Hi all. Buddy of mine has a 99 F150 that had a 4.6L engine. He recently swapped it out for a 5.4L Triton and added a Vortech 6 lb. blower. However, he is still running the old 4.6L ECU. Everything runs and the truck blazes off the tires. However, the question is, is that 4.6 ECU optimizing the potential of this blown 5.4 or not? We dont want to swap out the ECU for a 5.4L unit b/c of changing the wiring harnesses around. Does anyone know if custom burning a chip for the 4.6 ECU will be just as good as the 5.4, or should we swap the ECU for a 5.4 unit??  Thanks all!!

I'm almost positive the computers will be different (program wise), but this will be hard to find the correct answer.  You would need to,somewhere, find the programs for the 5.4L, and the Lighting for that matter, and compare them to the program to the 4.6L.  

Im pretty sure that those two ecu's are totally different programs. I think you'll be fine with a burt chip and the 4.6, but I dont know if the chip can match the 5.4L.

So I say: call Superchips or Hyperchips. Talk to there people and see if they can tune it to match the 5.4l  It just may be possible.

Please get back to the forum with that one. I am interested to know and i'll be doing my own swap soon.

they're the same basic computer. A tune on the 4.6 ECU will fully utilize the 5.4 if the tune is good.