We have been puzzled by the powerbands of some new cams we are trying out. All cams are a comp ground on 4x4 Extreme Lobes.

Car 1. LS1 with a LS6 intake, ported TB, Jet-hots and x-pipe. Cam is 246/252 .615/.625 110

Car 2. 396 with 04 GTO intake and stainless works setup. Cam is 246/252 .615/.625 110

Car 3. LS1 with 6.0L heads, FAST 90/90 setup, Full Exhaust. Cam is 244/246 .610/.619 110

Car 4. 427 AFR 225s, FAST 90/90 setup, kooks and full exhaust. Cam is 256/264 .625/.625 113

All cars quit pulling around 6200 rpms. and kinda flat line all the way to 7000. Car 1 falls a little in power after 6200 because the intake size is smaller. but only drops about 15 hp between 6200 and 7000. We don't think it is valve float due to the fact that they aren't really losing hp. I am wondering why these cars aren't pulling to at least 6800 rpm. Do you think the lobes that the cams are ground on doesn't allow them to pull that high. Do you think the cars need to be tuned in Speed Density? I am very stumped as to why all cars are performing the same. Different peak numbers but graphs are very similar. Any ideas?

 

maybe exhaust ?

 

4x4 extreme lobes are meant for trucks. The power and TQ come in early and fall off sooner as compared to a car. Trucks need there power low for pulling and to get the heavier truck moving. Probablly had the truck intake in mind as well when they designed it.

 

what ICL's?

 

But several graphs I have seen of big cams on XER lobes are doing the same thing. the cams aren't as big as these due the the fact that XER lobes can only be used up to a 248 duration. The more we look at the graph the more we think it is something in the tune....we are using HP tuners but I think it is something HP tuners won't allow us to change. That is why I was wondering if we tuned it in Speed Density if it would maybe allow us to tune something we weren't able to before.
what do you mean by ICL's

 

It's the intake manifold.

 

Intake Center Line. (LSA - advance = ICL)
So for example, the 1st 3 cams are on a 110 LSA. If they all had 2* advance built in, then you would have a 110+2, giving you a 108 ICL.

 

BTW, I'd like to know what kind of torque are those cams making? whats it making at 3000 rpm?

 

Cams are not advanced. I will post the torque of my car (Car 1) later today I don't have the graphs here at home.