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Rb26/30 Cam Choice?

James_03

By James_03,
in Engines & Forced Induction

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R32Abuser Mentor

R32Abuser

Posted
Posted (edited)

Depends on what you're after....

Response or Outright power/number? For me, Im after response. In saying that, I would go the 264° / 9mm option.

What head are you using out of curiosity? RB26? What turbos etc.?

All of the above makes a big difference when selecting a suitable camshaft.

Edited by R32Abuser
James_03 Mentor

James_03

Posted
  • Author
Posted

Yep it's a recently recod rb26 head with mild porting on in/ex. Has CP rb30det specific pistons in it giving a CR of about 9:1.

Like you I am after more mid range response then all out power. Just trying to find out what would be more beneficial to the 30 bottom end, either more duration with the HKS items, or less duration and more lift with the tomei?

I have been told the tomei type B's are a good all rounder, so leaning that way.

Cheers.

The Bogan Grand Master

The Bogan

Posted
Posted

What will you be reving it to and how much of a power band do you need, mine runs to 7200 and has a good torquey power band from just over 4000 all the way to 7200, my inlet side is standard but my exhaust side has a bit more lift

From my googling and shop talk you dont want to go to big with the 30 as it is limited with its lower RPM.

James_03 Mentor

James_03

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  • Author
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Good point you make mlr. Yeah I probably won't be venturing past 7000rpm. Maybe I should just keep what's in there, it has camtech at the moment but I have nfi what thspecs. I might take another look at the rb30 power thread and see what people are doing on stockers.

What would be your recommendation Dan? You must have seen a few of these came through your workshop by now.

The Dan Grand Master

The Dan

Posted
Posted

Well going off the size, that turbo is just bigger than a Z and just smaller than a GT4094 so you would be expecting somewhere about 500hp on 20psi before 7000rpm.

I would be going with a 260-270 deg advertised cam but pick something that has a 230-240 deg @ 50 as the faster ramp rate should give you better response.

a 260 won't fall over til around 8000 I don't think so it should be bang on the mark for what you want.

discopotato03 Grand Master

discopotato03

Posted
Posted

I don't know iff your head is assembled yet but one thing with RB TC heads is that they have a little less than an ideal ratio of valve sizes as in the exhaust is a little small but not by much . Slightly oversized exhaust valves can go in with refinished exhaust valve seats and a little throat blending .

The std size works ok on a standard engine but ones with better breathing really like this mod . The old SK R33 and mine really like this mod and appear to lose nothing anywhere - on both std and 256 8.5 Tomeis . The CR is up a littke at ~ 9.3 .

You can achieve the same thing with a bit more exhaust cam but mild valve train geometry is probably more reliable long term .

I reckon if anything is slightly lacking anywhere the bigger cylinders will make it more obvious - show it up sooner rev wise .

Food for though , cheers A .

bigmikespec Veteran

bigmikespec

Posted
Posted

Turbo is a borg warner S366 with .91 A/R on a lowmount HKS manifold.

Sounds good... do you mind posting some photos showing how the S366 will fit on the low mount HKS manifold? I am using a S366 too on my new engine!

I would give all the information on the engine and head to someone like Kelford so they can grind some cams for you to your application. If you had to choose between the two you already have go with the one with higher lift.

James_03 Mentor

James_03

Posted
  • Author
Posted

Yeah I just finished building the motor just recently, still only has 500k's on it. I regret not doing a little bit more head work now, ie exhaust side before it went on. I might contemplate it later on down the track.

Here are some pics for you Mike, don't mind the shitty welds it's pretty back yard spec.

I do love the s366 but, sounds like a 51r when it spools awesome turbo's for the price.

Cheers.

post-13028-0-24617000-1343224084_thumb.jpg

post-13028-0-76115300-1343224111_thumb.jpg

post-13028-0-46090100-1343224138_thumb.jpg

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