I really need help picking an engine. I have a 1991 nissan sentra se-r. I have seen all the forums on engines but dont know which one to get or where to get it from. the avenir or whatever sounds great with the tmic or fmic whichever. I dont know what to get, I know I might sound stupid but what is the avenir, anyways-if I do the avenir swap, wil I have any problems at all or anything that will hold back the swap. What extra parts will I need or will it just be a bolt on and run just fine stock-which wont be for long. Will i need to buy parts to get it running- someone help me i am going crazy here and relly *** this swap to go smooth fast and reliable. any informtion is appreciated.

First.. I advise you to find someone... or a shop that knows the SR20DET before you get started. The Blue Bird SR20DET will bolt right into your car.. with minor changes. You have to use your SR20DE FWD tranny with it.. and some other components.. but... by far.. it's one of the easiest swaps for your car.
Travis

The suggestion you made is taken care of, the tranny of course will have to be used as you say, is that petty much it- if it is then the swap will become fairly easy for me-the mods will come pretty fast to due to many connections with different places like perfomance shops and stuff like that. thanks for your information though. Oh and what else needs to be used to get the motor running from the se-r engine.

To swap over, you'll have to use the PS motormount bracket on the BBDET, I also recommend changing the rod bearings. Things like new water pump, oil pump, belts, and hoses are always safe bets too. Don't forget the thermostat, you also have to change over the thermostat housing and mounting assembly if you plan to use the bleeder. If the harness on the BBDET is cut up, the SE-R one will work fine, however there will be a few extra connectors as the BBDET doesn't have EGR. No worries there. I also would swap over all of the USDM accessories over, its just personal preference. You'll also need to swap over your coolant temp sensors. You'll have to shave the upper oil pan a bit to clear the crossmember, but its much easier than it sounds. I think thats it, its just off the top of my head. Anybody care to comment if I'm forgetting anything?
Also for the sake of all things turbo, please at least front mount the stock topmount intercooler. It also makes it easier for when you upgrade, all you have to do is cut the piping back a bit and slap the new IC in. I would also go 3" exhaust and a Walbro 255lph pump at 10 psi, it will be a nice ride.

If you go with the avenir, you will have trouble with the turbo outled that faces downwards, it will it the crossmember.

I have a BB U13, which is also fmic, and I had to rotate the comperssor housing and modify the outlet pipe

Thanks for all the help. You have a nx2000 though right. It is harder to get a bbdet in there as so I heard. I'm not saying anyone is special or anything thats just what I've heard and its hard to keep it cool. I have also heard the avenir turbo fits just fine without complications- but then again I could be wrong- but if I run into a problem like that then I could easily have that fixed in a day or two. If the outlet hits he crossmember, that could be modified though right-but I have never heard of this in the sentra se-r or I just wasn't paying any attention. Well thanks for all the help though.