I'm in the middle of an engine rebuild and while my engine is out I would like to upgrade my injectors. I am also planning on upgrading to the Walbro fuel pump. Do I just need to change the P2 position or what? I understand some have swapped in blues or uncapped yellows, I would like to get the fuel setup right from the beginning. Thanks in advance.

 

yellow/ blue/ blue is the best .

Next question .....

 

I also just got my engine rebuilt. while tuning mazdamaniac said my afr's went lean under WOT and was causing detonation.

My fuel pump has 90,000 miles, 20,000 boosted so I figured I am going to get the Walbro fuel pump also.

The only thing I am not sure of is what injectors I should get to obtain the most reliable power.

 

Sounds like you may need a few tweaks to the tune, lean is bad.

I always start rich an work towards leaner, it's easier than engine replacement.

 

It would appear that I am now on the hunt for blue injectors, where oh where are these blue injectors my build should be done in roughly 2.5 weeks and I need them

 

http://www.discountfuelsystems.com/s...&events=search

 

I'm not exactly sure if I want a remanufactured one, I'd rather get one straight out of an automatic. Unless I find one on here i'm going to search junkyards I guess

 

I have also been wondering about this for a while...
I just received my Greddy Turbo Kit w/ upgraded turbo, and I figure I will need to upgrade the fuel system while I am at it.

I already plan on doing the Walbro pump, but how do I know what size injectors to get?

I see some say you need to get much bigger, like the 650cc injectors from RC Engineering, and then others say just to use the blue 4 ports.

I plan on eventually getting up above 300whp, so are the blue injectors sufficient enough for this?

Thanks, Sean.

 

I have P2 Blue 880c and have no issues with getting enough fuel.

 

when you are upgrading injectors, it is important to consider what engine management you are using as this plays into injector staging. Personally, I plan on running yellow, blue, blue ... should be enough for 300 - 330 rwhp ... I think that is the optimal set-up if you are using COBB


oh and I DO plan to upgrade the fuel pump

 

Ok, and now I have a stupid question. When you say yellow, blue, blue....Where are you putting each? Like yellow in p1? blue in p2??

 

primary -> yellow

secondary -> blue

P2 -> blue

 

Awesome, definitely going to go this route and see what it gets me

 

P-1 = Stock red
P-2= Stock Yellow
Aux = 4 port AT Stock Blue

 

is the following a shitty version of the blues? and at $41 a piece are these going to crap out on me sooner rather than later?

"GB Fuel Injector - Direct OE replacement
2004 Mazda RX-8 Base 2 Cyl 1.3L -- GB MULTI PORT INJECTOR, REMANUFACTURED -- A high quality, direct fit OE replacement multi port injector; Features orifices that provide better fuel atomization, which is beneficial in reducing emissions; With GB's 12-month or 15,000-mile warranty.

Part Number: G5842-12331
Fit Note: Automatic Transmission, OEM# : N3H113250A, N3H313250A
Type: Direct OE replacement
Condition: Remanufactured
Quantity Sold: Sold individually"

 

This is wrong. Always put the largest injectors in the P2 position. The secondary (what you just called "aux") injectors are behind a valve and aren't always available for supplemental fueling. Additionally, they are partially tapered out of the equation relatively early in the RPM band.

The "green" injectors from the SII are the best choice for the primary 1.

 

how much do the greens flow? they are interchangeable?

 

They are a drop-in replacement and flow about 400cc, but their spray pattern is significantly improved over any of the previous designs. The result is much better economy and injected volume control and precision.

 

P-1 = Series II
P-2= 4 port AT Stock Blue
Aux = 4 port AT Stock Blue

Should that get me around 330whp?

 

I am trying to find the Green injectors from a Series II but I am not having any luck online. Anyone have a part number? I might need to call a mazda parts department but without knowing which position the green injectors are in, I am not sure they will be able to help me.

When I look them up on line they say, Housing or Manifold.

Also, denso shows the same part # for 2009 as 2004-2008 but is not showing anything for 2010. So did they switch to green injectors in 2010?

 

Might want to go with modded blues or yellows instead of stock blue.

 

The GB fuel injectors are "remanufactored" which means they are stock denso injectors that have been cleaned and maybe flow test. There is usually a core charge. Rockauto.com has the best price that I could find.

 

Thanks go out to Ash.

2 x N3R1-13-250 Green
2 x N3R2-13-250 Red

 

I'm hoping to hit 350whp eventually, my understanding was always

P1 - Green
Secondary - Blue
P2 - Blue

would be sufficient for that goal.
Didn't realize they meant modified blue for the secondary though?

 

Modifed blues or yellows will both work. Stock blues might work, but for the small extra cost, its just best to modify them. For a long while many people were using stock p1's and secondaries and only upgrading to the modified blues or yellows for the p2 position. However with that setup the injectors were reaching their limits.

I will be putting some modied yellows and pink denso injectors up for sale. The pink denso injectors were flow tested and flow 10% less then modified yellows.