Just how big an alternator do you need to run an aftermarket EFI? 90 amps seems serious overkill.
You don't need a big alternator to run EFI but you do need a good alternator. EFI is susceptible to electrical noise so the alternator needs to be a late model design, preferably an OEM alternator. I use factory Denso alternators on my EFI cars. I use the 60 amp Denso unit on both of my cars.
