FWD Performance stage 5 running lean with 10lbs boost

[tehdrizzle]

First let me say that this calibration kicks ---. I just got it installed today even though I've had it for about 3 months. Without touching anything else and a base fuel pressure setting of 55psi and the 10lbs that I'm still running for now I noticed a HUGE difference in power. Now my question is the only thing I have changed is the logic module from a stage 2 to the FWD Performance Stage 5 which is setup for my +20's. With the MP stage 2 LM I had around 10.8-11.1 afr at redline with a 3rd gear pull on my AEM Uego and that was with a base fuel pressure of 50psi. I turned it up to 55psi to be safe with stage 5 and with no other changes and still 10lbs of boost it's running 12.1-12.3 at redline with a 3rd gear pull. The calibration was setup for my +20's since I don't have +40's in the car. My setup is below:

Ported cylinder head
Ported 2 piece intake manifold
stock rebuilt garrett t-II
custom built FMIC (equal to 3 stock FMIC's)
2.5" mandrel bent intercooler piping
Mopar +20's
walbro 255lph fuel pump
Magnecore wires
Autolite AR51's
Forward Motion ported exhaust manifold
TU 3" swingvalve
3" mandrel bent exhaust (dumping in front of driver's rear wheel)

Any ideas or do I just need to up the fuel pressure?

[tryingbe]

Did you put in a 3 bar map sensor??? If not, put the old computer back in ASAP.

[tehdrizzle]

Did you put in a 3 bar map sensor??? If not, put the old computer back in ASAP.

Yes 3 bar map is also in the car.

[glhs727]

Bump up your fuel pressure..... report back....

[tehdrizzle]

Bump up your fuel pressure..... report back....

Bumped the base fuel pressure up to 60psi with vacuum disconnected from fpr and it's now at 11.6-11.9 afr at redline with 10lbs of boost.

[black86glhs]

That will work, but another 5 psi of base pressure would be a little better. Do you already have a 255 fuel pump?

[tehdrizzle]

That will work, but another 5 psi of base pressure would be a little better. Do you already have a 255 fuel pump?

Yes the Walbro 255 is already in the car. I just don't see how I can even get to stock boost levels if I'm already at 60psi base with vacuum disconnected and only 10lbs of boost is putting me at 11.6-11.9 afr.

[black86glhs]

Volume is a funny thing. The 255 supplies more volume than stock or even a 190 pump. Even though the injectors are only +20's, they can flow a little more due to the volume and added psi. As the pressure increases, the amount injected increases (in most cases).
It is also why others use +40's to get the proper amount of fuel without having to adjust pressures to make up for the lower flowing injectors.

[tehdrizzle]

What I'm not getting is with the MP stage 2 LM that I had in the car I was getting 10.8ish afr with this same setup and boost with less fuel pressure.

[trannybuster]

Not going to be exactly the same as MP. You running a egt guage also?

[glhs727]

because there is obviously different fuel curves/injector pulse widths. If you intend to only run 10 psi forever, then using the MP cal with +20's would be fine. If you plan to go beyond that, you will find that you will rapidily lean out as you increase your boost levels with the MP set-up.
also you are using a cal meant for 18-20 psi of boost and only boosting 10 psi. You might find once you get into the boost levels the cal was actually designed for, the fueling will be better. I have seen many good tuned cars that run lean at the lower boost levels and get fatter as the boost rises. Which is good as the motor isn't stressed under the light (10 psi) load, so running 11.8-12.0 at lower boost levels isn't critical and even helpful as the leaner condition helps with spool. as the boost is rising is the a/f dropping? At 60 psi fuel pressure and at 10 psi getting 11/6-11.9 sounds fine. What happens at 15 psi? 18 psi? You might find as you get into those areas the a/f gets better. BUT you may find that becuase of all your mods, especially all the porting/exhaust work, that you have surpassed the limits of the +20's and might have to break down and go with +40's, but you won't know that until you see where the fuel pressure vs boost level takes you.

[tehdrizzle]

because there is obviously different fuel curves/injector pulse widths. If you intend to only run 10 psi forever, then using the MP cal with +20's would be fine. If you plan to go beyond that, you will find that you will rapidily lean out as you increase your boost levels with the MP set-up.
also you are using a cal meant for 18-20 psi of boost and only boosting 10 psi. You might find once you get into the boost levels the cal was actually designed for, the fueling will be better. I have seen many good tuned cars that run lean at the lower boost levels and get fatter as the boost rises. Which is good as the motor isn't stressed under the light (10 psi) load, so running 11.8-12.0 at lower boost levels isn't critical and even helpful as the leaner condition helps with spool. as the boost is rising is the a/f dropping? At 60 psi fuel pressure and at 10 psi getting 11/6-11.9 sounds fine. What happens at 15 psi? 18 psi? You might find as you get into those areas the a/f gets better. BUT you may find that becuase of all your mods, especially all the porting/exhaust work, that you have surpassed the limits of the +20's and might have to break down and go with +40's, but you won't know that until you see where the fuel pressure vs boost level takes you.

Thanks for the information Cindy. As I increased the boost it continued to lean out more and I had to keep increasing the fuel pressure to keep it in the mid to high 11's in the afr. I'll get the car out this week, crank the boost up to around 18psi and see what afr I get. I just didn't want to increase the boost, lean out, and make an ashtray out of one or more of my JE's.

[trannybuster]

Sell those 20s now as a combo with your MP your selling, then viola +40s!

[glhs727]

yea, if you just get leaner as the boost goes up, you will be better off with the +40's. It is easier to under work a +40 than overwork a +20.