Does this prove David Vizard's 128 lsa formula ?

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Not sure why 273 is beating this to death?

Get your hands dirty, grab some camshafts > and start experimenting.

This is the fun of hot rodding, finding the better or worse senarios with real life experience.

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George Jets said:
Not sure why 273 is beating this to death?

Get your hands dirty, grab some camshafts > and start experimenting.

This is the fun of hot rodding, finding the better or worse senarios with real life experience.

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You guy’s are posting on my thread, I’m not allowed to answer back?

You have to do more than swap a few cams to do the R&D necessary to prove or disprove,

Someone send me a hydraulic roller like the crate cam but on a 104 and 8 degrees less duration and I’ll tell ya how it works compared to the one that came with it :)
 
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273 said:
I tend to agree with that statement.

Are they available to us ?


It's one of the dyno results the guy uses, no one is arguing with that going tighter generally makes more mid range torque that's common knowledge, the question is does the formula get you optimal lsa and does this optimal lsa gain you 40-50 lbs-ft and get you near the 1.40 lbs-ft DV claims over the 110-114 most cams are ground on? What was the gain of this eg., like 10 lbs-ft or so 108 vs 112 most would be glad to lose 10 for driveability.

No one arguing that, like saying does more duration tend to make more hp, question is does running tighter lsa then the formula recommends are you still gaining torque? And in the eg.. The guy shows seems you will, if that is true how's the formula recommendation optimal ?
Which is the whole bases of me posting this.

Just like everyone would expect, the question isn't does tighter lsa give more torque, it's does the formula give optimal lsa and more important match the claims of being up there choosing cams like 1% of engine builders.

Like said before you could probably do worse than using the formula as a guide line.
And I like the basic idea of tighter lsa less duration for same type cam as you would normally pick.

And these aren't setup as a real test, to do that 1st you'd have to run recommended cam and a bunch of cams on either side of the lsa while keeping overlap the same, maybe in that scenario we'll se the 40-50+ gains for 1% builder type torque. But what evidence I've seen so far I'm a bit doubtful, so until then I'll take it with a grain of salt.

And the main problem with his formula is picking overlap which the next main step so you can figure out duration.
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There is never going to be an optimal LSA when all the lobes are on one cam.

If that’s what you are arguing you’ll never be happy with any math to give you a starting point. And that’s what ALL the math is. A starting point.

That’s why testing matters.
 
This thread seems to be repeating stuff bout this... the guys that think DV is wrong or don't agree with him, how bout take 2 minutes to educate us on the proper way to select a cam? (not writing this in a dicky way, would just like to know the proper way if his is wrong)
 
Newbomb Turk said:
There is never going to be an optimal LSA when all the lobes are on one cam.

If that’s what you are arguing you’ll never be happy with any math to give you a starting point. And that’s what ALL the math is. A starting point.
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I'm get that, I'm fine with it as something getting you in the ball park, I've said that over and over again. My intent is not to disprove DV, but I'm not overly seeing proof either.

I'm not the one champion it, The whole point of this thread is about the dudes video not really DV, in the video he offers what he says is proof for DV system but to me doesn't seem like prove and cast some doubts all I've trying to say.

And far as I can tell no looked at buddy's proof, there coming at me with their preconceived notions on DV. DV fans seem to take it as a personal attack and non fans are like of course it's bull ****, and everyone else is meh about the formula or we don't got anything better.
Newbomb Turk said:
That’s why testing matters.
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I agree
 
Icetech said:
This thread seems to be repeating stuff bout this... the guys that think DV is wrong or don't agree with him, how bout take 2 minutes to educate us on the proper way to select a cam? (not writing this in a dicky way, would just like to know the proper way if his is wrong)
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This thread is about the guy's video about DV system mainly about what he shows as proof.

I'm not saying DV overall concept is wrong (haven't seen anyone prove it right either) I've over and over said I generally like it but take it with a grain of salt. What I've argued is the evidence so far don't match his claims of optimal, 40-50 lbs-ft gains over conventional 110-112 lsa cams being closer to the 1% of builders that make 1.40 lbs-ft per cid etc.. No one has shown any evidence to those far as I know and if there is glad to see it.

The evidence I've seen so far basically shows every degree tighter you go you gain a bit of mid range torque, I'm sure there's a point it will stop for each engine but it probably tighter than most of us wants to go. This is basically common knowledge, this proves DV formula how?
 
273 said:
This thread is about the guy's video about DV system mainly about what he shows as proof.

I'm not saying DV overall concept is wrong (haven't seen anyone prove it right either) I've over and over said I generally like it but take it with a grain of salt. What I've argued is the evidence so far don't match his claims of optimal, 40-50 lbs-ft gains over conventional 110-112 lsa cams being closer to the 1% of builders that make 1.40 lbs-ft per cid etc.. No one has shown any evidence to those far as I know and if there is glad to see it.

The evidence I've seen so far basically shows every degree tighter you go you gain a bit of mid range torque, I'm sure there's a point it will stop for each engine but it probably tighter than most of us wants to go. This is basically common knowledge, this proves DV formula how?
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Wasn't saying you in particular, it just seems a lot of people in this thread seem to know better yet haven't shared anything to show that... Just trying to learn a bit and be productive :)
 
Icetech said:
This thread seems to be repeating stuff bout this... the guys that think DV is wrong or don't agree with him, how bout take 2 minutes to educate us on the proper way to select a cam? (not writing this in a dicky way, would just like to know the proper way if his is wrong)
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How would I go about selecting a cam, is by the trends you see from all the other builds you seen over time and how there cams respond to cid heads cr driveability etc.. And what compromises you forced to live with a whittle it down from there.
 
Icetech said:
Wasn't saying you in particular, it just seems a lot of people in this thread seem to know better yet haven't shared anything to show that... Just trying to learn a bit and be productive :)
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I get that now, I misread it :)
 
I will say though.... i saw a documentary where one of the top DV proponents spent over a year building a $15k+ stroker ford with a dv cam.. and in the end it got smoked by a nearly stock 318 built by a caveman that uses cinderblocks to deck a block...... soo.... you may be right.. (it will never not be funny)
 
Icetech said:
I will say though.... i saw a documentary where one of the top DV proponents spent over a year building a $15k+ stroker ford with a dv cam.. and in the end it got smoked by a nearly stock 318 built by a caveman that uses cinderblocks to deck a block...... soo.... you may be right.. (it will never not be funny)
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That’s bad advertising, I’m not DV fan boy, but he’s probably had a big influence on how I think about performance engines since I got all his books. I’m sure you could do a lot worse and like for him for it’s about the whole car not just the engine.

Funny thing when people recommend cams on this site don’t really see anyone using DV system.
 
273 said:
That’s bad advertising, I’m not DV fan boy, but he’s probably had a big influence on how I think about performance engines since I got all his books. I’m sure you could do a lot worse and like for him for it’s about the whole car not just the engine.

Funny thing when people recommend cams on this site don’t really see anyone using DV system.
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i will say, i did use his formula picking mine.. i never really even considered LSA before and now i know a bit.. never enough though.
 
I’m starting a 5.3 LS build and I’m using a clay smith cam… I got it off a guy who used it for testing purposes on the dyno…it was the second best of the ones he tested… good enough for me
 
67autocross said:
I’m starting a 5.3 LS build and I’m using a clay smith cam… I got it off a guy who used it for testing purposes on the dyno…it was the second best of the ones he tested… good enough for me
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What are the specs on that one?
 
273 said:
How would I go about selecting a cam, is by the trends you see from all the other builds you seen over time and how there cams respond to cid heads cr driveability etc.. And what compromises you forced to live with a whittle it down from there.
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It’s about trends, but engine building changes and one has to keep up with that. I have a blind spot there.

For example, I don’t care what you do for cam timing and exhaust and intake tuning there is no way you can take 400 plus inches and shove it through a 1.600 exhaust valve and not have what I consider a ton of exhaust duration.

And that includes killing the r/s ratio, regardless of what the rod length doesn’t matter crowd says. It does matter (actually it’s not the length of the rod that matters but rather the ratio of the length of the rod relative to the stroke).

To that end, you need math that considers bore and stroke, bore/stroke ratio, rod/stroke ratio and other seemingly minute details.

If you go to speedtalk.com and go to the engine forum you’ll see at the top of the page there is a post that says a few Horsepower Chain books left. It’s worth every penny.

You can use that math and it will get you real close. Closer than anything else I’ve found.
 
Newbomb Turk said:
It’s about trends, but engine building changes and one has to keep up with that. I have a blind spot there.

For example, I don’t care what you do for cam timing and exhaust and intake tuning there is no way you can take 400 plus inches and shove it through a 1.600 exhaust valve and not have what I consider a ton of exhaust duration.

And that includes killing the r/s ratio, regardless of what the rod length doesn’t matter crowd says. It does matter (actually it’s not the length of the rod that matters but rather the ratio of the length of the rod relative to the stroke).

To that end, you need math that considers bore and stroke, bore/stroke ratio, rod/stroke ratio and other seemingly minute details.

If you go to speedtalk.com and go to the engine forum you’ll see at the top of the page there is a post that says a few Horsepower Chain books left. It’s worth every penny.

You can use that math and it will get you real close. Closer than anything else I’ve found.
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But your talking a higher level then I feel I can reach.
 
273 said:
But your talking a higher level then I feel I can reach.
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There is a lot of science involved with engine design. That's for sure. 99% of us just use what the engineers designed. They must have had a reason for what they did and why. It could be for power or economics and ease of manufacture. It comes back to How much power do I need and can afford. The engine brain surgeons can always squeeze a few more ponies out of an engine but at what cost? If you have the know how, a machine shop, and want to experiment go for it.The rest of us will just try our best to bolt a combination of parts together that we can afford and that works. Sometimes that's the smartest thing for us to do.
 
toolmanmike said:
There is a lot of science involved with engine design. That's for sure. 99% of us just use what the engineers designed. They must have had a reason for what they did and why. It could be for power or economics and ease of manufacture. It comes back to How much power do I need and can afford. The engine brain surgeons can always squeeze a few more ponies out of an engine but at what cost? If you have the know how, a machine shop, and want to experiment go for it.The rest of us will just try our best to bolt a combination of parts together that we can afford and that works. Sometimes that's the smartest thing for us to do.
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For most of us somewhat inefficient power (1.15-1.25tq per cid) is easier and probably cheaper or at least attainable for most and only need a decent understanding of things.
 
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