Friction cannot be accounted for by VE, and the VE "predicted" by that formula is not even close to empirical data I promise you that. My boss is Mr. Corriher, and no I don't believe he would appreciate me posting dyno data. I can promise you, though, no one gives the VE calculation on the display more than a glance.

You stick to building and selling CNC's, we'll stick to engine development and we'll call this thread done...

 

You mean the guy who owns the new holland tractor dealership?

But anyways, VE is not 'predicted' by that formula. It is an input by the person running it. MEaning someone must have already spun up the motor on a test bed to test the breathing. I thought you said you did this?

 

round and round we go.....

 

WOW! My brain really hurts now. I would have loved this sort of stuff many years ago but like I said, my brain hurts.

 

Interesting reading though!

 

Remember this?
Looks like a prediction to me, an extremely wrong one at that.

Mr. Corriher is the president of the engine company. If you'd met anyone from the Penske engine shop, you would know his name.

I can't say any more than I've already said, so you will have the last word on this one because I'm done.

My apologies to everyone else for crapping up what started out as a good thread.

 

solving a simple equation for a variable is not a prediction. Its called 'algebra'. most of us had it in 8th grade. some of us (apparently) didnt pass.

You yourself said the dyno was listing the VE as it listed the HP. How do you think it arrived at the VE? Lottery?

Methinks you got caught in a lie and you have only compounded it.

 

haha, lying about what?
<a href="http://picasaweb.google.com/Eric.W.Poe/Me/photo#5228593510958205282"><img src="http://lh3.ggpht.com/Eric.W.Poe/SI-yGI-TiWI/AAAAAAAAABo/v_aRpIPaGjg/s144/039.JPG" /></a>
yes, that's me at work with the Harley J. Earl trophy from this year's Daytona 500

 

well you did state you are an engineer for a Nascar engine builder.

Quite frankly - I dont buy it. No engineer ever came close to getting a degree to work in this field without understanding the basics. 'My Formula' as you keep billing it, predates both of us, our parents and likely your grandparents. As I said in an early post, this is not exactly new stuff, or all that hidden.

I have invented no new science here, but I have repeated what any actual engine builder who has spent any time near a dyno can repeat in their sleep. the fundamentals are so....we.....fundamental.

But your first post was an attack, and rather back down...well. but this is the internet and everyone is a 6'7" kickboxer with a super model girlfriend and a dodge viper killer in the garage.....

 

See my edited post above...I've been nothing but honest in everything I've posted here. My first post was an honest question as to how you expect a multiplication equation to be an accurate predictor of power output of an engine. I assume you didn't go to engineering school either since you know that engine performance can be calculated with simple multiplication. I can help you out with some basic thermodynamics if you'd like some engineering formulas. Take your trolling elsewhere.

 

knock it off all of you........

 

About time someone stopped this long drawn out debate.

 

I'm sorry for making it go on so long, everyone. This will be the last from me.

 

Example #1:
What HP from a 350 CID Torker-level engine @ 6,000 RPM at sea level?


14.7 Atmospheric Pressure
× 9.5 Compression Ratio
× 0.95 VE at RPM
× 350.0 CI
× 6,000.0 RPM
÷ 5,252.0 #
÷ 150.8 #
_________________
352 HP

Example #2:
Effect of a carburetor restrictor plate that causes 1.5 PSI additional manifold vacuum?


14.7
× 9.5
× 0.9
× 350.0
× 6,000.0
÷ 5,252.0
÷ 150.8
_______________
336 HP

So...how does 1.5 psi of additional manifold vacuum become 5% lost VE? How do those mathematically correlate? Just one example of misleading info on that link.

In other words..
you are settings "Mean effective pressure" = Air pressure * compression Ratio * Volumetric Efficiency.

Mean effective pressure tells us a lot about an engine - if it was instead, a compressed air line turning a perfectly efficient air motor, that is how much pressure the line would be (delivering your engine volume in air, at that presssure, a number of times per minute based on RPM). It matters on a LOT more factors than just the compression ratio and the VE. For example - the amount of energy in the fuel. The efficiency of the engine turning pressure into power. and a million other things.

edit - sorry, i just realized there was a page 2. Oops.

 

And by the way. the factor of 150.8 used on calculating mean effective pressure is used regardless of the fuel burned. All it does is convert units of pressure (force per suqare inch) into (torque per volume) . In a 2 stroke, it is actually halved.

MEP = 150.8 x (Torque / CID)