We have measured max lift and duration @1mm (always the same method, with indicator)
Diagrams would give total picture....
Few are same as factory specs, few are close, other are far away:

ITR 11.22mm/10.53mm 236°/236°
ITR 11.35mm/10.55mm 240°/233°
xs power 11.87mm/11.57mm 254°/250°
BC3+ 11.45mm/11.87mm 248°/244°
TODA B 11.87mm/11.85mm 254°/245°
skunk Pro 1 12.4mm/11.8mm 247°/248°
skunk Pro 2 12.16mm/11.49mm 250°/257°
skunk Tuner 2 12.06mm/11.63mm 260°/258°
RM M24x 12.56mm/12.57mm 254°/252°

Unfortunately we missed measuring Skunk Tuner 1, 3 and Pro3, RM M21, M25 and M21.5ish custom cams.

 

Pro1's are bigger than Pro 2's (lift) or is that a simple typo?
Good information though.

 

No, it is not a typo. Pro2s duration is one element in making them a more potent cam than Pro1s.

 

"Surprised" is the word maybe? I dunno....just goes to show that "specs" don't mean s_it.

Thankyou for sharing

 

Hmmm.....Not what I thought they would be.

Interesting info..

 

a word of caution when comparing cams using just lift and duration specs.
if you plot an opening point, closing point, and peak lift point, you are only describing a 'triangle'. The valvemotion when graphed results in a bell shaped 'curve' and not a 'triangle'. The effectiveness of the cam is based on how well the bell shaped lift 'curve' fills the needs of the given engine. i would recommend reading the section in our catalog that talks about amax, fast ramp, and gives more insight on duration numbers. http://www.skunk2.com/catalog/

 

It is also important to note that cam duration is best compared using both seat-to-seat duration and duration @ 1mm (or .050" or whatever). This will give you an idea of how fast the valve is accelerated open. As was indicated in a previous reply, more lift does not always mean more power. A cam that accelerates a valve open quickly does not need to attain as high a peak lift because it dwells near peak lift longer. In this case dwell is equivelent to more lift.

 

Thanks the recommendation, I am aware of them.
Triangle and curve: As I said, diagram (read curve) would give total picture (Rocker arm 1.55 rate is not constant if I am not mistaken, so it is also should be applied).

Anyway, max lift is max lift.
Total duration @1mm is not exactly what we measured, but sg. very close to it.
Your cams seems far away from specs from both lift and duration prospective, TODA, Honda, BC are very close match, Rocket duration is also off.
IMO: The advertised specs should be more close to reality.

Edit: I am not against anybody, I know cam spec is one thing, real world performance is another one.

 

Shhh, now you are spilling the beans.

 

Gross specifications are at least useful for determining valvetrain in terms of coil bind. And it's interesting the differences one sees between advertised gross specs and actual.

I also doubt that Skunk2 would appreciate someone posting a high resolution Cam Doctor table that could be used to duplicate S2's profiles.

 

In this current "I don't understand how to design crap for engines, I'll just copy something that works" industry, I'm sure it's been done already. Probably within a week or 2 of the said cam's release date.

 

Lol, don't reveal Blox's R&D methods.

 

Oh, I have no doubt that that's the case. I just find it interesting that a big cam mfgr comes and comments on gross cam numbers as if they're advocating a nice hi-fi table instead of a couple general numbers. Just seems counterintuitive.

Pirate

 

Although I don't have experience with Skunk2 cams I have to give them props for giving both seat-to-seat duration and @ .050" duration. A lot of cam manufacturers only give @ .050" duration so if you are trying to compare with another cam using only their published specs you really are comparing apples with oranges.

I'm a little confused with their marketing illustrations, though, as it seems to indicate that they are saying cams don't need clearance ramps. Considering how high many 4 cylinders rev these days it seems like they would have serious issues with valve bounce when the valve slams onto it's seat. It seems they are advocating extremely high seating velocities. Can Skunk2 comment on acceleration, velocity, and jerk of their cam designs at low lift?

Also, what does "The same camshaft design technology used in F1." supposed to mean?

 

mar778c- Thats funny.

 

XS POWER CAMS...where do you get them? ebay?

 

You know, I've heard that some companies are selling direct copies of other companies cams. Has anyone actually plotted the cams lift curves against each other or are the people who say this just basing this on the specs listed in their marketing information?

 

I would never buy such a cam
the owner bought it from eBay

 

It wouldn't surprise me to learn that some companies simply buy (from the manufacturer) and rebadge others' rejects to sell, and so on down the line,... but hey, as long as I can get a new, complete valvetrain package for $500 I'll have plenty left for rebuilds!

 

so the m24x primary and secondaries are only a 10th mil apart from each other?

 

'

No thats intake and exhaust lift on vtec lobe. and its 100th

 

Here is a pic (left to right: TODA B, ITR, RM M24x, RM custom xx).
Unfortunately we did not take a photo about the tool we were using, but it is quite simple... consist of a few cam caps (bolted on to a board), a 360 degree wheel bolted on to the cam like a cam gear and a indicator (also bolted on to the board).

 

i thought the blox method for R&D was Review & Duplicate

 

i know its ebay but the specs are better than itr and other cams...has anyone tried them? was wondering cuz i have a set of cams that looks just like xs power.

 

Actually the way I understood it, blox used to OEM for skunk 2, then when their contract expired blox just started selling all the parts that they were making for skunk 2 under the blox name. A friend of mine went to high school with the owner of blox and this came from his mouth.. I have no proof, but hes a pretty reliable source.