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Analyze my CAM specs?


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Hi Guys,

I have a new CNC'd 26 head with the Kelfords catalogue thrown in it, good for 12+rpm.

Flow specs:

   

.450"    Intake -295cfm    Exhaust 214cfm

Now my cam specs seem a bit wild/weird? Anyone have experience with  the Kelfords split type cams?

My specs are: Intake 278mm @ 10.8mm Exhaust - 286mm - 10.80mm

Any ideas what it would be like paired with a 3.2 and a 9180?

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The duration total or at 0.050"/1.25mm? Reason I ask is that that duration and that lift do not appear on Kelford's RB26 page. But nevermind, because I guess the specs are at the same lift as other Kelford cams, which is advertised duration at 0.35mm. So your 1mm lift durations will be ~242-245°. Moderately chunky!

in which case, they will probably be great. You will benefit from a big cam on a big engine. Your flowbench numbers have ~72% of the intake flow on the exhaust, so, maybe just maybe the split duration is not all that required. But I don;t think it will hurt anything.

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23 hours ago, GTSBoy said:

The duration total or at 0.050"/1.25mm? Reason I ask is that that duration and that lift do not appear on Kelford's RB26 page. But nevermind, because I guess the specs are at the same lift as other Kelford cams, which is advertised duration at 0.35mm. So your 1mm lift durations will be ~242-245°. Moderately chunky!

in which case, they will probably be great. You will benefit from a big cam on a big engine. Your flowbench numbers have ~72% of the intake flow on the exhaust, so, maybe just maybe the split duration is not all that required. But I don;t think it will hurt anything.

Thoughts? I've attached the specs sheet.

cams.jpg

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So, the X is their custom code. That means that someone ordered those cams to those specs, or Kelfords were asked to come up with cam specs to suit engine parameters given to them.

That spec sheet is interesting in that it differs from many of Kelford's off the shelf cam sheets in what lifts are used to spec durations. Nevertheless, it is pretty close to the 1mm lift territory I came up with, so I still think it will go well.

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12 minutes ago, GTSBoy said:

So, the X is their custom code. That means that someone ordered those cams to those specs, or Kelfords were asked to come up with cam specs to suit engine parameters given to them.

That spec sheet is interesting in that it differs from many of Kelford's off the shelf cam sheets in what lifts are used to spec durations. Nevertheless, it is pretty close to the 1mm lift territory I came up with, so I still think it will go well.

Yep, sounds right.. I had my head CNC'd as well, so thats probably what it is. I just dont want a super aggressive lumpy idle and bunny hop with my triple plate in slow speeds.

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272+ degree cams will definitely have a choppy idle, but I've not seen what they're like on a ported 26 head on a really big capacity bottom end. The big capacity should help.

I've driven 290° cams on a 2JZ and it idled like a motorbike (buzzy, changeable revs, clutch chatter like a bitch from the twin plate) but it was not struggle to get it moving and it was only soft below 2000rpm (IIRC).

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