I got a 91 hatch with a 98 ls swap, with a 91 ls ecu ,obd0, would i need to change it to obd1 or 2 to run ls vtec?

 

The reason people go with OBD0 so to get rid of the Emissions headache. But you dont get a knock sensor though.

The 91 ECU isnt going to accomodate VTEC for you. You will need at least a 93 if I remember right.

You can run pretty much whatever ECU you want as long as it has the code for VTEC on it. P28's are pretty much the standard that everyone wants to use. You can easily chip them and run whatever ROM you want.

Or to avoid a lot of headache get a 1st Gen GSR ECU and convert your harness for OBD1. I beleive they were 93-95 models. Cant remeber exactly.

 

I can convert a 88-91 PM6 (civ/crx Si) to have vtec out for you.. You'd have to tune it yourself though, or get someone to do it for you. I don't have maps for that engine for the PM6. You'll have to get a P28 chipped if you decide to go with a P28 instead, the stock D16Z6 program isn't the best for LSVTEC use either.