Stock Injectors = Maybe? Big NO?

[maxthehax]

Hey guys, looking for some opinions/facts from you!

The main purpose of those questions are for the ability to run the stock ecm at anytime I need it without injectors swap. So here it goes;

One year ago I got tuned on a mustang dyno with AEM fic.

Stock internals 200,000kms engine
Garrett GT2252
370cc deathswerks injectors
5.75psi spring

We made a safe 145whp / 145wtq

Couple months later the fic stop working, I remove it and run the stock ecm.
No surprise, the stock ecm is having a hard time running the bigger injectors which are twice the size of oem... So I swap the oem injectors back in the rail and run the car turbo'ed @5.75psi with stock ecm.

time goes on... Nowaday I have a brand new PnP harness with a brand new AEM fic plugged in the car, no tune.

Running the car stock I see that much of the problem is the Stoichiometric air/fuel ratio during acceleration! It removes all the low-end power...

During open loop, a/f are allright until about 1/2 - 3/4 of the throttle pedal.

So my idea is theres not much missing for the injectors to be ``allright``. I don`t think the oem injectors are already maxed out by the stock tune...

Maybe I could get tuned again with the sames number with stock injectors.
That way, if anything goes shit again, I can simply use the stock ecm without any fuel problem.

Thanks, and sorry for my poor english!

[Focus_Sh1ft]

There's no way you're maxing the stock injectors at ~6psi of boost. I can maintain 11.2-5 at 10 psi and 5k rpms, so you have plenty of room.

I don't know how you're tuned, but if you're in closed loop there won't be any problems with the ECM running larger injectors. Otherwise, you have to tune for them in open loop.

I'd recommend running an open wastegate until you're properly tuned. Stoich is too lean while under boost conditions. If you were only making boost in WOT then sure, but with such a small turbo you're probably making boost during part throttle.

[maxthehax]

Originally Posted by Focus_Sh1ft

There's no way you're maxing the stock injectors at ~6psi of boost. I can maintain 11.2-5 at 10 psi and 5k rpms, so you have plenty of room.

I don't know how you're tuned, but if you're in closed loop there won't be any problems with the ECM running larger injectors. Otherwise, you have to tune for them in open loop.

I'd recommend running an open wastegate until you're properly tuned. Stoich is too lean while under boost conditions. If you were only making boost in WOT then sure, but with such a small turbo you're probably making boost during part throttle.

Perfect! Exactly what I though!

You are right, closed loop adjust itself with the o2 with bigger injectors. But still, its not ''that good''...

Let's say that is alright with the boost, you just need to be very carefull with the throttle. NO WOT at all!!

thx!

[Focus_Sh1ft]

Let's say that is alright with the boost, you just need to be very carefull with the throttle. NO WOT at all!!

You actually have this backwards. If you were running closed loop without any tuning, you would ONLY want WOT. The car enters open loop and the mixture gets substantial richer. In partial throttle, you're maintaining stoich while throwing boost at the engine.