ECM - Computer Help
 

I am changing cams in my 502 due to a water reversion problem. It is a Gen V 502 w/30 over flat tops, stock rectangle port heads with factory multi port injected, running EMI exhaust and K&N filter with adjustable fuel regulator. It had a comp cam XM278H 234/237 at 50 and .564/566 lift, 112 ls. The computer is set for a XM284HR, which is 230/236 at 50 and .547/547 lift on a 112 lobe separation. From what I've been reading seems I'm beating a dead horse but have not seen the answer to this. I would like to install a comp custom grind of 224/230 at 50 and .570/578 on 112 or Crane cam HR288-2s-12 226/234 at 50 .587/610 lift at 112. I understand with more lift I should get more mid range ? If true I'm trying to get power between 2500 and 5400. I am trying to determine the computer ranges OR does the computer need to be reprogrammed. Arizona Speed programmed the computer and when I ask they say any change requires reprogramming - they wont give me any range parameters. Is that true ? Thanks for any and all info :confused:

Without plug readings or better yet A/F ratio readings it's all a guess. You'll probably be very close anyway.

Hondatv, Looks as though you are asking for trouble. I just did complete rebuild, from 350 to 383 inch motors, and fuel injector change from 22lbs to 36lbs injectors. Also did cam change. Call Mark Boos, at precision Marine in kenner louisianna. He spent several hours with me tuning in boat with lap top. $$$$$$ well spent. Maybe it would be great idea for his opinion anyway.
steve

Thanks for the info, I think it should be close. I was just wondering if anyone knows if I change duration (236 to 230) OR if I go with more lift (547 to 600) do I need to change the computer.