E46Fanatics - View Single Post - [Cooling System Upgrade] 1-BAR Radiator Cap
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Old 10-06-2012, 02:08 PM   #99
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Originally Posted by TerraPhantm View Post
I wouldn't worry about radiator efficiency - S54 has an 82 degree thermostat and cools just fine. In fact, the Z4M has the same radiator as the automatic 330i. The hit to gas mileage could be there, but my gut feeling is it'd be a pretty small hit. I don't really care about emissions.

And I do think there is a downside to higher pressures - the exploding expansion tanks. That's not really an issue on the M3, so I'm not going to consider running lower pressures. But if I still had a 330, I think I'd consider going down to 1.4 bar and a lower temperature thermostat
You may not need the extra cooling, or emissions, or gas mileage, but you can't use that as an argument to discount that BMW needed to do this for essentially a world market car. People are going to look at the gas mileage in the dealer parking lot, some cars are going to be stuck idling in traffic in 110F weather with AC on, and BMW did aim for a pretty high standard, and that's why the US market non-Ms at least are classified as Ultra Low Emission Vehicles.

The exploding expansion tank isn't a problem of the pressure, it's the problem of a poor expansion tank design. Doesn't the M3 have the exact same pressure, but almost non-existent expansion tank failures? Notice the fittings aren't failing, nor the hoses, nor radiator, nor any part of the block. JUST the expansion tank.

Last edited by mkodama; 10-06-2012 at 02:09 PM.
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