im doing a 200+whp ls/vtec build and will be running it on rc 310cc's and crome. will a adjustable fpr be of any use? or need even?

 

trust me your going to want that...that helps out on depending how much fuel you need and don't need to run. your not to know wheter your running rich or lean on the motor

 

thats what you have crome for. IMO you dont need an adjustable FPR. my 215whp motor is running a stock GSR FPR.zero problems

 

hm so one vote either way...i may just grab it just in case...cant hurt to spend the extra 50 bucks at this point i guess

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by killerpenguin21 &raquo;</TD></TR><TR><TD CLASS="quote">hm so one vote either way...i may just grab it just in case...cant hurt to spend the extra 50 bucks at this point i guess</TD></TR></TABLE>

If you have the ability to tune the injectors and view AFR's, it's really not necessary. I would however, make sure you have a fuel pressure gauge.

 

OMG I was totally pondering this EXACT situation last night but didn't post it.

I have a very similar setup and I kinda want to ditch the AFR, because that's like the one thing under my hood that screams 'illegal!'

 

well im definetly getting a gauge, but whats the point of gauge and no adjustability?

 

theres no point in adjusting fuel pressure when you can adjust AFR electronically via crome. the only thing the fpr does is adjust AFR. increasing fuel pressure willalso put more stress on the pump.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSRCRXsi &raquo;</TD></TR><TR><TD CLASS="quote">theres no point in adjusting fuel pressure when you can adjust AFR electronically via crome. </TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSRCRXsi &raquo;</TD></TR><TR><TD CLASS="quote">theres no point in adjusting fuel pressure when you can adjust AFR electronically via crome. the only thing the fpr does is adjust AFR. increasing fuel pressure willalso put more stress on the pump.</TD></TR></TABLE>

I'd beg to differ that point. There is definitely a difference in running 20 psi of fuel pressure vs. 70 psi of fuel pressure and still having the same AFR's through tuning.
You still want the WOT fuel pressure to be somewhere between 35 and 50 psi. There is an ideal psi for the best fuel atomization and it's most likely somewhere in that range. You're not controlling pressure from the ecu, only injector pulsewidth (time the injector is open measured in milliseconds).

Try it....
set your adjustable FPR to 20 psi, then tune your ECU to achieve your specific AFR's. Then, set it to 70 psi and tune for those same AFR's. You're going to see a difference in power on the dyno, although both AFR's are identical. This has to do with the fuel atomization (how it mixes with the incoming air charge).

 

so i might as well throw one on?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by killerpenguin21 &raquo;</TD></TR><TR><TD CLASS="quote">so i might as well throw one on?</TD></TR></TABLE>

Throw the gauge on first and make sure it's at a healthy pressure. If not, then yah, i'd say put it on.

 

STUCK B&M FPR at 40psi.




But I plan to grab a new adjustable one soon. There not crazy expensive

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bambam &raquo;</TD></TR><TR><TD CLASS="quote">

I'd beg to differ that point. There is definitely a difference in running 20 psi of fuel pressure vs. 70 psi of fuel pressure and still having the same AFR's through tuning.
You still want the WOT fuel pressure to be somewhere between 35 and 50 psi. There is an ideal psi for the best fuel atomization and it's most likely somewhere in that range. You're not controlling pressure from the ecu, only injector pulsewidth (time the injector is open measured in milliseconds).

Try it....
set your adjustable FPR to 20 psi, then tune your ECU to achieve your specific AFR's. Then, set it to 70 psi and tune for those same AFR's. You're going to see a difference in power on the dyno, although both AFR's are identical. This has to do with the fuel atomization (how it mixes with the incoming air charge).
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show me a stock fpr thats at 20 psi... im sure 20psi sucks, but no one would ever go that low so its a mut point. gsr stock fp is 45-50 psi thats plenty for atomization. you wont see any noticeable difference from adding more pressure IMO, and your still adding more (unneeded) stress to the pump.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSRCRXsi &raquo;</TD></TR><TR><TD CLASS="quote">show me a stock fpr thats at 20 psi... im sure 20psi sucks, but no one would ever go that low so its a mut point. gsr stock fp is 45-50 psi thats plenty for atomization. you wont see any noticeable difference from adding more pressure IMO, and your still adding more (unneeded) stress to the pump.</TD></TR></TABLE>

You're right, to a point. That's why I said throw a gauge on there FIRST to see if the fuel pressure is in the desired range. A bent nipple on the bottom of the stock FPR can send the fuel pressure up to an undesirable level. I've seen it. Chances are, it's good, but you never know.
The gauge is mandatory IMO, but the FPR can be skipped; unless, for some reason your fuel pressure is out of wack.

-bambam

 

whats the real difference between the aem adjustable unit and the Blox one that sits atop the stock fpr and makes it adjustable? would the Blox one be sufficient enough for ~350whp?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by killerpenguin21 &raquo;</TD></TR><TR><TD CLASS="quote">im doing a 200+whp ls/vtec build and will be running it on rc 310cc's and crome. will a adjustable fpr be of any use? or need even?</TD></TR></TABLE>
If you are using a stock fuel pump, there is no reason to install an adjustable pressure regulator. A stock GSR/ITR regulator will maintain a 47~54 psi rail pressure with any factory pump at output levels below 300 (N/A) whp. If you plan to make more than that, you should upgrade the pump and/or injectors before looking at an adjustable pressure regulator.

Just for reference purposes: I have recorded more than 265 whp with a stock GSR fpr, stock CX fuel pump, and 450cc injectors.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B20C5 Turbo &raquo;</TD></TR><TR><TD CLASS="quote">If you are using a stock fuel pump, there is no reason to install an adjustable pressure regulator. A stock GSR/ITR regulator will maintain a 47~54 psi rail pressure with any factory pump at output levels below 300 (N/A) whp. If you plan to make more than that, you should upgrade the pump and/or injectors before looking at an adjustable pressure regulator.

Just for reference purposes: I have recorded more than 265 whp with a stock GSR fpr, stock CX fuel pump, and 450cc injectors.</TD></TR></TABLE>
at what point do you need to decide that an adjustable fpr is required? i plan on 300-350 whp. i already have a 255lph pump, and plan on getting some injectors. when do i know that i need to upgrade the stock fpr and rail?

also, how doi decide what size injectors i need?

 

i believe a stock fuel reail is good for about 400bhp. and when you change the regulator depends on how good your stock fuel pressure is and what size injectors and what engine management you are useing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by g2_teg_ &raquo;</TD></TR><TR><TD CLASS="quote">
at what point do you need to decide that an adjustable fpr is required? i plan on 300-350 whp. i already have a 255lph pump, and plan on getting some injectors. when do i know that i need to upgrade the stock fpr and rail?

also, how doi decide what size injectors i need?</TD></TR></TABLE>

If you gonna be making power like that you obviously have some money invested into the engine.

I wouldn't waste time with a stock unit, its stupid. Get a Aeromotive FPR or something similar and good fuel pump.

 

what makes it "stupid"? if you have a working stock fuel pump, the stock FPR will work just fine, and the stock units are just fine for NA power. IMO you only need an aftermarket FPR with an aftermarket pump.

 

yeah so far theres like 2g's in the motor so im not gonna cheap out...and fpr's arent that expensive so i might as well. and it will be runnig with a walbro 255 and 310cc injectors

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by killerpenguin21 &raquo;</TD></TR><TR><TD CLASS="quote">yeah so far theres like 2g's in the motor so im not gonna cheap out...and fpr's arent that expensive so i might as well. and it will be runnig with a walbro 255 and 310cc injectors

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Unless you plan on boosting, your fuel pump is complete overkill, stock (Gsr/SI 135lph) is more than adequate. Put a gage on it and see if the fuel pressure's out of spec, if it's not and you do plan on running some proper tuning program like Hondata, you certainly don't need an FPR.

 

id rather be safe with atleast a walbro 190 or 255 than risk a stock pump leaning out. and it mayget boost in the future so why not do it? seems stupid to not spend the 100 bucks on a 255.

 

well its actually gonna be boosted (sorry guys). i'll be running probably 550cc injectors and a Holley 255lph pump. tuning will be done with Crome. i just wanna know if the stock fuel rail and fpr will be suffucient? if i upgrade, i know i want the GE fuel rail, but im not sure on the differences in the fpr. i know that the Blox FPR just bolts overtop of the stock unit. what are the disadvantages to that as opposed to something like the AEM unit?