How much power will this mod add... READ FIRST
11-04-2006, 04:48 PM
#1
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How much power will this mod add... READ FIRST
Ok, for all you people wondering how much power this mod will add please read this before posting.
I will try to explain this using simple term and for our Harvard folks throw in some math problems.
Let me make some axioms (assumptions) before I begin.
1. Advertised power gain is accurate to within 90%.
2. Mods being criticized are a part made by a reputable company. (EX: NOT turbonater)
3. This will be one or more mods to a vehicle.
Let me begin:
1. Standard 350z power 300HP at crank.
2. You decide to add a intake (Advertised gain is 5hp)
3. Assumed net gain will be 300+ (5*90%) or 304.5HP
YEA!!!
Now you want to add an exhaust!
1. Your assumed gain is 304.5
2. Advertised gain is 5HP
This is where it gets fun. Engines are a form of production, and therefore consume inputs to make an output therefore it is bound by laws, The more you input the more you output however you have what is called diminishing returns. Therefore I add in the law of diminishing returns. The more inputs you put into the engine the more you will get out however it will grow to a point and then begin to fall off. At no point will the engine ever lose power by putting more in but it will require more inputs to generate the same amount of outputs the higher you go (see fig-1). Where line 03 is tangent to the function is where your gains will begin to fall and will require more inputs to get more outputs.
3. Assumed gain= 304.5+f (k, (5*90%)) => 310HP
And so on
Let’s say you have a bunch of stuff, Intake, spacer, cats, exhaust, and you want to add headers. Then the following applies
1. Current power = 315
2. Header Gains = 15
3. Assumed gains = 315+f (k, (15*90%)) =322
Reason you have passed the peak of the marginal product of the mods and even though you gain you will always gain less and less the more you put on.
This is meant as a guide, not a answer key. Go with the advertized gains but remember they are the best modded compared to the worst baseline. So assume that they are 70-80% effective. And use common sence especially with silly mods like the turbonater. You have to pay for power.
I will try to explain this using simple term and for our Harvard folks throw in some math problems.
Let me make some axioms (assumptions) before I begin.
1. Advertised power gain is accurate to within 90%.
2. Mods being criticized are a part made by a reputable company. (EX: NOT turbonater)
3. This will be one or more mods to a vehicle.
Let me begin:
1. Standard 350z power 300HP at crank.
2. You decide to add a intake (Advertised gain is 5hp)
3. Assumed net gain will be 300+ (5*90%) or 304.5HP
YEA!!!
Now you want to add an exhaust!
1. Your assumed gain is 304.5
2. Advertised gain is 5HP
This is where it gets fun. Engines are a form of production, and therefore consume inputs to make an output therefore it is bound by laws, The more you input the more you output however you have what is called diminishing returns. Therefore I add in the law of diminishing returns. The more inputs you put into the engine the more you will get out however it will grow to a point and then begin to fall off. At no point will the engine ever lose power by putting more in but it will require more inputs to generate the same amount of outputs the higher you go (see fig-1). Where line 03 is tangent to the function is where your gains will begin to fall and will require more inputs to get more outputs.
3. Assumed gain= 304.5+f (k, (5*90%)) => 310HP
And so on
Let’s say you have a bunch of stuff, Intake, spacer, cats, exhaust, and you want to add headers. Then the following applies
1. Current power = 315
2. Header Gains = 15
3. Assumed gains = 315+f (k, (15*90%)) =322
Reason you have passed the peak of the marginal product of the mods and even though you gain you will always gain less and less the more you put on.
This is meant as a guide, not a answer key. Go with the advertized gains but remember they are the best modded compared to the worst baseline. So assume that they are 70-80% effective. And use common sence especially with silly mods like the turbonater. You have to pay for power.
11-04-2006, 04:50 PM
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Appendix:
Marginal Productivity
The assumptions given earlier imply that, for any given production function y = ¦ (x1, x2, .., xm), it is a generally the case that, at least up to some maximum point:for all i = 1, .., m, i.e. diminishing marginal productivity of ith factor.
Marginal Productivity
The assumptions given earlier imply that, for any given production function y = ¦ (x1, x2, .., xm), it is a generally the case that, at least up to some maximum point:
¶y/¶xi = ¦i ³ 0
for all factor inputs i = 1, 2, ..., m. In other words, adding more units of any factor input will increase output (or at least not reduce it). This is the heart of assumption (A.3). However, it is also common in Neoclassical theory to also impose (A.5), i.e. to assume "quasi-concavity" of the production function. It is often the case in economics that the quasi-concavity assumption implies that:¶2y/¶xi2 = ¦ii < 0
It is worthwhile to spend a few moments on the diminishing marginal productivity assumption. This means more we add of a particular factor input, all others factors remaining constant, the less the employment of an additional unit of that factor input contributes to output as a whole. This concept performs the same function in production functions as diminishing marginal utility did in utility functions. Conceptually, however, they are quite distinct.
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11-04-2006, 06:10 PM
#8
Hey UPS guy, sorry I completely forgot your name 
I have no idea WTF you're talking about, and I'm a friggin PhD student in Chem Eng lol!
Good luck trying to explain everything...
I see a major flaw already: hp gain claims are nowhere near 90% accurate!!
I have no idea WTF you're talking about, and I'm a friggin PhD student in Chem Eng lol!
Good luck trying to explain everything...
I see a major flaw already: hp gain claims are nowhere near 90% accurate!!
11-04-2006, 06:41 PM
#11
Originally Posted by Hraesvelg
I like fried chicken...
When u have several Mods, I dont think u can break them down individually. If they are good,legit Mods they have to be looked at as a whole.
Several Mods act as a Mod in it self--A balance-- working hand in hand to achieve a gain comprised of the total.
Otherwise u end up with a cumlative error
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11-04-2006, 08:35 PM
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So if I was to put a twin turbo system on my car with the stock intake and stock exhaust and dyno'd it I would get X for results. After if I ad a 5hp intake and 15hp exhaust I would gain less than 20hp?
11-04-2006, 09:30 PM
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Originally Posted by the7ferret
Appendix:
Marginal Productivity
The assumptions given earlier imply that, for any given production function y = ¦ (x1, x2, .., xm), it is a generally the case that, at least up to some maximum point:for all i = 1, .., m, i.e. diminishing marginal productivity of ith factor.
Marginal Productivity
The assumptions given earlier imply that, for any given production function y = ¦ (x1, x2, .., xm), it is a generally the case that, at least up to some maximum point:
¶y/¶xi = ¦i ³ 0
for all factor inputs i = 1, 2, ..., m. In other words, adding more units of any factor input will increase output (or at least not reduce it). This is the heart of assumption (A.3). However, it is also common in Neoclassical theory to also impose (A.5), i.e. to assume "quasi-concavity" of the production function. It is often the case in economics that the quasi-concavity assumption implies that:¶2y/¶xi2 = ¦ii < 0
It is worthwhile to spend a few moments on the diminishing marginal productivity assumption. This means more we add of a particular factor input, all others factors remaining constant, the less the employment of an additional unit of that factor input contributes to output as a whole. This concept performs the same function in production functions as diminishing marginal utility did in utility functions. Conceptually, however, they are quite distinct.
At the end... in a nutshell, do more research from this board, and when it comes to modding, be sure to spend some time on TUNING the car too... otherwise the A/F and timing will never be right
G/L
11-05-2006, 05:06 AM
#15
Originally Posted by godmans
This is a true Econ thingy, and for someone who comes from an Engineering background; I can tell you that it is kind of true that the effectivity of each mod decreases as you add more mods...that's why the Ricer Math is ALWAYS wrong... and you also have to take into consideration of the dependance...using your term the effectivness of a mod = f(x1, x2, ... xm) has a factor xn to xn+k, which are from the other mods...
1.) as pointed out, manufacturers claims are not 90% accurate.
2.) Manufacturers claims are not based on gains at peak HP. They are making these claims based on the highest gains seen. meaning, if they saw 15 hp gain at 2000 rpms, and only 2 hp gains at where peak HP is made, they claim 15 hp gains from the given part. That is why you can't add up parts in the "ricer math" standard.
In addition, every car is different. Every setup contains different variables, such as an intake paired with some 3rd party aftermarket exhaust, making it next to impossible for anyone to know without the assistance of a dyno, what actuals gains are.
11-05-2006, 09:43 AM
#16
Originally Posted by Zivman
2.) Manufacturers claims are not based on gains at peak HP. They are making these claims based on the highest gains seen. meaning, if they saw 15 hp gain at 2000 rpms, and only 2 hp gains at where peak HP is made, they claim 15 hp gains from the given part. That is why you can't add up parts in the "ricer math" standard.
+1
and on that same note, nothing pisses me off like people who say "Oh I felt lots of HP gain but serious loss of torque"
^^ some people don't realize that there is more to it than the PEAK torque number...
and they clearly don't realize that to make HP, you must make TORQUE, at a certain RPM
11-05-2006, 09:57 AM
#18
Originally Posted by Zivman
It's not the diminishing returns that makes ricer math wrong. It is much more simple than that and it basically results from two things:
1.) as pointed out, manufacturers claims are not 90% accurate.
2.) Manufacturers claims are not based on gains at peak HP. They are making these claims based on the highest gains seen. meaning, if they saw 15 hp gain at 2000 rpms, and only 2 hp gains at where peak HP is made, they claim 15 hp gains from the given part. That is why you can't add up parts in the "ricer math" standard.
In addition, every car is different. Every setup contains different variables, such as an intake paired with some 3rd party aftermarket exhaust, making it next to impossible for anyone to know without the assistance of a dyno, what actuals gains are.
1.) as pointed out, manufacturers claims are not 90% accurate.
2.) Manufacturers claims are not based on gains at peak HP. They are making these claims based on the highest gains seen. meaning, if they saw 15 hp gain at 2000 rpms, and only 2 hp gains at where peak HP is made, they claim 15 hp gains from the given part. That is why you can't add up parts in the "ricer math" standard.
In addition, every car is different. Every setup contains different variables, such as an intake paired with some 3rd party aftermarket exhaust, making it next to impossible for anyone to know without the assistance of a dyno, what actuals gains are.
11-05-2006, 12:54 PM
#19
This thread is a joke, no matter how smart you make it sound its ricer math at the end of the day. Tunes/every car is different, your not taking that into account with your equation, your assuming all cars will react the same in diff weather/altitude/octane levels, etc....
11-05-2006, 01:12 PM
#20
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Zivman:
Alberto:
If you dont keep all other things constant then the equation is so complex it cannot be solved. I know each car is different, but in general they all react the same. You put an popcharger on every stock 350 every 350 will gain some power, some gain 5hp some gain 2hp. I stated keeping all other things constant. Otherwise you end up with a equation that has a varbialbe for every factor.
Originally Posted by the7ferret
This is meant as a guide, not a answer key. Go with the advertized gains but remember they are the best modded compared to the worst baseline. So assume that they are 70-80% effective. And use common sence especially with silly mods like the turbonater. You have to pay for power.
Alberto:
If you dont keep all other things constant then the equation is so complex it cannot be solved. I know each car is different, but in general they all react the same. You put an popcharger on every stock 350 every 350 will gain some power, some gain 5hp some gain 2hp. I stated keeping all other things constant. Otherwise you end up with a equation that has a varbialbe for every factor.