Subject	Stock setup lends you:
Posted by	Jehannum on November 03, 2006 at 1:53 PM
	This message has been viewed 38 times.
In Reply To	Dynamic CR depends... posted by Jehannum on November 03, 2006 at 01:16 PM
Message	Because I don't know what the VTCs do to intake cam duration, I'm discarding them from the discussion (though I'd suspect that they increase dynamic compression ratio, as that's what makes sense for power outside of the spooled turbo, in addition to the fact that my calculated compression numbers for cranking pressure are lower than stock compression numbers, gained when the VTCs are engaged). Stock VG30DETT has a bore of 87mm, stroke of 83mm, rod length of 154.2mm, and a static compression ratio of 8.5:1, and 248 duration intake cam, with the valve closing 68 degrees ABDC. That means that the head volume is 65ccs, and the dynamic stroke is 61.2mm, which gets a dynamic CR of 6.54:1. Cylinder pressure at that CR with 15PSI of boost (at sea level) is 122PSI (8.4 bar). That effectively raises the dynamic boost compression ratio to 13.21:1. Your powers are useless! I'm wearing my tinfoil underwear!
Follow Ups	What does a turbo do that increases horsepower in a engine? (n/m) - canyoncarver 20:16:22 11/01/06 I like this question. - robo (sebring1970) 20:25:48 11/01/06 O.k., what is the effect on the combustion cycle - canyoncarver 21:02:38 11/01/06 I dunno, I'm going to guess that there is more air-fuel - robo (sebring1970) 21:53:30 11/01/06 If you have a cylinder full of air at atmospheric pressure - canyoncarver 06:14:32 11/02/06 Cylinder pressure. - Jehannum 13:47:32 11/02/06 Re: Cylinder pressure. - canyoncarver 14:45:35 11/02/06 Dynamic CR depends... - Jehannum 13:16:59 11/03/06 Stock setup lends you: - Jehannum 13:53:49 11/03/06 In a very simple explanation it supplies the engine with - boostedzxtt 20:35:29 11/01/06 www.Google.com - sfpearl300zTT 20:50:32 11/01/06 2nd that - - TT XTZ 12:09:56 11/02/06 Thats the one - sfpearl300zTT 17:05:08 11/02/06 What is the function of an engine? What does it do? (n/m) - boileralum 21:21:35 11/01/06 I know you know the answer, but you've provided me with an - TT XTZ 12:07:54 11/02/06 Quit f'ing around man, I know you know this answer. lol (n/m) - ZLover4Life 21:58:22 11/01/06 it blows (n/m) - Guapo 22:02:25 11/01/06 exactly. NA engines suck, but turbos blow. (n/m) - Z U N L 23:58:10 11/01/06 Well, there you go. (n/m) - RSR 06:09:20 11/02/06 Re: What does a turbo do that increases horsepower in a engine? - ouikikazz 04:51:16 11/02/06 RPM, PSI, and displacement...the air argument - Technomancer 13:43:52 11/02/06 That's a nice write-up.... I read it a while back. - canyoncarver 14:50:56 11/02/06 Not sure what you mean by this - Technomancer 18:59:18 11/02/06
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