Fuel system questions

[wowzers9930]

Alright so I plan to do a few upgrades to the fuel system soon and I was wondering what all I needed, btw I plan to use SAFCII for tuning

600cc + Injectors
http://www.ebay.com/itm/Nissan-RB25DET- ... b4&vxp=mtr

Walboro 255 fuel pump

Fuel pressure regulator
What is recommended for an FPR
Would this one be fine? http://www.ebay.com/itm/Red-Ajustable-F ... 1e74850fee

And what about a fuel rail is the stock one fine?

I tried searching but there is so many misguided forum post on this topic, I would appreciate some good solid info. Thanks

[Carl H]

you wont be 'tuning' 600's with an safc.

if you're running without an upgraded pump as is then you're on borrowed time already...stock pump barely keeps up with a stock sr.
much less a turbo i6

[wowzers9930]

Safc2 can use up to 680cc injectors, and yes I am on a stock pump. How hard is it to install the walley 255 is it plug and play?

And what FPR would you recommend, staying fairly cheap as well

[Miguelone]

Installing a Walbro is easy, it comes with all the stuff you need to mount it into your specific setup and has an instruction manual. Takes about half an hours, if that to put together. Then you just put the cradle back in the car and you're good to go. I'd recommend getting a new tank seal O Ring while you're at it.

[wowzers9930]

Alrighty, I think im going to be getting a 255 very soon then, can someone help me with what FPR to get?

[Miguelone]

For price/quality/ease of install I'd go with a Nismo fpr.

[wowzers9930]

Can it supply 600cc injectors?

[Miguelone]

Can it supply 600cc injectors?

No, you'll have to bring your own injectors

[wowzers9930]

I don't get that?

[Carl H]

lol, trust me an safc will NOT 'tune' 680s on a stock ecu...its a maf signal manipulator.
you'll need real management for it to work properly.

[Darius]

I agree with CarlH. Think about it for a second. You are almost doubling the fueling available to the engine, which means you could potentially double the power given the supporting turbo. Tuning with an SAFC is going to be very coarse. There are only a few rpm and load adjustment points compared to a standalone with rpm and load tables with reference cells in the hundreds.

So many people will spend thousands on turbos, manifolds, fuel pumps, injectors, regulators, etc. but then skimp out when it comes to EMS and tuning. Once it goes beyond bolt-on's and the stock turbo, you absolutely NEED to spend money on a good standalone EMS. The caliber of EMS varies with your goals but, nonetheless, a standalone is a must.

And I don't think you need an adjustable FPR just for installing a Walbro. The stock FPR worked fine for me on a supra TT pump for years. The only reason you need an adjustable FPR is if you want to increase the base fuel pressure to squeeze more out of the injectors or if your fuel pump is so huge that the FPR isn't large enough to return enough fuel at idle to adjust the base fuel pressure down to 43 psi.

[wowzers9930]

So if I wanted to squeeze more fuel through my stock injectors I would get an FPR and raise the pressure?

[Darius]

Yep you can do that depending on how much extra fuel you need. I wouldn't advise raising base pressure above 60 psi though or you'll get idle problems. But either way, if you do change fuel pressure, you'll have to re-tune the fuel map to compensate.

New flow rate = Old flow rate x (New pressure/Old pressure)^0.5

Say you have 370cc injectors and raise the base pressure to 58 psi with the vacuum line off.

New flow rate = 370 x (58/43.5)^0.5 = 427cc

It only increases peak flow by 15% so it isn't a huge increase, but it gives some more head room if you need it.

[boostedh23a1]

Couldnt agree more with the advice given. Motor rebuild cost more than an ems.