Say I slap a t3/t4 kit on a stock MR2 that already runs pig rich. WIll I need to tune it,. or will it blow the first time i run it hard? I know tuning is reccomended, but can the stock ECU run a t3/t4?
Yes you can run stock fuel on a t3/t4, but if it's already running rich you should tune it before you do anything.. The harder you flog an engine out of tune the better the chance of something breaking.
I would at least get something like an AFC or VPC AFC/Gcc combo. This way you can atleast ruff tune it. I ran my MR2 like this (20 psi) for over 1 year and had no problems. You should also install a Walboro or Supra TT fuel pump.