Group V vs. Group IV

[E46M3]

It seems to me that synthetics that are considered group V are about twice the price of Group IV synthetics.

I drive a tuned BMW 135i that runs about 18psi at WOT with full bolt on's. Intercooler, Downpipes with full exhaust, Cobb Stage II tune.

I am considering the following 2 oils for my next change and I am unsure about which one to go with:

Motul 8100 X-CESS 5W40 - This oil is BMW LL01 rated and I am pretty sure that it is a Group IV

Motul 8100 X-lite 0w30 - This oil is not BMW Ll01 rated and I think that it is an Ester based Group V Synthetic.

The 0w30 is twice the price of the 5W40 and I am not sure if it is worth the extra money or not.

 

[dparm]

Truth be told, most group V oils contain group IV anyways. This is needed so the oil is "balanced".

X-lite is indeed heavy in group V content. Motul has stated that the X-lite 0w30 is one of their premier products other than the "race" 300V. It supposedly contains the most group V out of any of their products, save the 300V race oil. It was formerly known as E-tech 0w40. I don't think the X-cess 5w40 contains much group V since they don't even mention it on the datasheet, but it's still a group III/IV oil and very good.

I would be inclined to run a 0w40 or 5w40 in that car. I would assume that since you are modified you don't care about running a BMW-approved oil for warranty purposes? If that's the case, I think Redline 0w40 would be a great oil (actually cheaper than the Motul X-lite).

 

[Artem]

It's not approved by BMW so why would you want to run it? It's also rather thin for your modded Bimmer, so that might also cause excess wear.

What's the big deal with what group it is anyway? There are a bunch of good oils off the shelf that will perform excellent in your Bimmer.

 

[dparm]

Originally Posted By: Artem
It's not approved by BMW so why would you want to run it? It's also rather thin for your modded Bimmer, so that might also cause excess wear.

What's the big deal with what group it is anyway? There are a bunch of good oils off the shelf that will perform excellent in your Bimmer.


X-lite 0w30 is not very thin. HTHS is 3.57. Should have good shear stability given its HTHS compared to the KV values.

Once you start running lots of power-adding mods, the manufacturer oil recommendation goes out the window (IMO).

 

[E46M3]

I really don't care if the oil is BMW LL01 rated or not. My understanding is that the rating only has to do with the additive package and how long the oil should last.

I will never run an oil longer than 6k in my car so this not a big concern to me. I am almost out of warranty as well.

I am currently running GC 0W30.

 

[bepperb]

Originally Posted By: dparm


Once you start running lots of power-adding mods, the manufacturer oil recommendation goes out the window (IMO).


Agreed, obviously you are generating a lot more heat than the manufacturer intended therefore a thicker oil, or at least a more heat tolerant oil, is something to consider. Long OCI is out the window as well, so some of those manufacturer specs are no longer relevant anyway.

 

[chubbs1]

I agree with dparm that RedLine 0w40 would probably be a match made in heaven for your vehicle. It is a very shear stable, predominantly grp V oil. I just don't think you can go wrong with it. If you are stuck on the MOTUL I would probably go with the 5w40. I don't like to get stuck on what grp. the oil is since the blending of the base stock is so important and therefore a well blended oil will be of excellent quality and all around performance.

 

[deven]

Originally Posted By: dparm
Truth be told, most group V oils contain group IV anyways. This is needed so the oil is "balanced".

Dan, the reason why ester oils have group IV oils is solely because esters are lousy at dissolving anti wear additives. They use Group IV oils as a vehicle to dissolve additives and then dumping it in the oil. Most ester oils contain very little Grp. IV oils, just enough to dissolve the additives without saturating them.

 

[Ben99GT]

Originally Posted By: deven
Dan, the reason why ester oils have group IV oils is solely because esters are lousy at dissolving anti wear additives. They use Group IV oils as a vehicle to dissolve additives and then dumping it in the oil. Most ester oils contain very little Grp. IV oils, just enough to dissolve the additives without saturating them.


You've got that all backwards. Replace every mention of esters with Group IV and vice versa and your post would be a little closer to reality, though additive solubility is hardly the only benefit provided by esters.

Article on esters by Tom NJ: http://www.bobistheoilguy.com/esters-in-synthetic-lubricants/

 

[Quattro Pete]

Originally Posted By: deven
Originally Posted By: dparm
Truth be told, most group V oils contain group IV anyways. This is needed so the oil is "balanced".

Dan, the reason why ester oils have group IV oils is solely because esters are lousy at dissolving anti wear additives. They use Group IV oils as a vehicle to dissolve additives and then dumping it in the oil. Most ester oils contain very little Grp. IV oils, just enough to dissolve the additives without saturating them.


Based on what I've read, Group IV (PAO) is actually a very bad additive carrier. That is why most group IV oils use mineral oil or esters as additive carriers. See the table on Page 3 of this PDF:
http://eng.rpi-inc.ru/materials/26/neo364/DAY2/SESSION7/RheinChemie.pdf

See also table on Page 5 here:
http://www.zddplus.com/TechBrief10 - Oil Base Stocks.pdf


Esters (group V) actually have a much better additive solvency than PAO.

I've seen an explanation given here on BITOG of why group IV is added to a predominantly group V oil, but I can't recall it now. Maybe someone will chime in...

 

[Ben99GT]

Originally Posted By: Quattro Pete
I've seen an explanation given here on BITOG of why group IV is added to a predominantly group V oil, but I can't recall it now. Maybe someone will chime in...


Seal compatibility, esters (and some other polar Group Vs) tend to promote seal swelling while non-polar PAO tends to cause seal shrinkage.

 

[Quattro Pete]

Thanks, Ben99GT!

 

[dparm]

I would be willing to bet that Mobil 1 0w40 would also work just fine. And at qt it's a good value.

 

[E46M3]

So which would you buy?

Motul 5w40 for $7.9 a liter
Motul 0w30 for $12.3 a liter
Redline 0w40 for $10.45 a liter

 

[CATERHAM]

Of the two Motul choices I too would prefer the X-Lite 0W-30 for it's ester content and higher 177 VI.
And if you don't mind the higher cost I'd certainly prefer it to the GC currently being used and even M1 0W-40 although the latter is hard to beat.

Regarding the possible need for a higher viscosity oil due to the increased turbo boost and power. In street applications, higher boost and power doesn't usually result in noticeably higher oil temp's (track use is a different story) so I'm sure the OP's fine with what he's using and planning on using.
Having said that it's always prudent to have an oil pressure gauge on board just to know whether you're at in terms of operational viscosity.

 

[CATERHAM]

Originally Posted By: E46M3
So which would you buy?
Motul 5w40 for $7.9 a liter
Motul 0w30 for $12.3 a liter
Redline 0w40 for $10.45 a liter

Red Line 0W-30 would be my choice and add some RL 0W-40 but only if need to based on oil pressure.

 

[deven]

Originally Posted By: Quattro Pete
Originally Posted By: deven
Originally Posted By: dparm
Truth be told, most group V oils contain group IV anyways. This is needed so the oil is "balanced".

Dan, the reason why ester oils have group IV oils is solely because esters are lousy at dissolving anti wear additives. They use Group IV oils as a vehicle to dissolve additives and then dumping it in the oil. Most ester oils contain very little Grp. IV oils, just enough to dissolve the additives without saturating them.


Based on what I've read, Group IV (PAO) is actually a very bad additive carrier. That is why most group IV oils use mineral oil or esters as additive carriers. See the table on Page 3 of this PDF:
http://eng.rpi-inc.ru/materials/26/neo364/DAY2/SESSION7/RheinChemie.pdf

See also table on Page 5 here:
http://www.zddplus.com/TechBrief10 - Oil Base Stocks.pdf


Esters (group V) actually have a much better additive solvency than PAO.

I've seen an explanation given here on BITOG of why group IV is added to a predominantly group V oil, but I can't recall it now. Maybe someone will chime in...

Thanks for the info. I guess what I should have said is that Grp V+IV is a better solvent than Grp IV or V alone. At least that is what I am led to believe by both Motul and Red Line techs. By using a small amouth of Grp IV with Grp V base makes the additives dissolve better than using either Grp V or IV base with a grp II+ carrier.

 

[Quattro Pete]

Originally Posted By: deven
By using a small amouth of Grp IV with Grp V base makes the additives dissolve better than using either Grp V or IV base with a grp II+ carrier.

Once again, this does not sound right. Group V oil does not need any other base to carry additives as Group V in itself is very much additive soluble. Group V oil needs other oil bases for seal compatibility, as was mentioned above.

 

[E46M3]

I think that I am going to go with the Redline 0w40. You can buy it by the 5 gallon bucket for about $9.65 per gallon here: http://www.thrustmotorsports.com/shop/index.php?l=product_detail&p=2676

I hear really good things about Motul but is it is about $12.3 per quart. Not that it is that much more money but I am not sure if the Motul 0w30 is any better than the RL 0w40 for my application. Both are Group V. I don't track my car (yet) however it does see WOT most days.

With my mods my 135i makes about 450hp at the crank and 425rtq so I am trying to protect the internals and the turbo's as much as possible.

 

[Ben99GT]

Good choice, and thanks for the link! I might have to buy a 5 gallon bucket of Red Line myself (0W-20).