D V Live now.

[SchmidtMotorWorks]

Wisdom comes through suffering. Aeschylus, Agamemnon

Anyone gullible enough to fall for the magic-beans claim that 2 variables is enough to spec anything about a cam will suffer.
Hopefully they will get some wisdom from that.

The narrow LSA that the 128 gimmick tends to produce might make more dyno HP than the cam that is actually optimum for the application that properly considered drivability, fuel economy, exhaust system, valve-train parts, emissions etc. But the customer will end up with a car that isn't pleasant to drive, burns eyes, and family and friends don't enjoy it either. That said, one can brag about a few HP while it sits in the garage.

When I was at Edelbrock, it was an everyday story from the tech line guys that they were frustrated that customers wanted to buy parts based on what they thought would make the most power above all else. Some of those guys had been at that job for decades and knew it was just a matter of time before they had to help the customers work through their disappointment in the drivability of the "max power combination" they chose against their advice.

[skinny z]

Wisdom comes through suffering. Aeschylus, Agamemnon

Anyone gullible enough to fall for the magic-beans claim that 2 variables is enough to spec anything about a cam will suffer.
Hopefully they will get some wisdom from that.

The narrow LSA that the 128 gimmick tends to produce might make more dyno HP than the cam that is actually optimum for the application that properly considered drivability, fuel economy, exhaust system, valve-train parts, emissions etc. But the customer will end up with a car that isn't pleasant to drive, burns eyes, and family and friends don't enjoy it either. That said, one can brag about a few HP while it sits in the garage.

When I was at Edelbrock, it was an everyday story from the tech line guys that they were frustrated that customers wanted to buy parts based on what they thought would make the most power above all else. Some of those guys had been at that job for decades and knew it was just a matter of time before they had to help the customers work through their disappointment in the drivability of the "max power combination" they chose against their advice.

What if we're building a maximum effort drag racing engine given the parts at hand but still needing a cam spec?
Do you feel there's any merit to the 128 "gimmick" then?

FTR, what Mike had suggested for a previous build and what TM had churned were similar but not the same. It wasn't until I approached Jones Cams a 2nd time with a more refined purpose (somehow this is always construed as being a street/strip deal when in reality, it's more strip than anything) that the two cams were more the same.

[SpeierRacingHeads]

If you want to listen to people tell someone what they want because it's what makes power, you should be on the end of my phone!

It's sad. One of the reasons I only do GM LS castings for the Stock and Super Stock guys. Only guys I want to deal with on those.

[SchmidtMotorWorks]

What if we're building a maximum effort drag racing engine given the parts at hand but still needing a cam spec?
Do you feel there's any merit to the 128 "gimmick" then?

No, of course not, 2 variables is not enough information to determine anything.
How do you know what the valvetrains dynamic capability is to determine the viable accelerations rates?

People with many multiples of the knowledge of gas and mechanical dynamics than DV has, have spent decades to develop 1D engine simulations.
Those simulation programs take many inputs because that is what is required to be comprehensive.

DV takes advantage of the human desire to have knowledge without doing the work required to understand.
People like to believe they know secrets.

It’s easier to fool people than to convince them that they have been fooled. Mark Twain

[skinny z]

SchmidtMotorWorks wrote:
> [quote="skinny z" post_id=928525 time=1667221283 user_id=6881]
>
> What if we're building a maximum effort drag racing engine given the parts
> at hand but still needing a cam spec?
> Do you feel there's any merit to the 128 "gimmick" then?
> [/quote]
>
> No, of course not, 2 variables is not enough information to determine
> anything.
> How do you know what the valvetrains dynamic capability is to determine the
> viable accelerations rates?
>
> People with many multiples of the knowledge of gas and mechanical dynamics
> than DV has, have spent decades to develop 1D engine simulations.
> Those simulation programs take many inputs because that is what is required
> to be comprehensive.
>
> DV takes advantage of the human desire to have knowledge without doing the
> work required to understand.
> People like to believe they know secrets.
>
> It’s easier to fool people than to convince them that they have been
> fooled. Mark Twain

Fair enough.
And thanks.
(I'll be calling Mr Jones anyway!)

[SchmidtMotorWorks]

Fair enough.
And thanks.
(I'll be calling Mr Jones anyway!)

Good decision, that aligns you with someone that has current knowledge and cares about your result.

[digger]

SchmidtMotorWorks wrote:
> Wisdom comes through suffering. Aeschylus, Agamemnon
>
> Anyone gullible enough to fall for the magic-beans claim that 2 variables
> is enough to spec anything about a cam will suffer.
> Hopefully they will get some wisdom from that.
>
> The narrow LSA that the 128 gimmick tends to produce might make more dyno
> HP than the cam that is actually optimum for the application that properly
> considered drivability, fuel economy, exhaust system, valve-train parts,
> emissions etc. But the customer will end up with a car that isn't pleasant
> to drive, burns eyes, and family and friends don't enjoy it either. That
> said, one can brag about a few HP while it sits in the garage.
>
> When I was at Edelbrock, it was an everyday story from the tech line guys
> that they were frustrated that customers wanted to buy parts based on what
> they thought would make the most power above all else. Some of those guys
> had been at that job for decades and knew it was just a matter of time
> before they had to help the customers work through their disappointment in
> the drivability of the "max power combination" they chose against
> their advice.

In fairness to DV I've only ever heard him say this "128" is for WOT performance (its a given in anycase) so those are moot points in the context

[skinny z]

digger wrote:
> SchmidtMotorWorks wrote:
> > Wisdom comes through suffering. Aeschylus, Agamemnon
> >
> > Anyone gullible enough to fall for the magic-beans claim that 2 variables
> > is enough to spec anything about a cam will suffer.
> > Hopefully they will get some wisdom from that.
> >
> > The narrow LSA that the 128 gimmick tends to produce might make more dyno
> > HP than the cam that is actually optimum for the application that properly
> > considered drivability, fuel economy, exhaust system, valve-train parts,
> > emissions etc. But the customer will end up with a car that isn't pleasant
> > to drive, burns eyes, and family and friends don't enjoy it either. That
> > said, one can brag about a few HP while it sits in the garage.
> >
> > When I was at Edelbrock, it was an everyday story from the tech line guys
> > that they were frustrated that customers wanted to buy parts based on what
> > they thought would make the most power above all else. Some of those guys
> > had been at that job for decades and knew it was just a matter of time
> > before they had to help the customers work through their disappointment in
> > the drivability of the "max power combination" they chose against
> > their advice.
>
> In fairness to DV I've only ever heard him say this "128" is for WOT
> performance (its a given in anycase) so those are moot points in the context

Just a follow up to that, I don't believe that 128 is intended for cam predicting. That would certainly be very lacking as has been pointed out.
That said, the TM program uses 128 at it's core however several other bits of engine data are needed for it to work.
But it's certainly not as thorough as has been explained here by our resident cam grinder.
Right or wrong, I'm just throwing that out there.

[SchmidtMotorWorks]

In fairness to DV I've only ever heard him say this "128" is for WOT performance (its a given in anycase) so those are moot points in the context

Wide open throttle or not, a cam design should be compatible wit the intended application, the typical DV book reader is working on street driven cars with a wide variety of exhaust and intake systems each changing the optimum LSA.

[SchmidtMotorWorks]

Just a follow up to that, I don't believe that 128 is intended for cam predicting. That would certainly be very lacking as has been pointed out.
That said, the TM program uses 128 at it's core however several other bits of engine data are needed for it to work.
But it's certainly not as thorough as has been explained here by our resident cam grinder.
Right or wrong, I'm just throwing that out there.

In DVs seminar promoting video he said that he would teach:
"the most important number when spec'ing out a cam, is it lift, duration, lobe centerline angle?
No I'll tell you the most important thing you can know about spec'ing out a cam, it's 128.
Don't bother to call the cam companies, they won't know about it"

Here is a link to the video.
https://www.youtube.com/watch?v=Y_6qBG3XknM

If that isn't misleading, nothing is.

[Tom68]

DV was very confident in the knowledge he is selling, comparing your knowledge to that that a deceased person would have come up with is more than a little weird in a sales pitch.

[Tom68]

Is there no edit option in this thread at all ?

There is no optimal intake to exhaust size that David says Smokey was looking for in that promo video, there's just compromises that have to be idealised.

Anybody that has ever looked at a 36HP or 40HP VW head will know this.

[Tom68]

EDIT OPTION ? attachment options ?

[SchmidtMotorWorks]

David called me on my personal phone to tell me that the was going to create this video.
I guess he hoped that if I posted there, it would generate views.
I did so, but most of them were deleted.
In the video he rambles incoherently about hand-filed cam masters and 3 arc cams and dyno tests from the 70's as though that is somehow relevant to modern cams.
Then goes on to lie and say that he always said 128 was only for SBCs. (watch his video, he said no such thing)
He claims that empirical data can't be wrong; obviously it can be poorly interpreted as evidenced by the improved output in engines over the past 40 years.
Then at the end he makes this absurd example of an eccentric circle being a smooth cam and it wouldn't work.
The sad thing to see is all of the comments of people that think what he says is great.

https://www.youtube.com/watch?v=6RrBUfgVxQs&t=765s

[Tom68]

Weird thread, can't "like" posts now.

David's allowed to be David, getting people to a seminar is one thing, but I'd imagine you'd come away with more questions than answers.

I posted the screenshot because it shows 59 likes for 31k views, I always like a video I view unless it's offensive, deceptive or irrelevant, don't know what other people do.