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      12-04-2010, 08:50 AM   #60
c4s335i
Second Lieutenant
5

 
Drives: 07 335i sedan
Join Date: Oct 2010
Location: Charlotte, NC


Posts: 266
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Quote:
Originally Posted by NiVeDh View Post
Amazing review as usual! With the lower oil temperatures, the oil viscosity will be different. If our engines are indeed designed to be run at a specific temperature with specific oils (LL-01 approved), then will you consider using a different brand/weight of oil that has similar characteristics at the lower temperatures?
Agreed. Upping the core size should really be the only goal. With the AR cooler, most people's street temps are staying around 230F with recorded max temps of 255 on the track. Staying in the range you can be sure you're not exceeding what the engineers had designed for that engine. Plus motor oil viscosity testing is done at the 210F range, so by lowering the temp 50 degrees you're effectively lowering the viscosity of the motor oil, which can lead to bearing clearance issues which can lead to failure, especially in track use. Not exactly a great feature. The bearing clearances are designed with heat and viscosity in mind, so again by changing this your changing the effective design.

Another point to consider is that since the pistons are oil cooled, you can also change the heat expansion tolerance that pistons were designed for to not have piston slap. In a non-oiled cooled piston motor, typically the piston design would include greater tolerance to allow for greater heat expansion of the hotter aluminum vs. a piston that is being cooled which will not expand as much.

Personally I plan on trying to come up with my own setup that uses a high efficient 25-27 row core, and hopefully won't require massive amounts of car manipulation to make it fit. We'll see what happens.

Does the Stett kit include a proper louvered vent? Or is it pretty much just hack a hole in the back and let the hot air hit the rotor? I'm not sure I like how the air guide is just removed as well. Obviously it will still get air, but not as efficient as with a proper air guide. Granted none of that matters on the street, but running 30 minute sessions on the track with 100F + temps can find the weakness of any setup.

Last edited by c4s335i; 12-04-2010 at 09:47 AM. Reason: update.