Mods installed: Motordyne ART pipes, Injen v3 intake, AAM fuel return system stage 0, walbro 255lp pump, DW 600cc injecter (new filters and O-rings), HKS AFK with dual 02 sensors, Uprev osiris


Spent quite a while with my tuner last night and even though we managed to fix the tables from what they were originally, so the Z doesn't hesistate when starting and the powerband is fairly smooth now. But the issue is we can't pull anymore power and by this I mean that with HFC's and stillen v2 intakes, i made 296hp on a dynapack and after i installed the mod's above, i am only making 271 hp. The weird thing is that even when we adjust the AFR, my power doesnt change much at all. My tuner is stumped and so am i, anyone have any inputs on what could be causing the wall to where i can't produce anymore power? should i go back to stock injectors?


edit: nvm, the hesitation on startup is back, it'll fire over, drop to nearly dead, and then it'll come alive.

 

why you have 600cc injectors on a NA car?

 

Its what I had just lying around in my pile of parts i've collected for my FI build next year, decided to put it on since with a good tune, it shouldn't matter if its stock or 600cc

 

true, and i see your thinking but to eliminate any variables i say put stock ones back on and see if it does the same thing. Some times the things you never would think of being a problem are the problem.

 

in for answers...

 

Yea, i'm thinking thats whats gonna need to happen.

also, on a side note, are DW 600cc injectors...noisy?? I can clearly make out the sound of the injectors spraying in succession when my engine is idling.

 

600cc's and expecially the AAM fuel return makes a ton of noise.

But it sounds like the problem is your tuner. I can tell by your startup issues he doesn't have the most experience.

 

Hmmm, anything the tuner should be looking at then? When we dynoed the first time, i made 253 and after map corrections, it came to 278 but thats where we hit the wall.

 

Did your tuner adjust for the new injector? In the Uprev manual it explains how to setup non stock injectors. How much are you changing the A/F ratio and expecting a change? Also from what ive seen (On HR motors at least.) NA Z's seem to respond more to ign timing changes more drasticly then fuel. Going from 12-13 A/F wont make much of a change.

 

The software has been updated for the bigger injectors and my timing is already pretty aggressive from my first tune which netted me my first power goals. Now i've lost a considerable amount of power with products that should have at least added a few. At one point, my A/F went to 15-16

 

Better to go back with mods or to find a tuner with specific experience.
You can also have problems at engine with such a/f...