FPR help smoother idle?

[cobrAA]

Would an aftermarket FPR helps smoother idle?

Since I installed the 700cc on my oem fuel system, I found my idle to be rougher. Since a FPR regulate and helps keep a constant flow, should it help my idle?

I bought an aftermarket fuel rail and I'm starting to think... I don't need this LOL

But.. if a FPR can help then I will keep the rail and go buy the hose and fitting needed. If not, guess you will see a rail in the FS section soon lol

[archaeic_bloke]

aftermarket fuel rails is 100% useless...sorry, u don't need it. hundreds of high power GTR's use oem rail. only reason to use aftermarket rail is if u need some weird non standard size of injector. try to sell it to someone who wants it.

did u get the car re-tuned after installing those injectors?

aftermarket FPR isn't necessary, people use it to squeeze more fuel from their injectors by creating excessive back pressure would forces more fuel.

does the "rough idle" bother you that much?

what kind of injectors are they?

[Zacho]

aftermarket fuel rails is 100% useless...sorry, u don't need it. hundreds of high power GTR's use oem rail. only reason to use aftermarket rail is if u need some weird non standard size of injector. try to sell it to someone who wants it.

did u get the car re-tuned after installing those injectors?

aftermarket FPR isn't necessary, people use it to squeeze more fuel from their injectors by creating excessive back pressure would forces more fuel.

does the "rough idle" bother you that much?

what kind of injectors are they?

Depending on your setup some a/m rails are aluminum with a sort of heat sink design to dissipate heat, dual feeds etc. But mostly looks.


OP: Did you install with new injector seals? Has your ECU had the appropriate dead time correction/fuel scale applied?

[cobrAA]

sard injector and the tuner installed the injector right before tuning the car.

[frankiman]

bigger injectors have always had problems compensating duty cycle at idle,
the bigger the injectors the worst it gets, theres no way around it,
it can be tuned out some via software, but theres always a limit to the hardware
a bit more pressure with FPR could help

thats why i think its ill-advised to use anything over 700cc on a <600hp car

case and point, me and Cobraa make pretty much the same power (~400whp)
hes using 700cc and i am using 555cc
my injectors peak at 81% duty cycle (so theres still 19% left!) but for reliabilty concerns, 80% duty cycle should be the limit you use your injectors at
which means i'm "maxed out"
Cobraa can probly make 500whp with duty cycle below or around 80%
my idle is perfect though

so why the F uck do people get 800cc+ injectors, for a setup that makes less than 600hp (which is 95% of owners), is completely a mistery to me

a buddy of mine ordered 1000cc injector dynamics injectors for his RB20 build, WTF?!

[cobrAA]

I know this frank. but I had a good deal on those 700cc injector from Mitch.. Anyways.. so my question was would a FPR help the situation. but I know I can't fit a Sard FPR to my oem fuel rail.

[frankiman]

read again^^

yes, problem with bigger injectors is that they just spew out lumps of fuel at low duty cycle, which is harder to burn because its not "atomized" properly
(for the same amount of fuel, 700cc injectos are at a much much lower duty cycle than the stock 444cc injectors)

so by increasing a bit the fuel pressure via an FPR can help

Nismo makes a FPR that is a direct replacement, i have one on my car

[Zacho]

If your tuner sucks or your injectors suck, then yes getting them to idle may be an issue. Even ID 2000's report no problems on most setups. Buying injectors too big for what you have is not stupid, why is it such a mystery to you? Leaving yourself headroom for future upgrades is a good idea. Buy once and forget.

But to OP: I think at the very best COULD is a maybe. Unless your current regulator is fubar, I would think there is something else causing this. Besides, adding an adjustable and increasing rail pressure simply will add more fuel in at idle anyway. A step backwards to solving the problem no?

[archaeic_bloke]

But to OP: I think at the very best COULD is a maybe. Unless your current regulator is fubar, I would think there is something else causing this. Besides, adding an adjustable and increasing rail pressure simply will add more fuel in at idle anyway. A step backwards to solving the problem no?

I agree with this, adding more pressure in the rail won't help his problem frank. it'll make it worse! LOL....

more pressure = more fuel squeezed out at each pulse, theoretically if u wanted to correct this using an adjustable FPR u could LOWER the pressure, (if this is what frank was getting at?) that might help, but it also might cause problems at higher RPM where increased flow is necessary...

maybe some sort of dynamic, electronically controlled FPR could help..lol.. imagine? an FPR that communicates with ECU and increases pressure as rpm rise? ahhaa that'd be awersome!

[frankiman]

even with higher pressure the flow rate stays the same (amount of fuel), but speed of flow increases, meaning better atomization, better burn

i gotz A- in fluid mechanics class :P

[cobrAA]

so Nismo sell a bolt-on FPR for the OEM fuel rail? I didn't know this.

[Zacho]

Then tell me why every single fuel calculator out there results in a higher inj flow as a result of a higher fuel pressure

http://www.rceng.com/technical.aspx

http://www.deatschwerks.com/catalog/fuel_calculators.php

Go crank your fuel pressure up on your car 10 psi and go drive it, you'll find out pretty quick. I've experienced a need to trim the fuel map with an increase in base fp

[Zacho]

so Nismo sell a bolt-on FPR for the OEM fuel rail? I didn't know this.

http://www.frsport.com/Nismo-Fuel-Pressure-Regulator-Type-A_p_2238.html

[frankiman]

so Nismo sell a bolt-on FPR for the OEM fuel rail? I didn't know this.

its basically a stock FPR with an adjustment screw on top of it

[Bossman]

http://www.frsport.com/Nismo-Fuel-Pr...-A_p_2238.html

The old style Tomei also has a direct fit adjustable FPR and looks exactly like the Nismo unit. I've also seen Apexi of the same style. If you ask me all these adjustable FPR as made by the same manufacturer like Denso is the manufacture for fuel injectors to HKS, Tomei, Nismo and and I think Sard.