The RB20DET turbo that comes standard on the R32 is well suited for general street driving, boosts up nice and quickly, and not too bad for a small sized turbo. But really, is fairly limited in its power, and maximum anybody can reasonable expect to extract from an RB20 is around 160rwkw. To extract the most from the engine, a larger turbo is required.
I managed to purchase a highflowed RB25DET turbo for $600AUD - not much more than a standard RB25DET turbo. The RB25 turbo is a good upgrade for RB20, and allows about 10% extra power for minimal cost. Another advantage is that it is true 'bolt on' turbo, meaning it bolts to the factory manifold, factory oil and water lines without modification.
This turbo had already put out 230rwkw (about 300hp) on an RB25, so would be happy to get somewhere near that on the RB20, and hopefully crack a (high) 12 second 1/4 mile before swapping out the engine.
It has been sitting here for a few months taunting me, so decided the time was finally right to put it on. No point putting it on a completely stock R32, but with the exhaust, Apexi SAFC, intercooler and a few other things sorted out, the time was right.
The whole job took about 8 hours spread over two days. About 4 hours off with the old turbo, and 4 hours on with the new. You can see the progress shots to the right, and also the rb20det turbo off the car, and the old turbo, and the new turbo side by side. The new turbo is not much larger, but its really in the internals that there is the biggest difference that allows it to flow a lot more power.
The job wasn't too difficult in any sense, just very fiddly, and especially lots of grazed knuckles, etc! The worst part was probably the water feed line behind the turbo - which proved difficult getting off, and getting back on the new turbo... A lot of swearing was used to help get the turbo on :-) You can see down the bottom the new turbo going on, and the end result. Not much different from casual glance, but a lot more power gains up my sleeve.
So... what's the difference now? To be totally honest, not much at the moment. The car is only running a conservative 9psi, and I believe the turbo will need around 14-16psi to really show its stripes. To raise the boost to 16psi is not safe though for the engine without getting it tuned. After that should be up around 180-190rwkw; 255rwhp (I am hoping at least). So that will be the next step in a few weeks.
I am going to put up a *full tutorial* up soon here on project32, showing how to swap your rb20det turbo for an rb25 turbo. This question gets asked so much, and there is no obvious guide that I know of on the internet for it.