So get this some noob tells me

[JJ Alfano]

that a SR20 has more displacement that a KA24. I told him that the motor numbers explain the displacement, and since 24 is greater than 20..he is an idiot. He then tells me "not really, the SR is turboed."


Am i in the wrong? Now, for the record, i think this guy meant to say was the compression was more because of the added boost, but then again...who knows with these noobehs

discuss.

[suprabrit]

haha I love know-it-all ricers!

My b/f's old boss (who owns 3 shops btw) tried to tell him that the displacement was determined by the intake manifold...lol.

[Casey]

uh ...

24 = 2.4 liters of displacement
20 = 2.0 liters of displacement

displacement = total amount of volume that all pistons displace

compresson = ratio of the (volume of combustion chamber when piston is at lowest point )/(volume of combustion chamber when pistion is at highest point)

motors range from 7:1 in extreme turbo applications
all the way to 14:1 15:1 in high compression applications, a diesel motor can be significantly higher.

increasing compression will always increase the efficiency of the motor. because more power can be achieved from a higher compression motor, while still using the same amount of fuel, typically you only reduce compression to account for higher boost levels.

idk guy sounds like an idiot

[Z infidel]

You should have slapped him with a 2x4.

[shawn shawn]

tell him the KA is a v6 and the sr is a inline 5

[DAsquintz]

tell him the KA is a v6 and the sr is a inline 5

lolz and tell him too pour more blinker fluid. his vtec will kick in faster.


You should have slapped him with a 2x4.

or a salmon

[Andy C]

This girl with a civic tried to tell me that she got more displacement from larger injectors. I didn't even want to go there, so i let her have it.

[danger355]

everyone knows the only thing that gives more displacement is aftermarket muffler bearings.

[Z-Bryan]

uh ...

24 = 2.4 liters of displacement
20 = 2.0 liters of displacement

displacement = total amount of volume that all pistons displace

compresson = ratio of the (volume of combustion chamber when piston is at lowest point )/(volume of combustion chamber when pistion is at highest point)

motors range from 7:1 in extreme turbo applications
all the way to 14:1 15:1 in high compression applications, a diesel motor can be significantly higher.

increasing compression will always increase the efficiency of the motor. because more power can be achieved from a higher compression motor, while still using the same amount of fuel, typically you only reduce compression to account for higher boost levels.

idk guy sounds like an idiot

I have a somewhat n00b question

I understand the 7:1 theory
But what is the unit of measurement for the 7:1
ltrs??

Pardon my n00b-ness

oh and also when people talk about gear ratios, what unit of measurement are they talking about too?

thanks

[Lone_Wolf]

i didnt even know that compression ratios went that low.. met a guy tonight with a supercharged camaro (w/ 7:1 compression) and he said since he didnt have an intercooler he needed as low compression as he could to keep temps down.


http://i36.photobucket.com/albums/e5/Jdugan06/102_3811.jpg


http://i36.photobucket.com/albums/e5/Jdugan06/102_3813.jpg

[Wes]

That shit is hot.^

[Lone_Wolf]

that shit is trash

[Wes]

I'd drive the hell out of that. With a big rebel flag on the roof, and with a mullet and a Motley Crue t-shirt, with Skynyrd blasting!

[Casey]

I have a somewhat n00b question

I understand the 7:1 theory
But what is the unit of measurement for the 7:1
ltrs??

Pardon my n00b-ness

oh and also when people talk about gear ratios, what unit of measurement are they talking about too?

thanks

its a ratio
it could mean anything

liters or diameter anything at all

you can calculate how much undisplaced volume in the compression chamber by doing this

put 2.0 over 8
equals to
x over 1

get comon denominators and solve
then divide the fraction out and you get the total undisplaced area.

there arent any units
but if you really feel like it you could turn it into units lol.... but a ratio doesnt have to be units

and gear RATIOS arent units either

like say the differential ratio is 4.02 or something like that
its a ratio over 1
so 4.02 : 1

for every 4.02 rotations of the driveshaft, the wheels spin one time.




i didnt even know that compression ratios went that low.. met a guy tonight with a supercharged camaro (w/ 7:1 compression) and he said since he didnt have an intercooler he needed as low compression as he could to keep temps down.




yeah they go that low
but its not to keep heat down
its to keep the engine from knock / preignition
if he had an intercooler it would solve that lol ...




That shit is hot.^

i like the motor... not so much the supercharger... twin turbos / twin intercooled superchargers ftw

[JJ Alfano]

^^ he was beat up in high school

[carlova78]

jayjay ur hom dawg. thanks for the help. shyea ace man was a noobie mc ooberton

[Casey]

^^ he was beat up in high school

me?
haha atleast i dont get raped over the internet lol....
only a true moron can make hijmself look completely stupid over text

[JJ Alfano]

and you succeeded by taking me serious.


gg

[Z-Bryan]

its a ratio
it could mean anything

liters or diameter anything at all

you can calculate how much undisplaced volume in the compression chamber by doing this

put 2.0 over 8
equals to
x over 1

get comon denominators and solve
then divide the fraction out and you get the total undisplaced area.

there arent any units
but if you really feel like it you could turn it into units lol.... but a ratio doesnt have to be units

and gear RATIOS arent units either

like say the differential ratio is 4.02 or something like that
its a ratio over 1
so 4.02 : 1

for every 4.02 rotations of the driveshaft, the wheels spin one time.


But that doesnt make sense

I could say I have 4:6

I could mean I have 4 apples to 6 oranges
If you say I just have 4:6 you could mean anything

You fuel tank doesnt just say 15 it says 15 gallons

There has to be some unit for 7:1
Every 7 so and so's to every 1 so and so

[S14Tech]

um its air's compression... 1 cylinder full of air with its piston at bottom dead center will become 1/7 its volume once the piston has reached TDC. Same amount of air, compressed 7 times as much, thus 7:1. Also works with pressure via boyles law or some shit, 1 atm of pressure becomes 7 at TDC due to the movement of the piston all the way up the cylinder. Am i right? or am i right?

As far as the ricers comment... an sr20 does technically move more air than a ka24, making it seem like its "displacing" air, but engine displacement being defined purely by spacial volume means that no matter what 2.4 >2.0. I just felt it necessary to note that.

[Z-Bryan]

ok I understand its in volume

Which is what I thought

and gear ratios
if it was 2:1
the first one spins twice for every time the 2nd one spins once

Got it

[JJ Alfano]

i feel smarter guys thanks!

[Casey]

um its air's compression... 1 cylinder full of air with its piston at bottom dead center will become 1/7 its volume once the piston has reached TDC. Same amount of air, compressed 7 times as much, thus 7:1. Also works with pressure via boyles law or some shit, 1 atm of pressure becomes 7 at TDC due to the movement of the piston all the way up the cylinder. Am i right? or am i right?

As far as the ricers comment... an sr20 does technically move more air than a ka24, making it seem like its "displacing" air, but engine displacement being defined purely by spacial volume means that no matter what 2.4 >2.0. I just felt it necessary to note that.


well pressure is inversly proportional to volume.

thus 1 liter of air at sea level = ~100kpa or 14.7psi or 1 bar
compress the air to .5 liters and you get 200kpa 29.4psi and 2 bar
decompress the air to 2 liters and you get 50kpa 7.35psi and .5 bar