Icemastr

iTrader: (2)

My car is starting to get pretty modified, and I am taking it in to get tuned, I thought I would be ok not modifying the fuel system yet but I am hitting 89% injector duty at 6000RPM or so in 2nd and 3rd gear. This is bad obviously... So I postponed my dynotuning because I dont want to do it half-way, my mods are: DP, Resonated Midpipe, Apex GT Catback, Apex Intake, Power FC/W commander, Greddy 2 row FMIC, HKS Plugs, wires, HKS Ignition Amplifier. I just barely did most of these mods realizing I would need to dyno tune it, I wanted to wait to do the fuel mods when I went with large single, or 2 good size twins, so will an upgraded in-tank fuel pump get my injector duty down enough to be running good until I upgrade my turbos, or do I need to just go ahead and get 1300 or 1600cc injectors, fuel rail, and fuel pressure regulator all too?

TwinTriangles

No, fuel pump will not affect your Inj. duty at all, I went with RC 1300cc sec inj., I would recommend getting tuned before you do anything else, like drive it, Go get tuned now while your waiting for you Injectors, %89 isnt the worst anyones ever seen, its max but its not bad by any means. Whats bad is that your running all those mods & havent gotten tuned yet, you must be running someones maps, right ?

rynberg

Upgrading the fuel pump will not change your injector duty. The higher flowing fuel pump will simply be ABLE to supply more fuel as bigger injectors demand.

If you get your secondaries bored out by RC Eng. to 1200-1300 cc, they will still fit in your stock rail. When you go to 1600cc, you will need a new fuel rail and regulator.

And yes, if you plan on running over 13 psi daily driving, you should really have upgraded secondary injectors and fuel pump.

BTW, perhaps your map is too rich (although probably not). It's possible with tuning, that your injector duty cycles may go down, but not that likely considering your mods.

ZoomZoom

iTrader: (2)

Actually your right and wrong. First of all a Fuel pump will help if its the fuel pump not able to keep up the pressure. Inj duty will be higher if the fuel pump is maxed out all other things considered. The Injectors will show higher duty even if Injectors are within thier efficiency range and if the pump is lacking ability to keep up pressure at higher consumtion rates the Inj will try to compensate with higher inj duty to supply the fuel. Not saying the Stock inj are up too task but adding a higher capacity fuel pump may in fact help bring inj duty down if in fact the Stock pump cannot keep up the fuel pressure in the lines at this boost level. The only way to determine that this is why your seeing higher inj duty is by putting a fuel pressure gauge on the car and monitor it while on a dyno etc. Your right. The car needs to be tuned and most likely fuel upgrades performed. With those Inj duty numbers your not able to tune the car as you cant add more fuel if you need too with an aready maxed out fuel system. Adding a Nippon Supra TT pump will help keep fuel pressure up and will also be a good pump when adding fuel upgrades. I would do it but it is not a fix all. Its a direct drop in pump that will support 450+ RWHP with upgraded Sec inj rail. You cannot TUNE a car for the boost your running when you already are showing this high Inj Duty. DO NOT GO GET IT TUNED FOR HIGH BOOST. Tunr down the boost and then after your fuel mods tune it with a wideband on a dyno with a Rotary Expert in TUNING. Not just an Engine builder.

Icemastr

iTrader: (2)

Right now I only plan on running .8bar boost, I am going single or some different twins in another month so its not that far off before it gets tuned for high boost, most of these mods were just barely installed within the last few days. I guess my real question is, is the stock FD fuel pump a smaller bottleneck than the stock injectors and will that provide me enough fuel until I move on to bigger things in a month or two?