Advise from S13 RB owners please

[gr8bryt]

Wuz up peeps, I've been doing a little bit of research and I've decided to go rb25 in my '90 hatch. I'm aiming for high output to the wheels (500+whp) and decided that I would prefer and A'pexi RX6B with the TCW77 compressor and P25 turbine for motivation. My question is how large of a turbo (dimension wise) could I use and still clear the hood and have room for the exhaust manifold and other ancillary components. I'm figuring that I'll have to get a custom manifold since most companies sell manifolds to fit inside the bay of a skyline.

[Darius]

If you are serious about going for 500whp+ and not just blowing smoke because it sounds cool, then you'll have to upgrade your internals for reliability's sake. A lot of aussie guys and u.s. guys now have proven that the stock rods/pistons are only good for about 500 for a short time period. If you're honestly looking for 500+whp, you'll need to have a boat-load of money to replace many other parts other than just a turbo (somewhere around $8,000-10,000). You'll need new fuel injectors, FMIC, standalone ecu, wideband O2 sensor, new fuel rail, fuel pressure regulator, fuel pump, new intake manifold, new head gasket and associated motor work, pistons and rods (forged or GTR), crank collar?, SS oil lines for the turbo, turbo, and a ton of other parts I'm too tired to type out.

To answer your turbo size question, I wouldn't worry so much about hood clearance, but one of my buddies had trouble fitting a large turbo due to the valve cover. The aftermarket exhaust manifolds that you find on ebay are disposable and will break unless they are supported somehow. Once they heat up, the weight of the turbo tends to sag them down and the welds crack. If you have one custom made, it will probably run you around $1000-1500. I believe it is difficult to fit the aftermarket cast manifolds as they were designed for RHD cars and didn't have a steering shaft to deal with, so they might not fit the turbo downpipe easily.

Hope that helps. whew!

[gr8bryt]

Yeah, I'm aware of the investment that it required for beefier internals and such; that's why I want to do it right the first time around. Weak components that break cause other things to break and I'm not trying to feel that! Granted this is going to be a comprehensive build up and that's why I'm asking people that have experience in these matters versus Joe Blow on the street. I've seen some pics of S13 engine bays w/ rb's and the exhaust manifolds always seem to look jacked up. I suppose that goes back to what you said about the design of the motor for rhd cars. I don't have a problem working to get the money, I just want it right. Taking shortcuts in the beginning will usually lead to piss poor performance in the end; however GR8NESS REQUIRES SACRIFICE!