Cam Shaft Choice For Rb30/26

[PALADN]

Hey guys here are the engine specs

Arias rb30/26 conversion pistons

PAR conrods

All ARP bolts (head/mains/rods/exhaust manafold)

High energy 8.5lt oil sump

Jun oilpump

RB26 head Ported

Garret GT3582R turbo

870cc injectors

I am now about to make a choice on cams for it. I would like some advice from anyone else that has done it. Please let me know.

Im chasing a little more power but the car is used for drift so its not a drag car.

[PALADN]

anyone help on this? lol

[NYTSKY]

Poncams will be enough,but if you want bigger you will need upgraded valve springs.

[2BNVS]

id just go with poncams, but if u wanted more go JUNs, i run 272 9.7 with jun springs

[Sydneykid]

The answer on duration depends on what RPM range you are targetting, be realistic. If you intend to use 7,000 to 9,500 rpm, something around 272 to 288 degrees would be the go. For 5,500 to 8,000 rpm, around 260 to 272 and for 4,500 to 7,500 rpm then 248 to 260 is the go. That's a simplification, but you get the idea. As for lift, once I know the effective rpm range, I then choose the highest lift I can for that duration. What valve springs you are using will also determine the maximum lift.

Cheers

Gary

[Cubes]

Drift...

As much lift as possible. 10-11mm lift and 265-272duration depending. 380-390rwkw without too much trouble with the .82.

Lift is the key. Duration simply drops the peak power roughly where you want it.

Expect it to cam over and sound extremely nice with 272's.

[Z24O]

just out of interest what are the std RB26 cam specs and rev range response?

[Cubes]

I've just came off the dyno with mine.. RB25 hydraulic head though.

Tighe cam regrinds 265in 263exh 9mm lift 221deg at 0.050".

200rwkw at 3500rpm and 256rwkw at 4000rpm @ 19psi boost then tails off quickly to 17psi where it makes 302rwkw at 6000rpm.

The cams have lost absolutely nothing down low its picked up power everywhere with its std centrelines inlet 110 LCA, Exhaust 115 LCA 112.5 LSA which = around 4-5degree's overlap.

Have yet to play with adj cam gears.

We had a few issues pushing more boost in.. It simply would not boost any more than 17psi over 5000rpm. Suspected a combination of the 1bar crappy Garrett actuator + 2" FMIC piping with a small 450x300 fmic.

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RB26 cams from memory are around 236 duration with ~8.5mm lift.

In short.. RB30's definitely respond to Cams.

[TiTAN]

Cubes, How much do the regrinds normally go for?

[bubba]

Cubes, what cams were you running before the regrind?

[Cubes]

standard r32 rb25de (240 7.8mm inlet - 232 7.3mm exhaust)

regrinds these days are $380.

[TiTAN]

noticeable in the idle?

[Cubes]

As its only running 4-5degree's overlap the idle is smooth. Its deeper and overall the exhaust is deeper and more throbby sounding.

Definitely doesn't sound like a regular rb20 or 25det.

Push in 5degree's advance to the inlet and it will lope like buggery.

I am running 20degree's static ignition which helps smooth idle when running bigger cams.

Generally richer afr's + more ignition timing will smooth an idle.

Leaner afr's and less ignition timing and it will lope.

But with mine.. ~5degree's overlap regardless if its running retarded or lean afr's it still idles smooth.

[discopotato03]

Hi Cubes , I asked in another thread about your cams but you may come here first .

From memory you used an R32 RB25DE hydraulic head so are the LCA's native to that engines cams or all RB25 cams ie 33 25DET cams ?

Very interested in these grinds - if they'll work in a 33 25DET engine .

Cheers A .

[Cubes]

The r33 rb25det lca's are different due to vct.

[SirRacer]

What are the pro's and cons of a regrind compared to a whole new billet cam?

What was the max size wise you could also go Cubes? Have been pondering a regrind of the cams i have in my engine.

Edited July 27, 2008 by SirRacer

[drgnball34]

may sound like a dumb question but could i regrind my poncams instead of folking out for another bigger pair?

[Cubes]

What are the pro's and cons of a regrind compared to a whole new billet cam?

What was the max size wise you could also go Cubes? Have been pondering a regrind of the cams i have in my engine.

I believe there is an 806C grind. Not sure on its specifics but thats where it ends.

More than a 265 duration and 9mm lift and you need valve springs, you'll need to machine the buckets.

Rip the head off spend $300 on a set of valve springs, machine the buckets and drop in a set of 10.5mm lift cams.

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I probably wouldn't bother regrinding a set of pon cams as you can still fetch good $$ for them s/h and then put a few hundred towards a new set imported from nengun or the likes.

A set of cams from Nengun are worth 800 odd delivered depending on brand.

[SirRacer]

I believe there is an 806C grind. Not sure on its specifics but thats where it ends.

More than a 265 duration and 9mm lift and you need valve springs, you'll need to machine the buckets.

Rip the head off spend $300 on a set of valve springs, machine the buckets and drop in a set of 10.5mm lift cams.

----

I probably wouldn't bother regrinding a set of pon cams as you can still fetch good $$ for them s/h and then put a few hundred towards a new set imported from nengun or the likes.

A set of cams from Nengun are worth 800 odd delivered depending on brand.

Cheers for the reply.

Ive already got some Performance Springs Valve Springs in there so they should do the trick, however have never heard anything about machining the buckets? What needs to be done here?

Can you also elaborate on LCA's. Ive never really looked into cams as i havent got my machine running yet, however need to start doing some research now as im almost there.

Edited July 27, 2008 by SirRacer

[Cubes]

Increased lift allows more power to be made at a given rev range.

Duration moves peak power higher up the rev range.

Really depends how hard you want to rev the 30. SK's recommendations are on the money.

I went for a 265 duration as Boostworx has had good results with them on the 30's with stock manifolds previously.

If you are running a nice inlet and exhaust smaller 256-260 cams will get you to 7.5-8k easily. Then tweak the inlet lca to move peak power around to where you want it.