Jump to content
SAU Community

Camshaft selection (RB25DE head/RB30 bottom)

InterC00l

By InterC00l,
in Engines & Forced Induction

 Share

Recommended Posts

InterC00l Rookie

InterC00l

Posted
Posted

Looking for cams for this engine setup. Preferably HKS's. Here in the US, it's impossible to find ANYTHING for the RB series. Are all RB series cams the same (critical dimensions, not lift/duration)? What I'm asking is, are cams for a RB20 head compatible with a 25 head? What about cams for a 26 head? Also, does the VCT affect anything as far as compatibility? I hope I'm not confusing you all too much, I'm new to the RB series. Also, if you could suggest shops that I could get these parts through, or even just part numbers to cams that will work (pref. HKS). Thanks

-InterC00l

Steve Grand Master

Steve

Posted
Posted

Hi, might be able to help with a couple of things,

HKS step one cams are compatible with NVCS, and will bolt straight up without any mods to the heads.

I am having fitted 256/8.8mm in and 264/9.0mm exh (both step one), which appears to be a good combo for the street and track, also will be fitting an adj exh cam gear to dial it in.

If you want to retain the NVCS, you cannot fit an adjustable cam gear to the inlet side.

HKS cams can be bought through www.greenline.jp at quite reasonable prices, but the us has HKS dealers, cant they order them in for you?

Sorry about part numbers, my cam boxes are in the workshop as my cams are being fitted and I am at home. I will try to remeber to get them next time I am down there.

RB26 cams are not compatible with NVCS also they are solid lifter, RB25 is hydraulic.

RB20 cams - I know nothing:).

Sydneykid Grand Master

Sydneykid

Posted
Posted

Hi Intercool, Steve covered most of it. RB20's are the same as RB25's except they don't have VVT. So you can use GTR cams in RB20's. Keep the lift under 9 mm and you won't have any trouble with using solid cams with the hydraulic lifters.

Our preferred camshafts for RB25DET are Tomei Poncams, they work very well with the VVT. There are accurately timed so we have found no advantage from using an adjustable camshaft pulley on the exhaust camshaft.

Hope that helps

InterC00l Rookie

InterC00l

Posted
  • Author
Posted

What about a solid lifter conversion? I believe Tomei makes one. Also, is it just the R32 RB25DE head that does not have VCT, or do all naturally aspirated RB25 heads lack VCT. I would rather run without the VCT.

As far as getting these in the US, I have people that can, but finding documentation on such items is dificult.

-InterC00l

Steve Grand Master

Steve

Posted
Posted

RB25DE from R32 does not have NVCS, from R33 it does.

If you want solid lifters and no NVCS, why not just use an RB26 head on your 3L bottom end. Probably easier and cheaper, plus you get the nice 6 throttle body plenum.

RB cams/NVCS specs are here: http://www.tomei-p.co.jp/_2003web-catalogu...haft-specs.html

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Duncan
      R33 GTR running -9 with no tune

      By Duncan · Posted

      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,.  
    • Duncan
      New kid on the block

      By Duncan · Posted

      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  
    • Duncan
      Coolant leak?

      By Duncan · Posted

      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
    • GTSBoy
      Coolant leak?

      By GTSBoy · Posted

      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.
    • Chupapy
      Coolant leak?

      By Chupapy · Posted

      Is it alright to top up with just another green coolant?
×
×
  • Create New...