Jump to content
SAU Community

Recommended Posts

hey, ive done some researching and can only really find people putting neo and s1-s2 heads on rb30- 25det bottom ends etc but havent found any info on puttin an s1 -s2 rb25 turbo head on a r34 neo natro asp bottom end, now people have said that cross matching the turbo blocks with the neo heads will create low compression ratios but if my rb25de neo has a CR of 10:1 it shouldnt drop the comp that much and thus having a nice CR and the strength of the neo bottom ends? also wanna know if the different piston design in the neo will interfere with the head/valves at all?

any info much appreciated

cheers dave

the neo has approx 10cc smaller chamber. find an online comp calculator and figure it out. At a wild gyes I would say you would get around 9:1 but it definitely seems pointless , can you explain what you plan to achieve with the engine?

sorry i didnt mention that i was turboing it, all my manifolds etc wont fit the neo na head(having smaller ports etc), i have the greddy style inlet and everything on an 25/30 in another car but have a gtr head for that now and wanna use the whole 25setup on this r34 gt4, cant just slip the 25/30 in cause of 4wd and would need adapter plates etc. im just tryin to use wat i have in the shed and wanted to make sure it was going to be all good before i rip both cars apart,

yeah i saw a stag neo det and manual box for like 1800 or something like that on ebay was cheap but i dont have that money to spend at the moment and have all this shit to use anyway, i'm not to concerned about the n/a bottom end it should be up to the task, they getting 500hp on stock bottom end neo det and de's use same gtr rods and pistons are a little thicker on top and made of same shit as turbo pistons, just hoping the CR is round 9:1 that way it should in theory be very close to det spec

yeah i dont think the squirters are gunna be an issue as im not going for all out power but having a thicker crown on the n/a piston would be more prone the heat soak but again shouldnt be a real issue on mild power figures i'll have a crack at it!

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Sounds like you've got an interesting adventure ahead here with local support if you have trouble! My guess is that, unboosted, you will be OK with a small upgrade like -9. What will happen is that once the stock ECU sees more airflow than it expects it will add a heap of fuel and pull a heap of timing to be safe because it can't understand how it could get that much air without there being an issue. You will see clouds of black smoke and it won't pull hard through the midrange and top end. So, overall it will be a bit frustrating but should be OK. If you are still nervous set the base timing back 2o through the CAS, but it will be even more sluggish everywhere. As said above through...this is not my guarantee your engine won't be blown into a million pieces, leaving you looking for very hard to find parts A better idea is get a computer with logging ASAP, wire in a wide band O2 sensor and a use remote tuner. I've done multiple cars this way and while it is not as good as a specific tune on a dyno they can get it 90% right. I'd suggest if you can afford an R33 GTR these days you can afford an ECU and tune. And if you can't afford that you sure won't be able to afford the rebuild if it goes bad in the meantime,.  
    • Yeah it would be nice if someone took the time to put that sort of information together, but there are a lot of variations in looms. I think you are making this way hard for yourself if you just want to get it running....sourcing an SR20 with the right wiring will be a billion times easier than matching the RB loom to an S15 chassis. If you do end up going this way, you just need to trace every wire in the loom with a multimeter, 95% of them will go to a location you can confirm at the ECU.....and then post it up for the next person who needs it  
    • Just top it up with water, and keep a general idea of how much you added. It is normal for water to be pushed into and pulled out of the reservoir through the cap, and it should not be more than half full or it will be likely to overflow when hot. Any decent mechanic can do a pressure test of the cooling system to confirm if you have a leak. Keep in mind if it is only leaking a little and when hot it may well evaporate before you see it hit the ground
    • I'd ask the shop what they used and use that. Mixing coolants is sometimes OK, sometimes not, and you have know the details of each coolant to know whether it's a good idea or not.
    • Is it alright to top up with just another green coolant?
×
×
  • Create New...