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the rpm achievable is the greatest factor in horsepower produced regarding a particular displacement. However, displacement is probably THE most imortant factor in power production.
 

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Discussion Starter #4
Hi Kevlar7R,

It is true that introduction of the fuel/air is the net result that determines the maximum power. However that is a little vague. What precisely limits it?

Hi apexismaximus,

You could have huge displacement, but what most important factor limits the amount of horsepower. High RPM is the net result, but what is the limiting factor?

Andy
 

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Andy said:
High RPM is the net result, but what is the limiting factor?

Andy
Based on that, I'd say you're looking for "piston speed".
 

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Discussion Starter #6
Hi Dad,

So far Kevlar7R was the closest. I'm looking for the single most important factor for maximum power.

Andy
 

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Okay, are you talking about the ability to use a combustable fuel, an energy containing substance??????????????? Ultimately, that is the limiting factor.
 

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well, then,

from a purely thermodynamic point of view, In order to produce more power, more fuel must be used. Therefore, to produce the maximum horsepower of the engine, it must be able to liberate the maximum amount of energy from the fuel supplied to it. This is independant of the total amount of fuel supplied, since that is directly related to displacement.
 

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I don't think IMHO that it's the most important factor but maybe he's talking about valve area???????? You sure ain't gonna move much charge with 1mm valves????????
 

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:confused: What's your point.

Andy said you were the closest with that answer so I'm trying to take the thought a step further. You didn't say valves or valve area though and they get kinda nit picky around here with these trivia threads. Improving 'flow' as you generically stated could take hundreds of forms from chamber shapes, porting/smoothing, angle valve jobs etc.

I guess we'll have to see what he says. Personally I think the question was a little too vague to begin with since there are quite a few design factors that are all individually critical to maximizing power production.
 

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Discussion Starter #15
Hi Guys...

Sorry this trivia was worded a little vague. I think the author of the link was implying, the intake valves are the bottle neck in most engine designs. So the bigger the intake valves the better the engine performance.

I agree that if you have small carbs and ports the intake valves size doesn't matter much.

Andy
 

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Must I think of everything?

Andy said:
"The single biggest factor that determines an engine's ultimate power potential is the total inlet valve area"
Pragmatically speaking (KISS philosophy, donchaknow), the single biggest factor that determines your engine's ultimate power potential is...the size of your wallet.
Like they say...speed costs money: how fast do you wanna go?
 

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Discussion Starter #17
Kevlar7R said:
For maximum horsepower, the introduction and removal of fuel/air mixture, and subsequently exhaust gasses must be maximzed.
My apologies Kevlar7R. You were 100% correct. I didn't word the trivia question very well. So I was just looking for the answer in the link. Sorry about that.

Andy
 

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The way I was taught to view increasing power in an engine was by increasing the acronym P.L.A.N. (Pressure, Length, Area, Number). Increase the pressure covers compression, cams, increased valve and port size, blowers, etc. Increase length of stroke improves leverage. Increase the area of the piston, more SI's for your P to work on. :) Increasing the number being RPM, number of times you do all of the above. Although when you start playing with all of this you start to see how inter-dependent so much of it is.

A question you might ask is what effect rod length has on an engine and why you might change it. This goes back to my days of building stroker Harley motors for drag racing and Chevy motors for Sprint cars, but is generic in the principles. I don't remember all of the specifics, but the principle and general directions I've retained. To me, the interesting point of these discussions isn't to make engine designers out of riders, but to be aware of some principles and how important ALL of the details are. One little change here might take 10 more changes in other parts to be optimized.
 

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Discussion Starter #19
Hi Dad,

Great question. I'm sure not too many people think about rod length and it relationship to engine performance.

From what I read, and it would be opposite to what I would have guessed, is that a short rod is better suited for low revving engines and produce more torque, and a longer rod is better suited for a higher revving engine.

Here is a good link that explains why, as well as other factors:

http://victorylibrary.com/mopar/rod-tech-c.htm

Andy
 

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The most power that an engine can produce is based on its size and its compression ratio. The more volume of air you can pull into a given cylinder the more power that cylinder will make.This is called volumetric efficiancy.Thats also why turbos work so well.
 
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