Fast xfi Sportsmann ecu

Hy, can evrywhere help me with fast xfi sportsman?

i am a Little confused with them, we have a Bbc 454, Stock Engine and they are Sitting a Weiand 170 small Compressor on it. we buy a fast xfi Sportsmann for Blown Applications. Now we have a Problem we have zwo throtlebodies wit 4 Injectors each Body. So we can only fit ohne of them on the small blower. Each throtlebody have 4 Injector 78 lbs ea. We can set in fuel Menu and Chose 4 injector for 8 cylinder. Now the Engine Runs really lean. We Must set Ve to over 140% at idle! Now we change Settings to 40 lbs injectors in fuel menu and See the Engine Runs pretty well with ve 50% at idle! Have anywhere an idea what we make wrong? Hope My englisch is Not to Bad!, thx Arthur