How are limitations of dwell over nose estimated?

[williamsmotowerx]

And obviously you've never designed a cam or measured one.

Those are not infinite design errors. Those graphs are of a measured cam. Those that have ground a cam or designed a cam know exactly what's going on in the "not smoothed enough" graphs

[user-23911]

It's called calculus.
To calculate velocity you measure the slope of the line ....lift vs angle.......so velocity becomes inches per degree

To calculate acceleration, you measure the slope of the line....velocity vs angle. Acceleration is inches per degree per degree.


It's got nothing at all do do with the cam design, it's all about how you measure and display the results.

When you make an error, those errors stack up so that everything afterwards is wrong.



That's WHY we learn things at school..........so that when someone makes mistakes and it's wrong.......then you KNOW it's wrong.



Otherwise we may as well just stick to using a bible.Or just stay ignorant .




BUT it's a really good example of using a computer to bullshit everyone and not even be aware of it yourself.

[Calypso]

To OP: dwell in the cam parameters or “dwell “ as if car hangs on after peak power?

[mekilljoydammit]

Acceleration is ALWAYS zero when at peak lift and zero velocity. So due to the sampling rate and lack of smoothing, that part is wrong.

Uh... I'm sorry, but did you mean that specifically for a cam dwelling at full lift? Because I know doing design work at my day job that on normal designs acceleration is not zero at peak lift, even with your point (that I agree with) about measurement errors.

[hoffman900]

Measuring used cams produces pretty noisy plots. Obviously, you want to smooth, to a point. There are different methods of smoothing as well.

It’s a very short thread, but Harold, Mike Sloe (currently at Howards), and Mike Jones replied on dwell at max lift here: http://www.speedtalk.com/forum/viewtopic.php?t=12171


Obviously, dwell at max velocity is an entirely different subject.

[strokersix]

Acceleration at peak lift is NOT zero, typically. Acceleration is zero somewhere around mid-lift.

A flat top on the lift curve might be for a lift limit rule?

[hoffman900]

Acceleration at peak lift is NOT zero, typically. Acceleration is zero somewhere around mid-lift.

A flat top on the lift curve might be for a lift limit rule?

That or in the case of a flathead, they just simply run out of room.

[user-23911]

Acceleration at peak lift is NOT zero, typically. Acceleration is zero somewhere around mid-lift.

You didn't learn calculus at school either then?


It ALWAYS is.
No exceptions.

[Stan Weiss]

No matter how many times you tell people they are wrong

No matter how times you what to talk about all of this higher math people need to know

You are the one that is wrong.

A particle of light traveling at the speed of light (constant velocity) has zero acceleration. Just like the lift on the cam can and does.

Stan

PS

The measurements from a Cam DR do have their limits. That is one reason why you can not take them an duplicate a cam.

How many dyno sheets have you seen without an smoothing that do not have peaks and valleys?

[mekilljoydammit]

Acceleration at peak lift is NOT zero, typically. Acceleration is zero somewhere around mid-lift.

You didn't learn calculus at school either then?


It ALWAYS is.
No exceptions.

Uh. Ok. Non dwell cam. What's the lift one degree either side of peak lift? Less. What's the velocity? Positive on the opening side, negative on the closing side. What's the acceleration? Negative the whole time.

You keep talking about people not learning calculus at school, but are you positive that you remember it?

[hoffman900]

Believe it or not, but he’s the only user on this site I have on “ignore”.

[user-23911]

Acceleration at peak lift is NOT zero, typically. Acceleration is zero somewhere around mid-lift.

You didn't learn calculus at school either then?


It ALWAYS is.
No exceptions.

Uh. Ok. Non dwell cam. What's the lift one degree either side of peak lift? Less. What's the velocity? Positive on the opening side, negative on the closing side. What's the acceleration? Negative the whole time.

You keep talking about people not learning calculus at school, but are you positive that you remember it?

One degree either side?

That's insufficient sampling.

Try 1/100 degree either side. All you need is 3 consecutive readings the same and the line is flat.
When there's no change in lift, velocity is zero, acceleration is also zero.
If your measurements show otherwise, your measurement method is wrong as are your results and therefore conclusion from it.

The only way it's otherwise is if you can make the lobe with a knife edge of infinitly small width which is impossible to make or to use.


A perfect example of giving a computer to a chimpanzee and getting it used as a hammer.

[digger]

Ever heard of a sin function?

Imagine the peak of the lift curve is sin, then velocity would be cos and acceleration back to sin but negative

[mekilljoydammit]

One degree either side?

That's insufficient sampling.

Try 1/100 degree either side. All you need is 3 consecutive readings the same and the line is flat.
When there's no change in lift, velocity is zero, acceleration is also zero.
If your measurements show otherwise, your measurement method is wrong as are your results and therefore conclusion from it.

The only way it's otherwise is if you can make the lobe with a knife edge of infinitly small width which is impossible to make or to use.


A perfect example of giving a computer to a chimpanzee and getting it used as a hammer.

Weren't you the one who was going on last page about measurement errors producing incorrect results?

I mean there's http://www.aetconline.com/wp-content/ed ... odbold.pdf having acceleration plots without going to zero at peak lift but probably that's from some other chimpanzee right?

[CamKing]

You didn't learn calculus at school either then?


It ALWAYS is.
No exceptions.

Uh. Ok. Non dwell cam. What's the lift one degree either side of peak lift? Less. What's the velocity? Positive on the opening side, negative on the closing side. What's the acceleration? Negative the whole time.

You keep talking about people not learning calculus at school, but are you positive that you remember it?

One degree either side?

That's insufficient sampling.

Try 1/100 degree either side. All you need is 3 consecutive readings the same and the line is flat.
When there's no change in lift, velocity is zero, acceleration is also zero.
If your measurements show otherwise, your measurement method is wrong as are your results and therefore conclusion from it.

The only way it's otherwise is if you can make the lobe with a knife edge of infinitly small width which is impossible to make or to use.


A perfect example of giving a computer to a chimpanzee and getting it used as a hammer.

Every engineer in the world is laughing their arse off at you, right now. A non-dwell cam, does not have zero acceleration at max lift.