Cam Lobe Design

[Stan Weiss]

I don't design cams. I do look at Cam Dr / Audie data. In this video Daniel Powell talks about .00033 as about max acceleration and the problem with this cam other than the noise is .00038 max acceleration.I don't own an Audie system. I do have a report from someone's Audie system for a BTR Stage 2 cam which shows Peak Open Acc. 0.000379. What have others seen?



Stan


This is a poor screen capture of the Erson cam that Eric used with his LS Cam Challenge engine . Which shows Peak Open Acc. 0.000384

[Stan Weiss]

I do have some old CamDr files, but I always look at them in crank degrees / numbers. I just changed this one, a Crane Blueprint version of the Pontiac Ram Air IV cam so that I could do cam numbers like Audie. The raw data has a huge amount of noise, but I was surprised at the Peak Opening Acceleration for a cam this old.

Stan

[Stan Weiss]

I see some people have shown some interest although no one has replied. I also posted this over on Speed Talk.

This is what Mike Jones / Jones Cam Designs had to say.

Looking at cam acceleration is meaningless, without knowing the rocker ratio. A cam designed for a 1.5 rocker, can get away with a higher cam acceleration, than a cam designed for a 1.7 rocker. It's valve acceleration he should be looking at.

as for max cam acceleration, I looked at one of my most aggressive Pro-Stock profiles(277@.050", .538" Lobe Lift).
On that profile, max accel is .000439
Our winningest Dirt Latemodel Intake profile had a max accel of .000486
The cam that powers the worlds fasted LT1-Gen5, has a max accel of .000405
On our Buick V6 Indy cam that set the record in 1992, accel was .000312

Here's some other people's cams I have checked
AMG: .001060
Brayton: .000417
Bullet: .000381
Comp: .000423
Comp: .000352
Comp: .000356
Musi: .000440
Musi: .000413
Murcury Marine: .000519
Schrick: .000522

These are all Cam accel, and don't tell you anything, without the rocker ratios
The 2 highest(AMG and Schrick) are both overhead bucket follower type cams, so they have no rocker ratio to multiply by. Their cam acceleration is their valve acceleration.

Stan

[Stan Weiss]

One of the things that is done on stocker cams is having the valve "dwell" at max lift. This is a velocity curve from an aftermarket manufacture, for what is called an exact copy of the Pontiac 744 cam. This cam was used in production Pontiac cars. You can tell a dwell cam because you have an area of horizontal / constant velocity over the nose. Does anyone know of any other OEM production cam that has dwell?


Stan