rising rate FPR
01-22-2004 | 06:52 PM
#1
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From: Atlanta
rising rate FPR
Anyone out there using a rising rate FPR and if so, where'd you get it. I just did a quick check at all the usual places and I couldn't find one. I don't want to go the standard 3 bar route. Any ideas. Thanks fellas
C-man
C-man
01-22-2004 | 08:06 PM
#3
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From: Santa Barbara, CA
"Anyone out there using a rising rate FPR and if so, where'd you get it. I just did a quick check at all the usual places and I couldn't find one. I don't want to go the standard 3 bar route. Any ideas. "
Don't get rising-rate mixed up with rising-pressure. The standard FPRs are all rising-pressure which adds 1psi of fuel-pressure for each 1psi of boost. So the rate-of-rise here is 1:1. You can get an aftermarket FPR that has adjustable rate-of-rise like 1.1:1 or 1.2:1. This one is about $259 from Bell Engineering:
But they only make a difference in the mid-range when boost goes from 0psi to max-boost. Once you hit max-boost, the fuel-pressure stops rising. It's the same pressure as if you had set an standard adjustable 1:1 FPR to a higher initial pressure.
A rising-rate or a rising-pressure regulator will do nothing to help you with an air-fuel ratio like this:
If anything, it would make the mid-range rich-dip even worse because the fuel-pressure increase as boost is building would be even higher than standard 1:1 ratio.
Adjusting fuel-pressure cannot straighten out a V-shaped air-fuel curve. That's because increasing or decreasing fuel-pressure will just shift the entire curve up and down.
Don't get rising-rate mixed up with rising-pressure. The standard FPRs are all rising-pressure which adds 1psi of fuel-pressure for each 1psi of boost. So the rate-of-rise here is 1:1. You can get an aftermarket FPR that has adjustable rate-of-rise like 1.1:1 or 1.2:1. This one is about $259 from Bell Engineering:
But they only make a difference in the mid-range when boost goes from 0psi to max-boost. Once you hit max-boost, the fuel-pressure stops rising. It's the same pressure as if you had set an standard adjustable 1:1 FPR to a higher initial pressure.
A rising-rate or a rising-pressure regulator will do nothing to help you with an air-fuel ratio like this:
If anything, it would make the mid-range rich-dip even worse because the fuel-pressure increase as boost is building would be even higher than standard 1:1 ratio.
Adjusting fuel-pressure cannot straighten out a V-shaped air-fuel curve. That's because increasing or decreasing fuel-pressure will just shift the entire curve up and down.
01-23-2004 | 01:27 AM
#5
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From: Atlanta
Sweet guys... exactly what I needed to hear... and yes I meant rising pressure... but what I am going to get is a 2:1 rising pressure FPR... i.e. 1 psi boost =2psi fuel pressure added on top of say, 50 psi base. Sound reasonable?
01-23-2004 | 03:02 AM
#6
Burning Brakes
Joined: Aug 2002
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From: Fort Lauderdale, Florida
no, as I understand it this would lead to your injectors seeing way too much pressure at full boost. With a standard rising pressure FPR (1:1) you don't want to set your initial fuel pressure much above 3 bar for the above reason.
John
John
