An AFPR will keep you from running rich. If you have a fuel pump that will overrun your FPR, you'll end up running pig rich.

 

but how do I know if I'm running too rich?? If I adjust the AFPR will it show up on a A/F ratio gauge??????

Please Help.

 

If your fuel pump is over running your fpr, you will know. You will have very little power, the exhaust will smell horrible, etc.

 

Then Basicly the only way to get the best out of it is to dyno it?

 

If you have a wbo2, you can use it to tune.

 

Where can I find a Wb02 How much do they ussually go for and how do they work??

Thanks for all input.

 

Where can I find a Wb02 How much do they ussually go for and how do they work??

Thanks for all input.

If you are looking for a WB02 I might be able to help you. I will let you know now that they are not cheap though. Email me and I'll see what I can do for you. Thank you.

Ivan

 

i wouldnt waste money on a wide band 02 *unless* i was running some sort of stand-alone. they are pretty expensive, and really not needed unless you have a flexible tuning platform. just my opinion though. (once you tune in your air/fuel ratio with a WB02 at the dyno, there is no need to have one, unless you change your setup)

 

can youy tune it with out thw Wo2?

 

Not properly.

 

what engine management are you planning on using??

 

Don't waste your money on an adjustable fuel pressure regulator.

That shop is probably used to working on Honda's and cars with MAP based FI, not MAFS based FI. You have a MAFS sensor, which reads the amount of air coming in...so it gives the right amount of fuel. Honda's (and others) have MAP sensors...so they read the pressure in the intake manifold, guess at the VE, and give fuel based on the guess. When you add an exhaust, intake, etc., to a Honda, you change the VE, and then the engine runs lean. When you change those things on a Nissan, the MAFS reads the extra air, and you don't run lean.

Don't get an adjustable fuel pressure regulator, you probably don't need one.

Dennis

 

:fonix:

i wouldnt waste money on a wide band 02 *unless* i was running some sort of stand-alone. they are pretty expensive, and really not needed unless you have a flexible tuning platform. just my opinion though. (once you tune in your air/fuel ratio with a WB02 at the dyno, there is no need to have one, unless you change your setup)

:fonix:

Since it was bumped, I decided to read and I got a pretty good laugh from both of these posts. My, how things have changed in 8 years.

 

 

afpr on a nissan

i kinda disagree with the last statement about the fuel adjusting wiht the mafs. i run a sohc and have exhaust intake no emmissions 225 walboro msd blaster and a few little things done to mine. i noticed my car was running a little funny. so i bought a wbo2 and founf im lean as hell if i stay under 2.5k rpm (20.9) once i start getting to 3k i start to be within normal ranges (12.8 to 16.2 depending on how heavy on the throttle) then i go rich as hell (8.9-10). since i dont have an safc to remap with the next best thing imo is an afpr so i could set my car richer around idle. but my situation shows the mafs reading doesnt always adjust the fuel properly on modified cars.

 

 

What's changed is people don't read stickies or the other wealth of information on here. There's been long discussions on this very matter.

It has been shown that you CAN run a Walbro 255 without a FPR but it is shown that the Walbro pumps more then the stock fpr was intended for. Again, you can run it. But it's a cheap investment to be able to adjust it to normal. Even if you don't have a standalone or wideband the numbers are on here what you should adjust the pressure to if you're running a Walbro on a SR. The walbro runs rich with a stock fpr. I would find it but you should of searched in the first place. Plus when you move on to more advanced tuning you'll already have it

 

^^ I respectfully disagree. Common miconception... Stock FPR will handle a Walbro 255's output all day long. It has nothing to do with a Walbro's output "overpowering" the stock reg, and everything to do with needing an aftermarket regulator once the actual demand becomes greater than the stock reg can compensate for... Which generally doesn't happen inside of 400+whp with respect to an SR.

I completely agree that having an aftermarket reg leaves much more room for growth than the stock unit- but for most setups, it's complete and utter overkill (but it sure looks cool under the hood lol).

Interesting old thread haha!

 

This is an old thread haha hopefully someone will chime in on this. I'm just saying what I've read on here, obviously there's a ton of BS info being thrown out, and the last thing I wanna do is spread it. "overpowering" was poor word choose. But if I have my facts straight it does run the mixture rich because of the stock fpr. Just not to the point of the engine not running obviously

 

Even at 100% injector duty cycle on the Power FC out-of-the-box tune, the SR runs inherently lean as soon as you start adding boost beyond the stock .7bar (10psi). Adding a Walbro 255 is not going to correct this. You can overpower (there's that word again lol) the injectors by adjusting the fuel pressure higher using an aftermarket reg, but it's still not going to be able to achieve significant fuel volume gains, as a matter of fact, your fuel volume in the rail will decrease under load due to the increased pressure and lower flow of the pump, possibly resulting in running leaner at higher rpm/boost levels/air volumes.

There is a reg, however, called a Turbosmart FMU (Fuel Management Unit) regulator What is a Fuel Pressure Regulator? Why & When do you need one? that that is effective at achieving greater rail fuel volume to some degree. But it's a specialty item that is mounted in addition to a factory FPR between the FPR outlet and the fuel tank return so that when you are not under boost, factory pressure is maintained. Kind of like a "piggyback" setup.

A Walbro 255HP's flow output depends on the regulated pressure of the fuel system. At 0psi, it will flow at 285lph, and at 40psi, it will flow at 255lph, which is close to the average[base] pressure of quite a few Nissan fuel systems. Basically, as regulated pressure increases, outflow from the fuel pump decreases; so as long as everything is functioning normally, there should not be any need for an aftermarket regulator to maintain standard to modded setups. Reference: Auto Performance Engineering - Walbro fuel pumps specs

When demand for fuel (highly modded/tuned) becomes great enough to warrant a second fuel pump, that is when it would most likely be considered imperative to source out an adjustable reg.

Old threads RULE hahahahahahah!

 

It made me laugh because the first guy said to not waste money on a FPR. Even a mildly tuned SR will benefit from an FPR, even if it's not "needed." They are cheap, and if you have added more air, more fuel can usually only help. An AFPR, IMO, is one of the best bangs for the buck. Combine it with a wide-band O2 (which they also said was uneccessary, unless you have a stand-alone) and you have a very cheap way to do a "grass-roots" tune.

Also, apparently ITR has never experienced fuel cut in a SR. The MAF can only compensate so much.

 

Each to their own I suppose=)

 

i guess everyone has their own approach to things. One of the best/most entertaining "tuning sessions" I've ever seen was a buddy that installed a SAFC, FPR, and wide-band and then attempted to get it dialed in on some back roads. It took a while, but it got there (sorta).

 

Did he bring a banjo for such a ******* setup? jk