Stock injector size?

[CobraBob]

Are the '03/'04 Cobra stock injectors 39 lb/hr?

 

[JDV]

Im curious to know this too, CB.

 

[ALA G8R]

Yes the stock injectors are 39lb/hr. You may be close to needing a higher flowing set.

Click

 

[08snake]

Yep!

 

[CobraBob]

The stock injectors are good for up to 500 rwhp. So I know I'm very close.

Thanks for confirming the size for me.

 

[Justin Blake]

I always thought it was the pumps, not the injectors.

 

[CobraBob]

According to the Apten website, the stock fuel injectors are good to around 500 rwhp with stock fuel pressure. They can raise the fuel pressure in a custom tune to compensate (which is what I will probably do since I'm getting a custom tune in April), but once you reach 530 rwhp they suggest upgrading to 50lb. or 55lb. injectors. The advantage of the injector upgrade is the reduced effort on the stock fuel pumps and to keep drivability excellent. I don't see me going above 510 rwhp so I am hoping the fuel pressure mod will work for me.

 

[davidmax]

Again over 500 rwhp I strongly suggest a return fuel system so you dont Pooch your motor,Dave Smilovic

 

[ALA G8R]

CobraBob,
I would try higher pressure from a custom tune first. If you can't get you A/F right with that then try larger injectors. Next, bigger pumps. I can't imagine you needing return style fuel system because you a tad over 500 RW.

I haven't seen alot of the KB folks installing a fuel return and most of them are way over 500. They just do 55lb injectors and focus pumps.

My $0.02.

 

[2003snake]

Many KB users using the KB BAP on the 39's without any problems.

I have steady fuel pressure 60, then 85 @ WOT @ 17# on a KB