I am asking cause I dont know, but can I install a blow off valve on my 86 xt turbo?

Not recommemded. Realize this is an ea82 with pre-OBD engine management, and is no comparison to modern day impreza. This does not mean you can't upgrade this car. You can use an intercooler and a recirculating valve.

 

Just realize and understand you are working with a strange and foreign car from the 1980's, unconventional by then and today's standards.

 

This is a car you are more or less going to have to 'invent' upgrades for, as there are no aftermarket parts for ea82 engines. But you can retrofit parts from newer subarus, and use aftermarket parts for the parts retrofitted.

 

Search the retrofit forums in regard to using impreza engines. Just a regular ej22 out of an early 90's legacy non-turbo has 20 more hp than the ea82 turbo

 

go to the xt forums and search 'monster wedge' to get an idea of what you can do with the car's original engine.