for 50% of the labor cost. Plus there is a savings on trips to the store or delivery charges, clean up materials, rubber gloves, crush washers, etc. etc. It gets worse if you are doing OCIs of 3000 miles. I haven't seen any definitive proof that the synthetic regime described is any worse for normal engines in normal use. On the other hand, you could argue that ordinary oil and filters could probably be used for double-length OCIs with no harm, and then you would be seeing a significant savings.
The presumption here is that syns and premium filters can go 2x futher ...
But further than what?
This is where most any typical person does not recognize/understand the bias in their own "experiment". By your logic, if the premium products were costing 2x more money, and got used for 2x more duration, then the ROIs would be equal. That is true. But that is predicated on SELF-IMPOSED, UNVERIFIED LIMITS.
My data base (over 15,000 UOAs) shows that pretty much all oils/filters can easily go 15k miles in most all applications, and have the wear rates still trend DOWN. There is no disparity in the macro data results; this is true of both normal products and premium products. The performance outputs are the same, but the premium products cost more. Hence, they exhibit a lower ROI.
My point is that the self imposed limits of 5k miles for normal products and 10k miles for premium products in your example are proof that self-imposed limits skew the data and obscure the truth. Those arbitrary limits do not reflect the actual performance in the real world; they only illuminate bias that limits the real ability of all products. It is proven that even conventional oils and normal filters exhibit wear trending down out to 15k miles. It is entirely possible that premium products would do that further; perhaps 25k miles or more? The point is that when self-imposed OFCIs take place, you're not testing the products; you're testing your bias!
If one sets arbitrary OFCI limits, typically 15k miles or less, then any convention products are going to exhibit a better ROI (defined as more return for less investment). If one were to run the OFCIs out to where the wear rates began to escalate slightly, indicating that the protection factor was now maxed out, and then measure the duration of use against the cost, THEN you'd know which is "better" for the true performance ROI factor. But since pretty much no one here has the stones to run OFCIs out to 20k miles, 25k miles, 30k miles on their standard filtering system (no BP system present), then you'll just have to accept the fact that we have no real understanding of how far ANY product can really go. So we're stuck with the self-imposed limits, which generate bias in the ROI.
What I know for a fact, what I can prove beyond any credible doubt, is that wear rates in nearly all engines continues to drop, out to 15k miles, regardless if you use normal or premium products. So if the output is the same (wear rates go down), and the inputs are different (cost of the OFCI), then the better ROI is the one that gives the same result for less expense. Hence, normal products are a smarter purchase.