Poncams Or Larger For Rb25/30

[stomper]

Hi all,

Just a little advice in terms of what cams would be worth running in the 25/30 build i have just started.

The head is a R33 RB25, and the intention is to disable the VCT and run adjustable cam gears. What cams would be a good option, or are the stock RB25 cams okay.

The current RB25 motor gives a little over 235kW ATW, and have saved my new SARD 850cc injectors to go in the new hybrid block.

Other parts will include:

CP forged pistons 9.0:1

1.4mm Head gasket

Forged pistons - make undecided

Adjustable cam gears

T04z or GT 3540 undecided

SARD 850cc injec

Thanks

[stomper]

Hi all,

Just a little advice in terms of what cams would be worth running in the 25/30 build i have just started.

The head is a R33 RB25, and the intention is to disable the VCT and run adjustable cam gears. What cams would be a good option, or are the stock RB25 cams okay.

The current RB25 motor gives a little over 235kW ATW, and have saved my new SARD 850cc injectors to go in the new hybrid block.

Other parts will include:

CP forged pistons 9.0:1

1.4mm Head gasket

Forged pistons - make undecided

Adjustable cam gears

T04z or GT 3540 undecided

SARD 850cc injec

Thanks

anyone got an opinion?

[Spoolup]

Depends on the power you are after and use.

For a good drivable street car with up to 400 - 450 rwhp, I would use the poncams.

anyone got an opinion?

[Cubes]

I'd match the cams to the turbo.

GT35r/T04z you really want to start looking at cams with decent lift (9mm+) with a mid 260 duration to make full use of the turbo on pump fuel.

Ideally for street gt35r/t04z a mid 260duration and 10-11mm lift but thats not easily achievable with the hydraulic head.

[Dale FZ1]

Go beyond 9mm lift and there are issues with getting valve springs that can physically fit and do the job without coil bind problems.

A good bet is to get the stock head and springs measured up so you have a known base to work from. There are good, useable cams and springs available to suit RB25 heads, but you'd likely need a 26 head if you want to be able to use some serious cams easily.

[R32 Driver]

a lil off topic

would 280 / 10.8 cams on a rb26/30 redline 7200

be to much? matched with a t51r KAI

[2BNVS]

r32driver: my mate had those cam specs on his car, biig idle lol

[shanef]

a lil off topic

would 280 / 10.8 cams on a rb26/30 redline 7200

be to much? matched with a t51r KAI

redline is too small, will need to be 8000rpm or more

[Cubes]

Why T51r and 7200rpm? :S

[NYTSKY]

A friend of mine is putting Poncams in his 25/30. Will have a power output of around 650hp.

[drgnball34]

will be interesting to see what power i can achive with my cam/turbo combo. As mentioned before, poncams 260 are the biggest the NEO head can take.

[Cubes]

Neo = solid followers.

Grab some suitable springs from performance springs and shove in a set of cams with decent lift. Decent lift and they make power so much easier on less boost with pump fuel and you don't need to ring its neck by running long duration cams to try and make the power. 8000rpm is really all you need with peak power sitting just over 7000rpm and holding nicely to 8k.

[Kranker]

on the subject of higher lift with a neo head

has anyone worked around the issue that Spool found with any lift over 9.xx mm lift, and exposed oil galleries (if my memory serves me correctly)?

[drgnball34]

on the subject of higher lift with a neo head

has anyone worked around the issue that Spool found with any lift over 9.xx mm lift, and exposed oil galleries (if my memory serves me correctly)?

intererest to know this aswell because if my cams are choking then will need to upgrade to something bigger. And 8k rpm is plenty for me.

[R32 Driver]

Why T51r and 7200rpm? :S

from what i gather

most 30s wont rev past 7200 safely

i know of one that ran 9 flat down the quater on a gt35

but when he upped his limit to 7500 he bent the crank

[2BNVS]

mine was reving to 7500 for 3 years 352rwkw no drama at all. wouldnt go more thant that though as its not needed. on a stock motor i wouldnt unless i wanted to rebuild it hehe

[Cubes]

Steve,

They don't bend cranks.

Speak to a few workshops that have built tough rb30's. Rods, pistons and a decent balancer is all that is needed.

[R32 Driver]

as far as i know

the crank bent on the dyno while increasing its rev limit

and it runs a ross balancer

most of the workshops here dun wanna know about the 26/30 (yay wa)

they either suggest a stroker or stick to the 2.6 and rev it a bit more

Im planning on

CP pistons

Spool rods

Cometic headgasket

Acl shells

crank collar

arp headstuds undecided 11mm or 12mm

arp main studs

N1 oil pump

4wd adaptor plate

ati balancer

will/wont this rev safely?

either that or i might just buy an engine from proengines/lewis engines

Edited November 9, 2008 by R32 Driver

[Cubes]

The workshops don't want to know of the 26/30 because they have no experience with them..

The cranks simply do not bend they break oil pumps so possibly a build issue due to lack of experience with the rb30's.

Speak to Rajab racing and a few of the other workshops (inc. proengines) that build serious RB's they know how to get them to hold together at high rpm. i.e grub screw the crank.

There are a few tricks to be performed its not just a matter of giving the rb30 a refresh and a good balancer then hope for the best.

[Spoolup]

My limiter is set at 8000 rpm, and I hit it regularly :-)