2" or 2.5" tubing for DIY FMIC setup??

[hotrodf1]

Hey guys,

I have been thinking about doing a DIY style FMIC sometime in the near future. It seems like most of the piping kits are in the 2.5" alum tubing. But when I look at the pics of most of the branded kits, the piping looks like it might just be 2.0". Can anyone suggest whether 2 or 2.5" tubing would be best for no more than 10psi on stock internals motor??

It seems the 2.0" would offer less turbo lag for sure, since the volume to fill would be quite a bit smaller I think.

From my meager math skills it looks as if sizing up from 2.0 to 2.5 increasing the volume inside the piping by a whopping 56%.

what do you guys think??

[505zoom]

Air expands and gets denser as it goes through the IC. So, if you want to keep the pressure and velocity exactly the same throughout the whole IC system, you need to use larger piping for the cold side than you use on the hot side.

As for the actual diameter, that depends greatly on how much power you are going to run.

[boostdprotegelx]

well i've got 2.5" cold and 2"hotside...

[hotrodf1]

well i've got 2.5" cold and 2"hotside...

Hmmm. Never thought about that.
I think maybe 505zoom meant to say they other way around? Since the air after the intercooler will be cooler and more dense, the pipe would be smaller to keep the velocity the same.

But does it matter anyway??

I suppose using the smaller pipe on the cold side would be one way to reduce the overall volume of the system without sacrificing the flow from the hot air direct from the turbo.

[505zoom]

Hmmm. Never thought about that.
I think maybe 505zoom meant to say they other way around? Since the air after the intercooler will be cooler and more dense, the pipe would be smaller to keep the velocity the same.

Nope... you need a larger volume pipe to deal with denser air.
Hot, thinner, less dense air = small diameter
Cold, thicker, denser air = larger diameter


But does it matter anyway??

If you want to half-ass it, no. If you want to do it right, yes.


I suppose using the smaller pipe on the cold side would be one way to reduce the overall volume of the system without sacrificing the flow from the hot air direct from the turbo.

(uhm)

[boostdprotegelx]

Hmmm. Never thought about that.
I think maybe 505zoom meant to say they other way around? Since the air after the intercooler will be cooler and more dense, the pipe would be smaller to keep the velocity the same.

But does it matter anyway??

I suppose using the smaller pipe on the cold side would be one way to reduce the overall volume of the system without sacrificing the flow from the hot air direct from the turbo.
no dude, he meant what i said. exactly how i have it. go get it done:)

[hotrodf1]

Hmmm.

I'm still having trouble getting my brain around this one.

2" pipe for hot air
2.5" for cold air.

Wouldn't that mean that there would be a lot more velocity in the small tube, considering that the same weight of air is traveling through the system. So then the air would be moving slower while in the intercooler (large x-sect area), and then would remain moving at the slower rate while it travels to the TB through the bigger 2.5" pipe?

Perhaps there's not as much velocity change as the air goes from the IC to the cold pipe, thus less turbulence??

maybe I'm trying too hard?

[boostdprotegelx]

Hmmm.

I'm still having trouble getting my brain around this one.

2" pipe for hot air
2.5" for cold air.

Wouldn't that mean that there would be a lot more velocity in the small tube, considering that the same weight of air is traveling through the system. So then the air would be moving slower while in the intercooler (large x-sect area), and then would remain moving at the slower rate while it travels to the TB through the bigger 2.5" pipe?

Perhaps there's not as much velocity change as the air goes from the IC to the cold pipe, thus less turbulence??

maybe I'm trying too hard?
trying to hard. ...that's what most people run.

[hotrodf1]

trying to hard. ...that's what most people run.

thought I might be. Are most of the professional kits done the same way as well?

I'm an engineer by trade so I'm usually drawn to the "why" side of things u know.

Hell,, it would be easier to snake the 2" tubing to the intercooler anyway, since the A/C compressor is in the way. . .
Maybe that's why???

sorry, couldn't resist. . . .

[boostdprotegelx]

thought I might be. Are most of the professional kits done the same way as well?

I'm an engineer by trade so I'm usually drawn to the "why" side of things u know.

Hell,, it would be easier to snake the 2" tubing to the intercooler anyway, since the A/C compressor is in the way. . .
Maybe that's why???

sorry, couldn't resist. . . .
could be man.. there's perf info on those. most guys go this way. like i said, i am too.

[hotrodf1]

could be man.. there's perf info on those. most guys go this way. like i said, i am too.

alright, will be filed under "things I learned today" :)

[boostdprotegelx]

alright, will be filed under "things I learned today" :)
hahah. i learn something new every day.especially working on cars.

like, o-rings on injectors are made an easy install w/ petroleum jelly.

[mryellermp5]

i have alot of misc 2.75" bends and lengths if interested and couplers w/ t-clamps i was gonna use for the coldside but i have alot exrtra...lmk

[505zoom]

Hmmm.

I'm still having trouble getting my brain around this one.

2" pipe for hot air
2.5" for cold air.

Wouldn't that mean that there would be a lot more velocity in the small tube, considering that the same weight of air is traveling through the system. So then the air would be moving slower while in the intercooler (large x-sect area), and then would remain moving at the slower rate while it travels to the TB through the bigger 2.5" pipe?

Perhaps there's not as much velocity change as the air goes from the IC to the cold pipe, thus less turbulence??

maybe I'm trying too hard?

Nope... here lemme try one more time on this one for ya.

Think of the system with a 2" diameter pipe going from the turbo to the IC. The air in this pipe is very hot after going through the compressor, so it is going to be thinner than it will be after it is cooled.

The hot air inside this pipe will have a given velocity/pressure for a given RPM/gear. Now that air gets cooled down in the IC, which makes it expand and be more dense.

If you then used a 2" diameter pipe from the IC to the motor, you would be basically cramming the cool, dense, expanded air into a pipe that is too small.

If you do it properly, and make the IC to TB pipe a larger diameter, then the colder denser air can move along at the same velocity and pressure as it was before it was cooled.

Hope this helps.

[boostdprotegelx]

Nope... here lemme try one more time on this one for ya.

Think of the system with a 2" diameter pipe going from the turbo to the IC. The air in this pipe is very hot after going through the compressor, so it is going to be thinner than it will be after it is cooled.

The hot air inside this pipe will have a given velocity/pressure for a given RPM/gear. Now that air gets cooled down in the IC, which makes it expand and be more dense.

If you then used a 2" diameter pipe from the IC to the motor, you would be basically cramming the cool, dense, expanded air into a pipe that is too small.

If you do it properly, and make the IC to TB pipe a larger diameter, then the colder denser air can move along at the same velocity and pressure as it was before it was cooled.

Hope this helps.


that should work wonders.

[BradC]

The hot air inside this pipe will have a given velocity/pressure for a given RPM/gear. Now that air gets cooled down in the IC, which makes it expand and be more dense.
Wouldn't air (a gas) contract when cooled?

[505zoom]

Wouldn't air (a gas) contract when cooled?

If cool air was lighter and thinner than hot air, then we would use cold air in "hot-air baloons", no? :)

[hotrodf1]

Wouldn't air (a gas) contract when cooled?

He's right . . .
remember from physics . . .

PV = nRT (IIRC, its been 8 or 9 years for my old ass)
Pressure * volume = n *r * T(temp)

So, if the temp goes down (after the IC) the equation shows that either the 1) pressure must fall, or 2) the volume must decrease.
We know the pressure should be close to the same before the IC as it as after the IC (maybe within a 1psi or so??), so with the same mass of air in the system, that only leaves the volume, which will be smaller.

This is why I thought the bigger pipe should carry the hotter air, which would be a larger volume (by weight) than the cold, dense air.

[awsmp5]

thats mind boggling... dense means more mass no? as in a dense rock has more mass in the same volume as a less dense rock so if the mass is going to be the same since there's no more air being added...
shouldn't the hot side be bigger than the small because hot air and hot hting in general expands?

[hotrodf1]

thats mind boggling... dense means more mass no? as in a dense rock has more mass in the same volume as a less dense rock so if the mass is going to be the same since there's no more air being added...
shouldn't the hot side be bigger than the small because hot air and hot hting in general expands?

More dense means more mass, as long as the volume is not changed.

yes sir, thats what I'm takling about if I read the post correctly

Mass is the product of volume and density

Mass = vol * density

[awsmp5]

yay physics i freakin hate that class

[hotrodf1]

yay physics i freakin hate that class

well its useful shit anyway

[awsmp5]

true true... especially for my engineering major...

[orphman]

one would assume... an i know ass u me.. etc .. but assume.. lets say you have 8 paritcles of air in a 2.5 inch part... as temp decrease the particels will become closer no..?. .. not more air or less air... just more dense... so i would assume.. to keep presure you would want larger on hot side... cooler on cold.. i could be totaly wrong but... i dunno.. that make any sense..?
think about it... but then again... maybe im missing something.. wich would nto be a first... (enguard)

[volcombro16]

Im running 2.5 on both sides at 8psi and i have great throttle response. Plus my charge pipe is ice cold all the time.

[awsmp5]

one would assume... an i know ass u me.. etc .. but assume.. lets say you have 8 paritcles of air in a 2.5 inch part... as temp decrease the particels will become closer no..?. .. not more air or less air... just more dense... so i would assume.. to keep presure you would want larger on hot side... cooler on cold.. i could be totaly wrong but... i dunno.. that make any sense..?
think about it... but then again... maybe im missing something.. wich would nto be a first... (enguard)

yeah thats how i was thinking...
but i dunno much about turboing cars so maybe we're missing something

[hotrodf1]

yeah thats how i was thinking...
but i dunno much about turboing cars so maybe we're missing something

all three of us are thinking the same, but it does not necessarily mean that we see all the angles of course.

I have been trying to think of why we might want the small pipe on the turbo side, but I can't quite get it.

Maybe a physics major could do some good. used to know one. Haven't spoken to him in years. nows probably not the time. . . .

I would like to see someone try the 2.5" tube from turbo to IC and then the 2" to the TB. maybe that someone is me. I dunno.

[orphman]

all three of us are thinking the same, but it does not necessarily mean that we see all the angles of course.

I have been trying to think of why we might want the small pipe on the turbo side, but I can't quite get it.

Maybe a physics major could do some good. used to know one. Haven't spoken to him in years. nows probably not the time. . . .

I would like to see someone try the 2.5" tube from turbo to IC and then the 2" to the TB. maybe that someone is me. I dunno.


if you go that route ... please keep me informed...

[khaosman]

Since this thread is alive, I'll throw this in. What do you guys use to cut the piping while you are piecing it together? hacksaw? That seems like it'd suck, but I guess it'd work...

[505zoom]

Trust me guys, you've got it backwards. Smaller diameter hotside, larger diameter coldside is the way to do it.

[JCell]

^^

completly agree, the best way to run a proper IC setup

[mryellermp5]

go to ur local home pot store or tool rental place and rent a metal chop saw..the one u pull down on (miter saw)..with a metal cutting blade on it...
Since this thread is alive, I'll throw this in. What do you guys use to cut the piping while you are piecing it together? hacksaw? That seems like it'd suck, but I guess it'd work...

[PlatinumMSP]

Hey guys,

I have been thinking about doing a DIY style FMIC sometime in the near future. It seems like most of the piping kits are in the 2.5" alum tubing. But when I look at the pics of most of the branded kits, the piping looks like it might just be 2.0". Can anyone suggest whether 2 or 2.5" tubing would be best for no more than 10psi on stock internals motor??

It seems the 2.0" would offer less turbo lag for sure, since the volume to fill would be quite a bit smaller I think.

From my meager math skills it looks as if sizing up from 2.0 to 2.5 increasing the volume inside the piping by a whopping 56%.

what do you guys think??

use 2.25" piping like the Perrin kit

[BradC]

He's right . . .
remember from physics . . .

PV = nRT (IIRC, its been 8 or 9 years for my old ass)
Pressure * volume = n *r * T(temp)

So, if the temp goes down (after the IC) the equation shows that either the 1) pressure must fall, or 2) the volume must decrease.
We know the pressure should be close to the same before the IC as it as after the IC (maybe within a 1psi or so??), so with the same mass of air in the system, that only leaves the volume, which will be smaller.

This is why I thought the bigger pipe should carry the hotter air, which would be a larger volume (by weight) than the cold, dense air.
Right, right, Ideal gas law. That what was on my mind when I posted, because of the direct proportionality of what we were talking about, anyone else care to chime in on how this works in the real world?


If cool air was lighter and thinner than hot air, then we would use cold air in "hot-air baloons", no? :)
I said air contracted when cooled, not expanded and rose. The reason a hot-air balloon fills, is because the heated air expands and fills it out, no?

[Speed3.5]

hmmmmmm
let me add 2 cents in this issue, bc i too am about to make a decision to choose what size to make the diy FMIC.
As future engineer i'd say that bigger size 2.5 would be from sucktion side ( intake manifold) , and about hot side this is give or take but since there's two forces acting and drastic temp changing you could go 2.25 from hot side, this being smaller might help on pushing much faster the air as the main force there is toward ic and hot air is hard to controll on the other hand the cold side could be bigger than the hot on helping pulling/sucking the air acumulated in the ic at much faster rate.

there's laws that apply but as far as i remember in physic or chem there's no example on turbo situation that we are dealing with. They cover mostly general situation.

But for curiousity, this mech from a mazda deal in wayne (around my area) he build his 4" cold and 3.5 hot size but his running a huge turbo.

[hotrodf1]

I'm toying with the idea of lurking around the H**** boards for a minute to see what they say. They have been doing this stuff for a while, too.

Get a second opinion just for fun.

[hotrodf1]

use 2.25" piping like the Perrin kit


here's the question of the day: is the Perrin kit 2.25" on both sides of the IC?? I know they use a huge IC, so if the 2.25" can feed it effectively, that might be the size.

[hotrodf1]

go to ur local home pot store or tool rental place and rent a metal chop saw..the one u pull down on (miter saw)..with a metal cutting blade on it...

or u can buy one at a place like Harbor freight tools for a onsale price of around $49. I use mine all the time. love it. High quality it's not , but it gets the job done everytime and beats the hell out of a sawzall (recip. saw)

[hotrodf1]

I did spend some time looking at compressible gas fluid flow. There is a calculator type deal you can get on the net and it showed that the hotter the air was, the less mass you could flow through a pipe, which suggests that to get the same flow capability throughout the system, you would want a larger pipe to the IC and smaller to the TB.

USing the calculator, I looked at different lengths of piping, and that didn't change flow all that much. But, using a 2" pipe seriously inhibited flow as compared with a 2.5" pipe. I dont' know what the cfm requirements for the MSP engine is, but the 2" pipe seemed hardly sufficient, if you wanted to keep a 1 psi drop or less.

At this point, I can't see that limiting that flow (and possibly increasing the pressure drop through the system, making the turbo work harder) with the 2" pipe would be a good thing.

I wish someone could explain the actual reasoning behind using the 2" to the IC and then the 2.5" to the TB.

The notes on the site did say that the high pressure side of a system was less finicky about flow restrictions than the low pressure suction side (which would be the CAI, SRI, etc.) And that makes sense.

Any more input on this???

[GA_MZDASPEED]

Hot air is thinner (less mass/volume, very low viscosity) and can be forced through smaller openings using less energy (think: water through a straw vs milk shake) the milk shake IS less dense but more viscous. If fluid dynamics can be used for advanced aerodymanics it makes sense that the idea of viscosity can be used in this discussion. the opening that ALMOST ALL of exhaust gases exit the turbo through is very small. this is done on purpose the small opening creates the EXTREME velosities that are needed to spool up the turbo and compress the cooler denser air on the compressor side. between the exhaust pulses of the engine these high velocity gases will accually PULL the slower gases behind it. the gases that get compressed on the compessor side rise in tempeture by hundreds of degrees. these now hot gases must now exit the compressor housing and do so through a relatively small opening to maintain this velosity and take advantage of the scavenging effect the high velosity gas has on the gases behind it. this means that the velocity of the hot gas is most important.(hot charge air in this instance) equal volume of gas through smaller hole = higher velocities

these gases then pass through the intercooler (or interwarmer) and emerge out the other side cooler denser and harder to push through the same diameter piper. while you can do it if you want to it will compress the gases and reheat them some (SEE : ideal gas law). the larger diameter pipe will move the gases with minimal reheating of the charge air.

also the velocity of the intake charge it not as important as one would think (in the charge pipe). the intake manifolds on modern engines are HIGHLY engineered to take advantage of the intake stroke pulses and tuned to produce a compromise of volume and velocity through the length and shape of the intake runners in combination w/ the specific volume of the plenum feeding those runners....so the intake charge velocities are generated there and the charge pipe can be larger to keep the reheating to a minimum.....you know.........maybee?

(blah)(blah)(blah)(blah)

[hotrodf1]

Hot air is thinner (less mass/volume, very low viscosity) and can be forced through smaller openings using less energy (think: water through a straw vs milk shake) the milk shake IS less dense but more viscous. If fluid dynamics can be used for advanced aerodymanics it makes sense that the idea of viscosity can be used in this discussion. the opening that ALMOST ALL of exhaust gases exit the turbo through is very small. this is done on purpose the small opening creates the EXTREME velosities that are needed to spool up the turbo and compress the cooler denser air on the compressor side. between the exhaust pulses of the engine these high velocity gases will accually PULL the slower gases behind it. the gases that get compressed on the compessor side rise in tempeture by hundreds of degrees. these now hot gases must now exit the compressor housing and do so through a relatively small opening to maintain this velosity and take advantage of the scavenging effect the high velosity gas has on the gases behind it. this means that the velocity of the hot gas is most important.(hot charge air in this instance) equal volume of gas through smaller hole = higher velocities

these gases then pass through the intercooler (or interwarmer) and emerge out the other side cooler denser and harder to push through the same diameter piper. while you can do it if you want to it will compress the gases and reheat them some (SEE : ideal gas law). the larger diameter pipe will move the gases with minimal reheating of the charge air.

also the velocity of the intake charge it not as important as one would think (in the charge pipe). the intake manifolds on modern engines are HIGHLY engineered to take advantage of the intake stroke pulses and tuned to produce a compromise of volume and velocity through the length and shape of the intake runners in combination w/ the specific volume of the plenum feeding those runners....so the intake charge velocities are generated there and the charge pipe can be larger to keep the reheating to a minimum.....you know.........maybee?

(blah)(blah)(blah)(blah)

First,

Thanks for the insight. I can see this side of the arguement. Basically, we are to flow the hot thin air through the smaller pipe, since it flows easier and we can keep the high velocity up as much as possible to aid in the filling of the system. You talked about scavenging low pressure air behind- but I think that only applies to the exhaust side (and only pre-turbo). I would think the intake side would approach a smooth flow the faster the turbine spins. Nevertheless, the outlet on the turbo is small, probably is for a reason.

Then after the air goes through the IC, it is more dense, which makes it a little harder to push through piping, so we ease the restriction and make the piping larger. However, we must also remember that now there is a smaller volume of air to travel through that pipe, which in itself will take away some restriction in flow through the piping. Without a lot more knowledge in the physics department I cannot prove or disprove either concept, but I know that each has merit on its own. One would win out over another, maybe the happy medium is in fact the larger pipe to feed the TB.

I guess I could do my PVC poor mans FMIC piping with both sizes and see what works better, turbo lag, etc. But I don't have access to a dyno, so the data would not be available. I could do an RPM slope graph with the LM-1, but that wouldn't show HP numbers, only relative numbers acceleration. But, it would tell which worked better, (if even measurable). And then the whole weather condition stuff comes in, and its probably a worthless test.

Okay, I think I'm sold on 2" to the IC and 2.5" to the TB. Plus it will be easier to run the 2" to the FMIC in the first place. And that's worth something . . . :D

[505zoom]

For testing you can always pick up a accelerometer.

[Kypatrick]

im not arguing but doesnt air EXPAND when its heated? Just tryin to make sense of it all!

[hotrodf1]

For testing you can always pick up a accelerometer.

I do have a G-tech, but it's the older single vector type. Wish I had the tri-axis. Guess it would anyhow.

[hotrodf1]

im not arguing but doesnt air EXPAND when its heated? Just tryin to make sense of it all!

We talked about all this earlier. You might go back and read the entire to see what you can find. There was a good bit of discussion.

[hotrodf1]

For the record,

The turbo guys at hotrodders site said the same thing: 2.0" first to carry the less viscous (easier flowing) hot air, then 2.5" to carry the thicker air to the TB.

One guy had that size piping on a 2.8L Datsun making 350 at the crank on 15 psi. If it good enough for him, surely it is for me :D

[Lodivigo]

Come on guys, volume and density are NOT the same thing! My $.02, I have to agree with what everyone else is saying. Mass/Density and Volume are two completely different things. Mass/Density= the number molecules inside something solid, liquid, or gas (like oxygen), Volume= the size or amount of space an object takes up. That being said, everything expands when it is heated, gas, liquid and solid (Law of Thermodynamics). When air is heated it's VOLUME does expand, it's MASS/DENSITY does not.


Time for an analogy, take the internal combustion engine, it's basically a really big turbocharger/air compressor. It takes in cold air, heats it up (through compression and combustion), and lets out air that is much hotter than it was coming in. If what you guys are saying is true about needing bigger pipes for cold air and smaller pipes for hot air then how come exhaust piping is always bigger than intake piping? If you use that logic then we should all be running around with 3" intake pipes and 2"-2.5" exhaust pipes right? Everyone knows that's not an efficient setup! It's the other way around, smaller piping for the intake so the cold air (with MORE DENSITY but LESS VOLUME) has more velocity and bigger piping for the hot exhaust air (with LESS DENSITY but MORE VOLUME).


But hey what do I know? I'm an Electrical Engineer, not a Physics teacher. Don't take my word for it, take the book's. Sorry about the shitty scans, btw.

[SeR_Cyclops]

lol nice....

[505zoom]

...If you use that logic then we should all be running around with 3" intake pipes and 2"-2.5" exhaust pipes right? Everyone knows that's not an efficient setup! It's the other way around, smaller piping for the intake so the cold air (with MORE DENSITY but LESS VOLUME) has more velocity and bigger piping for the hot exhaust air (with LESS DENSITY but MORE VOLUME).

You are talking about a totally different system. We are talking about intercooler piping, not the difference between pipe sizes for exhaust gas and intake air. And in reality, you are actually wrong about intake being smaller than the exhaust and it being the way to go. There are a lot of setups where the intake piping is the same size or even bigger than the exhaust.

You guys can analyze this to death, and the answer was in my first post.

LARGER IC pipe for cool air, smaller IC pipe for hot air.

No mathematical theory or physics preaching is going to change that. Don't believe me still?... fine, build a shitty system, and enjoy your even slower car.(evil)

[505zoom]

For the record,

The turbo guys at hotrodders site said the same thing: 2.0" first to carry the less viscous (easier flowing) hot air, then 2.5" to carry the thicker air to the TB.

One guy had that size piping on a 2.8L Datsun making 350 at the crank on 15 psi. If it good enough for him, surely it is for me :D

But you are apprehensive about listening to someone who runs the same boost and power numbers on a stock motor 2.0L MSP?... lolwtf.(screwy)

[Lodivigo]

You are talking about a totally different system. We are talking about intercooler piping, not the difference between pipe sizes for exhaust gas and intake air.

It's an analogy, look to the deeper meaning...it still deals with the subject of air and how it reacts to temperature change. (braindead


And in reality, you are actually wrong about intake being smaller than the exhaust and it being the way to go. There are a lot of setups where the intake piping is the same size or even bigger than the exhaust.

Ummmm no. Ok...setups with intake piping being the same size as exhaust piping is one thing, I'm sure there are setups like this that make great power, but it makes absolutly no sense to have intake piping bigger than the exhaust. Why? Well for starters what the hell is your engine gonna do with more air than it can get rid of? That is a "shitty system".


No mathematical theory or physics preaching is going to change that.

This sentence makes no sense to me, do the laws of Physics not exist under certain hoods or just yours? (headshake


Don't believe me still?... fine, build a shitty system, and enjoy your even slower car.(evil)

Lol, I'm not the one building the system, hotrod is. But if your non "shitty system" reflects your physics knowledge, I'm not too worried about being slower. :rolleyes:


lol nice....

Lol, thanks.


Cheers Everyone (cheers)

[505zoom]

Lol, I'm not the one building the system, hotrod is. But if your non "shitty system" reflects your physics knowledge, I'm not too worried about being slower. :rolleyes:

Excuse me? I know who is building the system, and I wasn't even talking to you except for the first part of my post where I was directly replying to you. You can pretty much suck my balls now though asshole.


it still deals with the subject of air and how it reacts to temperature change. (braindead


Hmm, well when your derived conclusion is dead wrong, obviously it doesn't in this case.


Ummmm no. Ok...setups with intake piping being the same size as exhaust piping is one thing, I'm sure there are setups like this that make great power, but it makes absolutly no sense to have intake piping bigger than the exhaust. Why? Well for starters what the hell is your engine gonna do with more air than it can get rid of? That is a "shitty system".

Ummmm, ok... 4" inlets are on a lot of turbos out there, many of which are running on cars with a 3" or 3.5" exhaust. I was only making a point that you can't just say "intake pipe is smaller than exhaust pipe, so the same rule must apply here". It doesn't work like that.


This sentence makes no sense to me

Then let me clarify what I meant for you... When you take a bunch of crap that doesn't even begin to apply to the question at hand (what I meant when I said "mathematical theory or physics preaching"), you are never going to change the simple fact that it works better to do it the way that I (and everyone else who knows what the fuck they are talking about) say to do it. Does my sentence make any sense to you now? Stop spreading misinformation... It is NOT better to do it the way you are saying to do it.

[Lodivigo]

(encourage

I don't have time to give a good decent reply to this right now since I am at work...but wow dude, you wanna preach to me about spreading misinformation? You are dead wrong about the way air acts in regards to volume when it is heated, less dense air does not mean less volume, can I make it anymore clear? Forget about the analogy and comparitive examples brought up, we are talking about air....it's density, and it's volume, pure and simple. It doesn't matter what kind of example or setup we are talking about because it's all fucking relative! Air acts the same no matter what application because of fundamental laws of Physics!!! Please, prove me wrong, I'm not talking about different systems making different powers and shit like that. No...prove me wrong and show me that air is the one thing in the universe that doesn't expand in volume when you add thermal energy (heat).

As for being an asshole, I could really care less how I come off to you. You and I have one thing in common, intolerance for people who spread misinformation, and YOU are spreading misinformation about how air works when heated and cooled regardless of whatever system we are using as an example.

Back to work, more replies later. I do hope some Physics educated peeps will have chimed in by the time I get off of work.

[orphman]

damn.. its sad a simple discussion turned into a nasty argument... lets all rem. there are many ways of doing things.. even if one is " right" and one is "wrong..." you got to rem. the world was flat beofre some one questioned it... so.. it doesnt hurt to toss ideas back and forth..

even if we already know one way or the other.. it never hurts to inform...
information is that.. good or bad... right or wrong.. each of us needs to be the judge... not the executioner

[Lodivigo]

damn.. its sad a simple discussion turned into a nasty argument... lets all rem. there are many ways of doing things.. even if one is " right" and one is "wrong..." you got to rem. the world was flat beofre some one questioned it... so.. it doesnt hurt to toss ideas back and forth..

even if we already know one way or the other.. it never hurts to inform...
information is that.. good or bad... right or wrong.. each of us needs to be the judge... not the executioner

Agreed, like I said...sorry if I come across as an asshole, but the snide comments about other peoples "shitty systems" and being slower just seemed rather pointless. Needless to say it rubbed me the wrong way, whether or not it was directed at me. Keep it civil, keep it intelligent, not immature and unproductive.

30 mins till lunch...and another 4 hours to go.

[Lodivigo]

Fuck it, who needs a lunch break.


Excuse me? I know who is building the system, and I wasn't even talking to you except for the first part of my post where I was directly replying to you. You can pretty much suck my balls now though asshole.

Not even gonna waste time with this useless statement, civil and intelligent, not immature and dumb.


Hmm, well when your derived conclusion is dead wrong, obviously it doesn't in this case.

Like I said, prove it. Prove to me that when you heat air it's volume doesn't expand and that in fact it contracts. Unless you've discovered some new gas law or variant of thermodynamics, you're not gonna win this one. The scans I provided were taken directly from a Physics book, I'm not making this shit up. I'm not saying that you are, but if you're gonna argue about it you'd better have some hard data to go along with it.



Ummmm, ok... 4" inlets are on a lot of turbos out there, many of which are running on cars with a 3" or 3.5" exhaust. I was only making a point that you can't just say "intake pipe is smaller than exhaust pipe, so the same rule must apply here". It doesn't work like that.

Please explain why it doesn't work like that. Why would the Ideal Gas Laws and general theory of Physics suddenly change when applied to intercooler piping? You continue to talk about different setups and how this is different from that and whatnot but you still haven't addressed the subject of air and how it reacts when cooled and heated. You can't say it's not a relevant subject from setup to setup because ALL of them work off the principals of Physics dealing with gas (air), there is no way of getting around that.


Then let me clarify what I meant for you... When you take a bunch of crap that doesn't even begin to apply to the question at hand (what I meant when I said "mathematical theory or physics preaching"), you are never going to change the simple fact that it works better to do it the way that I (and everyone else who knows what the fuck they are talking about) say to do it. Does my sentence make any sense to you now? Stop spreading misinformation... It is NOT better to do it the way you are saying to do it.

OMG, this last line, please show me exactly where I typed up how to do anything setup wise on intercooler piping! You are the one telling other people how they should build their cars, not me...get it straight. I called you out on the fact that you're running around saying that air gets denser and therefore has more volume when they are not even the same thing! You keep typing up the same thing claiming that Physics doesn't apply to this argument. Are you freaking serious?!?! Physics just magically doesn't apply here??? Please get a clue.


25 minutes left to eat, not too bad.

[hotrodf1]

Wow.

Out of hand it did get.

As far as the arguement for using a smaller intake than exhaust, it doesn't hold up. Yes, the same mass of air might occupy less volume before it gets heated in combustion, however in a low pressure / high pressure system (think A/C compressor, turbos, IC engine) the suction side is always more sensitive than the pressure side. That's why the big hose on your power steering is the suction. Also why a free flowing intake to the turbo is important.

I already stated previously that the pressure side of the system is less sensitive to flow restrictions than the suction or low pressure side. That's straight off the air flow physics site, forget the name.

[hotrodf1]

But you are apprehensive about listening to someone who runs the same boost and power numbers on a stock motor 2.0L MSP?... lolwtf.(screwy)

Hey - just trying to get some facts, not just someone's opinion ya know. That post you are referring to said that you were RIGHT. The hotrodders.com guys areed. No need to insult . . .

[Lodivigo]

However in a low pressure / high pressure system (think A/C compressor, turbos, IC engine) the suction side is always more sensitive than the pressure side. That's why the big hose on your power steering is the suction. Also why a free flowing intake to the turbo is important.

I'm totally in agreement with that. Volumetric efficiency, air velocity, and the least amount of restriction possible are very important in the low pressure side. However you must remember that an intake that is too large in diameter will hurt air velocity. There has to be balance in size overall. There is an ideal diameter piping for maximum air velocity but any bigger than that and you're just adding more area that the air has to flow across, too much area=drag.



Out of hand it did get.

Sorry to shit on your thread dude, I hate smart ass comments though and couldn't resist. I will try to refrain if 505 can, hopefully it gets better from here on out.




Lol, I'm not gonna get any work done today...

[Lodivigo]

Finally done with work, thank god.

I thought I'd post some interesting reading from Corky Bell's book. The first two pages deal with intercooler piping and air velocity. According to him 2.5" piping is good to around 400hp. The math hurts my head right now but if you want to find the coefficient of drag of 2" piping just plug that into the formula where 2.5" is. If your planning to stop at 300-400hp then I'd say 2.5" is a good place to start.

The last two pages touch upon piping diameter as well but for the exhaust side. Yes yes I know, different setup/subject/whatever, but it does talk about air velocity, the expansion of gas (air) due to temperature, and the extra piping volume needed to accomidate it.

I'm done for now, time to hit the bar (drinks) (thinkbeer

[Maz2001MP]

I have 2.75 piping on the cold side and 2.0 on the hot, I have some lag but full boost comes on at about 2800 rpms