cam guru's???????

1. ## cam guru's???????

Look at this chart. Why does the torque fall way off and the hp keeps climbing????

2.

3. Because it needs more plunum volume and or more carb.

4. Hp is a function of torque and rpm.
HP= (tq x rpm) /5252
So, if tq falls less than rpm raises the hp raises. IE: More work is being done ! Force=torque and work done=hp

5.

6. Originally Posted by cfm
Hp is a function of torque and rpm.
HP= (tq x rpm) /5252
So, if tq falls less than rpm raises the hp raises. IE: More work is being done ! Force=torque and work done=hp
Exactly, the question has nothing to do with the cam.

Another way to look at it is: Torque is what a Dyno measures, It then uses the equation above ( (tq x rpm) /5252 = HP ) to calculate the work being done AKA Horsepower.

http://en.wikipedia.org/wiki/Horsepower
http://www.howstuffworks.com/horsepower.htm

7. [QUOTE=396_Ways_To_Spit;156709]Look at this chart. Why does the torque fall way off and the hp keeps climbing????
QUOTE]

Just curious, why do you ask ? Do you think the trq should not drop off ?

Using the equation posted above; if thatsame engine could some how produce the max trq # of 790 lbs ft at 8,000 rpm's it would be making 1,203hp.

It's just a function of engine dynamics.

Sleeper CP

8. I was just curious because the motors that Chris Straub has designed cams for never lookd like that...................

9. looks like a nice curve to me, look how long it holds max torque throwout the range

10. Originally Posted by 396_Ways_To_Spit
I was just curious because the motors that Chris Straub has designed cams for never lookd like that...................
I've had cam's done that have falling off the edge of the earth 200 rpm's beyound called for max hp rpm. One lost 28 hp and two other's 16 -18.(I'm assuming that's what you mean or do Chris's cam's hold trq longer) The RM 565 cam is a drag car engine designed to rev to 8,000 rpm not a jet boat or even a v-drive for that matter.

The current cam in my 565 hold's it's trq along way like that one, but not to 8,000 rpm's it's a matter of the cam, head's and intake working together:

That's over 700 lbs ft from 4,800-7,000

Sleeper CP

11. Originally Posted by 396_Ways_To_Spit
I was just curious because the motors that Chris Straub has designed cams for never lookd like that...................
#1 - most engines you'll see on the board will have dyno sheets showing say from 3k-6k or so. The chart above is 5500 -8k.

Don't let graph's fool your thinking unless you are using same exact data points. Then, overlay the graphs when comparing motors, especially similar build motors. Some intersting stuff comes out. A 'wide flat' torque isn't always what it seems to be. Sometimes it is. Looking at one graph and relying on memory for the next doesn't work too well. Been there, done that !

12. Michael,
That 565 RM combo is designed for a given rpm range. The cam selected does what they want it to do. Same as I what I do design a given combo to operate in a customers desired power range.. . .this is what is key. An engine may make 850HP at 7500 rpm but if your max rpm is going to be 6800 then you have thrown away part of your useable powerband because you cant get there.

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