I just realized I rarely see any times w/ all these "great" XE Comp grinds. I hear they are good, but haven't seen any proof to it. And everybody talks about them like they are the best thing since sliced bread. I'm curious as to what kind of times you guys are running w/ your XEs, and Traditional guys, feel free to chime in here as well. I am going to the track tomorrow in Houston at HMP (4pm gates open, if you're in the area, come by and race!), I'll come back here w/ my times, as I have the CC305.

 

Time in signature

 

Cam design is always a trade off. The XE lobes are an "extreme" example of a current trend in cam design, which is steeper ramps with consequent increased duration for degree of lift. This is generally a great thing for street and street/strip cars as it allows you to run a relatively short duration cam that still has a large area under the lift curve. This tends to preserve the low end and mid-range while still making good peak power.

The downside is that these cams will not rev as high at the same spring pressures. If you have high rev setup, with huge intake ports, they may not be for you. But for most street and street/strip cars, lobes like these can work extremely well if properly selected. Blower cars love them!

Rich Krause

 

I love my 242/248

 

I'm happy with mine. I'm just a set of 3.73s away from 11.90s and if I had gone with the 230/236 then it would be even better.

 

The XE lobes come in high and low lift versions. Most XE cams I have seen people use are the low lift lobes. I am a fan of the high lift lobes.

The high lift series (pn 31xx) are very aggressive and are similar to the smaller SR lobes. In comparision, they still have more advertised duration than SR lobes with comparable duration at 0.050", so they are a little slower off the seat. But ther duration at 0.200" and lobe lift are in the same ballpark as the SR lobes. The will require just as much pressure over the nose as comparable SR lobes, though you can get away with less seat pressure. This will require premium valve train parts (pushrods, rockers, retainers, locks) just like an SR cam.

Rich Krause

 

Someone correct me if I’m wrong, but it seems like the EX cams drop hp really quickly after the peak. This leads me to think that it your shift points aren’t nailed down, your gonna run slower.

I love the midrange, throttle response, and driveability with my EX (3300 lobe) cam. On the downside, I also haven’t seen them dyno or trap higher than traditional lobe cams.

 

I did alot of searching into this a while back. There are a few exceptions but most of the heads and cam cars making big power or cars running 11s on stock heads are not using XE grinds.

 

If we only knew what lobes some of those "custom" cams had...

 

A also noticed that. I've been on this board ALOT and just from seeing people's sigs, XE cams seemed to be generally lower on the power than other cams.

I still get like though over cam specs ...

 

So the 33xx has the less agressive lobe ramp up?

 

Yeah I agree, all the fastest "off the shelf" cars are running traditional ramps. I've yet to see a stock headed 11 sec XE car. I've seen several 11 sec traditional cars. Makes me wonder to the greatness of them....hmm.

 

Numbers with CC305, on stock heads, in my sig.

The XE grinds seem to work ok. My buddy has a 383, home ported heads, and a XE 236/242. He ran a 12.0 @ 117 with a miss up top (still trying to track down the miss). They work, but they wouldn't be my first choice in cams.