RB25 in S13 game plan

[madmaxfreelance]

Hiya everyone, I'm getting ready to start cobbling together some parts for a swap into my S13 and wanted to run my game plan by ya to get some feedback. My final goal is 500 whp, short term goal is "get a rb in my car."

So far, my understanding is that the RB20 transmission will bolt up fine to the RB25 and work with the S13 driveshaft and line up the shifter correctly without hacking up the trans tunnel.

I also know that the RB20 transmission is weaker than the RB25 transmission. How much weaker I can't seem to tell exactly. Will it hold 500 whp? Where's the line on it?

So here's my current game plan:

Engine: Buy RB25DET series 2 motorset with no trans. Replace all gaskets, valve seals, belts, and timing pulleys before installation. Fix oil pump problem if necessary? Does that apply to s2 motors?

Mounting: zerolift mounts and some decent aftermarket motormounts (nismo or something)

Drivetrain: RB20 transmission with stock S13 driveshaft and the Z32 LSD that's already in my car.

Wiring: seems to be a wealth of resources for wiring it up online. Not scared :p

Manifolds/Turbo/Injectors: I'm a complete turbo noob, so my plan is to keep it stock till I get everything else installed and working and then go for some upgrades down the road when I have a better understanding of forced induction tuning.

Downpipe: Get one of those ebay conversion downpipes. I mean it's a piece of pipe, the Chinese can handle that I think. Dunno if this will work with the zerolift mounts and stock cat location though.

Intercooler: silvia SMIC. I loathe cutting, grinding and welding so looks like FMIC is out.

I've already got dual electric fans and a walbro fuel pump in my car.

Any input or corrections are welcome, specifically I'm trying to make sure that I am correct in thinking that the zerolift mounts + RB20 trans + stock driveshaft will play nice together.

Thanks

[TheRBguy]

Rb20 transmissions are like a ka transmission and more than likely will explode if you put 500hp to it.

[madmaxfreelance]

kk, so I guess it would be a better value to just boost the ka than run an rb25 on the bush league transmission...

is there any advantage to using the vg30dett transmission w/rb25 in the s13 over the rb25det trans?

[TheRBguy]

Rb25 transmissons are awsome, i hear that the z32 transmission is good as well but dont have any experience with them.

[madmaxfreelance]

most of what I can find online seems to say that the z32 box is the same as the rb25det box - just the shafts are different lengths etc.

mainly wondering if there's any fitment advantages to using the z32 trans+rb25 bellhousing (assuming I could source that)

[LSDrift]

Unless you have easy access to a Z32 trans or something, I wouldn't waste my time trying to mate the two. I'd just fork out the dough for a RB25 engine/trans combo. You might save yourself $1000 in buying the motorset only but it'll be a pain in the a** in some other ways. If you really feel like that's what you have to do or something though there's quite a few threads out there on using the Z32 trans. In terms of fitment, I'd just save myself time and headache and go with the Mckinney engine/trans mounts. I can't comment on the Zerolift setup but using the Mckinney mounts puts the engine about as far back as you can get it, and also aligns the RB25 trans perfectly with the S13 shifter position. Then all you need is a driveshaft, steel or aluminum, that's premade for the swap. There's tons of places out there, I got my aluminum one from shaftmasters.

As far as exhaust goes, using Mckinney mounts mind you, my turbo elbow on the stock turbo is probably 1/16th of an inch or just a little bit more away. This being ok, I had my exhaust fabbed up at a local exhaust shop with a 3" magnaflow turbo resonator muffler straight through to the Apexi N1 muffler at the rear. They made me a downpipe and everything for about $400 said and done.

[madmaxfreelance]

yeah I'll just get the motor with a trans, I'm trying to save money but avoid half-assing it
hopefully, I don't get screwed over and end up with a RB20 trans anyways :/

I think the zerolifts are designed to line up the rb25 trans with the shifter hole, can anyone confirm or deny?