I must say the more analysis I see from the XL line the more I become impressed. Early on in my business I didnt push it a whole lot if at all simply because it wasnt the long drain I was used to from Amsoil. However, after acquiring a customer that insisted on nothing but using XL oil I decided to start looking into just how well it did. So I did some free oil analysis a few years ago and the initial results, to say the least, surprised me.
After that, I focused on just how far the oil could go. It seemed that when I saw the first couple of oil analysis from the XL line it was clear that 7500 miles was a bit on the conservative side. I was speculating at the time that 12k miles would be about the limit of the oil under normal conditions, though I didnt tell my customers this simply because I had no data to back it up.
Well Joe has come along and put the oil through its paces. Not only has he went well beyond the mileage limit, he stressed the oil further by subjecting it to three auto crosses. Now, I know from experience that the Zetec motor tends to be slightly less destructive to motor oil. Even so, three autocrosses definately put some stress on that oil.
You will notice the TBN is at 1.54. This will normally get flagged at 2.0 and a recommendation that the oil be changed. So he definately used the oil up. His motor is not consuming any oil so he doesnt get the benefit of small boosts in additive package. His Oxidation and Nitration numbers were also elevated. This indicates to me that if he continued to use this oil, TBN aside, his wear numbers would have begun to rise significantly.
I believe the most autocrosses I have seen on the XL oil is three to date. I have one other customer that autocrosses seriously and he too usually has about two or three events on his oil. I have ran him up to 10k miles and he was still comfortably within the oils limits.
If Joe had not had the three events on his oil I think he could have stretched the oil out a bit further, though how much would be difficult to determine without further testing. Suffice it to say that I wouldnt push the oil past 11.5 - 12k under normal driving and would scale that back to perhaps around 10k with driving such as autocrossing in the mix.
I dont believe he was using the newer EaO filters on that run, so it would be interesting to see how the EaO affects the endurance of the oil. With its better filtration I would think it would add more comfort area by keeping the oil cleaner and, of course, anytime you can keep the oil cleaner you can extend its drain interval.
I would also point out the Viscosity of the oil. It has barely changed. nearly 11.5k miles and it is still clearly a 20W oil. That in itself shows some serious stability in the oil.
____________________ My car is a synner! It uses Amsoil Synthetic Lubricants.
2001 Pontiac Grand Prix GTP
It whines a lot, but I like it
