---- Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM> wrote:
> Then we should research how much zinc additive is correct.
>

Scott, I am not an engineer.  My niece's husband is a petroleum products engineer for one of the big companies.  A lot of his time has been devoted to fuels, but he is conversant with lubricants, and a big part of his job has been focused on emissions reduction.  He simply says that the additives in oils provide the best combination of excellent oiling (ie, protection) and low emissions, and that the flap about low zinc levels has mostly been stirred up by folks who build modified engines and oil marketers who use it to promote their exceptionally high priced products.  Some of the majors have then stuck in products to meet the demand, but not because they are needed.  His company does that, too, marketing them mostly as "racing oils," but selling them through outlets and advertising that reach owner's of non-racing vehicles who can be led to believe that their vehicles need them.

Bottom line is, he says the automotive and petroleum marketing companies HAVE researched how much zinc is needed, and that amount is in the oils that meet the published standards.

Being ignorant, I have tried to trust the experts, rather than go my own way.  I have found that some oils seem to hold pressure better than others.  For example, Castrol 20W50 holds pressure at high ambient temperatures better than does Pennzoil 20W50.  Being an empiricist, I'd say experience with a particular oil should be a good way to go, so long as the oil chosen meets the standards required for your vehicle.

If one believes his vehicle needs the extra zinc, and is willing to pay the premium price up to legal limits for the zinc, then I guess buy it.  But my caveat of up to the legal limits of zinc is intended to mean protect the emissions control system of the vehicle, also.

mcneely