Compression Ratio
m6250a312
volume of one cylinder at bottom dead center compared to the same cylinder
at top dead center.
Boycot Mobil.
Kooj wrote in message <20000617220717...@ng-cp1.aol.com>...
> What does it mean when it says 9.4:1 or something like that for the
>Compression Ratio on a car?
Casper
the piston at Bottom Dead Center and Top Dead Center.
The Formula is CR= (V + Vcl) / Vcl
CR = Compression Ration
V = total volume (BDC)
Vcl = Clearance Volume (TDC)
While this sounds simple, accurate measurements are
important for an accurate ratio computation.
Clearance volume is the volume at TDC, above the piston
(actually the top piston ring to be exact). Head volume (CC),
thickness of the head gasket, valve notching of the pistons, and
the shape of the pistons (pop-up/dished) also affect this measurement.
Cylinder Volume is measured by the bore and stroke (TDC to BDC).
Without getting more technical, that's about it.
"Kooj" <kayd...@aol.com> wrote in message news:20000617220717...@ng-cp1.aol.com...
Casper
Just about the only time you would want "less" CR would be if you
are running a SC/Turbo... Why you ask? Because you are already
compressing the air/fuel via the SC/Turbo... Too much compression w/out
a high octane fuel will cause detonation. Yes, this is also the same
thing as spark-knock and pre-ignition, regardless of what you've read in this NG.
You will also need to change your timing curve.
Hope this helps,
"Kooj" <kayd...@aol.com> wrote in message news:20000617230135...@ng-cp1.aol.com...
> So is it better to have larger ratio or smaller? Or does it depend on the car?
Kooj
Kooj
>the piston at Bottom Dead Center and Top Dead Center.
>
>The Formula is CR= (V + Vcl) / Vcl
>
>CR = Compression Ration
>V = total volume (BDC)
>Vcl = Clearance Volume (TDC)
>
>While this sounds simple, accurate measurements are
>important for an accurate ratio computation.
>
>Clearance volume is the volume at TDC, above the piston
>(actually the top piston ring to be exact). Head volume (CC),
>thickness of the head gasket, valve notching of the pistons, and
>the shape of the pistons (pop-up/dished) also affect this measurement.
>
>Cylinder Volume is measured by the bore and stroke (TDC to BDC).
>
>Without getting more technical, that's about it.
>
>
>
>
>
>> What does it mean when it says 9.4:1 or something like that for the
>> Compression Ratio on a car?
>
So is it better to have larger ratio or smaller? Or does it depend on the car?
Mike
compression ratio means a higher cylinder pressure on the compression
stroke. A higher cylinder pressure prior to the detonation of the fuel air
mixture means you will get more power. This is what the
blower/supercharger/turbo does for you. They force more fuel air into the
cylinder therefore causing you to have a higher cylinder pressure before
detonation. The problem with having a high compression ratio is
pre-detonation. essentially you car turns into a diesel. As most people
know a diesel does not have spark plugs. This is because the diesel engine
creates such high cylinder pressures the fuel just explodes. So since you
are creating a much higher cylinder pressure and therefore causing the fuel
to become more unstable you need to make sure nothing will cause the fuel to
explode before you want it to. A iron head should be good to about 10.0 to
10.5:1 compression ratio without no worries ( just run higher octane gas).
Since you have all these explosions going on in the combustion chamber the
chamber gets hot. Any sharp edges on the head or piston will concentrate
heat. This will cause the gas to explode too soon. To avoid this you could
polish your piston surface and head surface. That will allow to get higher
compression ratios. Alternatively you could get Aluminum heads. Aluminum
heads dissipate heat faster then cast iron heads. This will allow you to
run even higher compression ratios. If you are running a blower, or
equivalent, you have to be careful of the amount of boost you obtain. This
will cause you to have higher cylinder pressures very easily. Also to avoid
pre-detonation you could run higher octane gas. A higher octane gas has
more resistance to explosion then lower octane gas. If you are
pre-detonation you should be able to here what most people call a "Pinging"
noise coming from your block. The end result of pre-detonation is lack of
power, undue stress to the rotating assembly (which could result in an early
frag), and piston with burnt hole in them. I hope this answers your
question Kooj. There are a bunch of tricks people use to help get higher
compression ratios. I recommend you pick up a book like " how to hot rod
your (insert engine here)". It is a very good book and has some great tips.
Mike
Casper
"Mike" <mik...@nycap.rr.com> wrote in message news:y1Y25.10826$rc.8...@typhoon.nyroc.rr.com...
> creates such high cylinder pressures the fuel just explodes. So since you
That's called combustion. Gasoline is both flammable and combustable.
Flammable = will inginte when contacted with a flame and/or spark.
Combustable = will inginte/explode when a certain temperature (flash point)
is reached. No flame or spark needed.
> are creating a much higher cylinder pressure and therefore causing the fuel
> to become more unstable you need to make sure nothing will cause the fuel to
Fuel doesn't become more unstable, so to speak. the flashpoint remains the same
for any given octane rated fuel. You are just reaching the flashpoint sooner via more
compression (heat) before you want it to happen... raising octane raises the flash point.
Gasoline is a fairly slow buring fuel, and that's the reason you need a spark prior
to max compression to help maximize the effeciency of it, it sort of gets the ball
started rolling... This is also why the more compression you have, the less "advance"
spark you need.
I'm not picking on your simplification, just pointing out that it was almost too
simple, to the point of being misleading to someone that wasn't as knowledgeable
as you.
Casper
"Mike" <mik...@nycap.rr.com> wrote in message news:mSd35.14104$rc.1...@typhoon.nyroc.rr.com...
> This could go on forever...
To quote myself, just incase you got to defensive and didn't read down far enuf!
> > I'm not picking on your simplification, just pointing out that it was
> almost too
> > simple, to the point of being misleading to someone that wasn't as
> knowledgeable
> > as you
bla, bla, bla... and so on...
> I recommend next time you decide to one up someone you should make sure you
> are technically correct.
I'll not even go there... especially against someone that can't even spell.
Hope you had as good a Father's day as I did! Cheers!
Casper
"Mike" <mik...@nycap.rr.com> wrote in message news:mSd35.14104$rc.1...@typhoon.nyroc.rr.com...
> This could go on forever...
> news:skolvb...@corp.supernews.com...
> Combustible and flammable are by, Webster's, definition the same thing
Sorry, I missed this little "bit" of knowledge from you in my response.
You are entirely wrong! Take some, no a lot, of chemistry classes..
You'll discover that there is a LOT of things you didn't know.... or Webster
for that matter... ;)
Mike
"Casper" <stop...@msn.com> wrote in message
news:skolvb...@corp.supernews.com...
>That's called combustion. Gasoline is both flammable and combustible.
>Flammable = will ignite when contacted with a flame and/or spark.
>Combustible = will ignite/explode when a certain temperature (flash point)
>is reached. No flame or spark needed.
Combustible and flammable are by, Webster's, definition the same thing
flam搶a搓le adj. Easily ignited and capable of burning rapidly;
inflammable.
com搓us暗i搓le adj. 1.Capable of igniting and burning. 2.Easily aroused
or excited.
ex搆lode 1.To release mechanical, chemical, or nuclear energy by the sudden
production of gases in a confined space: The bomb exploded. 2.To burst
violently as a result of internal pressure.
If you are going to be defining words you should define them properly.
>Fuel doesn't become more unstable, so to speak. the flashpoint remains
the same
>for any given octane rated fuel. You are just reaching the flashpoint
sooner via more
>compression (heat) before you want it to happen... raising octane raises
the flash point
un新ta搓le 1. a.Tending strongly to change 4.Chemistry.
a.Decomposing readily. b.Highly or violently reactive
Once again my description of becoming unstable was technically accurate.
Since everyone knows fire is nothing more then a chemical reaction it was
very accurate by stating adding pressure (pressure is energy which is then
released as heat, another form of energy) to the system the energy of the
system is increased. As the energy of the system is increased the system
will want to release this energy. Hence becoming unstable. By raising the
compression ratio from one value to the a higher value the fule will become
more unstable.
I recommend next time you decide to one up someone you should make sure you
are technically correct.
"Casper" <stop...@msn.com> wrote in message
news:skolvb...@corp.supernews.com...
>
> "Mike" <mik...@nycap.rr.com> wrote in message
> I'm not picking on your simplification, just pointing out that it was
almost too
> simple, to the point of being misleading to someone that wasn't as
knowledgeable
> as you.
>
>
Mike
spell.
Ok, let's keep this discussion on the up and up. Everyone make spelling
errors. Childish comments like that get you nowhere. You should spell
check you original post before you make another foolish comment like that.
Mike
"Casper" <stop...@msn.com> wrote in message
news:skquac...@corp.supernews.com...
>
> "Mike" <mik...@nycap.rr.com> wrote in message
news:mSd35.14104$rc.1...@typhoon.nyroc.rr.com...
> > This could go on forever...
>
> To quote myself, just incase you got to defensive and didn't read down far
enuf!
>
> > > I'm not picking on your simplification, just pointing out that it was
> > almost too
> > > simple, to the point of being misleading to someone that wasn't as
> > knowledgeable
> > > as you
>
> bla, bla, bla... and so on...
>
> > I recommend next time you decide to one up someone you should make sure
you
> > are technically correct.
>
Mike
>Combustible = will ignite/explode when a certain temperature (flash point)
>is reached. No flame or spark needed.
Flammable and combustible liquids are liquids that can burn. They are
classified, or grouped as either flammable or combustible, by
their flashpoints. Generally speaking, flammable liquids will ignite (catch
on fire) and burn easily usually at normal working temperatures.
Combustible liquids have the ability to burn at temperatures that are
usually above working temperatures.
There are several specific technical criteria and test methods for
identifying flammable and combustible liquids. Under the Workplace
Hazardous Materials Information System (WHMIS), flammable liquids have a
flashpoint below 37.8°C (100°F). Combustible liquids
have a flashpoint at or above 37.8°C (100°F) and below 93.3°C (200°F).
Note it doesn't say anything about having to apply a spark or explode. Only
burn. So once again flammable and combustible are for all intents and
purposes the same thing.
A material's flammable or explosive limits also relate to its fire and
explosion hazards. These limits give the range between the lowest
and highest concentrations of vapor in air that will burn or explode.
The lower flammable limit or lower explosive limit (LFL or LEL) of gasoline
is 1.4 percent; the upper flammable limit or upper
explosive limit (UFL or UEL) is 7.6 percent. This means that gasoline can be
ignited when it is in the air at levels between 1.4 and 7.6
percent. A concentration of gasoline vapor in air below 1.4 percent is too
"lean" to burn. Gasoline vapor levels above 7.6 percent are
too "rich" to burn. Flammable limits, like flashpoints however, are intended
as guides not as fine lines between safe and unsafe.
Notice there is no "combustible limit". That is because there is no
difference between combustible and flammable when we are talking about the
time derivative of expansion.
> You are entirely wrong! Take some, no a lot, of chemistry classes..
>
> You'll discover that there is a LOT of things you didn't know.... or
Webster
> for that matter... ;)
Just because you took high school chemistry doesn't mean you are a Chemist.
My fathers day was excellent. Thank you for asking.
Mike
"Casper" <stop...@msn.com> wrote in message
news:skqusq...@corp.supernews.com...
>
> "Mike" <mik...@nycap.rr.com> wrote in message
news:mSd35.14104$rc.1...@typhoon.nyroc.rr.com...
> > This could go on forever...
> > "Casper" <stop...@msn.com> wrote in message
> > news:skolvb...@corp.supernews.com...
>
> > Combustible and flammable are by, Webster's, definition the same thing
>
Casper
"Mike" <mik...@nycap.rr.com> wrote in message news:Xni35.16129$rc.1...@typhoon.nyroc.rr.com...
> There are several specific technical criteria and test methods for
> identifying flammable and combustible liquids. Under the Workplace
> Hazardous Materials Information System (WHMIS), flammable liquids have a
> flashpoint below 37.8°C (100°F). Combustible liquids
> have a flashpoint at or above 37.8°C (100°F) and below 93.3°C (200°F).
>
> Note it doesn't say anything about having to apply a spark or explode. Only
> burn. So once again flammable and combustible are for all intents and
> purposes the same thing.
Dude, you are totally off base here, and you DON'T want to go any further!
Yes, my education goes way beyond the High School level, unlike yours.... idiot!
I know WHAT I'm talking about, unlike you, just looking up the definition of words.
Get a life!
I bated a hook for someone, much like you, but he knows who he is..
Quit nibbling at the hook and let him take the bate! You moron!
Mike
and you NOTHING. Just because you say something doesn't make it fact. For
someone who seems to be so right and knowledgeable you seem to act far more
like a child. No need for name calling. We are having a debate about
factual knowledge. You haven't said anything that could possibly change my
mind or the others reading this post. You have not presented a case with
any fact. Did you win the Nobel prize for Chemistry or something? Who are
you that makes you think that just because you say something makes you
right? I have no problems with admitting I am wrong but until you prove me
such I will not.
> I know WHAT I'm talking about, unlike you, just looking up the definition
of words.
> Get a life!
You were the first to inaccurately define the 2 words, not I. I am just
clearing up a mistake you made. So YES it is a discussion about definition.
Mike
"Casper" <stop...@msn.com> wrote in message
news:skreiks...@corp.supernews.com...
Casper
"Mike" <mik...@nycap.rr.com> wrote in message news:y0n35.16410$rc.1...@typhoon.nyroc.rr.com...
> See unfortunately for you I have brought factual knowledge to the table
> and you NOTHING. Just because you say something doesn't make it fact. For
Dude, go back to school, and yes, this time learn something... then, you will look
back on this thread and say, "boy, was I an idiot"......
ho...@nospamextremejeep.com
Been cruising this thread...sorry Casper, you lose. Say something besides
"I'm right and you're wrong, neenor neenor" and maybe you'll earn
something besides of rank of "Namecalling moron."
http://www.osha-slc.gov/SLTC/smallbusiness/sec8.html
Are flammable and combustible the same? The definitions of the WORDS may
make them sound like they're the same...but technically, they're not.
--
--
Hogan Whittall
'47 CJ2A - 302, C5, 5.38's, yada, yada
'98 XJ Classic - BFG MTs, RS9ks
__________________________________________________________________
This is formal notice under California Assembly Bill 1629, enacted
9/26/98 that any UCE sent to my email address will be billed $50
per incident to the legally allowed maximum of $25,000.
__________________________________________________________________
Erich Coiner
>
> Dude, you are totally off base here, and you DON'T want to go any further!
> Yes, my education goes way beyond the High School level, unlike yours.... idiot!
>
> I know WHAT I'm talking about, unlike you, just looking up the definition of words.
> Get a life!
>
> I bated a hook for someone, much like you, but he knows who he is..
> Quit nibbling at the hook and let him take the bate! You moron!
If you had been paying attention instead of spanking your monkey in all
that way beyond education you would know the word is bait, not bate.
Erich
Casper
<ho...@NOSPAMextremejeep.com> wrote in message news:HSs35.14$WW1....@news.pacbell.net...
> Casper <stop...@msn.com> wrote:
> Been cruising this thread...sorry Casper, you lose. Say something besides
> "I'm right and you're wrong, neenor neenor" and maybe you'll earn
> something besides of rank of "Namecalling moron."
Good for you... You've been paying attention. for the most part.
But, I think "some" of it got by you. Re-read this thread again and see
if you get it.
The name caller get's called a name... ummm... getting the picture yet?
Next week, we'll have another class..... what should the subject be this time?
> http://www.osha-slc.gov/SLTC/smallbusiness/sec8.html
>
> Are flammable and combustible the same? The definitions of the WORDS may
> make them sound like they're the same...but technically, they're not.
So, are you agreeing with me or not? make up your mind. Also, I don't think I'd
use OSHA as a source of knowledge.
Some fodder, just for you.... Have you ever heard of grain silos exploding?
Well, it happens... and why, because of combustion, here's that word again, brought
on by heat, here's that word again. No fire and;/or spark present, just heat.
Why shouldn't you leave oily rags in an enclosed area? Uh, yes, you run the possibility
of combustion happening...
Getting the picture yet? So, there is more than "just" a technical difference between
being flammable and combustible.
Casper
incorrect sentence, because it doesn't make much sense.
On second thought, please don't.
"Erich Coiner" <coi...@epg.sdd.hp.com> wrote in message news:394E6519...@epg.sdd.hp.com...
Mike
must get ignited. Without the ignition there would be no explosion. We all
understand that. The problem is with what you said.
(me)
>> creates such high cylinder pressures the fuel just explodes. So since
you
(you)
>That's called combustion. Gasoline is both flammable and combustible.
>Flammable = will inginte when contacted with a flame and/or spark.
>Combustable = will inginte/explode when a certain temperature (flash point)
>is reached. No flame or spark needed.
The fuel obviously must catch file some how. Now since fuel has higher
ignition temperature it meets the requirement for COMBUSTION NOT FLAMMABLE.
No one is disagreeing with you on this point. You were correct in that
sense but you were not correct in correcting me by stating the fuel doesn't
explode. The fuel does explode.
"Casper" <stop...@msn.com> wrote in message
news:sktp08...@corp.supernews.com...
Erich Coiner
I'm not because the sentence is correct. It is just a more complex
structure than someone with a six grade education can understand.
Thanks for confirming you are an illeducated buffoon.
Erich
Casper
"Erich Coiner" <coi...@epg.sdd.hp.com> wrote in message news:394FAC1F...@epg.sdd.hp.com...
<snip> The sound of the line being cut....
I'm fishing for carp, not rock bass.... find another hook.
Casper
Casper
<coi...@epg.sdd.hp.com> wrote:
(snip) The sound of the line being cut....