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Fuel pressure question.

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Old 05-05-2014, 03:23 PM
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Fuel pressure question.

I have a HSR and my FPR went out. Instead of waiting on a mail order on from Holley or an aftermarket one I just piced up a Buick one from the local autoparts store.
My question is I though that it would have a static fuel pressure of 43.5. Wrong, it is at 39psi... Should I let that bother me to bad?
My injectors are already too big IMO 36#.
I have a 355 with vortec heads. My cam only has .475 lift and a 108 lobe separation.
Thanks for any advice
Old 05-05-2014, 06:36 PM
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Re: Fuel pressure question.

https://www.thirdgen.org/forums/tech...formation.html



Originally Posted by riche
I though that it would have a static fuel pressure of 43.5.
it is at 39psi...
With or without the vac line connected ?
Old 05-05-2014, 09:29 PM
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Re: Fuel pressure question.

With it disconnected, it drops to 30 psi connected.
Old 05-07-2014, 06:53 AM
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Re: Fuel pressure question.

I used this calculator,
http://www.witchhunter.com/injectorcalc1.php
With a static pressure of 39 psi the injectors drop to 34 lb injectors. I don't believe that hurts me with my setup. Just looking for some reassurance that I am ok assuming that. B/c you know what they say when you assume...
Old 05-19-2014, 08:46 AM
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Re: Fuel pressure question.

With no vacuum you really want 43#. Lower than that and the fuel doesn't atomize as well. GM figured this out with the LS engines as they run much higher fuel pressure. AFPR aren't expensive and a good one will last many many years.
Old 05-19-2014, 12:12 PM
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Re: Fuel pressure question.

Thanks Tibo,
That was what I am worried about. We are only talking about 4.3 PSI but if that is enough to make the injectors not atomize correctly then I need to get a different regulator. I might go give Autozone hell and tell them to give me another FPR. Does anyone know if a Buick Grand National was suppose to have 43.5 PSI?
I should have just waited and ordered a Kirban...
Old 05-19-2014, 01:42 PM
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Re: Fuel pressure question.

Just ask them to return it as defective because it doesn't put out a proper pressure. If the guy says no ask for a manager and if he says no ask for the district manager, all while being polite. Buy an aftermarket.
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