Rb30/26 Cam Selection

[danny14]

Just remember a 30 bottom end with a correct tune will absorb a lot of the lumpy idle of a 280 degree cam for the street.

However if your going 7250 rpm, stay 274 degree and lower.

The less duration, the harder it is to get a large lift without crazy ramp rates....

If you tell a cam grinder your winding 50+psi into it and spinning it a light speed and want a gigawatt of power expect something that will drive on the street like a dog, make sure you give the grinder realistic figures, specifications and expectations.

Without wanting to offend anyone here, i only listened to the cam builders, Kelford has a lot of experience and development with 30's due to Rips, Camtech also has experience with them, after meeting the owner and having a discussion with them i learned their chief engineer was involved in the development of the Bathurst GTR's camshafts and many 26/30's for street, track and drag.

One more thing to throw into the mix about large durations that you may not understand or is seldom spoken of, if its found to be a little too high in its RPM ceiling and your missing bottom end torque, its possible to advance the cams with adjustable cam gears to remove from the peak and add to lower down while your tuning it, or to move the power graph a little more down and to the left of the dyno sheet.

Talk to the engine builder and cam grinders.

If its Rob from Rips building your engine, your in very good hands for cam choice.

Also that link i gave you for the 182-E cams, have a read of what is says, then think about what you asked for, a RB30, street, track and drag......but if your engine is going to stop around 7K, you may want less duration to help the bottom end torque.

Edit, i just read that Rob advised on 272, which falls into the area we have been discussing.....

Thanks alot for that . Where did you read that rob advises on 272 's

[GTRPSI]

I didnt read it about the 272, you mentioned you had been advised this and he is building your engine, sounds correct, i did read on the big high powered builds he goes 280 and up on the UK forum but he spins these harder, 8000+.

The specs that have been suggested to me are
272.°adv,234 @1mm

Edited April 15, 2014 by GTRPSI

[danny14]

I didnt read it about the 272, you mentioned you had been advised this, sounds correct, i did read on the big high powered builds he goes 280 and up on the UK forum but he spins these harder, 8000+.

Hey man but kelford offer a 272 at like 8.0 lift there isnt much else with that duration in the 272

[GTRPSI]

182-S sounds about there....270-274 10.5 lift....noted its good on E85 if you want to boost it.....

http://www.camshaftshop.com/products.php?productid=41337

If you have a laggy turbo and want quicker spool 182-C, 272, 10mm lift.

http://www.camshaftshop.com/products.php?productid=1021#specs

The website has all the info.

Id be leaning towards the S if racing and C if needing more street drivability.

Edited April 15, 2014 by GTRPSI

[danny14]

Yeah I have to do the mods to head so lobes dont foul but !! Trying to work out if its worth it or not

[GTRPSI]

The mods are easy, its just clearancing by grinding the head to clear the lobes and not a big $ factor, most people do this themselves at home, but what you do need to factor on is if they have a smaller base circle needing thicker buckets and the valve springs they recommend.

Contact them and see what they say.

Edited April 15, 2014 by GTRPSI

[danny14]

I have been speaking to them will cost 600 nz extra aswell as 995 nz cams for the mods to head to get the bigger lift to fit

[GTRPSI]

Most likely most of the $600nz will be for the thicker buckets, and the rest for the clearancing, ask them whats in the $600.

[danny14]

Most likely most of the $600nz will be for the thicker buckets, and the rest for the clearancing, ask them whats in the $600.

this is what they told me

to make any cams with more than 9mm of lift physically fit into the cylinder head extra machining is required so the lobes do not foul on the head casting as well as extra time in machining the shims for clearancing as the higher lift cams have a smaller base circle than the lower lift ones.

You are looking at an extra $600NZD for the head machining and $12NZD per shim modification

[XKLABA]

I have 9.15mm lift ( all boltin poncams are this )in my head with no clearance issues, 9.5 is the limit with 32mm base cicle, obviously the smaller base circle the more lift so if you go to a 31mm base circle them you can go 10.5 lift, 10.4 is what I would do as a max on a stock head, before clearance becomes an issue, you just have to get thicker buckets and good spring, 9.15 is as far as I would go without springs

Just a tip, less lift less volume - more lift more volume, which do you think is going to spool a turbo faster ?

[zebra]

Please for the love of all things dont go a 272deg cam with 8mm lift.

Get something around 260 with 10+ mm

[danny14]

I have 9.15mm lift ( all boltin poncams are this )in my head with no clearance issues, 9.5 is the limit with 32mm base cicle, obviously the smaller base circle the more lift so if you go to a 31mm base circle them you can go 10.5 lift, 10.4 is what I would do as a max on a stock head, before clearance becomes an issue, you just have to get thicker buckets and good spring, 9.15 is as far as I would go without springs

Just a tip, less lift less volume - more lift more volume, which do you think is going to spool a turbo faster ?

More lift more volume faster spool ? :-)

My head wont be stock getting there springs cnc full port job on ex an inlet plus stg2 manifold port

[turboedsloth]

182-S sounds about there....270-274 10.5 lift....noted its good on E85 if you want to boost it.....

http://www.camshaftshop.com/products.php?productid=41337

If you have a laggy turbo and want quicker spool 182-C, 272, 10mm lift.

http://www.camshaftshop.com/products.php?productid=1021#specs

The website has all the info.

Id be leaning towards the S if racing and C if needing more street drivability.

I am in the middle of piecing my build and have been looking at cams.

Would the 182-c's 272 dur 10mm lift be suited to a 3.2 bottom end with gt3788 turbo?

[danny14]

I am in the middle of piecing my build and have been looking at cams.

Would the 182-c's 272 dur 10mm lift be suited to a 3.2 bottom end with gt3788 turbo?

I have been speaking with kiel from kelford cams in nz. He recomends me using the 182 -s 274 10.8 lift but there needs to be mods done to shims and buckets for clearance in the head for them to fit I was quoted 600 nz for the marching etc and 12 for each shim mod thats in nz $$ too I am going to go ahead with it I have gone this far might aswell do it once .im running a gt3582r im not sure about tour turbo . My head is costing me me 6600 nz

[Ben C34]

Suprised at turbo choice to be honest.

[danny14]

Why is that ?

[Ben C34]

Your going all out on the head, which is good, but then using an old school turbo.

[danny14]

Thats what rob is using on a few builds he is doing at the moment thinks its an excellent combo

[Ben C34]

It's certainly not a bad turbo, but if it was me doing your build, I would be looking at Forced Performance or Borg Warner turbos.

[bigmikespec]

More lift more volume faster spool ? :-)

My head wont be stock getting there springs cnc full port job on ex an inlet plus stg2 manifold port

If you are using a GT35R with the 0.8 (ish) housing and a 3.5" exhaust then you are wasting $6k... sorry. Exhaust back pressure will be too high to take advantage of cams with overlap. I would also forget about any cams that have increased duration over stock with what ever you get done.

I would have bought a gearbox with an OS Giken gearset for that money.