Amsoil 5w-40 in 225 Hp, Audi TT Roadster

[TooSlick]

Note 1)
Plugs and air filter were changed by dealer prior to this run @ 40k service

Note 2)
Five ounces of LC20 added 500 miles prior to taking this sample, to check effect on viscosity. I believe OAI has re-calibrated their FTIR machine recently, which may account for the seemingly high, Ox/Nit readings?

Oil Used------------AFL/ATM/AMO
Miles on sample---9600/9500/5500
Oil added---------0.75/0.75/0.5 qts
OEM Air/Oil filters

EOT Viscosity(Cst)-----13.75/11.35/12.5

Nitration---------25.0/7.0/1.0
Oxidation---------58.0/10.0/3.0

TBN---------------5.1/5.4/8.1

Water--------------0/0/0
Fuel---------------< 1%/< 1%/< 1%

Wear Metals: 5w-40/10w-30/10w-40

Fe, 17/9/8
Cr, 1/1/1
Pb, 1/2/2
Cu, 10/13/9
Sn, 0/0/0
Al, 5/2/2
Ni, 0/0/0

Si, 13/9/6****

Oil Additives:

Boron, 6/25/3
Na, 6/5/4
Mg, 177/701/67
Ca, 3549/2204/3068
P, 1279/908/997
Zn, 1380/1220/1193
Moly, 2/3/7

All in all, about what I expected...you can see the direct effect of dirt levels on upper engine wear. Additive package looks like a CI-4+/SL, HD diesel oil and even with the five ounces of 10wt LC20 added just prior to testing, viscosity did not drop much from 14.5 Cst baseline.

Am now using 0w-40/AFF and will do an early check @ 3k miles to evaluate Oxidation/Nitration levels.

TS

 

[benjamming]

Ted,

How can good conclusions be drawn from these samples without running the same oil at least back-to-back? Will this not limit the information you can gather from these UOAs? Could it not even lead to false conclusions? Maybe not I don't know.

 

[TooSlick]

Well, my original intent was to run all the A3/B4 rated, gas engines oils first and then all the CI-4/SL stuff, so that the additive chemistries were similar from one run to the next. As you can see, this 5w-40 is a fortified version of the old 10w-40. The 0w-40/AFF I have in there now looks like the 10w-30, but with relatively higher additive levels of Ca/Mg/P/Zn/B.

You never get optimum results if you switch chemistries the way I'm doing, but these UOA's certainly look fine to me.

 

[buster]

Ted, did you notice any performance gains/losses when going up to the 40wt viscosity?

 

[TooSlick]

I ran the S2000, 0w-30 just prior to this and performance was better than with the 5w-40. The trip computer indicated I was getting about 2%-3% better fuel efficiency with the 0w-30. I forgot to test the S2000 before having the dealer change it out at the 40k mark, however. After this 0w-40 run is over, I plan to go back and do a 10k run w/ the 0w-30.

One interesting thing is that even though I'm switching additive chemistries w/ each change, there are no spikes in iron or bearing wear, ie none of the dreaded "additive clash". It seems like you can get excellent results with Amsoil, right from the first batch you run. The additive package of the 0w-40 in there now looks nothing like this 5w-40, as it has 800+ ppm of Mg, 100+ ppm of boron and only about 2500 ppm of Ca. The only thing that's similar is the high level of AW and antioxidant additives, ie ZDDP. So it will be interesting to see if these very low, wear rates continue.

I do like this 5w-40 for European engines, high mileage engines that burn oil using 5w-30/10w-30, and for low rpm, pushrod engines that are running under heavy loads, ie towing, hauling or Four Wheeling. And - of course it goes without saying I like it better than any wimpy, 0w-40 formulation...

Ted

 

[buster]

I think Redline, or maybe other mostly Ester based oils show spikes when switching to or from them. All other oils, dino and synthetic seem to be compatible across the board and no jump in wear metals is usually seen. I think the "additive clash" argument is over rated. As long as your draining 90% of the oil out of your engine, the new oil will clean up whatever is left and lay down it's chemistry. Might deplete TBN a little bit, but thats about it. Just my observations.

 

[TooSlick]

I think it's the high level of MoDTC and not the ester base that causes the high lead and copper levels, with RL, Synergyn, etc.

When MoDTC reacts under heat/pressure, it forms sulphur compounds which are even more aggressive than ZDDP. This is what strips the oxide layer off the bearings....

Tooslick

 

[The Critic]

Ted,
The oil was run for 10K in a 1.8L, high performance 225HP engine that is NOTORIOUS for having some fuel dilution. Remember you last UOA with ATM 10w-30? It had 1% Fuel Dilution according to Blackstone.

This could have easily caused the viscosity drop from the 14.5 baseline. Next time, you should take a sample of the oil before adding LC, then take another sample after adding LC, to see the viscosity drop, if any.

The elevated Oxidation IMO could simply be caused from the LC doing some cleaning.

Michael

 

[jason07-1zzfe]

Good call Michael

 

[TooSlick]

Michael,

Oil Analyzers has recently re-calibrated their FTIR - Fourier Transform, Infared Radiography - machine. They were running into issues testing oils that had a significant ester content. The specific problem was that many types of organic esters absorb light in wavelengths that are very close to those for nitrated and oxidized oil.

What OAI has done is significantly tighten up the wavelength "bandwidth" they are looking at. This way they can separate out the actual # of nitration and oxidation, from the baseline "signature" of the unused oil.....If you do some hunting around 3w.noria.com, there is a good explanation of the FTIR method.

These levels of nitration/oxidation are in line with what I used to see when OAI did all their testing in-house and not through Cleveland Tech Center. What you're seeing now is the percentage of the allowable limit for Nit/Ox and not the raw data expressed in Abs/Cm. The relatively higher level of oxidation is due to the fuel contamination issue you cited - nice catch on that one!

 

[TooSlick]

Bump...

These are the three previous Amsoil formulations I've tested in my Audi TT, for comparison to the 0w-40 results that were recently posted.

Note that the 10w-40 was only used for 5500 miles, so the results aren't directly comparable....

TS