Im going to be installing an andjustable fpr soon, and had a quick question.

If im not mistaken the fpr just decrease the size of the orfice that the fuel flows throw and it makes more pressure. But if the actual volume of fuel decrease's then what does the added pressure really do?

Im pretty sure the ratio of pressure to volume is 50/50 so as one goes up the other goes down. so my question is where is the added fuel coming from?




"Kick azz is my boost hero!!! "

What happens is the fpr controls the amount of fuel returned from the rail, and this is how it regulates pressure, the volume of fuel is not decreasing before it gets to injectors, just after the fpr valve. If your running a higher pressure, the orifice on the return line closes so more pressure is built up before that. This is how I have always understood it works.


___________________________________________________________________

Mitsu TD06-20g |3" Downpipe w/ Cutout | 61mm Bored TB |
HP Tuners | Innovate WB02 | Spec Stage 3 | TurboTech Upper | Full Addco Sways | Sportlines & Yellows |

^^ thers more to it then that, even returnless fuel systems use them

Darkstars wrote:^^ thers more to it then that, even returnless fuel systems use them

If a system is returnless, then it's the fuel pump itself that varies the pressure. How would a vacuum operated FPR function in a setup like that?




14.330 @ 96.37mph

the problem is I read that way to early in the mourning after just waking up LOL.


I didn't read what he was trying to say right... all fuel systems have a way to vary fuel pressure, weather its voltage to the pump or vacum signal to a mechanical FPR, but they all vary pressure, when I read it early it sounded like only systems with return lines regulate pressure... which really has nothing to do with the original question anyway so I don't know where that came form LOL

alright no mater posting in the A.M. till I wake up enough to be coherient hahah

Asuming i understand your question right- the added fuel that your engine gets is due to the higher rail pressure. The PCM controls the amount of fuel through injector pulse width (the amount of time the injector is spraying fuel) The PCM doesnt actually know the fuel pressure so it is programmed to run on the pressure the stock regulator provides. Whn the actual fuel pressure is higher than it is expected to be more fuel flows through the injector in the same amount of time. The fuel pump is capable of providing more fuel than the engine needs- thus the return line- so the regulator is just holding back some of the fuel that would be returned to the tank otherwise

_





Now with northstar V8, IRS, 20's n 22's

Jcavi wrote:If im not mistaken the fpr just decrease the size of the orfice that the fuel flows throw and it makes more pressure. But if the actual volume of fuel decrease's then what does the added pressure really do?

Remember, the FPR goes after the injectors, not before (like on carb'ed apps).
The rail is a control volume system, and the pump supplies a constant (nearly) mass flow of fuel. When the FPR closes, it reduces the volumetric flow of the fuel back to the tank, therefore increasing the fuel mass in the rail. This leads to a lower specific volume of the fuel in the rail, and therefore a increased pressure.




fortune cookie say: better a delay than a disaster

yeah I was a bit trashed when I wrote this. it was one of those things that sticks in your head and wont go away. that makes sense thanks guys

by the way has anyone used or heard of using a weapon R afpr for boost?


"Kick azz is my boost hero!!! "

i have one but im not boosted. I do remember reading that they DONT recommmend that you use it with boost.

Jcavi wrote:by the way has anyone used or heard of using a weapon R afpr for boost?

I wouldn't use a no-name regulator on a motor that I wanted to keep...
My buddy just hit the dyno, and they couldn't tune his car for crap because his regulator was so inconsistent.




fortune cookie say: better a delay than a disaster

I woulndt really consider weapon R a no name? Its a pretty decent unit. does anyone know for sure if it will work after boost?


"Kick azz is my boost hero!!! "

Jcavi wrote:I woulndt really consider weapon R a no name? Its a pretty decent unit. does anyone know for sure if it will work after boost?

Weapon R = no name.
If it's less than ~$100, it's not worth the risk




fortune cookie say: better a delay than a disaster

OHV notec wrote:

Jcavi wrote:by the way has anyone used or heard of using a weapon R afpr for boost?

I wouldn't use a no-name regulator on a motor that I wanted to keep...
My buddy just hit the dyno, and they couldn't tune his car for crap because his regulator was so inconsistent.

so youre saying he used a weapon R?
Ive had mine for 2 years and its consistant. higher prices doesnt mean better product. thats just a retarded way to think.
no name means no name. dont make up your own twisted definition. this isnt something off ebay that reads "aem STYLE" that actually has NO NAME.

thank you. I feel the same way. Im more concearend about part quality and cunstruction not price.


are you boosted?


"Kick azz is my boost hero!!! "

no...buts it held up running over 60psi for over a year now. i just remeber reading somewhere that they are not meant for boost. you might want to check up on that.

There are parts inside of a FPR that are sensitive and critical. I lost a motor once to a problem with an FMU.
Because of this, I would never cheap out on a FPR. Fuel system and wastegates are the two areas where spending money is worth every penny. I'd buy a Chinese turbo before a Weapon-R (no-name) FPR.




fortune cookie say: better a delay than a disaster

OHV notec wrote:There are parts inside of a FPR that are sensitive and critical. I lost a motor once to a problem with an FMU.
Because of this, I would never cheap out on a FPR. Fuel system and wastegates are the two areas where spending money is worth every penny. I'd buy a Chinese turbo before a Weapon-R (no-name) FPR.

since you cant use it with boost.....it doesnt matter anyways. you also say this like "name brand" FPR's or FMU's NEVER EVER FAIL.
thats what gauges are for.

whiteboyz24 wrote:

OHV notec wrote:There are parts inside of a FPR that are sensitive and critical. I lost a motor once to a problem with an FMU.
Because of this, I would never cheap out on a FPR. Fuel system and wastegates are the two areas where spending money is worth every penny. I'd buy a Chinese turbo before a Weapon-R (no-name) FPR.

since you cant use it with boost.....it doesnt matter anyways. you also say this like "name brand" FPR's or FMU's NEVER EVER FAIL.
thats what gauges are for.

How so? He is clearly saying that you should only buy the highest quality when it comes to critical components to minimize risk,

I.E. not WEAPON Rice


___________________________________________________________________

Mitsu TD06-20g |3" Downpipe w/ Cutout | 61mm Bored TB |
HP Tuners | Innovate WB02 | Spec Stage 3 | TurboTech Upper | Full Addco Sways | Sportlines & Yellows |

Weapon R is not a no name company... they are very well know.... but every single thing they make is garbage LOL

are they really that bad? can any one elese shed some light on the quality of there products


"Kick azz is my boost hero!!! "

First off, Weapon-R is far from a "no-name" crap company. I'm not saying they're Jesus, but, they're definitely not generic. They're even featured as a parts option in Juiced 2 (new tuner-based video game, which sucks, for those who don't know). And again, I'm not saying because they're in a game that that validates them, but I'm pretty sure OBX isn't an upgrade option in NFS: Pro Street.

They had a pretty cool cold-air intake conversion I bought for a Nissan pickup I had a few years ago, and it was well made, right down to having their logo stamped in each silicone coupler and even the clamps, which has nothing to do with the performance/quality aspect of it. but it does show that they're willing to spend a little extra cash on the details. I've got their oil catch can on my car right now, which serves a pretty basic function, but again, it's well made and well constructed.

I think they're just lesser known to this crowd as I don't believe they make any J-specific parts.

Now, as for your question Jcavi, this is what I found on their site:

"Weapon*R has developed a Compact Sized Adjustable Fuel Pressure Regulator, for High Performance Vehicles, it is constructed of 6061 T-6 Billet Aluminum and is capable of supplying enough fuel for engines in excess of 1000 horsepower. Weapon*R Adjustable Fuel Pressure Regulators have threaded ports, which allows you to tailor the regulator output to ANY fuel pump, whether it be the stock unit or a high-flow aftermarket pump."

Interpret that as you will...

Weapon R is not top notch stuff but yes there are plenty companies alot worse then them. Heres my thoughts on them... the first intake I bought was the Weapon R intake... you had to trim the coupler off the TB and install solid engine mounts to keep the intake from denting the hood up. Shows there comitment to research and design there. Did they make a couple measurements on where to bend the pipe and call it a day? Definetly not the quaility, fit, and finish I would expect out of a good product. There header I had as well and same sitaution, just not impressed with the product not to mention it was a blatent rip off of the RKSport header. Maybe its just my personal opinion but to me Weapon R just screams cheap.

Then again it could also be contributed to the lack of intrest in J-bodys that most companies have LOL

Im going to put the uint on my car, then run the guage to the cabin and watch the readings. I watch for puleses, contiued pressure climb under boost, along with other things. I guess what Im getting at is that the only real way to find out is to try it out, and if it works out then great, weve got a great alternitve to for fprs. if not..... well, lets not go there.


"Kick azz is my boost hero!!! "

aeromotive FTW

Jcavi wrote:Im going to put the uint on my car, then run the guage to the cabin and watch the readings. I watch for puleses, contiued pressure climb under boost, along with other things. I guess what Im getting at is that the only real way to find out is to try it out, and if it works out then great, weve got a great alternitve to for fprs. if not..... well, lets not go there.

I don't think the question is will it work or not, the question is will it be durable and continue to work and have some good measure of reliability.


___________________________________________________________________

Mitsu TD06-20g |3" Downpipe w/ Cutout | 61mm Bored TB |
HP Tuners | Innovate WB02 | Spec Stage 3 | TurboTech Upper | Full Addco Sways | Sportlines & Yellows |