|Phosphorus is the P in ZDDP, and it's the part that provides the anti-wear properties (the rest of the ZDD_ just goes along for the ride). When people talk about 'Zinc' levels, they're missing the whole point. The minimum phosphorus level I'll use in a Lotus engine that is already broken in is 1200 ppm (parts per million, or 0.12%).
Mobil 1 15W50 contains that amount... 1200 ppm. I've used it for the street, but I prefer more phosphorus. Especially if an occassional autocross or a track day is likely... or if you just enjoy driving in a more spirited manner. If you're going to 'get on it', then more phosphorus is better.
Mobil 1 20W50 V-Twin Motorcycle oil used to be sold as an automotive oil, and it was highly recommended by Lotus back in the day. But it contains 1600 ppm phosphorus, which is more than the API currently allows for automotive use. So Mobil 1 simply re-branded it as a motorcycle oil. It's the same great stuff, still great in your automotive engine, still available in local stores... just look in the motorccle aisle. It is more expensive than the 15W50.
Mobil 1 0W-50 Racing Oil contains 1750 ppm phosphorus. It's billed as a 'racing oil', but it contains a full street additive package. As usual, if more is better, it's also more expensive. It's rarely found on the shelf at your local auto parts store, but any Mobil dealer can order it for you... just plan ahead.
Mobil 1 Extended Life 10W60 contains 1300 ppm phosphorus, and both the 1300 and the 10W60 would be very good in a Lotus 9XX engine. Unfortunately, it's sold in the UK & Europe (I'm envious), and isn't available in North America. Of course, there's always the internet.
Valvoline 20W50 VR1 Racing Oil is available as either a mineral oil or full synthetic, and all versions contain 1300 ppm phosphorus. Like the Mobil 1 racing oil, it also contains a full street additive package, and it's readily available at retail.
Just read the VR1 label carefully since the mineral, synthetic and NSL versions' package labels look almost identical. Read the fine print to be certain you're getting what you want.
VR1 NSL stands for Not Street Legal, but that has nothing to do with being "legal". It's a pure racing oil, and contains NO STREET ADDITIVES. It will protect your engines cams and bearings, but if you use it on the street, it must be changed every 500 miles or 3 months (that recommendation comes from Valvoline). The short change interval makes it considerably more expensive over time than the other VR1 versions.
Brad Penn®, Penn Grade 1 Hi-Perf Oils contain 1400 ppm phosphorus, and is available in a 20W50 viscosity. It's cult popular with street rodders and drag racers, but it's not commonly available at the local auto parts store. It has a unique green color. If your car leaks a little onto the floor, there will be no doubt about whether it's motor oil or gear oil. Overall, it's very good stuff... just plan on having to order it.
Castrol GTX is a well respected mineral oil name based on past history; however it’s ZDDP and phosphorous levels are not published and web hearsay indicates GTX’s ZDDP level was cut roughly in half with the exception of one grade. GTX 20W-50 is still safe to use in a flat tappet cam engine that has already been broken-in, but it’s not exactly rich in ZDDP / phosphorus.
Last edited on 09-03-2020 06:19 pm by Esprit2