Jump to content
SAU Community

Recommended Posts

im looking for cams for my rb25 and was just after some recomendations from people who have changed theirs.

im looking at tomei poncams (256 grind) for both exhaust and intake.

im currently running 1 bar of boost through a stock internal motor that has a gt30/40 turbo and autronic smc ecu. its making 302rwhp.

any help would be great

Link to comment
https://www.sau.com.au/forums/topic/61182-cams-for-an-rb25det/
Share on other sites

I know that a lot of guys swear by the Tomai Poncams but i was advised that the HKS 256 IN and 264EX are a little more powerful and still retain the VVT. I went the HKS route and after a minor hickup being sent the wrong HKS EXH Cam from Japan with the wrong CAS fitting (R34 CAS), I must say i am very happy now and the car is making good power around 260kw at the rear wheels.

Ian

R32, R33 or R34.

The Tomei Poncams are designed to work perfectly with the single stage VVT in the R33 and the constantly variable in the R34.

The 260 degrees ones are often spoken about as the best to buy.

That's what I have my eyes on to answer the question once and for all about the power gains on a stock turbo.

BASS OUT

fresh: are you serious?!

cams and head gasket is my next move too, SK backs the 260 poncams strongly, so thats a good indication.

Ive also heard to go HKS 256in and 264 ex. What is the advantage of doing this as opposed to 260in and ex?? Can anyone say which route is better?!

fresh: are you serious?!

cams are my next move too, SK backs the 260 poncams strongly, so thats a good indication.

Ive also heard to go HKS 256in and 264 ex. What is the advantage of doing this as opposed to 260in and ex?? Can anyone say which route is better?!

Bass, how much do you love your buddy club P1s!? I just put a set on, great rims, bargain price.

SK, what stops us from throwing in a solid setup to replace the hydraulic?  As with my old torrie we simply through in a solid profile and solid lifters and ditched the hydraulic stuff!

You have to change everything, valves, springs, followers, seats, guides, retainers and collets. They are all different dimensions to allow for the extra thickness required for the hydraulic followers.

Last time I added it up, it was much cheaper to buy an RB26 top end.:D

You have to change everything, valves, springs, followers, seats, guides, retainers and collets.  They are all different dimensions to allow for the extra thickness required for the hydraulic followers.

Last time I added it up, it was much cheaper to buy an RB26 top end.:D

So wouldnt this apply to the GTR cams in a RB20/25... = cant be done without changing all that?

So wouldnt this apply to the GTR cams in a RB20/25... = cant be done without changing all that?

Some explanation required............

RB25's have VVT and RB26's don't.

But RB20's don't have VVT, so you CAN use RB26 cams in an RB20.

But that wasn't the question....

The question was can you simply swap over the followers from hydraulic to solid

And the answer was no, you have to swap everything.

Hope that clarifies:cheers:

couple more things SK, when adding a set of poncams, im guessing you want to use new lifters too?  and how are original 1994 stock valve springs going to fare, is it wise to throw some new springs in while your there?

thanks!

Personally I am not a fan of standard RB vlave springs, even new they are a bit soft for my liking. That said their quality is OK, they don't seem to soften off much. Poncams are designed to work with standard everything else, so I haven't heard of anyone with a problem.:rofl:

Hi Guys,

I have a question on this too. I am ooking at 256 degree/8.8mm lift HKS cams IN & Exh. Is it better to run a 264/9 Exh cam with 256/8.8 In? to run with a GT30R turbo.

Will this also require new springs?

Thanks

Hi Guys,

I have a question on this too. I am ooking at 256 degree/8.8mm lift HKS cams IN & Exh. Is it better to run a 264/9 Exh cam with 256/8.8 In? to run with a GT30R turbo.

Will this also require new springs?

Thanks

It's fine to run 256/8.8mm lift IN and 264/9.0mm lift EX. Thats the way i have my R33 GTS-t setup. 264/ 9.0mm EX still retains VVT. When you install them make sure you coat all the journals and bearings with "mollybond" yellow tube, and rev to constant 2000 RPM for 15 minuites to break in the cams. It's not necessary to install new springs with these cams.

Ian

It's fine to run 256/8.8mm lift IN and 264/9.0mm lift EX. Thats the way i have my R33 GTS-t setup. 264/ 9.0mm EX still retains VVT. When you install them make sure you coat all the journals and bearings with "mollybond" yellow tube, and rev to constant 2000 RPM for 15 minuites to break in the cams. It's not necessary to install new springs with these cams.

Ian

Cool thanks for that!! :cheers:

Looks like I will follow that route then :) The rev limiter on mine has been removed. Is it a safer option to install new sturdier springs to allow higher revs? Is there anything else that needs to be done to allow higher revs safely? Not astromonomical revs...just a bit higher. It seems to rev over 8500 comfortably without valve bounce. I was told that it had internal work done on it when i bought it, but someone else listened to the exhaust note and said that it still had standard cams.

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

    • Hi. Sry iam not a mechanic and iam not at the car atm so i dont know 100% but they told they measure those and even try to change those. AFM they have two. Coils are new a they have my old one too. Plugs too. ECU...we have 25 NEO stock and Nistune 25 NEO.   But i dont know if any one those could be the problem and why/if/what can cause this, Only thing they did not check is fuel...but that walbro 255 is new(like 1,5 years)... That fuel pressure gauge idk...but i let them know Any suggestions?   EDIT: how can they know if it is like you say he ECU pull power when it reaches a specific boost level that is too high? Tha car has boost controler
    • Can you clarify what you mean by boost cut, do you mean it misfires both when under load (driving) and when stationary and out of gear? Or does the ECU pull power when it reaches a specific boost level that is too high (boost control issue)? Does it occur at idle with no throttle? When you say "the ECU is OK", what ECU is it and why do you think it is OK? Have you used the NEO ECU, and if so do you have a MAP sensor attached? Same for the AFM, why do you think it is OK? Do you have any way to put a fuel pressure gauge on it (even just a mechanical one between the fuel filter and fuel rail)?
    • Hi.. Just another problem. So maybe you can help. I(my mechanic) done swap from my RB20DE NEO to RB25DET NEO. Everything is OK but we have a boost cut. Coils/Plugs are ok...AFM is ok. ECU is ok. I have Walbro 255 but it "changed" sound few months ago(you can hear it ouside) you did not hear that when it was new(maybe faulty?) Sooo...what now? What can cause this boost cut? It is even when you standing still...
×
×
  • Create New...