Subject	RE: Idle psi
Posted by	Broke_as_**** on April 13, 2007 at 2:19 PM
	This message has been viewed 59 times.
In Reply To	Thanks for the replies.. posted by Zenica on April 13, 2007 at 02:12 PM
Message	The idea, as you're aware, is to maintain a 43.5 psi pressure difference between the fuel rail and the intake manifold. That's the important part. That's why the fuel pressure rises +1 for every +1 of boost pressure. However, since vacuum is measured in inches of mercury pulled (because obviously you can't measure negative pressure as psi), it's not a 1:1 ratio. So that 10 inches of vacuum only requires 38 psi of fuel pressure to maintain that 43.5 psi difference. 1989 240SX Fastback. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1995 300ZX Twin Turbo Warning: Objects in mirror aren't as fast as they thought they were.
Follow Ups	My Z is sick. - Zenica 13:53:55 04/13/07 50 psi is a bit low for full throttle - spyhunterTT(nj) 13:59:16 04/13/07 Re: 50 psi is a bit low for full throttle - Zenica 14:02:41 04/13/07 it is very easy, its on top of the plenum. like 2 10mm bolts - NobleZ 14:06:27 04/13/07 Your fuel pressure should be 43.5, at zero manifold - octavian-z 14:04:21 04/13/07 I forgot, also check your FPR (n/m) - octavian-z 14:06:34 04/13/07 correct, but will dip below that at idle, since - Guapo 14:09:28 04/13/07 Thanks for the replies.. - Zenica 14:12:47 04/13/07 RE: Idle psi - Broke_as_**** 14:19:24 04/13/07 It's an erratic jump because the fuel pump controller - octavian-z 14:26:21 04/13/07 With your mods, you should be around 375 rwhp. - eriksu9 14:25:04 04/13/07 Re: With your mods, you should be around 375 rwhp. - Zenica 14:32:47 04/13/07 that doesn't sound too far off - spyhunterTT(nj) 14:38:33 04/13/07 Re: that doesn't sound too far off - Zenica 14:41:48 04/13/07 A vacuum leak would cause him to run rich, not lean. (n/m) - Billteed1 15:00:52 04/13/07 I should have said a boost leak. - Billteed1 15:27:16 04/13/07 I would check for a vacuum leak after checking the FPR - olyar15 14:29:29 04/13/07 How would they let in unmetered air - Billteed1 15:02:38 04/13/07 Not on the inlet side - Broke_as_**** 15:07:42 04/13/07 Re: Not on the inlet side - Zenica 15:17:04 04/13/07 Carb sprary is good for find a leak... - Broke_as_**** 15:51:36 04/13/07 Re: Carb sprary is good for find a leak... - Zenica 16:00:27 04/13/07 I see - Billteed1 15:25:28 04/13/07
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