If you decide to go the S15T28BB route buy it new from Nissan as, depending on how nice you are, they charge $1300-$1400 with next day delivery. For that price it's not worth risking bolting on a second hand one for $800 IMHO.
Regards Matty

My suggestion is on a stock motor you cant go past the 320hp GT25 they are on special at moment for $1500 GT25 320hp I used to have one on mine very responisive expect around 230- 250rwhp @15psi = heaps in a 1200 ute If you want even more you can got the 400hp GT28 for $1950
GT28 400hp
will not be as responsive but when on full boost will pull like a train good for around 280-320rwhp if the other engine bits and fuel system are up for it.

for $1600 you can buy a GT25 turbo, garrret say it can run anything up to and including 25PSI all day, day in day out!!!!

Damo

i would personaly look at the VF22 STi WRX turbo - they're easier to get a hold of than the S15 T28s and are almost the same turbo but the wastegate is 2.0mm bigger from memory - oh, and they're cheaper! about $1800 new from subaru.

otherwise, if you're looking at a full custom jobbie or an easy bolt on mod, go the T28 or what NIS15L said about the GT30

ca18's go pretty hard if u just swap the stocky turbz for a T28 BB turbo out of an S15. that way it is a decent upgrade, and im pretty sure it fits on the stock manifold, wont have huge lag, and the turbo will only cost about $600-800 if not cheaper

You have heaps of options here simon there alot of "bolt on turbo" options for the CA18DET depending on the money you want to spend if you want brand new, aftermarket such as HKS or a nissan turbo from a wreckers.

I would sugeest a Garret GT28 ball bearing with internal waste gate which is a bolt on replacement and sell brand new for around $2100

The fact your still running standard computer is a factor to.Did you apgrade your air flow meter if not do so to a z32 AFM which allows you to run more boost also think bout getting your ecu chip for some more tunning flexibilty.

Personaly my ute is being built with big power in ming so i have an aftermarket computer and so on so i will be putting up with the standard turbo till i can bolt on a custom manifold GT30 ball bearing turbo and big external gate.

Hope this helps Cheers Luke

I am thinking of saving my money for an upgrade to the turbo on my CA18DET ute, and am after some advise or suggestions.

I have driven a ute with a CA in it and it was sucking through a T3- yipee
It went hard!

My fuel set up is more than adequate to run larger boost/turbo, i have a front mount and the engine is backed by a standard 180sx auto box, with the standard computer.

whats the opinions????