if I replace the pistons and the intake manny and the head and cam is it possible to turbo it with out having to replace the block and the ecu
The block would probably work but your ecu wouldn't (assuming you have a NA 2.0) The ecu on the NA is for TBI, for the turbo its MPFI.
<img src="http://www.geocities.com/fudd_22602/elmer-shoot.gif"> Old school Js rock
You can get NA birds with MPFI after 91. And to answer your question, yes you can do it but its better to get the turbo wiring. The turbo ECU and wiring is designed to accept boost so it can handle it alot better, it also has a knock sensor to adjust your timming curve so you dont detonate. But lets say you decide to stick with your Na wiring.....It would be just like turboing any other car that isnt turbo'd from the factory, but you got the advantage cause its easier to get a hold of some forged pistons. You will need the pistons and the exhaust manifold for sure (and the turbo, duh) The intake mannifold dosent really make a big diffrence that I know of. (I would swap it anyway just cause it says turbo on it, lol) You will also need a boost guage and a air fuel guage, The air fuel guage is a must of any turbo car your playing around with espicially cause yours dosent have a knock sensor. With this gusge you can tell when your running to lean or rich so you know how much more fuel to add or take away or how much air to add or take away.
Another problem for you is fuel, you also need the fuel to support boost, swaping in the turbo fuel injectors would be a good idea (I'm not 100% sure if they will swap into a NA intake manifold) and a adjustable fuel pressure regulator. A manual boost controller is a good idea too theres a link to a site that tells you how to make one for something like $3 in my FAQ, just do a search for "2.0 FAQ" and you'll find it.
You dont need a turbo cam....actually the cam in the MPFI 2.0s is better than the turbo one, you "can" run a Na cam on a turbo motor but never run a turbo cam on a NA motor. And as for swapping the head, I'm pretty sure the NA and turbo head is the same, but I've never seen proof. When you get your motor apart check to see if the turbo pistons are dished more than the NA pistons, if they are the head is the same and you can keep your NA head. If the top of the turbo pistons are the same as the NA pistons then the head is diffrent and needs to be swapped to lower the compression.
Thats about all I can think of right now, I dont think I missed anything.
Good luck with it.
