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Fuel pressure

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Old 06-25-2004, 01:16 PM
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Fuel pressure

Does anyone know how much fuel pressure will affect the A/F?

I had a high flow fuel pump installed, complete with fuel regulator, and every once in a while I will get a CEL for 'running too rich.' Will lowering the pressure prevent this? I am running 380cc injectors and have been told by some people that as long as there is pressure at the injectors that is all that really matters, and that the exact pressure isn't critical. Any thoughts?

Kevin
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04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS
 
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Old 06-26-2004, 11:27 AM
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Re: Fuel pressure

You better find some new friends to take advice from!

43.4/34psi=1.27647 take square root= 12.98% more fuel flow in grams per time period [weight of fuel]

Most injectors follow this formula at least to 60 psi and down to 30 psi

 
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Old 06-26-2004, 12:57 PM
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Re: Fuel pressure

That is some useful information, but it is useless to me because I don't understand it. Where did the 43.4 come from? I am assuming that the 34psi is fuel pressure. Also, why did you take the square root? And the 12% is 12% more then what?

This is exactly the type of info I am looking for, I just need to know exactly how it all works!

Thanks,


Kevin
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AIM: KPiersonTec
04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS
 
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Old 06-26-2004, 02:23 PM
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Re: Fuel pressure

http://www.rceng.com/technical.htm

By SAE definition fuel injector flow is measured at 3.0 BAR or [14.7= 1 BAR x 3 = 44.1 psi] by US convention this is rounded to 43.4 psi to reflect a more average barometric pressure.

When you gave me 380 cc I knew it was flowed at 43.4 psi so I arbitrarily picked 34 psi [which would be the standard Nissan idle fuel pressure on engines equipt with a vacuum fuel pressure regulator] not G35.

 
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Old 06-26-2004, 02:38 PM
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Re: Fuel pressure

kp-

aside from mechanical FPR settings, i think you need a true mapping (TS reflash aint gonna cut it, unless they have your car in - hand)

have you considered a control unit, to help with fuel and ignition timing (at certain rpm intervals)?

eS

 
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Old 06-26-2004, 08:36 PM
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Re: Fuel pressure

hehe I'm not a big fan of control boxes. But, I have yet to see an A/F curve for my car. The guys at Crawford Z say it looks good, but they didn't have a printout.

I was told that TS has developed generic mapping for the Procharger. I know it won't be perfect, but I would imagine it is close enough to provide the performance and reliability I am looking for.

Es, have you installed your VDC mod yet?

Tech, thanks for the in dept description, it helped me out a lot!


Kevin
www.KPtechnologies.net
AIM: KPiersonTec
04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS
 
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Old 06-26-2004, 08:40 PM
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Re: Fuel pressure

kp-

ima keep hounding you till you get precise fuel and ignition management!! (lol!!) det. doesnt have to be so precise, remember.....

and YES, i have the VDC REMEMBER module wired in..... the dealer did it while the exhaust and cats went on..... its great, and WELL worth the money you charge....

now wheres' some header pics (pre-during-post install) of your beast??? im on the fence, still.......

-eS


 

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Old 06-26-2004, 09:45 PM
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Re: Fuel pressure

I don't have any pics of the headers, the only good pic I do have was taken at a Cincinatti area meet.

http://www.my350z.com/forum/showthre...0&pagenumber=4

My car is about half way down the page, you can't miss it! It's the only supercharged car. As far as headers go, I'm not sure about all of them, but the Crawford ones require you to 'rock' the engine because of thier extreme length. With a supercharger mounted on the engine the engine will NOT rock far enough (according to Crawford Z). You will have to remove your Supercharger before you can install Crawford headers.

I can't wait to get home and look further into my fuel issues. My father has taken over ownership of my car since I left for Baltimore. He is a die hard American car buff and thought I was wasting my money on my *** car. Now, he can't get enough of the power!



Kevin
www.KPtechnologies.net
AIM: KPiersonTec
04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS
 
  #9  
Old 06-27-2004, 12:08 AM
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Re: Fuel pressure

Hey KP--

i suggest you give a PM to "whosdady" on my350Z.... you'll find him on the F/I section often; he's a VEry experienced (and knowledge ATI user) who has taken his setup waaay beyond stage one (or so)..... he has been of great help w/ questions to me and my vortech system too....

give him a PM; i think he can at least point ya in the right direction....

-es

 
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