Armen's car acts like a Hotcam at low rpm & a big cam at high rpm, thats the whole point of an XE cam, a duration of 230/236 on an XE cam compares to a 218/228 hotcam because the amount of time it takes go get to full lift on an XE 230/236 cam is the same amount of time as a hotcam 218/228 using a fater ramp rate, & the time it takes between you just start to open your valve at .050 lift to the time you reach full lift is what effects drivability, as soon as the valve comes off the seat, then immidiately you start reversion/loosing compression/vacume, so in that time is when you start to surge, if you can get the valve open real fast then you have full flow fast & the airflow isn't disrupted as long, because its durring the valve opening that you disrupt the airflow & end up with cam surge because over your overlap, like a 112 lsa, as your exhaust is just about to close the intake is already opening, so if you can keep the LSA but slam the exhaust shut & get the intake open real fast you won't be loosing much in the overlap & have a duration of 230 with most of it being open instead of "opening" like on a cc306, it's intake spends most of its time opening & the exhaust valve "closing" instead of being closed.

The reason GM doesn't put XE cams in our cars from the factory is because as said before, they wouldn't last 10000 kilometers with cheap valve train parts that GM provides us with in these cars, now with upgraded valve train you can go XE. Now the reason these cams fall off at high RPM is not yet known so well, but it is thought that you get valve float since the ramp up & ramp down rates are much faster leaving a lot of the work for the spring, if the valve spring isn't strong enough it won't be able to close the valve ontime before it has to open again.


Enough said, I'm still researching these XE cams, there is way more to them then just this. lets not go too much into detail.