Thread: Turbo Boost PSI
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      08-28-2011, 05:17 PM   #30
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Drives: 2011 1M, 2003 330i ZHP
Join Date: Apr 2008
Location: California

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Originally Posted by Daniel135i View Post
that's still an incredibly small amount of boost stock. My 95 3K VR4 was cranking 14 stock. So was my 2005 SRT4.
This is the danger of throwing numbers around out of context. Most Turbo motors in the past ran 8:0 - 8.5:1 compression ratios to prevent detonation. Modern motors with direct injection like the 1M run 10:1 compression ratios. So you see, 12 lbs of boost with such a high compression ratio is actually a TON OF BOOST.

12 lbs of boost on your VR4 or SRT4 running 10.1 compression on 91 Octane gas would not have been pretty.

That is the reason boost in now controlled more carefully than before. The motors are running leaner, higher compression and higher revs.