Hey guys,
I recently recently had a GT40r turbo installed in my fd. The engine is basically stock and had been rebuilt with OEM parts. I did some of the supporting mods minus the fuel system.
So I called my mech this morning and he told me the car is running great. He tuned it to 15psi. What is confusing my is he said the injector duty cycle was around 85%. Is this normal? I would have thought that the fuel would have maxed out long before 15psi with that turbo.
If it is normal what advantage would it be to upgrade the fuel?

Mods:
Microtech EMS
Greddy EBC
Greddy 2 row FMIC
HKS cast manifold
38mm Turbosmart wastegate
Custom 3 inch exhaust

 

Wait...your saying you tuned a 40r to 15psi on a stock FD fuel system? I cant imagine there is ANY way that fuel system is stock. I mean hell, on stock fds, you cant really safely put over 13psi on the stock twins without upgraded injectors. Something isnt right, the injectors must be upgraded. Or you are so lean its amazing. What is your A/F ratio at full boost?

 

how much power did you make?

Are you saying this is with stock injectors, or just with stock rails and other parts.

What kind of fuel pump??

 

I know, i can't imagine it as well. The only thing is my fd is a 99 series8 model but i don't think the fuel system is different.
I only talked to my mechanic briefly on the phone this morning. I am away at school that is why i dont have details. Cant wait to go back and see exactly what is going on.

 

The entire fuel system is stock. Pump, injectors, lines etc.

He did not dyno it yet. He tunes on the street with a wideband

 

do you log fuel pressures? it seems like you are just asking for trouble not upgrading your fuel system.

 

I find it very hard to believe he only hit 85% on 15lbs. My buddy hit 100% duty cycle on non sequential twins

 

So i talked to him again today and he said at full boost the AFR was about 11.5:1He also explained ( I cant remember exactly what he said) that the microtech EMS had being very versatile had alot to do with allowing for such tuning.

 

Not possible on a stock injectors. You're either making crap for power, or chances are you don't have stock fuel injectors.

 

I don't know if i am thinking about this correctly but if my stock fuel system cannot keep up with the 15psi of boost then i would be running lean (if we disregard the statement the mech made about AFR being around 11.5 on boost). This should actually increase power vs running rich right? And the engine would have already detonated.

I highly doubt the pump nor the injectors were upgraded. The car was bought from japan in stock form. Everything stock except for a catback.

Please bear with me guys, I am just trying to figure this thing out.

 

my injectors are maxed on stock twins @ 12psi! U said you got the car from japan, in that case chances are things not visible to the eye has been changed. Its either that or your not making more than 320whp.

 

The car came with a stock ECU so is it still possible for the fuel to be modified?