afpr?
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Registered User
Joined: Apr 2004
Posts: 309
From: Missouri
afpr?
i was reading over on ws6.com and they said that a ajustable fuel pressure regulator gave him like 15 hp. Is it really worth getting? how much are they? how hard are they to instal?
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Joined: Dec 1969
Posts: 3,499
From: PORTLAND, OR, MULTNOMAH
Re: afpr?
AFPRs allow you to regulate (change) your fuel pressure, however your PCM will adjust the injectors to negate any gains you realize from leaning it out.
Many have gotten them and adjusted the WOT fp from the stock 44-46 to around 38 and seen a gain of up to 17hp, but as I mentioned the PCM will undo the gain.
When you get a tune, your tuner will most likely prefer that you stay with the stock fp.
There are different brands and not too hard to install, but why bother, since you probably aren't going to change it anyway.JMHO
Many have gotten them and adjusted the WOT fp from the stock 44-46 to around 38 and seen a gain of up to 17hp, but as I mentioned the PCM will undo the gain.
When you get a tune, your tuner will most likely prefer that you stay with the stock fp.
There are different brands and not too hard to install, but why bother, since you probably aren't going to change it anyway.JMHO
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Joined: Feb 2004
Posts: 4,800
Re: afpr?
Tuning for an obd2 car starts around $125 and can correct the fueling which is what the AFPR tries to do, the tuning however is more precise and NOT LEARNED OUT, it can also adjust spark and tranny settings.
So let us review $100+ to halfassed play with fueling, or $125 to finetune fueling, spark, and tranny.
AFPR do have uses but basically if you have to ask what they are your car does not need one. They can be used to make injectors act larger than they are rated for, not a good idea with stockers since they do bad things when overpresured and a good set of injectors is only about $220 anyway so it isn't a worthwhile savings to try to keep using stockers by overpressuring them. The guys with wild applications who already spent big money on BIG injectors and are begining to tax them, those are the guys that have a warranted use for an AFPR.
Some have claimed that they needed one to compensate after fuel system mods caused average pressure to rise after they had all their tuning done, well dialing back the pressure would only be benificial IF they can verify that the pressure curve of the adjustable is identical to the stocker, if it isn't then the tune will be off anyway.
So let us review $100+ to halfassed play with fueling, or $125 to finetune fueling, spark, and tranny.
AFPR do have uses but basically if you have to ask what they are your car does not need one. They can be used to make injectors act larger than they are rated for, not a good idea with stockers since they do bad things when overpresured and a good set of injectors is only about $220 anyway so it isn't a worthwhile savings to try to keep using stockers by overpressuring them. The guys with wild applications who already spent big money on BIG injectors and are begining to tax them, those are the guys that have a warranted use for an AFPR.
Some have claimed that they needed one to compensate after fuel system mods caused average pressure to rise after they had all their tuning done, well dialing back the pressure would only be benificial IF they can verify that the pressure curve of the adjustable is identical to the stocker, if it isn't then the tune will be off anyway.
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