Compressor map - Revision history

Nyet: /* Boost from Pressure Ratio */

2016-08-27T02:17:14Z

Boost from Pressure Ratio

← Older revision		Revision as of 02:17, 27 August 2016
Line 61:		Line 61:

	[https://www.google.com/#q=2.5++(1+bar+-+1+psi)+-+1+bar+-+1+psi+in+psi <code>2.5 (1 bar - 1 psi) - 1 bar - 1 psi in psi</code> = 18.3 pounds per square inch ]		[https://www.google.com/#q=2.5++(1+bar+-+1+psi)+-+1+bar+-+1+psi+in+psi <code>2.5 (1 bar - 1 psi) - 1 bar - 1 psi in psi</code> = 18.3 pounds per square inch ]

			As you can see, as ambient pressure drops (e.g. higher elevation) or intake/IC drops increase, your boost limit (for a given PR limit) decreases along with it.

	==Air Flow==		==Air Flow==

2016-08-27T02:16:38Z

Examples

← Older revision		Revision as of 02:16, 27 August 2016
Line 45:		Line 45:
	*[http://www.google.com/search?q=%281+atm+%2B+22+psi%29%2F%281+atm+-+1+psi%29%3D <code>(1 atm + 21 psi + 1 psi) / (1 atm - 1 psi) = 2.68</code> ]		*[http://www.google.com/search?q=%281+atm+%2B+22+psi%29%2F%281+atm+-+1+psi%29%3D <code>(1 atm + 21 psi + 1 psi) / (1 atm - 1 psi) = 2.68</code> ]
	*[http://www.google.com/search?q=%281+atm+%2B+24+psi%29%2F%281+atm+-+1+psi%29%3D <code>(1 atm + 23 psi + 1 psi) / (1 atm - 1 psi) = 2.83</code> ]		*[http://www.google.com/search?q=%281+atm+%2B+24+psi%29%2F%281+atm+-+1+psi%29%3D <code>(1 atm + 23 psi + 1 psi) / (1 atm - 1 psi) = 2.83</code> ]

			As you can see, as ambient pressure drops (e.g. higher elevation) or intake/IC drops increase, your pressure ratio increases along with it.

	==Boost from Pressure Ratio==		==Boost from Pressure Ratio==

2016-08-27T02:12:47Z

Pressure Ratio

← Older revision		Revision as of 02:12, 27 August 2016
Line 25:		Line 25:
	*<math>P_{boost}</math> is pressure at the throttle body inlet		*<math>P_{boost}</math> is pressure at the throttle body inlet
	*<math>P_{ambient}</math> is ambient air pressure		*<math>P_{ambient}</math> is ambient air pressure
	*<math>P_{ICdrop}</math> is intercooler pressure drop (pressure difference between <math>P_{outlet}</math> and <math>P_{boost}</math>)		*<math>P_{ICdrop}</math> is intercooler pressure drop (pressure difference between <math>P_{outlet}</math> and <math>P_{ambient} + P_{boost}</math>)
	*<math>P_{id}</math> is intake pressure drop (pressure difference between <math>P_{inlet}</math> and <math>P_{ambient}</math>)		*<math>P_{id}</math> is intake pressure drop (pressure difference between <math>P_{inlet}</math> and <math>P_{ambient}</math>)

2016-08-27T02:12:06Z

Pressure Ratio

← Older revision		Revision as of 02:12, 27 August 2016
Line 27:		Line 27:
	*<math>P_{ICdrop}</math> is intercooler pressure drop (pressure difference between <math>P_{outlet}</math> and <math>P_{boost}</math>)		*<math>P_{ICdrop}</math> is intercooler pressure drop (pressure difference between <math>P_{outlet}</math> and <math>P_{boost}</math>)
	*<math>P_{id}</math> is intake pressure drop (pressure difference between <math>P_{inlet}</math> and <math>P_{ambient}</math>)		*<math>P_{id}</math> is intake pressure drop (pressure difference between <math>P_{inlet}</math> and <math>P_{ambient}</math>)


	To calculate pressure ratio from boost:

	<math>\frac{P_{ambient} + P_{boost} + P_{ICdrop}}{P_{ambient} - P_{id}}</math>.

	===Examples===		===Examples===

2016-08-27T02:11:49Z

Pressure Ratio

← Older revision		Revision as of 02:11, 27 August 2016
Line 18:		Line 18:
	==Pressure Ratio==		==Pressure Ratio==

	Expressed as <math>\frac{P_{outlet}}{P_{inlet}}</math> or, more commonly, <math>\frac{P_{boost} + P_{ICdrop}}{P_{ambient} - P_{id}}</math>		Expressed as <math>\frac{P_{outlet}}{P_{inlet}}</math> or, more commonly, <math>\frac{P_{ambient} + P_{boost} + P_{ICdrop}}{P_{ambient} - P_{id}}</math>

	Where		Where

2016-08-27T02:11:22Z

Pressure Ratio

← Older revision		Revision as of 02:11, 27 August 2016
Line 18:		Line 18:
	==Pressure Ratio==		==Pressure Ratio==

	Expressed as <math>\frac{P_{outlet}}{P_{inlet}}</math> or, more commonly, <math>\frac{P_{~~MAP~~} + P_{ICdrop}}{P_{ambient} - P_{id}}</math>		Expressed as <math>\frac{P_{outlet}}{P_{inlet}}</math> or, more commonly, <math>\frac{P_{boost} + P_{ICdrop}}{P_{ambient} - P_{id}}</math>

	Where		Where
	*<math>P_{outlet}</math> is the absolute pressure at the turbo compressor outlet		*<math>P_{outlet}</math> is the absolute pressure at the turbo compressor outlet
	*<math>P_{inlet}</math> is the absolute pressure at the turbo compressor inlet		*<math>P_{inlet}</math> is the absolute pressure at the turbo compressor inlet
	*<math>P_{~~MAP~~}</math> is ~~[[MAP]]~~ ~~(manifold~~ ~~absolute~~ ~~pressure)~~		*<math>P_{boost}</math> is pressure at the throttle body inlet
	*<math>P_{ambient}</math> is ambient air pressure		*<math>P_{ambient}</math> is ambient air pressure
	*<math>P_{ICdrop}</math> is intercooler pressure drop (pressure difference between <math>P_{outlet}</math> and <math>P_{~~MAP~~}</math>)		*<math>P_{ICdrop}</math> is intercooler pressure drop (pressure difference between <math>P_{outlet}</math> and <math>P_{boost}</math>)
	*<math>P_{id}</math> is intake pressure drop (pressure difference between <math>P_{inlet}</math> and <math>P_{ambient}</math>)		*<math>P_{id}</math> is intake pressure drop (pressure difference between <math>P_{inlet}</math> and <math>P_{ambient}</math>)

2016-08-27T02:10:22Z

Boost from Pressure Ratio

← Older revision		Revision as of 02:10, 27 August 2016
Line 53:		Line 53:
	==Boost from Pressure Ratio==		==Boost from Pressure Ratio==

	To ~~back~~ calculate boost from desired pressure ratio:		To calculate boost from desired pressure ratio:

	<math>P_{boost} = PR (P_{ambient} - P_{ICdrop}) - P_{ambient} - P_{id}</math>		<math>P_{boost} = PR (P_{ambient} - P_{ICdrop}) - P_{ambient} - P_{id}</math>

2016-08-27T02:10:11Z

Pressure Ratio

← Older revision		Revision as of 02:10, 27 August 2016
Line 28:		Line 28:
	*<math>P_{id}</math> is intake pressure drop (pressure difference between <math>P_{inlet}</math> and <math>P_{ambient}</math>)		*<math>P_{id}</math> is intake pressure drop (pressure difference between <math>P_{inlet}</math> and <math>P_{ambient}</math>)


⚫	~~Alternately, if boost is known, it is approximated by~~ <math>\frac{P_{ambient} + P_{boost} + P_{ICdrop}}{P_{ambient} - P_{id}}</math>.
			To calculate pressure ratio from boost:

		⚫	<math>\frac{P_{ambient} + P_{boost} + P_{ICdrop}}{P_{ambient} - P_{id}}</math>.

	===Examples===		===Examples===

2016-08-27T02:09:06Z

Boost from Pressure Ratio

← Older revision		Revision as of 02:09, 27 August 2016
Line 60:		Line 60:
	and you get:		and you get:

	[https://www.google.com/#q=2.5++(1+bar+-+1+psi)+-+1+bar+-+1+psi+in+psi <code>2.5 (1 bar - 2 psi) - 1 bar - 1 psi in psi</code> = 15.8 pounds per square inch ]		[https://www.google.com/#q=2.5++(1+bar+-+1+psi)+-+1+bar+-+1+psi+in+psi <code>2.5 (1 bar - 1 psi) - 1 bar - 1 psi in psi</code> = 18.3 pounds per square inch ]

	==Air Flow==		==Air Flow==

2016-08-27T02:08:36Z

Boost from Pressure Ratio

← Older revision		Revision as of 02:08, 27 August 2016
Line 54:		Line 54:
	<math>P_{boost} = PR (P_{ambient} - P_{ICdrop}) - P_{ambient} - P_{id}</math>		<math>P_{boost} = PR (P_{ambient} - P_{ICdrop}) - P_{ambient} - P_{id}</math>

	For example, with 2.5 PR, ~~2psi~~ IC drop, and 1psi inlet drop, type this into google (assuming you live at sea level):		For example, with 2.5 PR, 1psi IC drop, and 1psi inlet drop, type this into google (assuming you live at sea level):

	<code>2.5 * (1 bar - 2 psi) - 1 bar - 1 psi in psi</code>		<code>2.5 * (1 bar - 1 psi) - 1 bar - 1 psi in psi</code>

	and you get:		and you get:

	[https://www.google.com/#q=2.5++(1+bar+-+2+psi)+-+1+bar+-+1+psi+in+psi <code>2.5 (1 bar - 2 psi) - 1 bar - 1 psi in psi</code> = 15.8 pounds per square inch ]		[https://www.google.com/#q=2.5++(1+bar+-+1+psi)+-+1+bar+-+1+psi+in+psi <code>2.5 (1 bar - 2 psi) - 1 bar - 1 psi in psi</code> = 15.8 pounds per square inch ]

	==Air Flow==		==Air Flow==