I'll post the mods that I have that relate to this topic.

272/272 cams
walbro 255lph fuel pump
3in TBE w/ test pipe
K&N cone filter (no maf pipe)
Halman MBC set around 22psi for this run
TurboTrix custom reflash
ECU+ EMS
AEM UEGO Wideband gauge type
Straight C-16 leaded gas

Ok it's a long story, but this is doing a 1/4 mile run at the drag strip. I was in the process of dialing this in, I know that the run is fat, but I'm seeing the same thing on pump gas. 94% duty cycle on stock injectors is not good IMO. I've seen people say that you don't need new injectors until you upgrade your turbo.

You can see that I've added 20% fuel over my flash, this is due to my AFR's being very lean with the flash. In order to run 20psi on pump I need to run around 20% fuel from 4k on, but it maxes the injectors out. I think something is wrong.

 

i think i still have my HKS 680's laying around... pm me if your interested.. i noticed a significate gain when i went from stock injectors to the 680s on 264 HKS cams...

 

Mine are also maxed out..even worse actually. I don't even have cams and the ECU+ is showing mine are at 94% starting at 6000rpm and max out at 98-99% in the upper rpm range I'm even running leaner than you are..around 11.2-11.6:1

 

it could be a faulty reading. If you trust the reading, check the fuel pump install. The o-ring/rubber hat looking thing that secures the fuel pump outlet nozzle to the fuel pump cradle could be leaking by in a severe fashion, in essence giving you a built in fuel pressure regulator in your gas tank. Do you have a way of monitoring fuel pressure? If the fuel pressure is staying up at the desired level, the problem should be with the injectors. I'd check fuel pressure if possible.

 

Or....maybe the 780cc injectors I just bought will fix the problem and I can start running 23psi again =)

 

unless your making north of 380 whp on your setup, the 780's probably won't fix your problem. Best of luck either way. Keep us posted, I'm curious if the 780's actually do fix your problem.

 

Are these runs on race gas? If so there is something definitely wrong as you definitely shouldn't need injectors with your mods. I could see possibly on pump gas but not on race gas.

 

Yes, race gas. C16

 

Yea then something definitely isn't right as IDC's typically are lower on C16 than pump as you can pull more fuel and add more timing on C16 than pump. What are your IDC's on pump?

 

IDC is the same because I only ever really adjusted fuel/boost just a tiny bit, my laptop died after that at the track.

 

Got ya

 

Is this an ECU+ issue? I see 85% idc at ~5800rpm and 99% by 6800rpm. Unlike your charts though, my a/f nosedives from mid 11's to mid 10's once the injectors max out and the timing flatlines at the same spot as well. I have bigger injectors to put in, but my mods are very similar to yours. I was also under the impression that I should need them at my mod level, but the numbers don't lie, do they?

Have you used the dyno feature of the ECU+, and if so what hp are you at? My barely tuned (only had the unit for a couple of weeks)pulls have me in the 370's. If we are both in that area, maybe we do need bigger injectors.

 

haha, Thats nothing, my injectors hit 100% a couple times, but now they are at 98% at 7000rpms

with Cams, EBC, TBE, and aggressive timing they will go quick!

 

Doesn't help that you have added 20% fuel at WOT. Cams, BC, and other stuff will get you to 100% pretty quick

 

But look at his a/f curve, if he wasn't dumping in fuel he'd be melting stuff. Makes me wonder about his ecu flash...