blackbird345

I'm over 100% duty cycle at 5800 rpms and plan to run 7000, what size injectors should I go up to?

TurboLX

Before swapping injectors (again), make sure that the rest of your fuel system is keeping up. Have you confirmed that you are not dropping fuel pressure? Better yet, if you have boost you should be running a 1:1 pressure regulator that raises actual rail pressure above 58psi when in boost. If you run 10psi of boost, you should have 68psi on the gauge from the rail unless either the pump or supply lines are inadequate. "60's" are really 73#/hr on a 58psi system and can support a LOT of power if you have the pressure all the way up.

That said, the next step is the Siemens/Conti 80's that actually flow closer to 93#/hr on the GM systems. The only downside to injectors this large is that you begin sacrificing short pulse and idle control. Obviously. getting the right data for them makes this MUCH easier, as does using the 1:1 regulator mentioned above since that actually makes them a slightly lower flow rate under the vacuum of idle. The 80's are good for over 1000hp.

thesubfloor

Have you checked your AFR at WOT? I was running a duty cycle in the mid 90's but dropped it into the low 80's simply but not running it as rich.

9secz

I ran Delphi 96s on my Camaro for 4 years with an Acceleronics injector driver box. *No* problems with idle or throttle response if you use low impedance injectors. The big high impedance injectors open quite slowly, and to make matters worse, a set of 8 will likely have different opening times. That variation is not such a big deal at WOT when the pulsewidth is nearing 20 ms, but it is very big deal at idle where the pulsewidth is getting down towards 1 ms. Recently I saw an injector flow mismatch of 20% at 1.5 ms on a set that matched within 3-4% at 15 ms.

Edward Trayler was running 120s with the Acceleronics box last time I checked with him.

Jeff

blackbird345

I have BAP but I need to check the fuel pressure to see if thats dropping. The AFR is increasing and got up to around 12.4ish when I let off so it doesn't give me the option of running leaner. I talked to ECS today and they're saying I'd need to get their stage 1 kit or get a smaller pulley for the SC....decisions decisions....I know which is the most fun solution :-)

DOUG @ ECS

With your forged engine, your going to need a greater fuel supply. The stg 1 kit will be plenty. Then you can properly see if your going to run out of injector, but my initial thought is you will be fine. Are you running meth injection?

blackbird345

No meth, would that fix the problem if I used the meth as extra fuel?

excessive81

eth is a band aid not a fix for your problem...as is a bap. i would get fuel system and call it a day since you already have forged motor grab a pulley and max out the blower

blackbird345

Blower already maxed out according to Paxton. After changing out the engine its hard to spend more money on the car...hence why I was trying to avoid additional fuel system...I guess I'll have to...