Mobil 1 oil weight
t44tqtro at gmail.com
Tue May 1 08:10:59 EDT 2007
Note that all of the BMW M cars now are using a special formulation Castrol
10W60 oil and the spec oil for the Ferrari Enzo is also 10W60 Shell.
Not to detract from your post, but there are still high performance engines
running a minimum 10 weight synthetic oil.
***Total conjecture follows****
Maybe this is part of the reason why some very high strung engines are
failing now when put under high stress, because the quest for efficiency
does not leave enough room for proper lubrication?
Honda S2000 w/ original 2.0L engine
Corvette Z06 w/ LS7 engine
BMW M3 w/ S54 engine
A lot of s-listers running high hp seem to have experienced main bearing
failure, although that's the cost of playing when you're making more than 2x
the original engine output.
I'll find out what guys are running in 996/997 Cup/GT3RS/RSR cars, although
I don't know what the bearing clearances are in the race engines and if they
are different from the production street car engines.
On 4/30/07, LL - NY <larrycleung at gmail.com> wrote:
> Dynamic journal bearings require viscosity to work. The larger the
> of the bearing (all else being equal, RPM, temp, BMEP i.e. engine load)
> thicker the oil required to maintain an adequate film at the bearing.
> designs (such as the I-5), due to the mass production machining
> at the time, coupled with need for extended high speed autobahn running,
> have somewhat larger than what is standard bearing clearances compared to
> current production, hence it was typical for most of the German mfgs to
> heavier weight oil (at the expense of fuel economy and friction, but to a
> GREAT advantage to wear) than most other their other contemporaries. As
> production mfg tolerances have become much tighter, it has become possible
> to use the super low viscocity oils even in extended autobahn running.
> Witness the E36 BMW M3 and it's use of the 0W-40 M1 so mentioned. I will
> have to review the said charts Grant refers to, but bearing (pun intended)
> in mind the bearing clearance parameters of old vs contemporary, I'm going
> to have to go on record that I'm skeptical that the added cold flow
> characteristics (heck, also bear in mind residual film will be thicker for
> the heavier weight oils) will offset the lack of loaded bearing film when
> the engine is being worked, at least with respect to the older high
> clearanced engines. Will have to check back on this when I have time to
> the references.
> LL - NY
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