LSA for daily
11-28-2017, 07:06 PM
#41
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Y=1/x as x-->0...
Last edited by Darth_V8r; 11-29-2017 at 10:24 AM.
11-29-2017, 10:12 AM
#43
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Valve Overlap Requirement = DD vs WOT % HI ALL, the Air Flow through the engine MUST go in ONE direction, UNLIKE the above posters !
I will use MY method for Camshaft Specification.
I ask FIRST the mode of engine operation DD/TT (Day Driver/Trophy Truck)
The DD = 90% Throttled Operation AND 10% WOT
The TT = 10% Throttled Operation AND 90% WOT
The next question is where the customer wants Maximum Torque to occur.
UNDERSTAND when the engine is throttled the exhaust pressure is GREATER than the intake pressure causing Internal EGR with the sound of "chop" heard in the exhaust pipe.
This effect is witnessed by the ear on the bench dyno/rolling road AND the "chop" will stop when the throttle is opened even at LOW RPM.
We need high overlap to make WOT power OR low overlap to make fuel consumption low when the engine is throttled.
The best thing, NOT stated above, IS "tech" on head flow, LOW LIFT FLOW.
Good Low Lift Flow (Hendrick Head) would allow for Wider Lobe Centers AND good power.
My cam specification for the OP :
A set of heads PORTED for BEST Low Lift Flow.
A camshaft (DD) of 226/232 .580"/.560" 116 C/L
As for Infinity = Mass of the Universe is 10*55 power in Grams. (Infinity DOES NOT EXIST)
Lance
I will use MY method for Camshaft Specification.
I ask FIRST the mode of engine operation DD/TT (Day Driver/Trophy Truck)
The DD = 90% Throttled Operation AND 10% WOT
The TT = 10% Throttled Operation AND 90% WOT
The next question is where the customer wants Maximum Torque to occur.
UNDERSTAND when the engine is throttled the exhaust pressure is GREATER than the intake pressure causing Internal EGR with the sound of "chop" heard in the exhaust pipe.
This effect is witnessed by the ear on the bench dyno/rolling road AND the "chop" will stop when the throttle is opened even at LOW RPM.
We need high overlap to make WOT power OR low overlap to make fuel consumption low when the engine is throttled.
The best thing, NOT stated above, IS "tech" on head flow, LOW LIFT FLOW.
Good Low Lift Flow (Hendrick Head) would allow for Wider Lobe Centers AND good power.
My cam specification for the OP :
A set of heads PORTED for BEST Low Lift Flow.
A camshaft (DD) of 226/232 .580"/.560" 116 C/L
As for Infinity = Mass of the Universe is 10*55 power in Grams. (Infinity DOES NOT EXIST)
Lance
11-29-2017, 11:50 AM
#45
TECH Senior Member
11-29-2017, 12:24 PM
#46
10 Second Club
Not everyone is a cam guru, or has a cam card. If you have two identical cams but the LSA is different it gives you an indication on how they're going to differ.
11-29-2017, 12:30 PM
#47
TECH Senior Member
Right! To put it another way, the LSA in itself is not the critical spec, but it DOES help me get what IS, OVERLAP!
11-29-2017, 02:08 PM
#48
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I sorta look at it like short-hand notation.
For example, when you say 383, there are lot's of ways to get to 383, but most people assume 3.9" bore and 4" stroke. Or a 402 as 4" bore and 4" stroke. Or a 427 is naturally assumed to be 4.125 x 4.000. Now, the actual bore and stroke are more important than the displacement, but it's faster to just type 383 or 427.
Similarly with cam spec, You can write "227/235-112+3" OR you can write: "IVC=42.5 ABDC, EVO = 52.5 BBDC, IVO = 4.5 BTDC, EVC = 2.5 ATDC."
Both say exactly the same thing. So, to me, LSA doesn't really matter, except as part of the shorthand notation for describing the valve events. I'll probably get the same youtube video posted at me LOL, but that's OK.
So, to me the answer to the OP's question 'What LSA...?" really is "Depends on your durations...."
Very well said. I've tried to describe this as a "vacuum leak at the valves", but basically, you've got air going into the intake from somewhere it is not supposed to, which is why larger overlap cams chop. Also why when someone asks for a cheap way to make the idle choppy, tell them to disconnect a vacuum line.
OP, I doubt you will get a better answer than this^^^. I would advance it 4 degrees so the intake centerline is 112 and intake valve closes at 45 vs 49.
For example, when you say 383, there are lot's of ways to get to 383, but most people assume 3.9" bore and 4" stroke. Or a 402 as 4" bore and 4" stroke. Or a 427 is naturally assumed to be 4.125 x 4.000. Now, the actual bore and stroke are more important than the displacement, but it's faster to just type 383 or 427.
Similarly with cam spec, You can write "227/235-112+3" OR you can write: "IVC=42.5 ABDC, EVO = 52.5 BBDC, IVO = 4.5 BTDC, EVC = 2.5 ATDC."
Both say exactly the same thing. So, to me, LSA doesn't really matter, except as part of the shorthand notation for describing the valve events. I'll probably get the same youtube video posted at me LOL, but that's OK.
So, to me the answer to the OP's question 'What LSA...?" really is "Depends on your durations...."
UNDERSTAND when the engine is throttled the exhaust pressure is GREATER than the intake pressure causing Internal EGR with the sound of "chop" heard in the exhaust pipe.
This effect is witnessed by the ear on the bench dyno/rolling road AND the "chop" will stop when the throttle is opened even at LOW RPM.
This effect is witnessed by the ear on the bench dyno/rolling road AND the "chop" will stop when the throttle is opened even at LOW RPM.
A set of heads PORTED for BEST Low Lift Flow.
A camshaft (DD) of 226/232 .580"/.560" 116 C/L
A camshaft (DD) of 226/232 .580"/.560" 116 C/L
11-29-2017, 02:41 PM
#49
I sorta look at it like short-hand notation.
For example, when you say 383, there are lot's of ways to get to 383, but most people assume 3.9" bore and 4" stroke. Or a 402 as 4" bore and 4" stroke. Or a 427 is naturally assumed to be 4.125 x 4.000. Now, the actual bore and stroke are more important than the displacement, but it's faster to just type 383 or 427.
Similarly with cam spec, You can write "227/235-112+3" OR you can write: "IVC=42.5 ABDC, EVO = 52.5 BBDC, IVO = 4.5 BTDC, EVC = 2.5 ATDC."
Both say exactly the same thing. So, to me, LSA doesn't really matter, except as part of the shorthand notation for describing the valve events. I'll probably get the same youtube video posted at me LOL, but that's OK.
So, to me the answer to the OP's question 'What LSA...?" really is "Depends on your durations...."
Very well said. I've tried to describe this as a "vacuum leak at the valves", but basically, you've got air going into the intake from somewhere it is not supposed to, which is why larger overlap cams chop. Also why when someone asks for a cheap way to make the idle choppy, tell them to disconnect a vacuum line.
OP, I doubt you will get a better answer than this^^^. I would advance it 4 degrees so the intake centerline is 112 and intake valve closes at 45 vs 49.
For example, when you say 383, there are lot's of ways to get to 383, but most people assume 3.9" bore and 4" stroke. Or a 402 as 4" bore and 4" stroke. Or a 427 is naturally assumed to be 4.125 x 4.000. Now, the actual bore and stroke are more important than the displacement, but it's faster to just type 383 or 427.
Similarly with cam spec, You can write "227/235-112+3" OR you can write: "IVC=42.5 ABDC, EVO = 52.5 BBDC, IVO = 4.5 BTDC, EVC = 2.5 ATDC."
Both say exactly the same thing. So, to me, LSA doesn't really matter, except as part of the shorthand notation for describing the valve events. I'll probably get the same youtube video posted at me LOL, but that's OK.
So, to me the answer to the OP's question 'What LSA...?" really is "Depends on your durations...."
Very well said. I've tried to describe this as a "vacuum leak at the valves", but basically, you've got air going into the intake from somewhere it is not supposed to, which is why larger overlap cams chop. Also why when someone asks for a cheap way to make the idle choppy, tell them to disconnect a vacuum line.
OP, I doubt you will get a better answer than this^^^. I would advance it 4 degrees so the intake centerline is 112 and intake valve closes at 45 vs 49.
That video I posted was for kingtalon's posts.
11-29-2017, 03:23 PM
#50
TECH Senior Member
11-29-2017, 07:36 PM
#51
This guy gets it. As x approaches zero what happens to the whole equation? The whole thing will blow up to infinity as x becomes infinitesimally small.
Likewise what would happen if x approached infinity, the whole equation would go to zero. Equations like this, and others, help explain phenomenon where regular trigonometric or pre-calculus type equations are either less exact, or much more cumbersome to work with.
y=1/x is a calc-1 equation. Calc2 deals with some whole, solid objects, like if I wanted to program a machine to cut a washer out of a piece of metal I would use calc2, there is some integration around an axis to get whole 3dimentional areas.
Beyond calc2 of course is calc3 and differential equations, which I suppose leads us into kinetics, multiple moving particles, cross products and rotating bodies in long-impossible to memorize equations. These are necessary for mechanical engineering (like if you wanted to become a civil engineer, just to start down the pathway you would want calc3 + differentials before dynamics, statics, etc...). I am pretty sure even some of the statics (non-moving structures which do not bend or break, a prequel to strength of materials) use vector calculus which requires partial differentials.
It is fun, but challenging, speaking of which I have to study...
Likewise what would happen if x approached infinity, the whole equation would go to zero. Equations like this, and others, help explain phenomenon where regular trigonometric or pre-calculus type equations are either less exact, or much more cumbersome to work with.
y=1/x is a calc-1 equation. Calc2 deals with some whole, solid objects, like if I wanted to program a machine to cut a washer out of a piece of metal I would use calc2, there is some integration around an axis to get whole 3dimentional areas.
Beyond calc2 of course is calc3 and differential equations, which I suppose leads us into kinetics, multiple moving particles, cross products and rotating bodies in long-impossible to memorize equations. These are necessary for mechanical engineering (like if you wanted to become a civil engineer, just to start down the pathway you would want calc3 + differentials before dynamics, statics, etc...). I am pretty sure even some of the statics (non-moving structures which do not bend or break, a prequel to strength of materials) use vector calculus which requires partial differentials.
It is fun, but challenging, speaking of which I have to study...
Last edited by kingtal0n; 11-29-2017 at 07:42 PM.
11-29-2017, 10:52 PM
#52
10 Second Club
This guy gets it. As x approaches zero what happens to the whole equation? The whole thing will blow up to infinity as x becomes infinitesimally small.
Likewise what would happen if x approached infinity, the whole equation would go to zero. Equations like this, and others, help explain phenomenon where regular trigonometric or pre-calculus type equations are either less exact, or much more cumbersome to work with.
y=1/x is a calc-1 equation. Calc2 deals with some whole, solid objects, like if I wanted to program a machine to cut a washer out of a piece of metal I would use calc2, there is some integration around an axis to get whole 3dimentional areas.
Beyond calc2 of course is calc3 and differential equations, which I suppose leads us into kinetics, multiple moving particles, cross products and rotating bodies in long-impossible to memorize equations. These are necessary for mechanical engineering (like if you wanted to become a civil engineer, just to start down the pathway you would want calc3 + differentials before dynamics, statics, etc...). I am pretty sure even some of the statics (non-moving structures which do not bend or break, a prequel to strength of materials) use vector calculus which requires partial differentials.
It is fun, but challenging, speaking of which I have to study...
Likewise what would happen if x approached infinity, the whole equation would go to zero. Equations like this, and others, help explain phenomenon where regular trigonometric or pre-calculus type equations are either less exact, or much more cumbersome to work with.
y=1/x is a calc-1 equation. Calc2 deals with some whole, solid objects, like if I wanted to program a machine to cut a washer out of a piece of metal I would use calc2, there is some integration around an axis to get whole 3dimentional areas.
Beyond calc2 of course is calc3 and differential equations, which I suppose leads us into kinetics, multiple moving particles, cross products and rotating bodies in long-impossible to memorize equations. These are necessary for mechanical engineering (like if you wanted to become a civil engineer, just to start down the pathway you would want calc3 + differentials before dynamics, statics, etc...). I am pretty sure even some of the statics (non-moving structures which do not bend or break, a prequel to strength of materials) use vector calculus which requires partial differentials.
It is fun, but challenging, speaking of which I have to study...
11-30-2017, 11:16 AM
#53
If you want to be lazy and not over think the moment, without gling into calc3... a cam with 0 overlap at .050 is a great balance of an aggressive tone while pulling enough vacuum to power accessories. If you want something more stealthy that can hide behind a good catback, a 222-224 cam with a 116CL advanced 4 degrees will be fine. Any cam around that spec will be fine. On the more aggressive of the daily driver spectrum you could rock a 228/232ish cam. I personally would want the more aggressive ramp rates for my application even in a DD. At the end of the day, as long as you dont under or overcam the car, your honest with your goals, you will be fine. Its all subjective. Perhaps you want a car you have to wring out to make power. Or maybe you want a smooth linear torque curve for canyon carving. Just tell the manufactuers what you plan on doing and how you want it to ride, install it and go.
Well this thread became worthless fast. Quit arguing about your wasted government sponsored education and help the guy out with his original question. Doesnt take calc 3 and a PHD to understand an engine. Christ.
Well this thread became worthless fast. Quit arguing about your wasted government sponsored education and help the guy out with his original question. Doesnt take calc 3 and a PHD to understand an engine. Christ.