Ant: Out of curiosity, I looked into the racing oils a bit further. It looks like, just over the last couple years about when SL oil was introduced, the racing blends kicked down their zinc content due to the potential for deposits and long-term cat converter damage. Valvoline's site was down when I sent my earlier message, so I couldn't verify the info I had. It's now back up, and it turns out their VR1 Racing multiweights have 0.137% zinc, close to Delo's concentration, and also similar to Kendall Super D3 (diesel) multiweight at 0.13%. So just a couple years ago the racing blends had an edge, but now the "diesel" oils mentioned above are comparable in regards to zinc. I wouldn't worry about phosphorus since for SL oils it's limited to 0.1% or 0.08%, something like that -- no SL oils will have an edge in terms of phos.
[ November 22, 2003, 11:08 PM: Message edited by: TC ]