Pushrod or OHC

[henk4]

Originally Posted by Matra et Alpine

Also, some old seasl had issues if they were made of buta-n rubber. ( Phased out of cars 10+ years ago ) So on really old cars the switch might cause some early cracking and deteriotion on pump seals and pipe seals. NOT an issue with younger cars.
Well that's according to BP ( my rally driver's ex-BP, what he doens't know about oils/petrols/diesels and a few "fun chemicals" isn't worth knowing

This is a surpise for me, never heard of any warnings about this in countries were low sulpher diesel became mandatory. I am sure that it that would have caused problems motorist would have risen their voices

[Matra et Alpine]

Originally Posted by henk4

This is a surpise for me, never heard of any warnings about this in countries were low sulpher diesel became mandatory. I am sure that it that would have caused problems motorist would have risen their voices

It was the case, I checked with mate.

BUT, there's a new one on the block I didn't realise and that is near-ZERO sulphur diesel. Seemingly in the EU each nation has to start supplying it this year and by 2008 it's to be the only option.

He sent me this link ... http://www.bp.com/genericarticle.do?...tentId=2017538
Note that this has a lubricant ADDED to counter the lack of ANY sulphur.

he coudlnt' point me at the actual BP publication on this issue as it's old and doesn't seem to be online. BUT he did but me this from an additive supplier
"9. What do we mean by lubricity of diesel fuel?
Diesel being refined from crude oil has an inherent lubricating property or lubricity. Modern refining methods being
used to produce low sulphur diesel fuels as required by EC legislation, remove the sulphur and other compounds in the
diesel which provided this lubricating property.
10. Why is lubricity important?
In Sweden and Japan when these new fuels were introduced there were many fuel pump failures due to the lack of
diesel fuel lubricity. Low Sulphur Diesel is now common in the UK and although it now contains additives to address
lack of lubricity, many feel that it is insufficient."


EDIT: aha, a wee google found an Aussie version of the paper he descibed, it's at http://www.bp.com.au/fuelnews/ADF2202.pdf

[jcp123]

I wish we got the low-sulpher diesel here. Maybe the EPA numbnuts would quit b!tching about diesel cars.

P.S. Ive asked a few times but nobody seems to know...does the higher efficiency of a diesel car offset the higher pollution per gallon of fuel?

[SlickHolden]

The Diesel we get here isnt the best.

[Matra et Alpine]

Originally Posted by SlickHolden

The Diesel we get here isnt the best.

You guys get the low-sulphur BP stuff.

it might not be widespread which would be a bummer

[Matra et Alpine]

Originally Posted by jcp123

P.S. Ive asked a few times but nobody seems to know...does the higher efficiency of a diesel car offset the higher pollution per gallon of fuel?

You get slightyl more NOx and more particulates ( though the latest technology is REALLY cleaning that up aven MORE than current gen Euroepan diesels which you NEVER see soot from ) but a LOT LESS CO2.
Dont'; knwo abotu the realive outpu per mile travelled.
I'm sure there's an article a whiel back had the figures, I'll try find it

[henk4]

Originally Posted by Matra et Alpine

[i]"9. What do we mean by lubricity of diesel fuel?
Diesel being refined from crude oil has an inherent lubricating property or lubricity. Modern refining methods being
used to produce low sulphur diesel fuels as required by EC legislation, remove the sulphur and other compounds in the
diesel which provided this lubricating property.

What do I read here? Is Sulphur the lubricating component or are other compounds responsible for lubricating or both?
In the early nineties I prepared a paper for the Society of Marine Engineers about the economic effects of making zero sulphur fuel oil mandatory for marine diesel oils (up to 380 cst). Oil companies were unhappy to treat residual fuel oil used for bunker fuels as they were unwilling to pay for large scale desulphurisatio plants. They were just happy to sell the residuals as they were. To make a long story short, we calculated the costs effects of doing that, and of course you would find a change in the delivered cost of goods somewhere in the third decimal.
However even in this group of marine engineers nobody raised the issue about additional costs related to the reduction of the lubrication effects of the fuel, and although I trust your spokesman, the attitude of oil companies about sulphur reduction has always been hostile as they fear not to be able to recover the investment costs of the plant changes.

What may happen is that some component will be added to new diesel fuels that could play the role of the lubricant, like the stuff epople use for replacing the lead in the lead-free petrol.

[Matra et Alpine]

Originally Posted by henk4

What do I read here? Is Sulphur the lubricating component or are other compounds responsible for lubricating or both?

After I originally posted that I foudn a link in Australia's BP PR site ( thanks google ).
Which says "Sulphur compounds in diesel fuel act as natural lubricants for fuel system components such as fuel pumps and injectors. Removing sulphur reduces the natural lubricity of the fuel."
Don't see any poitn in BP distorting it as they are the most ardent developers and suppliers of low and ultra-low (near zero) sulphur diesels. ( The local BP refinery is fun to watch the trucks. The refinery is owned and operated by BP, but you wil see EVERY company tanker come in to pick up fuel - including Shell Optimax - it's a slightly different mix pls an additive )
[quote]about additional costs related to the reduction of the lubrication effects of the fuel, and although I trust your spokesman, the attitude of oil companies about sulphur reduction has always been hostile as they fear not to be able to recover the investment costs of the plant changes.[/QUOTE}
The UK fuel suppliers are a cautious bunch after the debale of the Esso additive thatr gummed up engines
BUT the EU requirement measn they have to develop it and then charge the matchin price

What may happen is that some component will be added to new diesel fuels that could play the role of the lubricant, like the stuff epople use for replacing the lead in the lead-free petrol.

Most of the sources I'd cited said exactly that.

[charged]

[quote=Matra et Alpine]After I originally posted that I foudn a link in Australia's BP PR site ( thanks google ).
Which says "Sulphur compounds in diesel fuel act as natural lubricants for fuel system components such as fuel pumps and injectors. Removing sulphur reduces the natural lubricity of the fuel."
Don't see any poitn in BP distorting it as they are the most ardent developers and suppliers of low and ultra-low (near zero) sulphur diesels. ( The local BP refinery is fun to watch the trucks. The refinery is owned and operated by BP, but you wil see EVERY company tanker come in to pick up fuel - including Shell Optimax - it's a slightly different mix pls an additive )

about additional costs related to the reduction of the lubrication effects of the fuel, and although I trust your spokesman, the attitude of oil companies about sulphur reduction has always been hostile as they fear not to be able to recover the investment costs of the plant changes.[/QUOTE}
The UK fuel suppliers are a cautious bunch after the debale of the Esso additive thatr gummed up engines
BUT the EU requirement measn they have to develop it and then charge the matchin price

Most of the sources I'd cited said exactly that.

It has lower lubrication qualities than high sulphur fuel,alot of people I know have problems with the bp ultimate its lower sulphur levels than other herein Oz.The seals in the pump leak,personally I run a additive so this problem doesnt effect my diesel.I find it produces less smoke than Shell etc.

[Slicks]

Originally Posted by Matra et Alpine

OK, lads, I know we've lots of yongseters who're 12-15 and doing junior grade science. I'll let you correct Slicks, coz I'm just plain tuckered out with this. I won't to go back to intelligentcarpage.com and get away from such blatant ---------

Dictionary: Mass
"The physical volume or bulk of a solid body."
"Abbr. m Physics. A property of matter equal to the measure of an object's resistance to changes in either the speed or direction of its motion. The mass of an object is not dependent on gravity and therefore is different from but proportional to its weight."
Now what is mass Matra?

There was never a TIMES, what you smokin' ??
I said +-10% limts. THAT is the standard way to measure bandwidth on may things. Go check your speaker specs ( they typically use -3dB points ( dBs are for another discussion )

Taking 20% of something is the same at multiplying it(times) .20(or 20%). So yes, there was a times. Whats this +-10% thing, some new formula you have now? Are you trying to cover up that other 20% formula you had?
Quote from YOU:
"The "usable" power band is NOT the complete band unless that band is inherently flat and within 20% ( some use 10 ) of the peak."
BTW are we talking about speakers or engines?

And as you said, a peaky engine isn't good.
Because you need to change gears a lot to keep it "on song" and maximise the performance through bends ( it's pretty much irrelevant on straights )
SO, LET ME WALK YOU SLOWLY THROUGH IT AGAAIN - please read it this time......
A wider power band enables a car to be in the correct gear for longer time and in cornering chainging gear loses you lots of time as in addition to the shift thime you ALSO have the loss of control impact.
WHERE the powerband happens does NOT matter as the gearbox ratiosn adn final differential drive are the ONLY factors that relate the engine speed to the wheel speed.

As of right now im not talking about where the powerband occurs, stop trying to go off topic. A wider band is a wider band, and from my calculation the Z06 has a wider band.

Whether it's from 1500-4500 or 5000-8000 is irrelevant. The driver has 3000 rev range to use.
WHAT part of this do you struggle to comprehend ?

What part do you struggle to comprehend?
Z06
75% of 350peak hp=262hp, found at roughly 4100RPMs. So thats 4100-6200RPMs from 75% of peak power to peak power.
Elise
75% of 166peak hp= 124hp, found at roughly 6000RPMs. So thats 6000-7500RPMs ffom 75% of peak power to peak power.
The Z06 has 2100RPMs, where as the Elise has 1500. Anywhere in there does it imply anything about where the revs occur matter? No.

Let me explain why what you TRY to suggest is NOT used by mechanics, tuners or race teams.
IF you have an engine with a peak at 2000 revs and another at 400 revs and a trough of 10-20% in between then in reality you are MOST of the time down on power by 20%.
Your silly numebr above PRESUME a graph shape which is seldom availabel in real life.

???
Your little 20% formula is flawed in that it goes by revs, not the powerband. The higher the car revs, the bigger the band according to that formula:
20,000RPMs peak power * 20% = 4000RPMs
10,000RPMs peak power * 20% = 2000RPMs
Do you see? You cant go by the RPMs the peak power occurs at, you must go by the POWERBAND, not REVS.
example:
350peak POWER * 75% = 262hp, find the RPM with that occurs at and you have a POWERBAND of 75% from peak power.

THAT is why the +-10 is typically used as a GUIDE.
REMEMBER these are GUIDES to teasm in setting up and tunign the cars. it is the DRIVER who ultimately will ask for fine tuning of power band to optimise it for a race.
BUT, if we are going to compare then as a starting point we SHOULD use the standard guide that best reflects usability for the driver.
taking a calculation as you have down based on a peak power point does NOT manage to reflect the peask and troughs. By using a +/- limits then you are able to ensure the relevance of the measurement. YOU find this technique used in everything from weighing your corn flakes packet to the calcualtiosn for landing a missionon mars !! ( just different numbers on the limints and differnet measurements )
The number YOU calcualte is just peak power with a ratio, it gives NO consideration to the SHAPE of the rest of the power band and thus is useless in real life.

And your 20% formula is biased toward revs, and based on revs, so shows nothing about the powerband.

That's OK, it joins all the other words you dont' understand.
BUT, we sure know ehat a REDNECK is

Yeah, the steriortypical southerner, good one. Being down there on vacation myself, they are very nice people (I actually didnt run into any real "rednecks").

From a Nascar race team site - it took me a 10second google to find you this ( shame you're too lazy ) - "On qualifying day, teams will put on a big plenum manifold in order to get peak horsepower. This impacts the amount of air coming through the carburetor into the engine. The key is maximum RPMs. On race day, when the power band needs to be moved down a little bit, they’ll put on a little smaller plenum manifold."
So, see teams playing with the power band to MATCH the RACE NEEDS.
That was only one.

Wow, thanks for showing absolutly nothing...
Revs matter to them because DISPLACEMENT IS LIMITED. Of course they match the powerband to the race needs, not all tracks are the same...

Ontop of that are the countless hundresd of people over the years who I've met and had the common sense to shut up and learn from rather than try to show them how smart I am. When I post somethign, it's NOT a random thought for the night or a made-up quote to "win" - only losers play that "shit"

Dont flatter yourself, im not try to be "smart" for anyone, im try to show you your flawed formula. I, like everyone else, is learning, learning different things, and when someone makes a mistake, usually it will be corrected by someone else.
Ironically enough, most of your posts seem to be a drunken piss war before you go to bed. Using "owned" in big red letters, trying to look like a leader of some kind. Getting all the anger out from a stressful day at work, telling americans that they suck for one reason or another, or how the country sucks. If i didnt know already I'd think you were just some highschool kid looking for some place of acceptance,constantly getting lopped up and telling people off.

I post because I've experienced it. I've spent hours at a time in codl wet paddocks and parc fermes spannering for teams to get a chance to drive when I was older. I just TRY to pass that on to folks in UCP to save them getting arthritis !!!! Maybe some of them will get the chance earlier because they learned more sooner.
You seem to only want YOUR POINT vinidicate.
I'm trying to spread some experience and truths. REAL practical stuff. Not fantasies of the mind or made up on the spot or googled at the time !!!!
YOU have a MAJOR problem that I am more knowledgeable than you.
Get over it.

lol, I could'nt care less that you know more than me. Youve been on this earth much longer, and should know more. Do you care that I know more about paintball than you? No (I hope not), who cares? It seems you need to get over yourself.

[johnnynumfiv]

Slicks, just give up, you make yourself look like a complete ass.

[Matra et Alpine]

Originally Posted by Slicks

Dictionary: Mass
"The physical volume or bulk of a solid body."

They laymans answer and common term

"Abbr. m Physics. A property of matter equal to the measure of an object's resistance to changes in either the speed or direction of its motion. The mass of an object is not dependent on gravity and therefore is different from but proportional to its weight."

That closer to actual answer as it is a little simplified for understanding.

Now what is mass Matra?

Well you've answered it already.
If you want to talk about objects in motion, then it is the proper scientific term and the latterr.
NOT the "space taken up".
So, WHY did it take a response from you and a reply from me for you to realise that ?
Again, you'd have best kept quiet

A much BETTER concept of what mass IS is the amount of matter an objecy has. Clearly how compressed an object is and what crystaline or bonded structure it takes affects the volume any object takes up. So usign volume/space/size is NOT best The point about mass is it affects the movement of a body and hence why it's used. Weight is the measured effect ofgravity on the mass of an object. SO when measuring lateral G to ebe 100% factual , correct and accurate, it's the MASS you're concerned with.

Taking 20% of something is the same at multiplying it(times) .20(or 20%). So yes, there was a times. Whats this +-10% thing, some new formula you have now? Are you trying to cover up that other 20% formula you had?

WOW, arithmentic fails you when you get heated.
Just take the +10 and the -10 and tell me how many units between ?
THAT'll be 20 then. So +-10 and range of 20 are the same thing !!
Engineers tend to use +-ranges, marketing tend to use range.
There CAN be a subtle difference but only if you are usign an averaging meaurement technique - too deep to go into

Quote from YOU:
"The "usable" power band is NOT the complete band unless that band is inherently flat and within 20% ( some use 10 ) of the peak."

Makes sens enow huh

BTW are we talking about speakers or engines?

It doens't matter
See you've seen it mentioned wrt speakers. It is used for ANY 'system' pridcing an output across a range. It can be frequency, distance, revs, speed, time. It can measure ouput, distortion, noise, any physical trait of the measured system.
It is used to scientificlaly analyse the system under test.
In this case we're clearly talking the power output curve of the engine.

As of right now im not talking about where the powerband occurs, stop trying to go off topic. A wider band is a wider band, and from my calculation the Z06 has a wider band.

True, because you pushed it out to 25% limits.
10% + or - on a power output is hard to detect, and is commonly used for most measured systems.
I'd be happy to discuss the relative merits and risks in extending that band.
Liek all measurments, we need to consider the "desired outcome" when using a measurement.
I'd taken +-10 as it's a norm, you either selected or had seen published 25% as it gives the Z06 a little more chance to show 'wider' power. BUT it does that now with th elimits being 25% lower and THAT is goign to be noticable and affect the REAL WORLD performance. +-10 will not be noticable in the REAL WORLD.

What part do you struggle to comprehend?

That you take a peak point and then use IT as the reference for the bad limits.
THAT would not hodl up to ANY scrutinify in a statistical significance test.
You are determining the limits based on a distance from a peak. THAT is irrelevant and especially is HIGHLY DANGEROUS in a system which contains multiple peaks very close in magnitude - which to choose ? Users of this technique are often trying to massage the numbers by then chosing the peak they want to give the results they require to justify their a-priori assesments !!
Hence why scientists and engineers use +- limits !!!

The Z06 has 2100RPMs, where as the Elise has 1500. Anywhere in there does it imply anything about where the revs occur matter? No.

YES, because you have chosen a single point where a single peak lies in the rev range and THEN picked a single point on the up and down bell curve that matches those. You really should just draw upper and lower limits and see.

HOWEVER, the LARGEST discrepeancy is your use of the 25% below points.
That means you can take an engine with a say 125hp peak at 5000 revs for 500 revs and is 24% BELOW that for the rest until falling to 25% at the end limit you want to chose. SO you are then accepting an engine that across MOST of it's rev range is a VERY NOTICABLE 24% lower !! Clearly that engine SUCKS.
I prefer the 10% limits as more REAL WORLD +-10 you aren't goign to motice too much.
[quote]???
Your little 20% formula is flawed in that it goes by revs, not the powerband. The higher the car revs, the bigger the band according to that formula:
20,000RPMs peak power * 20% = 4000RPMs
10,000RPMs peak power * 20% = 2000RPMs
Do you see? [?QUOTE]
NO, because the % is on the POWER not the revs.
There is NO POINT in measuring %age across a powerband as it's the actuall power badn rev RANGE that matters.
The 80/20 rule we'll explin seperately, as clearly soem have never heard of Koch and read his articles.

You cant go by the RPMs the peak power occurs at, you must go by the POWERBAND, not REVS.
example:
350peak POWER * 75% = 262hp, find the RPM with that occurs at and you have a POWERBAND of 75% from peak power.

WHY 25% ?
+- 10 as I've already stated and I think most woudl agree is seldom noticable.
+25 is a larger chuck and whilst may be valid, can equally as shown above be TOO wide. For example, why not 50% ?? or complete rev range ? ( The latter because EVERY high reving engine would meaure better, the fact that after a revvy engine peask it tends to drop failry quickly means the +-10 are better limits to use than 50% where the revvy engine woudl clearly win. BUT not be any use at all in the REAL WORLD !!

And your 20% formula is biased toward revs, and based on revs, so shows nothing about the powerband.

huh ? It shows the powerband where the power remains within +-10%, an amount we'd all agree is not too noticable.
You want to squeeze it to a larger %age so that the engines you like 'win' but I STILL CONTEND the reason NOT to do that is because NOW you're looking at a greater power los within that powerband that DIRECTLY AFFECTS the REAL WOLD performacen of the car.
Just as anyone claiming that a Civic engine is better because at 50% IT has the wider powerband. Clearly nonsense.

Yeah, the steriortypical southerner, good one. Being down there on vacation myself, they are very nice people (I actually didnt run into any real "rednecks").

Just as all stingy folks in Britain aren't Scots

Wow, thanks for showing absolutly nothing...
Revs matter to them because DISPLACEMENT IS LIMITED. Of course they match the powerband to the race needs, not all tracks are the same...

STOP thinking racing ONLY as you get it on your tracks.
NOT all formula are capacity limited - get that right FIRST.
SECOND. Get it right what they're saying. THEY are adjusting the Powerband of the car to suit the needs of the driver. How do you think they MEASURE it ?
You tried to "diss" experience. It sure is better than stupidity.
So powerband is changed by teams, HOW do you think they decide if and engine change is beneficial or not ? the WHOLE badn ot the USABLE BAND.
You clearly haven't grasped the concept of USABLE power yet. If the power in the USABLE BAND changes significantly across the rev range then it is an undrivable car as the forces at the wheels vary and alter the grip and handling. IF the power stays within a tight band ( eg +-10 ) that the driver whill not notice the variation and it will have less impact on the handling and ultimate lap times of the car. See, REAL WORLD, not theories in mags and bars

[Matra et Alpine]

Dont flatter yourself, im not try to be "smart" for anyone, im try to show you your flawed formula. I, like everyone else, is learning, learning different things, and when someone makes a mistake, usually it will be corrected by someone else.
Ironically enough, most of your posts seem to be a drunken piss war before you go to bed. Using "owned" in big red letters, trying to look like a leader of some kind. Getting all the anger out from a stressful day at work, telling americans that they suck for one reason or another, or how the country sucks. If i didnt know already I'd think you were just some highschool kid looking for some place of acceptance,constantly getting lopped up and telling people off.

aha, the GWB approach.
I don't like the UN or Saddam so I'm gonna ignore you and tell you you dont' understand and prove myself right

Let's turn it around, as so far all you've tried to do is put up arguments ( which dont stand ) about the statments I've willingnly backed up with evidence and experience.

So, I'll be kinder, TELL ME why 25% ?

Anger ? The only thing I get angry over is obstinacy and stupidity. Either on on it's own can be OK. Combined together is dangerous in forums where it can be taken as truth unless justified.
So JUSTIFY with examples on the 25%.
WHAT difference does it make in a corner if the power is 25% lower ?
WHAT difference does it make in a sequence of norners if the powerband is 1000 revs narrower ?
AND please have the decency to accept being treated in the same way you galdly dish it out.
So facts will be required to be real and backed up by real world evidence.
They will ahve to stand up to scrutiny from an engineering and logical perspective.
MOST of all they have to make a difference.

lol, I could'nt care less that you know more than me. Youve been on this earth much longer, and should know more. Do you care that I know more about paintball than you? No (I hope not), who cares? It seems you need to get over yourself.

wow, that surprised me
You CLEARLY DO, as you NEVER accept "experience" when it's posted and force me into justifying and providing the links, the evidence and the references. THAT I take the time to do that at the start rather than telling you to piss off is one of my "better" flaws. Because you MIGHT learn and certainly OTHERS learn more - coz they can see how NOT to learn too

That to many it's claer all you're trying to do is justifu an engine.
ANd in doing so you have really missed the wood for the trees.
AND I've even pointed out the main tree and you don't grasp it.

THAT is, a wider powerband of 250bhp is not necessarily better than a narrow powerband of 300bhp. THEN we get into 'mass' considerations and transmission. BUT you are so BLINDED by the mistakes you made at the start you've lost ALL objectivity. Try to get it back in the 25% discussion and PLEASE post the reply in a "Slicks 25% band explanation" thread and let this return to cars

[Slicks]

I dont see any reason to start a whole new thread, no one is talking in here, and this is relivant to engines.

Originally Posted by Matra et Alpine

They laymans answer and common term

That closer to actual answer as it is a little simplified for understanding.

Well you've answered it already.
If you want to talk about objects in motion, then it is the proper scientific term and the latterr.
NOT the "space taken up".
So, WHY did it take a response from you and a reply from me for you to realise that ?
Again, you'd have best kept quiet

Where did we talk about objects in motion? Were talking about weight, hy are you getting so side tracked?

A much BETTER concept of what mass IS is the amount of matter an objecy has. Clearly how compressed an object is and what crystaline or bonded structure it takes affects the volume any object takes up.

How compressed an object is is more of density than mass...

So usign volume/space/size is NOT best The point about mass is it affects the movement of a body and hence why it's used. Weight is the measured effect ofgravity on the mass of an object. SO when measuring lateral G to ebe 100% factual , correct and accurate, it's the MASS you're concerned with.

And since gravity is all the same on earth, making all weight proportional, we dont have to even have this conversation. BTW were not measering lateral Gs.

WOW, arithmentic fails you when you get heated.
Just take the +10 and the -10 and tell me how many units between ?
THAT'll be 20 then. So +-10 and range of 20 are the same thing !!
Engineers tend to use +-ranges, marketing tend to use range.
There CAN be a subtle difference but only if you are usign an averaging meaurement technique - too deep to go into

So why the sudden change from "20% formula" to "+-10 formula"?

Makes sens enow huh

Only to you...
BTW we disscussed "usable" in that same thread, and "usable" power is convienient power, power that can be used easily. That means not hitting the rev limiter to get power. A completely "usable" powerband would trully be from idle RPMs to redline, because you can use the whole thing, not just the top.

It doens't matter
See you've seen it mentioned wrt speakers. It is used for ANY 'system' pridcing an output across a range. It can be frequency, distance, revs, speed, time. It can measure ouput, distortion, noise, any physical trait of the measured system.
It is used to scientificlaly analyse the system under test.
In this case we're clearly talking the power output curve of the engine.

Hehe, yes, and not speakers.

True, because you pushed it out to 25% limits.
10% + or - on a power output is hard to detect, and is commonly used for most measured systems.
I'd be happy to discuss the relative merits and risks in extending that band.
Liek all measurments, we need to consider the "desired outcome" when using a measurement.
I'd taken +-10 as it's a norm, you either selected or had seen published 25% as it gives the Z06 a little more chance to show 'wider' power. BUT it does that now with th elimits being 25% lower and THAT is goign to be noticable and affect the REAL WORLD performance. +-10 will not be noticable in the REAL WORLD.

You want 20%, fine. Although im sure youve done this calculation, finding the Z06 still with a wider band, and reluctant to post it.
350hp*80% is 280, found roughly at 4400 RPMS
Thats 4400-6200RPMs
166*80% is 132, found roughly at 6500RPMs
So thats 6500-7500RPMs.
So again, which is wider?

That you take a peak point and then use IT as the reference for the bad limits.

You took the peak RPM, not even thinking about the power.

THAT would not hodl up to ANY scrutinify in a statistical significance test.
You are determining the limits based on a distance from a peak. THAT is irrelevant and especially is HIGHLY DANGEROUS in a system which contains multiple peaks very close in magnitude - which to choose ? Users of this technique are often trying to massage the numbers by then chosing the peak they want to give the results they require to justify their a-priori assesments !!
Hence why scientists and engineers use +- limits !!!

Please, then I would like you to give a formula that is justifyable, and proove why its better than mine. Your last 20% formula did not work, so dont bother with that one.
[quote]
YES, because you have chosen a single point where a single peak lies in the rev range and THEN picked a single point on the up and down bell curve that matches those. You really should just draw upper and lower limits and see.

NO, because the % is on the POWER not the revs.
There is NO POINT in measuring %age across a powerband as it's the actuall power badn rev RANGE that matters.
The 80/20 rule we'll explin seperately, as clearly soem have never heard of Koch and read his articles.

You were the one that used the formula, you used revs, not power.

WHY 25% ?
+- 10 as I've already stated and I think most woudl agree is seldom noticable.
+25 is a larger chuck and whilst may be valid, can equally as shown above be TOO wide. For example, why not 50% ?? or complete rev range ? ( The latter because EVERY high reving engine would meaure better, the fact that after a revvy engine peask it tends to drop failry quickly means the +-10 are better limits to use than 50% where the revvy engine woudl clearly win. BUT not be any use at all in the REAL WORLD !!

Actually I used 25% because it was an example on another forum. I went to another forum to ask about your little 20% formula, thinking maybe that I over looked something and someone could explain it to me (cause we all know how good you are at explaining things...). I got the same response from everyone: "Is this guy serious, that is clearly biased toward revs".

huh ? It shows the powerband where the power remains within +-10%, an amount we'd all agree is not too noticable.
You want to squeeze it to a larger %age so that the engines you like 'win' but I STILL CONTEND the reason NOT to do that is because NOW you're looking at a greater power los within that powerband that DIRECTLY AFFECTS the REAL WOLD performacen of the car.
Just as anyone claiming that a Civic engine is better because at 50% IT has the wider powerband. Clearly nonsense.

No, your 20% formula shows just simply 20% from the RPM where the peak power occurs to the peak power RPM. Thats it, it has nothing to do with the power the car makes or the powerband, making it useless.

[SlickHolden]

Originally Posted by Matra et Alpine

You guys get the low-sulphur BP stuff.

it might not be widespread which would be a bummer

Don't think we will ever fully grasp Diesel like you guys have.