Are intercoolers really that effective???

[GWInquisitor14]

Alright now, i dont wanna sound stupid w/ this question and I know my rating is still at newbie, but here is my question...how effective are intercoolers really?...I know everyone is gonna be like oh they are great, they cool the air coming into ur engine from the turbo, blah blah blah yes i know but lets look at it from the scientific view

Boyles law states P1 + V1 = P2 + V2
meaning that when the pressue increases, the volume decreases. This shows that yes science is correct, cuz when a turbo increases the pressure coming in, that volume of air is decreased so u can fit that same amount plus more into the same size container ie the cylindar.

Now you have Gay-Lussac's Law (yes i've mad almost all the jokes in chem class myself about the name)
it states P1/T1 = P2/T2
mean that when the pressure increases so does the temp, that is why people think they need an intercooler. Now, this also says that when the temperature falls, so does pressure. That is why now in the winter many ppl are running on flatter tires, its colder so they have less pressure in their tires. So now wouldn't cooling that incoming air just make that pressure go back up. Now i'm not saying that w/ an intercooler u'll go back to normal atmospheric pressure, im saying that when ur running 7 PSI, and u have an intercooler maybe it drops down to 6 or 6.something. So wouldn't it make more sense to cool the air, the compress it?
If there is more to this chemistry than I know, please respond w/ that because I am only in high school chemistry but this is something that dawned upon me while actully paying attention for once. Once you hear pressure and psi come outta a teachers mouth, it grabs ur attention.

[killah_xft]

well the intercoolers are effective to cool the air going into your engine from the hot turbo... it's the same effect as a cold air intake... colder air just combusts better.. I don't know specifically why but it does. Also with an intercooler, you are supposed to run at a higher PSI to compensate for the intercooler. Such as if you were running at 5-8 PSI with a straight turbo. When you install an intercooler you should bump it up to about 12-18 PSI. Depending on the size of the Intercooler, and how much actual boost you wanted to run..

[tibby01]

Originally Posted by GWInquisitor14

Once you hear pressure and psi come outta a teachers mouth, it grabs ur attention.

spoken like a true tuner. good job lol.

the thing is that you cant cool the air, then compress it. any amount of cooling you do to the air(however you plan on doing it) will be nulled not only when it is compressed, but also when it hits the turbo, which is connected to the exhaust manifold.

also, you're turbo can only create so much pressure. the intercooler drops the pressure(by dropping temperature), while keeping the number of moles of oxygen the same. so the whole point of the intercooler is to get more oxygen in the same amount of space by cooling the air. more oxygen allows for more fuel to burn, which equals more power. the intercooler also helps in reducing premature combustion in the engine by keeping temperature and pressure down.

now sometimes an intercooler isnt needed. it can sometimes drop the pressure because they sometimes have a larger volume than the piping, which causes lag. sometimes the intercooler efficiency is not enough to overcome the fact that they can add a little bit of lag, and also aerodynamic drag to the compressed air. to find IE, find the difference between the temps of the air before the intercooler and ambient air, and then divide that by the difference between the temps of the air before and after the intercooler.

if that didnt explain it, ask again. im pretty tired(just worked8 hours and went to college for 6 hours) so i could have messed up on something, so if any of you see a mistake, correct it.

[PunkAlex]

Science is great-really it is-but lets talk real world applications:

Would you really want to run your street car at 20 psi on pump gas without one?

[andera]

alex, i would. because i need an engine rebuild hehe

[IntegraB18LS]

Originally Posted by killah_xft

colder air just combusts better.. I don't know specifically why but it does.

Not true, hotter air will compress and ignite alot easier, hell it will even do it without a a spark depending how hot or how much compression/boost you are running (just like a deisle engine)

colder air will allow you to add more fuel to it because (my brain does not want to work right now, its either more or less dense, sorry long week, brain shut down) ANYWAYS more air + more fuel = more power.
colder the air the more fuel you can add.

well so then yes colder air does combust better if you mean its alot more stable, when you dump in hot compressed air it just wants to combust ASAP and that is what detonation (pinging) is


bed time
Kyle

[tibby01]

Originally Posted by IntegraB18LS

(my brain does not want to work right now, its either more or less dense, sorry long week, brain shut down)

cold air= more dense

more dense= more molecules of owygen

more oxygen molecules= more available molecules for fuel to use when combusting

cause fire cant exist without good ole' o2.

[Bronco2]

BTW-the post 96 terminology is "after cooler",which makes more sense. Compressing air causes it to heat, cooling the after the turbo condenses the air to more O2 in less space. Most modern diesels run an aftercooler as big as the radiator. I am not a college student,do not know the math,but it must work.

[Creepingdeath]

You guys are too damn smart

[Hypsi87]

I know it's not a Honda but to give you a comparison..... The 1984/85 Grand Nationals where not intercooled. the max safe boost you can run on pump gas for the "hot air" cars is like 12 PSI. the 86/87 GN's where intercooled and the max safe boost on pump gas is 17 PSI. Same compression raitos between the two motors. The major difference is the intercooler.

[Reed]

bernouli's principle
( we don't need to worry that much about velocity)
( we just want to shove as much air (density) into our cylinders as we can)

(< = increase, > = decrease)

< velocity = > pressure, therefore > temp
< pressure = < temp, and > velocity
< temp = < pressure, therefore > velocity
> velocity = < temp, therefore <pressure
> pressure = > temp
>temp = >pressure

increasing pressure increases density (turbo)
decreasing temperature increases density (intercooler)

turbo heats charge air through compression and because turbos get very hot, and even though the intercooler decreases our velocity it will increase our density which is what we want.

we can't cool the air before the turbo because passing atmosphere through the intercooler around the air that is already at atmosphereic temp will not cool anything, we must wait until the air is hot from compression

there are alot of facts here and if i messed anything up or if something doesnt make sense, fell free to correct me or ask what i mean