Rb30/26 Cam Selection

[aero]

guys, i'm doing the rb30/26 conversion with the following specs:

forged bottom end

GT35/40

RB26 ported head

Greddy Plenum

I'd like to run some decent boost through it.

I'm looking at the Tomei cams. I want good responsive power across the range, not just top end, so nothing too laggy.

Am I better off going for low lift like a 9.15mm with 260 duration, or should I go for something with a little more lift?

Appreciate any recommendations

thanks

[luke gtr]

id go for the 9.15s.

drop in.

and should serve purposes well.

[XKLABA]

lift, go for lift, 260 x 10.8mm procams, or since your in Sydney run over to Unigroup and have a chat about the cams they have, I believe they have a set that are 260 x 10.8 also but with a sharper ramp rate

[GTRPSI]

Dont go too high in duration, stay around 260 for good response and drivability.

The more lift, the more flow during the duration....but the more strain on the valve train.

[r32-25t]

As above lift makes power and lower durations help with low down torque , if you keep that in mind and you'll be safe

[Piggaz]

lift, go for lift, 260 x 10.8mm procams, or since your in Sydney run over to Unigroup and have a chat about the cams they have, I believe they have a set that are 260 x 10.8 also but with a sharper ramp rate

This. They even use the OEM buckets.

[aero]

thanks guys, going to get a Tomei 260 x 10.8 or Unigroup cam

[sky30]

how much are the unigroup cams?

[Piggaz]

how much are the unigroup cams?

I forget what I paid now. They're a tad more exxy than the Jap stuff but that's because Yavuz gets them done one or two sets at a time. Both profiles use the standard buckets, so although the sticks are more expensive, you don't have the added cost of Tomei buckets for the 30mm base circle.

[danny14]

Anyone used kelford cams ? Kelford is building my heqd in nz because rob at rips is building my 30 bottem so I figured I would get it all done there and use his head guys kelford cams ..

[danny14]

The specs that have been suggested to me are

272.°adv,234 @1mm

[XKLABA]

It depends what RPM you want the engine to work in, if your happy spinning it to 10k then those cams are ok

What lift are they ?

Personally I would never use 272s on a road car, 260s max I have 250 poncams in ATM and they are quite nice alround

My advice, and although I'm just some clown on the Internet, would be get the head here and put the Unigroup cams in it

[danny14]

It depends what RPM you want the engine to work in, if your happy spinning it to 10k then those cams are ok

What lift are they ?

Personally I would never use 272s on a road car, 260s max I have 250 poncams in ATM and they are quite nice alround

My advice, and although I'm just some clown on the Internet, would be get the head here and put the Unigroup cams in it

Im using one of robs 7250 with a full cnc ported head feom kelford cams .

They have suggested the L182 -cs or b, s on this page

http://www.camshaftshop.com/products.php?categoryid=83

[XKLABA]

The Bs are a joke, [email protected]

The Ss dont give a lift WTF

There are two Cs again WTF

One of the Cs is [email protected]

The other is 272@10

None of these would be particular nice in a street car, or track car for that matter

They also don't seem to have a very sharp ramp rate

[danny14]

The Bs are a joke, [email protected]

The Ss dont give a lift WTF

There are two Cs again WTF

One of the Cs is [email protected]

The other is 272@10

None of these would be particular nice in a street car, or track car for that matter

They also don't seem to have a very sharp ramp rate

Ok well thats interesting anyone else got same views or different views on this. Kelfod are a pretty reputable company I cant see them selling me the wrong cams when they know what my application is .

[Piggaz]

I second Mick .

Why have a cam that can spin to 10,000 RPM when only revving to 7250 RPM.

Mick has 250's on his RB 30 and doesn't nose over at all.

[GTRPSI]

Depends on what the owner told the cam grinder.

We gave our 2630 engine specs to both Kelford and Camtech, both came back with the exactly same answer, 280 degrees, 11.5 lift.

All depends on what info you feed them, thats what they have to work from.

On a side note RIPS has been known to use the 182-E very successfully in their builds, 280, 10.55mm http://www.camshaftshop.com/products.php?productid=1023

We ended up going Tomie Pro cams 280 11.5mm......

Much of it is how they are degreed in and the engine setup/build to work with them, we have a acquaintance that ran 280 11.5 in his 2JZ 3.4L Stroker, dyno gave up and couldn't read at over 1200Hp on his last tune, he does not take it over 8000, run in was at 800Hp.

First tune with a smaller turbo...

Fun on the smaller turbo....

He took it to the Snowy Mountains 1000 last year with a bigger turbo, highest top speed was his at 308Kph, but no traction being rear wheel drive, a R35 GTR was on top with the quickest time.

Really does come down to what your planning to do with the engine, compression, fuel, boost levels, the list goes on.

Yep on the street, stay with less duration if response and earlier power what your aiming for.......apples for apples....

If you want to drag and have a dyno queen with lots of boost, big cam duration, if you want to actually drive the thing comfortably on the street, don't do it, listen to what others are saying here, less duration will be your friend.

Edited April 12, 2014 by GTRPSI

[danny14]

Depends on what the owner told the cam grinder.

We gave our 2630 engine specs to both Kelford and Camtech, both came back with the exactly same answer, 280 degrees, 11.5 lift.

All depends on what info you feed them, thats what they have to work from.

On a side note RIPS has been known to use the 182-E very successfully in their builds, 280, 10.55mm http://www.camshaftshop.com/products.php?productid=1023

We ended up going Tomie Pro cams 280 11.5mm......

Much of it is how they are degreed in and the engine setup/build to work with them, we have a acquaintance that ran 280 11.5 in his 2JZ 3.4L Stroker, dyno gave up and couldn't read at over 1200Hp on his last tune, he does not take it over 8000, run in was at 800Hp.

First tune with a smaller turbo...

Fun on the smaller turbo....

He took it to the Snowy Mountains 1000 last year with a bigger turbo, highest top speed was his at 308Kph, but no traction being rear wheel drive, a R35 GTR was on top with the quickest time.

Really does come down to what your planning to do with the engine, compression, fuel, boost levels, the list goes on.

Yep on the street, stay with less duration if response and earlier power what your aiming for.......apples for apples....

If you want to drag and have a dyno queen with lots of boost, big cam duration, if you want to actually drive the thing comfortably on the street, don't do it, listen to what others are saying here, less duration will be your friend.

Thanks for that info appreciated . I told them it would be driven street/track/circuit so I dont know my engine that rob is building is only the 7250 rpm 30 so im unsure on what cam to use bit muddled up

[danny14]

(Not a daily street driven sometimes track the rest of the time )

[GTRPSI]

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.....

Edited April 13, 2014 by GTRPSI