Subject	Boost = pressure
Posted by	BobbyT on September 14, 2009 at 3:48 AM
	This message has been viewed 186 times.
In Reply To	How do turbos degrade and fail? posted by Zarcasm(Hfd, CT) on September 13, 2009 at 10:09 PM
Message	Power is a function of air, not air pressure. A boost level is like a hp/liter level--meaningless without a number of liters to multiply by. You can equate psi with power when everything else is the same because more pressure flows more air. But between different engines, different turbos, or even identical engines and turbos in different conditions, you can't equate boost with flow. 16" diameter gas main at 100 psi vs a little shop air hose at 100 psi. At the same pressure they'll flow vastly different amounts, just like a big vs small turbo. An old and new turbo at the same boost wouldn't be quite as dramatic; say like a clear air hose vs one restricted with gunk.
Follow Ups	How do turbos degrade and fail? - Zarcasm(Hfd, CT) 22:09:45 09/13/09 read inside - jdubs 22:25:50 09/13/09 Helpful but everything here assumes like-new performance - Zarcasm(Hfd, CT) 09:05:36 09/14/09 Re - pacmanpth 22:48:20 09/13/09 Don't the intercoolers relieve the temperature concerns? - Zarcasm(Hfd, CT) 08:56:15 09/14/09 No, intercoolers have nothing to do with going beyond - boost420 11:50:23 09/14/09 Re - pacmanpth 11:57:18 09/14/09 So installing a BIGGER intercooler will alleviate intake tmp - Zarcasm(Hfd, CT) 14:55:44 09/14/09 how do you sound so intelligent yet know how 2 destroy cars? (n/m) - SuparexTT 15:55:13 09/14/09 Boost = pressure - BobbyT 03:48:45 09/14/09 Engine benefits from both airflow AND pressure. - Zarcasm(Hfd, CT) 08:49:37 09/14/09 "Airflow" implies the rate of mass flow - pacmanpth 11:59:40 09/14/09 If my math is correct... - Adam (NoVA) 13:08:16 09/14/09 You are referring to compression ratio, not compression. - zellamay 13:41:49 09/14/09 Correction: "It's just NOT as simple ... (n/m) - zellamay 14:09:34 09/14/09 yes, i was attempting to illustrate that its more - Adam (NoVA) 14:48:47 09/14/09 Thanks for the reference - makes good sense. (n/m) - Zarcasm(Hfd, CT) 15:08:21 09/14/09 The engine will not "benefit from the increased pressure" - zellamay 13:21:13 09/14/09 Read ^ this post ^ Zarcasm - BobbyT 13:58:19 09/14/09 It's NOT just about the number of molecules! - Zarcasm(Hfd, CT) 15:24:54 09/14/09 I was under the impression that the fact that the molecules - Z_Cherub 15:51:31 09/14/09 You are exactly right. At the same (boost) pressure, - zellamay 16:35:46 09/14/09 Molecules probably have the advantage, BUT... - Zarcasm(Hfd, CT) 22:02:51 09/14/09 There are a couple of issues here. I don't understand your - zellamay 23:17:00 09/14/09 Molecules probably win / MechE = Mechanical Engineer - Zarcasm(Hfd, CT) 08:16:54 09/15/09 Molecule # doesn't "win"; it's THE limiting factor - BobbyT 05:05:42 09/16/09 Well said. - Z_Cherub 15:20:30 09/17/09 boost is actually a measure of restriction. (n/m) - Antonio(AZ->NYC) 09:38:31 09/14/09 What do you mean? - Zarcasm(Hfd, CT) 21:34:42 09/14/09 restriction imposed by the engine itself - aliaZ 06:13:21 09/15/09 In other words, your turbo smacks a bunch of air molecules - BobbyT 05:11:02 09/16/09 not really - aliaZ 09:04:57 09/16/09 The point was that you're putting things in a close volume - BobbyT 17:18:00 09/16/09 an engine is not a closed volume - aliaZ 17:31:53 09/16/09 Zarcasm is insistent that secondary characteristics matter - BobbyT 05:18:08 09/17/09 Can a used turbo be refurbished to close to new performance? - Zarcasm(Hfd, CT) 08:48:07 09/14/09 A used one can even be improved (SP500 etc), depends on - Bernie (NoVA) 11:10:32 09/14/09 Well depends on what? What typically gets damaged? - Zarcasm(Hfd, CT) 15:32:50 09/14/09 Depends on what is damaged, if the housing is cracked or - Bernie (NoVA) 16:07:01 09/14/09 yes, but why? Newer technologies (better/stronger spool) - boost420 13:20:22 09/14/09 Can you give me some new vs refurb turbo comparisons? - Zarcasm(Hfd, CT) 15:35:56 09/14/09 Are you asking for compressor maps or just - boost420 15:43:37 09/14/09 If you're mechanically inclined, using "off the shelf" - boost420 17:02:48 09/14/09 Off the top of my head: you can do a cheap rebuild of - zellamay 16:44:32 09/14/09
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