If a RB25 turbo was bolted to a RB20DET, are there any mods that would need to be done? can i still use the 3" dump off my RB20 turbo?

you can still use the dumppipe - exactly the same flange. the oil & water lines should be pretty much the same. Do a search on www.skylinesaustralia.com (http://www.skylinesaustralia.com) and you'll find out for sure.

yeah. same everything. and you can run more boost with a 25 turbo on there. and it'll pull to red-line as opposed to yours which prob dies a bit up top. 12-14 psi. much further and the ceramic turbo might argue...

Why can you run more boost?

Steel Blade as opposed to Ceramic I think..

ive heard its a pretty poor upgrade, obviously u get a little bit more topend, but u still cant run too much boost, from what i read about 12psi max as the ceramic wheel will fly off. go on SAU and get one of these highflows, http://www.skylinesaustralia.com/for...owtopic=131723 (http://www.skylinesaustralia.com/forums/index.php?showtopic=131723)

The Rb25 turbo on an rb20... Push 14-15psi in to it, tune and you can expect ~190rwkw. And they lag around the same as an rb30 with a gt35r 1.06 on its side. But obviously have stuff all torque off boost. :P The best option for an rb20 is to slap a highflow on it and push as much boost as you can in to it; the little 2ltr needs all the help it can get to bring up that mid range power.

I have a vl with an rb20 setup in it, runnin all stock gear, an rb25 turbo is bigger but lags till u hit 3rpm, what ive done is still using the same turbo and running hear, ive thrown a microtech, boost controller and its running on a safe level at 13psi, i also have a custom made cooler kit which was made from west side mufflers, 3inch turbo bak exhuast and running top of libe nissan oil, plus a racing fuel setup, anthony from maatouks racing tunes my car and got 312horses at the wheels, u need to establish a good setup first and obviously there is trial and eror, if u want to see how my car go's jump on youtube and type in eski23q and have a look any questions u need to no ask me and ill try and help u out