Rule of Thumb Accuracy

[SchmidtMotorWorks]

I know what the cam companies know about their products. I also know they want to sell what they have that makes the highest profit margin.


In your hippie world that just doesn't happen.

So wide LSA are more profitable than narrow LSA?

[GARY C]

I know what the cam companies know about their products. I also know they want to sell what they have that makes the highest profit margin.


In your hippie world that just doesn't happen.

So wide LSA are more profitable than narrow LSA?

Come on... whats more profitable?
Mass producing a bunch of generic cams that will work or grinding each one for it's intended application?

Plus if you get it right the first time then you can't get them to buy 3 more to test.

I thought you knew about marketing?

[BigBro74]

..Let that's just it. There is NO de facto LSA. And it damn sure isn't 110 like Comp has used to kill performance through advertising. It's stupid.

The cynic's postulate is that Comp and others go wide on the LSA to save customers from themselves, as they indulge in a lemming-like rush to the bottom of the page for the cam they think they need.

Exactly.

But what would a cam company know about marketing their products?

Jon- you make Gary’s point! The marketing often worked better than the cams that kids (like me) (with no money) put in their 8:1 350 engines - and until I read a book by the OP I couldn’t figure out why it didn’t make good power. It was okay. But meh.
The knowledge no matter how rudimentary was a good leg up!

[SchmidtMotorWorks]

Jon- you make Gary’s point! The marketing often worked better than the cams that kids (like me) (with no money) put in their 8:1 350 engines - and until I read a book by the OP I couldn’t figure out why it didn’t make good power. It was okay. But meh.
The knowledge no matter how rudimentary was a good leg up!

It makes mine, they understand what will make their customers happy by their criteria, not yours.

You have different taste that the main stream customer.

The main stream customer would not like your cam.

That is what I have said from the beginning; tastes differ.

[GARY C]

The cynic's postulate is that Comp and others go wide on the LSA to save customers from themselves, as they indulge in a lemming-like rush to the bottom of the page for the cam they think they need.

Exactly.

But what would a cam company know about marketing their products?

Jon- you make Gary’s point! The marketing often worked better than the cams that kids (like me) (with no money) put in their 8:1 350 engines - and until I read a book by the OP I couldn’t figure out why it didn’t make good power. It was okay. But meh.
The knowledge no matter how rudimentary was a good leg up!

I still remember when you couldn't run a dirt track cam in a drag car.

[user-23911]

Nor can you run an N/A cam in a turbo car........but I do.

[BigBro74]

Jon- you make Gary’s point! The marketing often worked better than the cams that kids (like me) (with no money) put in their 8:1 350 engines - and until I read a book by the OP I couldn’t figure out why it didn’t make good power. It was okay. But meh.
The knowledge no matter how rudimentary was a good leg up!

It makes mine, they understand what will make their customers happy by their criteria, not yours.

You have different taste that the main stream customer.

The main stream customer would not like your cam.

That is what I have said from the beginning; tastes differ.

What you are saying is may be true but how am I to discern whether I am a mainstream customer or not if I have no knowledge of camshaft attributes??

Your way is vital to an OEM auto manufacturer but detrimental, time consuming and wasteful to anyone making an attempt to modify an existing (60 year old) engine platform.

[GARY C]

Nor can you run an N/A cam in a turbo car........but I do.

Yes, the info sheet I got from DV in relation to Cam Master and Turbo cams recommended trying to build the system where the pressures would work with a N/A cam or as close as possible and they would usually start with a cam that was close and then fine tune it based on the pressure differential of inlet vs outlet. This was late 80's early 90's so I am sure tech has changed some with modern day components.

[SchmidtMotorWorks]

What you are saying is may be true but how am I to discern whether I am a mainstream customer or not if I have no knowledge of camshaft attributes??

Your way is vital to an OEM auto manufacturer but detrimental, time consuming and wasteful to anyone making an attempt to modify an existing (60 year old) engine platform.

If you don't know, you are a main stream customer.

By the time you do know that you want more performance but don't know to accomplish it, I would prefer to see people develop their minds with real science and become smarter.
That makes fewer people with cars that they are not smart enough to handle, fewer hospital and funeral visits.

[GARY C]

What you are saying is may be true but how am I to discern whether I am a mainstream customer or not if I have no knowledge of camshaft attributes??

Your way is vital to an OEM auto manufacturer but detrimental, time consuming and wasteful to anyone making an attempt to modify an existing (60 year old) engine platform.

If you don't know, you are a main stream customer.

By the time you do know that you want more performance but don't know to accomplish it, I would prefer to see people develop their minds with real science and become smarter.
That makes fewer people with cars that they are not smart enough to handle, fewer hospital and funeral visits.

Unlike the Pro Cars that blow up, split in half, crash into the wall and maybe take out 20 others with it?

[SchmidtMotorWorks]

What you are saying is may be true but how am I to discern whether I am a mainstream customer or not if I have no knowledge of camshaft attributes??

Your way is vital to an OEM auto manufacturer but detrimental, time consuming and wasteful to anyone making an attempt to modify an existing (60 year old) engine platform.

If you don't know, you are a main stream customer.

By the time you do know that you want more performance but don't know to accomplish it, I would prefer to see people develop their minds with real science and become smarter.
That makes fewer people with cars that they are not smart enough to handle, fewer hospital and funeral visits.

Unlike the Pro Cars that blow up, split in half, crash into the wall and maybe take out 20 others with it?

Sorry, you didn't understand the point.

[BigBro74]

Real science....... what, put the 268H in the large hadron collider and see if it changes the lobe center angle so it runs better

[statsystems]

If you don't know, you are a main stream customer.

By the time you do know that you want more performance but don't know to accomplish it, I would prefer to see people develop their minds with real science and become smarter.
That makes fewer people with cars that they are not smart enough to handle, fewer hospital and funeral visits.

Unlike the Pro Cars that blow up, split in half, crash into the wall and maybe take out 20 others with it?

Sorry, you didn't understand the point.

As an engine builder the LAST thing I want is a customer who THINKS he knows what he's doing because he listened to someone like you. I send them down the road and let them be some other builders nightmare.

[statsystems]

Real science....... what, put the 268H in the large hadron collider and see if it changes the lobe center angle so it runs better

You see when you point out to Jon that you are a normal customer he say you aren't. He is a contrarian of biblical proportions.

[digger]

this is from another forum posted by David on about the 4th page. it pertains to the methodology used.


https://www.pistonheads.com/gassing/top ... 103886&i=0


"Firstly I get on the dyno and test – and test – and test to an almost unbelievable extent. During those tests I change one factor (but without losing the possible influences of other factors) and retest then another and retest. The bulk of the LCA computations that I have developed for my Cam Master program relates to flow Vs cubic inches with the valve size only in the equation for the determination of velocity both at the seats and in the ports and it’s effect on through-flow during overlap.

I must admit I have not fully comprehended DB’s theory on why the valve diameter and displacement have nothing to do with the LCA. That said I can tell you all that the bulk of the LCA determination testing was done on SB Chevy’s, BB Chevys, SB Fords and Pinto engines (Plus anomalies such as the A and B series engines). For the SB Chevy’s I ran a variety of displacements from about 300 inches (5 Litres) to 434 inches (7.1 Litres) but mostly with engines from 306 inches to 406, with heads on having intake valves from 1.84 to 2.125 in diameter. Also I tested with at least 3 CR differences in each displacement of short block. For the smaller displacement engines testing with the higher CR was plagued with the high piston crown causing a potential bad burn (although I did resolve that within reason). That usually involved shaving the heads to the point they had only a minimal life so a perfectly good set of factory ported heads went down the toilet in an hour or so of running. But that’s life.

Along with the displacement Vs valve tests intake valve acceleration scans were done by virtue of a special set of adjustable ratio rockers. (1.45 -1.68). This and one of the early Jesel belt drives meant I had at least a fair number of tests that could be done without tearing the test engine down. So to sum up this barrage of tests we had the following test parameters.

Variables considered:-
Test 3 - 5 cams with LCA’s from 114 to 102 in at least 3 displacements and 3 intake valve sizes.
Test as per above with at least 2 longer duration (single and dual pattern) cams again with 3 - 5 LCA’s.
Test each of above with at least 3 CR’s.
Test each of above with at least 3 rocker ratio’s.
Test most of above with three different rod lengths (5.56, 5.85 and 6.125)

Non Variables:- Engine was equipped with a good exhaust system having 1-5/8th primary’s 33 inches average length and 12 inch X 3 inch secondary.
Intake was a good single plane 4 barrel setup using a Braswell carb that had good booster signal and about 820 cfm of flow.

Essentially all the data and effect curves developed made the assumption that both the intake and exhaust system were effectively functional. That was because I would not be running any of my engines with a poor intake or exhaust.

In all, on the SB Chevy alone, these tests amounted to a little over 8000 saved and useful dyno pulls."



i personally could see a full street exhaust and dual plane adding a shift to results