Rb25det Vs Rb25det Neo

[Nissanisamazing]

I know this is asked all the time but i cant realy find a thread that answers all my questions. Im going to buy an Rb25 and im not sure which would be the better engine for me to swap into an s13, the second gen r33 or r34 Neo. Im not going to be keeping it stock so im just wondering what would be better for me in the long run. Also i've heard the availability of Neo parts is a bit limited and just wondering if someone could explain further on this also. Any input is much appreciated.

[FutureFab]

I had a rb25 s1 for about 4 years. It was a very good motor to me. It never let me down. The hydro lifters are nice cuz you dont have to adjust them vs the solid lifters in neo need you to pay attention to them. The s1 has many ecu options that plug in, z32, power fc and aem are a few. Neo has differant ecu plug so ecus are limited. Pfc is available but costs more. You can retro fit r33 harness on to Neo to use more available ecu options but will require all sensors. Both are good, just depends how far you want to take it.

Stock the s1/s2 have 9 to 1 compression ratio, neo has 9.5 to 1. Neo has more snap to it when pressing accelerator. S1/2 rev to 7000 factory, neo revs to 8000 factory. Neo is fabled to have gtr rods.

[zerodameaon]

I did some research into putting a Neo head onto my S1 RB. Never mind the conflicting reports of it working, the thing that stopped me from doing it was the lack of parts available. IDK if that has changed in the last two years, but there was limited aftermarket support and what there was seemed pretty pricey in comparison to building the S1 head. I know you want stock but once parts start wearing out on a Japanese engine sometimes the stock replacement parts can cost the same as the aftermarkets.

[FutureFab]

Putting a neo head in is easy. Lefty loosey, righty tighty. Finding shims is no fun tho.

[godzillarb]

If you stay stock, neo. If you mod, go s2. Finding little parts for the neo is a nightmare.

[EnemyS15]

^^ agreed!

[Syncade]

Finding RB25 Neo parts back in the day was really difficult but it is becoming easier as the years pass.

I am selling mine (all stock) if you are interested.

[godzillarb]

The main thing I'd recommend is getting an aem ems so you can swap sensors around and "force" things to work. On an R34 neo I worked on, we had all sorts of problems getting neo sensors to work on a greddy intake manifold since the car was tuned with pfc.

[Nissanisamazing]

Yea, i have no intentions on keeping it stock and it seems like the series 1 or 2 RB would be the better choice for modding. My brother told me its even hard for him to find parts for his series 2, and like you guys said it would seem like hell to find stuff for the Neo. I have a while to even start the swap, so ill probably do a bit more research but the R33 engine just seems like the better choice for my cause. Thanks for the help.

[godzillarb]

I'm running an s2 with pfc in my daily. Haven't had any issues with parts yet. Coils went out and threw in a 300zx ignitor and some splitfires I had laying around. Worked like a charm!.

[EnemyS15]

There are an abundance of series 2 parts as there is series 1. Neo parts are limited to availability and fabbing.


Go with S1/2 Rb and call it day.

[Nissanisamazing]

I do believe i am going with the S2. Seems like the easier cheaper choice, and any issues i have my brothers already gone threw thats also a plus. So thanks everyone i really apreciate it.

[FRpilot]

Bringing a thread back (not entirely from the dead).

What parts are HARD to find for the neo engine? Are we talking gaskets and stuff or aftermarket parts? If I get a neo, I'm getting it for the head with solid lifters and most likely not going to bother with cams or anything. Are we talking about shims and stuff you have to replace or is it easier to get an s2 and do SLA conversion with tomei parts?

[S12 Drifter]

Originally Posted by FRpilot

Bringing a thread back (not entirely from the dead).

What parts are HARD to find for the neo engine? Are we talking gaskets and stuff or aftermarket parts? If I get a neo, I'm getting it for the head with solid lifters and most likely not going to bother with cams or anything. Are we talking about shims and stuff you have to replace or is it easier to get an s2 and do SLA conversion with tomei parts?

the neo has the crank collar fixed.

[badboy6686]

Originally Posted by S12 Drifter

the neo has the crank collar fixed.

This is not guaranteed, The last Neo I had the pleasure to disassemble did not have the updated crank collar.

[MADE]

I had had both engines the NEO was better hands down. The parts that were/ are to find were usually out of production on limited non common parts.

Power FC (Recently resolved as Apexi came out with a new model) You could choose another EMS before, but I was kinda limited to the PFC.
Injectors (Only a couple company made top in Top mount injectors)
Nothing in the head is interchangeable but cams were always available from Tomei,
Intake Mani is different as well and at the time Only Cockpit Tatebayashi made them pretty sure they are making knock off's now.
I got a gasket kit from Nissan parts cc so that not a problem.
To date I had no problems with my lifters on the NEO,

[FRpilot]

why is it better? is the neo head better flowing?

Seems like you can use greddy intake manifold, your choice of aftermarket fuel rail depending if you want top feed or side feed injectors, pfc.

[FutureFab]

A normal rb intake manifold will bolt onto neo head. Ports and spacing is the same on both engines. The stock manifolds are different size runners but you can make your neo run on S1 pfc/aem if you swap to S1 intake mani and sensors. I noted alot of differences with pics in the Rb Faq thread page 32.

[Miguelone]

Neos are a better engine. Parts aren't really limited at all, lifters same as 26, stock rods, same as 26. Aftermarket bottom end, same as 25. Better cams, better head flow, Just as many aftermarket intake plenums available, same hot side options. Better stock turbo(Not like that will bother you if you're not keeping it stock but still) I have an S1 25DET, I had an S2 25DE. I've worked on all 3 and 26's quite a bit and the Neo really is the best option of the lot. It's newer, it has the best bits of both worlds & parts supply isn't limited as people are making out. Maybe not as easy to find cheap plentiful ebay crap locally to you but look into shit from Japan, Aus & New Zealand, there's a lot of great gear.

[Tan-R]

Does anyone know if you can swap the vvl switch between a series 2 and a neo?