stavo pensando di provare il bardhal 5w40 (nno so se technos o xtc)
poi mentre girovagavo su intenert ho letto questo..
Secondo voi è ancora valido ?
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Using Teflon(R) Additives - Not Very Smart
By James R. Davis
I will admit at the outset that I have no experience whatever in using Slick 50 (nor will I ever). Further, though much will be said of Slick 50 in what follows, it is all generally true also of any other synthetic additive containing Teflon(R).
Slick 50 is a PTFE related product (ie, a Teflon(R) powder suspended in standard oil). Powder, you will note, is a SOLID. Your oil filter is designed to remove solids and tests have shown that oil filters clog substantially sooner when Slick 50 is used than if using standard oils without it - naturally. Manufacturers claim that the particle size of this powder is smaller than the pore size of oil filters, implying that they will pass right through them, but they do not also say that these particles expand rapidly when exposed to heat - so that they may well pass thru when cold, but not after they reach normal engine temperatures. Tests also demonstrate that other oil passageways also tend to clog when PTFE is used.
Tests? By whom? Are they credible? Answer: by organizations like NASA Lewis Research, the University of Utah Engineering Experiment Station, and even DuPont Chemical Corporation, the corporation that invented PTFE (Teflon(R)) and that provides PTFE to the manufacturers of these 'magic' oils.
Wait! They sell the PTFE to companies like those that make Slick 50 yet they argue that it clogs oil filters and other oil passageways? Not exactly. In a statement issued about ten years ago, DuPont's Fluoropolymers Division Product Specialist, J.F. Imbalzano said,
"Teflon is not useful as an ingredient in oil additives or oils used for internal combustion engines."
They went on and REFUSED to sell PTFE to anyone that intended to do so!
Naturally, they were sued by, guess who, on grounds of 'restraint of trade'. DuPont lost and have changed their position as follows: DuPont now states that though they sell PTFE to oil additive producers, they have "no proof of the validity of the additive makers' claims." They further state that they have "no knowledge of any advantage gained through the use of PTFE in engine oil."
NASA Lewis Research also ran tests on PTFE additives and they concluded that:
"In the types of bearing surface contact we have looked at, we have seen no benefit. In some cases we have seen detrimental effect. The solids in the oil tend to accumulate at inlets and act as a dam, which simply blocks the oil from entering. Instead of helping, it is actually depriving parts of lubricant."
As to my earlier assertion that Teflon(R) cannot be made to bond to engine parts, despite what Slick 50 says, the Chief Chemist of Redline Synthetic Oil Company, Roy Howell, says:
... to plate Teflon on a metal needs an absolutely clean, high temperature surface, in a vacuum. Therefore, it is highly unlikely that the Teflon in Slick 50 actually plates the metal surface. In addition the Cf (Coefficient of friction) of Teflon is actually greater than the Cf of an Oil Film on Steel. Also, if the Teflon did fill in 'craters' in the steel, than it would fill in the honing of the cylinder, and the oil would not seal the piston rings."
Well, you get the picture. PTFE products like Slick 50 tend to clog oil filters and passageways, resulting in faster ENGINE WEAR. Further, Teflon(R) is NOT as slippery as an Oil Film on Steel.
Nobody is arguing that you won't get higher engine performance (power) or better gas mileage if you use it. On the other hand, if your engine wears out faster I wonder if that's worth it along with the very much higher price.
If you find that you have to change your oil more often, and use this pricey stuff in it each time, the effective cost is even higher. If you decide that clogged oil filters and oil passageways are something you'ld rather do without, how do you get rid of it once you put it into your system? Well, in the case of your clutch, by taking it apart and cleaning it! That's an expensive additive 'cost'.
It is no wonder as far as I'm concerned that Slick 50 is often called 'snake oil'. You might not be stupid if you put it into your motorcycle, but I would be."
