Cam lobes explained
02-15-2010, 02:32 PM
#6
Because this is my current cam:
http://www.compcams.com/Cam_Specs/Ca...csid=1088&sb=1
and I think it is XR lobes. I want to order a bigger cam this week and looking for what's the hot lobes.
http://www.compcams.com/Cam_Specs/Ca...csid=1088&sb=1
and I think it is XR lobes. I want to order a bigger cam this week and looking for what's the hot lobes.
02-15-2010, 02:51 PM
#7
Different lobes have different ramp rates as to how fast they open/close the valves. Good for power, bad for valve springs lol.
My cam is on XE-R lobes and it runs pretty good.
Best thing to do is call a sponsor or Comp cams and talk to someone about what your wanting from the car/engine, ask about lobes and see what they say.
My cam is on XE-R lobes and it runs pretty good.
Best thing to do is call a sponsor or Comp cams and talk to someone about what your wanting from the car/engine, ask about lobes and see what they say.
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02-15-2010, 03:12 PM
#9
02-15-2010, 03:18 PM
#10
There is more to it than this but someone like PatrickG will have to explain the rest.
If you know the advertised duration (.006) of a cam you can calculate the ramp rate. To do this you take the duration @.006 and subtract it from the duration @ .050. A number of 53 or higher denotes an XE lobe or other mild lobe and a number of 49 or lower denotes an XE-R lobe or other aggressive lobe.
The discussion was about EPS lobes but the idea is the same for all lobes.
The new Hot Rod magazine has a good cam article that explains a lot too.
If you know the advertised duration (.006) of a cam you can calculate the ramp rate. To do this you take the duration @.006 and subtract it from the duration @ .050. A number of 53 or higher denotes an XE lobe or other mild lobe and a number of 49 or lower denotes an XE-R lobe or other aggressive lobe.
The discussion was about EPS lobes but the idea is the same for all lobes.
The ramp rate from .006" to .050" for the EPS lobes is 49 degrees. This is fast, but ramp rate is not the only determining factor in how spring friendly a cam is and how stable it will be at rpm. Acceleration and jerk are much more important factors and it is here where the EPS lobes are superior to the XE-R lobes. Acceleration and jerk are much more controlled with the EPS lobes vs. XE-R lobes even though they match the XE-R lobes at 49 degrees and have more lift.
11-04-2010, 07:11 PM
#15
11-04-2010, 11:05 PM
#16
guys you are making his question seem way more complicated then he's really asking.. I don't believe he wants an explanation on how ramp rates work or how to calculate them.. I believe he is asking what types are the MOST aggressive to LEAST aggressive i.e LSL LSK XER XR etc. Rank those in order for him and I think he'll have his question answered.
11-05-2010, 12:13 AM
#17
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Well, everyone is sticking to explaining comp lobes, which is great and all but I want to mention Cam Motion. Their lobes make power, and open and shut valves very quickly. They accomplish this in one way by running a smaller then normal base circle. Doing so is very common in aftermarket cams, however, with Cam Motion lobes it is more pronounced.
11-05-2010, 05:19 AM
#18
Here is an example of 3 different line of Comp lobes, the XE-R is the least aggressive and the LSL and LSK are the same, the lower number difference between the .006 and .050 lift is the least aggressive.
PHP Code:
Type Lobe# 0.006 0.050
Xtreme Energy XE-R 3722 273 224
Xtreme Energy LSL 13017 277 227
Xtreme Energy LSK 2127 277 227
