Rb26/30 Cam Choice?

[James_03]

Hey guys,

Choice between 272 cams and 8 lift, or 264 and 9 or so lift?

What would people go?

[R32Abuser]

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 July 23, 2012 by R32Abuser

[James_03]

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.

[jangles]

Can't get higher lift?

[James_03]

Yeh I can, but it's probably going to require springs and possibly retainers but, and then maybe the head clearanced as well.

If I could get away with doing just springs, then I would look at it.

[James_03]

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

[The Dan]

Cams need to match turbo/s, never just an engine combo. Unless it's N/A, then you match it to torque converter or vice versa but who gives a f**k about N/A

[The Bogan]

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]

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]

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.

[James_03]

Thanks for the input guys I appreciate it.

[discopotato03]

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]

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]

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.

[bigmikespec]

Looks good... I am amazed you made the S366 fit down there!

Have you done any power runs on dyno yet?

[James_03]

Nah no power runs yet, just had a run in tune done so far. I will complete the run in this weekend and back for a proper tune next week.

[GTR_JOEY]

A little off topic, but I'm assuming you used a low mount set to avoid bonnet clearance issues with the 30 block?

Btw the BW turbos sound bloody awesome coming on boost...

[The Bogan]

Btw the TO4Z turbo sound bloody awesome coming on boost...

Fixed

[GTR_JOEY]

Haha sounds better then a Z mark.. Stop trolling