'90 celica GTS

Can I bolt on a turbo to this engine w/o an engine swap?

That really depends on
A) how much boost you plan to run
B) how strong the stock internals are
C) are there even direct bolt on turbo kits, or is gonna be a custom setup?

Might be better to ask in the Celica section, where they are apt to know more about that specific engine.

Also need to know if its a Japanese spec, or European, or American spec Celica, as they all used differnt engines.

american

So its got a single cam fe motor in it?

i guess, im buying the car used. '90 GTS

you can bolt a turbo to anything. What'll it do, how long it'll live, how much power it will make.....those are very different questions.

1990 USDM ST184 Celica GTS packs a 5S-FE 2.2L 16v DOHC I4. It's not the best motor in the world for boosting but it can certainly be done and there are kits out there for it. I've seen some arguments though that it is better for ultimate HP and price just to swap a 3S-GTE turbo 2L from an MR2T or Alltrac Celica in to the car.

Yes it is possible to turbo the 5S-FE. While we were doing the engine build on my All-Trac, we used the factory turbo/exhaust manifold from my alltrac to turbo his '90 GT. You will need an exhaust manifold and turbo from an All-Trac or MR2 turbo. You will also need the 2bar MAP sensor from the All-Trac or MR2. You will need a 3S-GTE oil pan. Custom water and oil lines to the turbo. MKIII n/a supra injectors. Also a 3" downpipe for a 3S-GTE on ebay would work nice to replace the alltrac cast iron cat/downpipe. You will also need to get a front mount intercooler and piping. We got a kit for my friend's car for about $175 on ebay, turned out to work nicely.

http://photos-647.facebook.com/ip006/v23/53/104/51204144/n51204144_30235647_2333.jpg

the stock internals can handle 6psi dont go above that unless you want disaster

I have seen some celicas with some strong turbo setups, if you can find some forged internals from a reputable company you can make that celica run with an evo. One that I read about ran 13.0 in the 1/4 with 15 psi of boost on pump gas!! That was a 1982 GTS I think.