Guru_4_hire

Here are some dyno graphs of cams

X-treme energy 268 Hydraulic flat-tappet camshafts


X-treme energy 270 Hydraulic roller


Looking at these dyno graphs makes me wonder why I would want to goto a hydraulic roller cam? They are practically the same, whats up with that?

Jack71

Those cams are almost identical except for one is a roller. The whole point of a roller is you could go with a more aggressive grind while maintaining a smooth idle and keeping vacuum.

There is minimal benefit when the grind is the same. Less friction but that won't help the numbers much. Why not step it up to a 280HR !


[Modified by Jack71, 9:19 PM 8/30/2003]

Guru_4_hire

I guess looking at the springs I have I am gonna have to stick with a flat tappet cam -- I cant afford to be machining the heads and buying new springs and retainers and stuff like that

Jack71

Yep ,plus you would need the lifters and cam button. Rollers are expensive.

Guru_4_hire

Oh well, I guess I will investigate more options

I have some aftermarket pro-topline torker heads, and I am trying to hit 400hp on 9.5 compression headers and some form of a dual plane intake(so I can get rid of this damn single plane that came on the car :cuss )

Jack71

Try an Edelbrock airgap and some 1.6 rockers may help the lift a bit too.

MotorHead

Hydraulic rollers don't seem to be that much better than flat tappet cams. I do beleive however you can run more lift with the same duration as flat tappet and in theory make the same power with less duration or more power with the same duration which everway you want to look at it.

I just bought a solid roller cam today, Comp Cams XR280, over .570 lift and 245 duration, going to put it in the 427ci small I am building :D


[Modified by MotorHead, 11:03 PM 8/30/2003]

desi

:eek:

Guru_4_hire

1.6 rockers would net me .528 lift and I dont think the springs would be happy with that

The Money Pit

I can't believe the roller cam setup is worth the cost for what little gain either.You can make incredible power with a hydraulic flat tappet cam,and if you don't mind adjusting valves,go solid.I myself am at a point where I'm happy with the power,but for the next go around may play with lobe centers to crispen up the throttle responce a bit.I figure I've got at least 4 cam changes staying with a hydraulic before I'd spend the same amount on a roller.That's quite a bit of experimentation.

Guru_4_hire

Oh well -- I am trying for 400+ on my torker cylinder heads. Might need a port job on them at some point

Langadorf

Hydraulic rollers allow you to run a more radical cam (and thus, make more power) that behaves like a smaller cam at idle. As someone mentioned earlier, it doesn't make any sense to compare hp/tq numbers on a flat tappet vs a hydraulic roller with the same grind - of course they'll be the same. Now if you compare a flat vs roller based on similar idle/low speed behavior, you'd find that the hydraulic would make alot more power. Hydraulic rollers are just the best way to get the most power out of a street ride. Why else would the OEMs use them?

joe73vette

you'll probably find the roller cam you compared makes a lot more vacuum than the flat tappet one. joe