Audi Junkie

I've been putting in overtime at theoildrop.com From what I can gather, a chipped 1.8t is very hard on oil. Synthetic is a must. Synthetic means several things though. Group III is "cheaper" hydro-cracked molecules (big molecules made smaller) and has decent properties which can be enhanced with good additive packages to perform even better than the true synth that everybody whines about.(small molecules made bigger) That kind of synth is Group IV (PAO) or Group V (Esters) In your engine, there is not really a ton of difference except: wear, friction, seal swelling/shrinking and deposits. Wear and friction can be minimized with additives like moly, phosphorus, zddp, etc. These are *important* to handle the Extreme Pressure of turbo & diesel engine parts. EP additives take over and form a barrier when the oil film is broken down(squeezed) and prevents metal contact and scoring. Otc oils have minimal amounts of these compounds. Seal swelling is addressed in advanced formula synthetic Group IV and V oils by blending PAO and esters, to balance the fact one swells them and one shrinks them! As far as deposits, it is a critical consideration in 1.8t engines. When you shutdown, a portion of oil in the turbo is cooked and this is where vastly different results occur. A PAO (polyalphaolefin)sp? Group IV oil will leave a hard (plastic?) deposit where a ester based Group V oil *will* evaporate cleanly without a deposit. (possibly, Group III does too) This is where reading and learning the whole story is important, the PAO has a higher flashpoint, but leaves the harmfull deposit when it does burn off. Looking at the specs alone is misleading. As far as I can tell, a Group III oil with good additives can therefore be better in your engine then the eliteist Group IV! It tests better, works better but people want the built-up "true synth". Now, the big question is what are the contents of the various otc oils! Mobil 1 0w-40, GroupIV, NOT the Group III that everyone (including me) speculated Mobil 1 SuperSyn had converted to. Is it beter than a good III? No, for the one reason of the PAO deposits, additive packages may not be as good too. It is not a bad oil, but there is a bias against it at TOD.com Surprisingly, the ACEA 3/upcoming GF-4 rating is a bad thing in terms of the metallic additives that protect your engine! This is mostly because of strict Euro enviromental regulations, and the 0w weight is for fuel savings not for top engine protection!(CAFE standard mpg is based on recommeded oil grades!) So, a quality API SL Group III synth is fine, which allows more choices other than M1, like 5w-XX. BTW-Most otc synths are, regardless of what the maker says, Group III, specialty synths are IV and V as well as M1.
What you want in your chipped 1.8t is something like the Mercedes-approved synths:
(I put them in order based on my readings)
1)Kendall GT-1 FullSynth 5W-40
2)Chevron Supreme Synthetic 5W-40
3)Valvoline Synpower 5W-40
4)Havoline Synthetic 5W-40
5)Pennzoil Synthetic Euro 5W-40
6)Mobil 1 0W-40 and 15W-50
7)Quaker State Synthetic Euro 5W-40
8)Castrol Syntec 10W-40 and 5W-50

or if you drive it really hard, use a mixed-use oil like Delvac 5w-40 or Rotella T 5w-40 with plenty of EP additives. Testing seems to be the key to finding out what is in an oil and what it does over time. 2 tests, before and after. It is a bit confusing but people at theoildrop.com can help interpret test results. I am, by far, not an expert.

AggregatVier

So which ones are group 5?

Dustin A4

Can you post a link to the website.

Audi Junkie

I think Redline was mentioned as a mostly Group V, which shrinks seals! It is really up to the consumer to decide what properties of an oil is important to them and try to find one that matches. Unfortuantely, there is nothing usefull printed on the side of the can.

Audi Junkie

This is one page I read. The whole story is a bit of a mosiac, many pages and opinions to digest. Use the search function.

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=000032#000033

jquattro

wonder what is actually going on in the "Oil World". You mentioned RedLine in a later answer, but did not rate it? Also, did you learn about AMS and/or Royal Purple? Thanks Again!

HKsupastar

Question: how does AMSOIL rank in all of this?

Audi Junkie

Well, most are just ok, but priced very high. If an oil is over-specialized it will not have "balance" in it's formulation that is ALWAYS important. Just refer to the mixing of IV and V to balance seal swelling, if you favour one for say friction, you could compromise the seals. There is always a trade-off. The same thing applies to additives as well as base stocks. Amsoil is good, but I did not focus on the specialty oils, just the Mercedes-approved ones.

Audi Junkie

It appears that an oil can be "over-specialized" and Group IV PAO (which I believe it is mostly) has it's limitations. People like it because it costs more to manufacture, period. Quality otc Group III synth outperforms PAOs, especially in turbos.

HKsupastar

ok cool! thanks for the research!