darien99

03-27-07, 05:10 PM

I was thinkin' about going down into the wheel well for my cold air intake, has anyone done this? Anybody have pics of their's?

View Full Version : Show off your Cold air intakes!

darien99

03-27-07, 05:10 PM

I was thinkin' about going down into the wheel well for my cold air intake, has anyone done this? Anybody have pics of their's?

Ranger

03-27-07, 05:45 PM

Wheel well! :eek: Holy water injestment, Batman.

chazglenn3

03-27-07, 06:11 PM

:histeric:

Raze

03-27-07, 08:15 PM

Ranger you crack me up dude...

weister42

03-27-07, 09:01 PM

I think the factory air system is totally fine until the actual air inlet behind the driverside headlight, which is smaller than the rest of the system.

Someone here did a dyno with and without the entire factory air intake system and got a ~7HP increase though, so if you want you can just stick a cone filter in front of the throttle body and stick the MAF sensor in between. But that's kinda ghetto...

Someone here did a dyno with and without the entire factory air intake system and got a ~7HP increase though, so if you want you can just stick a cone filter in front of the throttle body and stick the MAF sensor in between. But that's kinda ghetto...

darien99

03-27-07, 09:03 PM

Water? What's that? :)

I've been running my cai 4" above the ground on my neon for about 200,000 miles now, not a single problem, and it dropped .3 off the 1/4. Since we're restricted on the amount of modification available for these cars, we have to make the best of each one. I'm not going to settle for those ebay intakes and call it good. :rolleyes: I did that on my Dakota and ended up going a tenth slower. So I made my own and went .2 faster. BTW- the Dakota took air from the wheel well stock, I don't think they were too worried about water ingestion.

I've been running my cai 4" above the ground on my neon for about 200,000 miles now, not a single problem, and it dropped .3 off the 1/4. Since we're restricted on the amount of modification available for these cars, we have to make the best of each one. I'm not going to settle for those ebay intakes and call it good. :rolleyes: I did that on my Dakota and ended up going a tenth slower. So I made my own and went .2 faster. BTW- the Dakota took air from the wheel well stock, I don't think they were too worried about water ingestion.

darien99

03-27-07, 09:04 PM

I think the factory air system is totally fine until the actual air inlet behind the driverside headlight, which is smaller than the rest of the system.

Someone here did a dyno with and without the entire factory air intake system and got a ~7HP increase though, so if you want you can just stick a cone filter in front of the throttle body and stick the MAF sensor in between. But that's kinda ghetto...

Well I don't have to worry about the MAF. :) I was hoping to stick most of the cone into the original air passage area- perhaps open that up.

Someone here did a dyno with and without the entire factory air intake system and got a ~7HP increase though, so if you want you can just stick a cone filter in front of the throttle body and stick the MAF sensor in between. But that's kinda ghetto...

Well I don't have to worry about the MAF. :) I was hoping to stick most of the cone into the original air passage area- perhaps open that up.

wydopnthrtl

03-27-07, 09:13 PM

I've enlarged the stock passages and when at the track add a 4" pipe that feeds from the grill. It's definately noticable over 60mph too. (dropped me about 1/10th and gained about 1mph in the 1/4)

Rich

Rich

codewize

03-27-07, 10:28 PM

I just put my factory air box back in. I was looking for something and I had it all apart when I realized my installation job left a lot to be desired. Mostly the fault of Volant providing no way to mount the box to the car, poor cable routing for the PCM, mis-drilled holes for the PCM bracket, and no way to make a tight seal to the pass-through.

SO I have a few things in mind. Most of the mounting got worked out today and I'm going to do something similar to the duct work thing that wydopnthrtl mentioned but I'm going to be more subtle and design something like the factory trumpet, just larger. That will all be integrated with the sealing solution I come up with.

In addition to those changes I am also going to work with internal baffles while I have a dyno available. I'm going to do a run with the factory box first, other reason I put it back in. Then with the Volant, then some trick baffling. Whatever puts down the best numbers is what we keep. Then we do it all over again when the exhaust goes on.

OH and BTW, going into the wheel well is a dumb idea. You'll suck water like crazy and the rotation of the wheel will pull air away form the intake during rotation. We are talking about Chrysler products above. The engineers over there are not geniuses.

SO I have a few things in mind. Most of the mounting got worked out today and I'm going to do something similar to the duct work thing that wydopnthrtl mentioned but I'm going to be more subtle and design something like the factory trumpet, just larger. That will all be integrated with the sealing solution I come up with.

In addition to those changes I am also going to work with internal baffles while I have a dyno available. I'm going to do a run with the factory box first, other reason I put it back in. Then with the Volant, then some trick baffling. Whatever puts down the best numbers is what we keep. Then we do it all over again when the exhaust goes on.

OH and BTW, going into the wheel well is a dumb idea. You'll suck water like crazy and the rotation of the wheel will pull air away form the intake during rotation. We are talking about Chrysler products above. The engineers over there are not geniuses.

Raze

03-28-07, 06:51 AM

We are talking about Chrysler products above. The engineers over there are not geniuses.

The GM engineers aren't 'geniuses' either...

The GM engineers aren't 'geniuses' either...

darien99

03-28-07, 08:08 AM

The GM engineers aren't 'geniuses' either...

Exactly. After actually working for both, I'd definatly say Chrysler has the edge in the engineering department over GM.

Exactly. After actually working for both, I'd definatly say Chrysler has the edge in the engineering department over GM.

darien99

03-28-07, 08:20 AM

OH and BTW, going into the wheel well is a dumb idea. You'll suck water like crazy and the rotation of the wheel will pull air away form the intake during rotation. We are talking about Chrysler products above. The engineers over there are not geniuses.

So why haven't I (or anyone else with a Dodge) ever sucked water?

FYI Dodge does NOT have intake sealing problems on every V6 they ever built like GM does. Dodge does NOT have blower motor resistor problems on every 8-10 cars, and if they did they're easily accessable, unlike GM. Dodge does NOT have ABS problems due to corrosion like most of the GM trucks. Dodge does NOT have an intermediate steering shaft rattle AT ALL where GM does on vehicles all the time, starting under 15,000 miles. You hardly ever see swaybar endlink problems with dodge, again you can watch 10-15K mile GM's come in under warranty with that nasty front end clunk. I never seen a HD Ram come in with an a/c compressor exploding because the truck couldn't handle having a plow on the front. Working for GM I now see this biweekly.

I could go on forever. Point being Chrysler engineers may not be perfect, but they have a hell of a lot better idea of whats going then some other companies. :tisk:

So why haven't I (or anyone else with a Dodge) ever sucked water?

FYI Dodge does NOT have intake sealing problems on every V6 they ever built like GM does. Dodge does NOT have blower motor resistor problems on every 8-10 cars, and if they did they're easily accessable, unlike GM. Dodge does NOT have ABS problems due to corrosion like most of the GM trucks. Dodge does NOT have an intermediate steering shaft rattle AT ALL where GM does on vehicles all the time, starting under 15,000 miles. You hardly ever see swaybar endlink problems with dodge, again you can watch 10-15K mile GM's come in under warranty with that nasty front end clunk. I never seen a HD Ram come in with an a/c compressor exploding because the truck couldn't handle having a plow on the front. Working for GM I now see this biweekly.

I could go on forever. Point being Chrysler engineers may not be perfect, but they have a hell of a lot better idea of whats going then some other companies. :tisk:

jadcock

03-28-07, 11:10 AM

You hardly ever see swaybar endlink problems with dodge, again you can watch 10-15K mile GM's come in under warranty with that nasty front end clunk.

You must be excluding the minivans. On the Chrysler minivan forum, that's probably THE most asked-about topic -- the swaybar end links and bushings that repeatedly fail. Our '03 has had three sets of both, in only 70k miles. Many others have the same story. Other than that, the van has been great. All vehicles have their own issues. It's nice that we have choices.

You must be excluding the minivans. On the Chrysler minivan forum, that's probably THE most asked-about topic -- the swaybar end links and bushings that repeatedly fail. Our '03 has had three sets of both, in only 70k miles. Many others have the same story. Other than that, the van has been great. All vehicles have their own issues. It's nice that we have choices.

fubar569

03-28-07, 02:58 PM

I've enlarged the stock passages and when at the track add a 4" pipe that feeds from the grill. It's definately noticable over 60mph too. (dropped me about 1/10th and gained about 1mph in the 1/4)

Rich

i have nothing now but plan on something similar to this once my hand gets better...

i am also dreaming up a MUCH better solution to the traction control idea...tapping into the ETBCM or whatever is about next to impossible without major disassembly of the car just to get to it (least on my deville)...im thinking of doing a one-off and cutting into the wires in the wheel-well area for ease of install purposes...or doing 4 seperate modules located and mounted near each wheel well...

Rich

i have nothing now but plan on something similar to this once my hand gets better...

i am also dreaming up a MUCH better solution to the traction control idea...tapping into the ETBCM or whatever is about next to impossible without major disassembly of the car just to get to it (least on my deville)...im thinking of doing a one-off and cutting into the wires in the wheel-well area for ease of install purposes...or doing 4 seperate modules located and mounted near each wheel well...

darien99

04-01-07, 09:53 AM

I was checking out the big area in front of the grille yesterday, I love that large amount of area! :)

Now if we could only route pipe from the tb to that area, we could hang a huge K&N cone in there.:highfive:

Now if we could only route pipe from the tb to that area, we could hang a huge K&N cone in there.:highfive:

fubar569

04-01-07, 01:14 PM

I was checking out the big area in front of the grille yesterday, I love that large amount of area! :)

Now if we could only route pipe from the tb to that area, we could hang a huge K&N cone in there.:highfive:

i hogged the stock airbox and passageways out as far as possible, and cut out the silencer chamber and made that another intake hole...

its gulping alot more air now and the sound is nice...

in the future i am going to drop something in the grill/lower fascia for a ram-air/cold-air effect...and see if that further helps

Now if we could only route pipe from the tb to that area, we could hang a huge K&N cone in there.:highfive:

i hogged the stock airbox and passageways out as far as possible, and cut out the silencer chamber and made that another intake hole...

its gulping alot more air now and the sound is nice...

in the future i am going to drop something in the grill/lower fascia for a ram-air/cold-air effect...and see if that further helps

Ranger

04-01-07, 04:49 PM

You'll have to be somewhere around 100 MPH before you actually start to see any "ram effect".

darien99

04-02-07, 09:40 AM

You'll have to be somewhere around 100 MPH before you actually start to see any "ram effect".

If this were true the Ram air WS6 wouldn't be any faster than a regular ls1. :thumbsup:

If this were true the Ram air WS6 wouldn't be any faster than a regular ls1. :thumbsup:

darien99

04-02-07, 09:43 AM

i hogged the stock airbox and passageways out as far as possible, and cut out the silencer chamber and made that another intake hole...

its gulping alot more air now and the sound is nice...

in the future i am going to drop something in the grill/lower fascia for a ram-air/cold-air effect...and see if that further helps

I built a ram air/K&N cylinder intake in back of the grille setup on my turbo van many years ago. It dropped a couple tenths, and this is on a TURBO engine! :thumbsup:

Behind that caddy grille is the way to go! :stirpot:

its gulping alot more air now and the sound is nice...

in the future i am going to drop something in the grill/lower fascia for a ram-air/cold-air effect...and see if that further helps

I built a ram air/K&N cylinder intake in back of the grille setup on my turbo van many years ago. It dropped a couple tenths, and this is on a TURBO engine! :thumbsup:

Behind that caddy grille is the way to go! :stirpot:

jadcock

04-02-07, 11:43 AM

If this were true the Ram air WS6 wouldn't be any faster than a regular ls1. :thumbsup:

If you plan to put scoops on the hood like a WS6, then you have a valid comparison. Otherwise, apples-to-oranges. And the WS6 package is also more than simply Ram Air, making it even more of an apples-to-oranges comparison.

If you plan to put scoops on the hood like a WS6, then you have a valid comparison. Otherwise, apples-to-oranges. And the WS6 package is also more than simply Ram Air, making it even more of an apples-to-oranges comparison.

Ranger

04-02-07, 09:46 PM

OK, I found this in doing some research. Found it in a discussion forum about "ram Air". Not my calculations, but I think it proves my point.

"So the less restriction and the more booste = MO POWER. And the size of the hole does not put a cap on the amount of air that can be pushed through. Example - A water faucet... more pressure, more water.

ummm boost is restriction, boost is the measurement of air you do not use. Also just because you have more pressure, does not mean that you have more volume. All it means is that you have more of a restriction.

I have posted this before but, I thought it was appropriate for this discussion.

Hmmm I was in a coma like state earlier today ( sitting through a four hour training lecture at work). Anyway I was wondering how fast the air in a 3" inlet pipe to the turbo would be traveling if 800 cfm of air was going into the turbo. So when I came up with my answer it woke me up enough to ask my buddies at work to calculate it for them selves and see what they came up with. I didnt tell them how I went about calculating it to avoid getting them started on the wrong foot incase I was wrong. They came up with the same results as I did. When I asked them how they went about calculating it they had approached it the same way I did.

here is how I did it:

1) I'am going to use standard temp and press for the air

2) area of 3" pipe = pi * radius squared

3.14 * 1.5in * 1.5in = 7.07 in2

3) Inside volume of pipe = area * length

I wanted to know how long a piece of 3" pipe had to be to half an internal volume of 1 cubic foot. I rearanged the equation:

length = volume / area

length = 1 ft3/ 7.07 in2 = 1 ft3 * 144in2 / 7.07in2 = 20.4 ft

4) OK now I know that 1 ft3 is the volume of a 20.4 ft long piece of 3" pipe. I also know that Iam looking for 800 ft3/min. so this is next:

Speed of the air in the pipe (mph) = (800 * 20.4 * 60) / 5280

800 is cfm (ft3/min)

20.4 (ft of pipe for one cfm)

60 (convert from minutes to hours)

5280 (convert from feet to miles)

ANSWER: 185.45 mph!!! Air speed in a 3" pipe with 800 cfm of air moving through it. Makes me shake my head but it appears to be right. I also calculated for a 4" pipe and the speed dropped to 104 mph.

There is no intended point of this. I was just kind of suprized by my answer and thought I would pass it along. BUT....it does make me wonder how much ram effect some of these late model cars get at 60 mph or even 80 mph with the little factory snorkels. Maybe they're just fancy looking cold air induction set ups? it does not ram air.

This is why I don't think ram air works. it might be a cold air intake but it is not ramming the air in the engine."

And this from Wikipedia.

"However, Fluid Dynamics can support claims that only 3 % higher volume of intake air is accomplished at speeds attainable by high performance and race cars (and an intake on the side reduce the volume by 3 %). Forcing a large volume of air into a cone by motion alone is only possible at supersonic speeds (below that it reduces the volume)"

And then there is this.

"Heard of the 'Ram Air' effect where the speed of the air hitting the vehicle

builds up pressure in a forward facing air duct and helps 'supercharge' your

engine a bit. ?

Well, at 'typical' street speeds the effect is very very small.

The formula for that is:

Inches of water pressure from Ram Air = (mph) times (mph) divided by 2025.

So at 70 mph the ram air effect is:

(70 mph) times (70 mph) divided by 2025 = 2.4 inches of water.

So the very best possible air inlet tube designed for Ram Air would actually

have a positive pressure of 2.4 inches of water.

How much pressure is an inch of water ?

One psi of pressure is equal to about 28 inches of water.

You can get this by dividing the cubic inches in one cubic foot ( 12 x 12 x

12 ) by the weight of one cubic foot of water ( 62.4 lbs).

The air pressure around us is averages about 14.5 psi at typical heights above

sea level.

So another way of looking at it is that the air pressure around us is about

400 inches of water. ( 14.5 x 28).

So the best Ram Air system at 70 mph gives you a boost of about 2/400 or one

half of one percent. Small.

Ram air started in airplanes where it means more. An airplane going 300 mph

gets a boost of:

300 x 300 divided by 2025 = 44 inches

This is a percentage boost of 44/400 or about 11%".

"So the less restriction and the more booste = MO POWER. And the size of the hole does not put a cap on the amount of air that can be pushed through. Example - A water faucet... more pressure, more water.

ummm boost is restriction, boost is the measurement of air you do not use. Also just because you have more pressure, does not mean that you have more volume. All it means is that you have more of a restriction.

I have posted this before but, I thought it was appropriate for this discussion.

Hmmm I was in a coma like state earlier today ( sitting through a four hour training lecture at work). Anyway I was wondering how fast the air in a 3" inlet pipe to the turbo would be traveling if 800 cfm of air was going into the turbo. So when I came up with my answer it woke me up enough to ask my buddies at work to calculate it for them selves and see what they came up with. I didnt tell them how I went about calculating it to avoid getting them started on the wrong foot incase I was wrong. They came up with the same results as I did. When I asked them how they went about calculating it they had approached it the same way I did.

here is how I did it:

1) I'am going to use standard temp and press for the air

2) area of 3" pipe = pi * radius squared

3.14 * 1.5in * 1.5in = 7.07 in2

3) Inside volume of pipe = area * length

I wanted to know how long a piece of 3" pipe had to be to half an internal volume of 1 cubic foot. I rearanged the equation:

length = volume / area

length = 1 ft3/ 7.07 in2 = 1 ft3 * 144in2 / 7.07in2 = 20.4 ft

4) OK now I know that 1 ft3 is the volume of a 20.4 ft long piece of 3" pipe. I also know that Iam looking for 800 ft3/min. so this is next:

Speed of the air in the pipe (mph) = (800 * 20.4 * 60) / 5280

800 is cfm (ft3/min)

20.4 (ft of pipe for one cfm)

60 (convert from minutes to hours)

5280 (convert from feet to miles)

ANSWER: 185.45 mph!!! Air speed in a 3" pipe with 800 cfm of air moving through it. Makes me shake my head but it appears to be right. I also calculated for a 4" pipe and the speed dropped to 104 mph.

There is no intended point of this. I was just kind of suprized by my answer and thought I would pass it along. BUT....it does make me wonder how much ram effect some of these late model cars get at 60 mph or even 80 mph with the little factory snorkels. Maybe they're just fancy looking cold air induction set ups? it does not ram air.

This is why I don't think ram air works. it might be a cold air intake but it is not ramming the air in the engine."

And this from Wikipedia.

"However, Fluid Dynamics can support claims that only 3 % higher volume of intake air is accomplished at speeds attainable by high performance and race cars (and an intake on the side reduce the volume by 3 %). Forcing a large volume of air into a cone by motion alone is only possible at supersonic speeds (below that it reduces the volume)"

And then there is this.

"Heard of the 'Ram Air' effect where the speed of the air hitting the vehicle

builds up pressure in a forward facing air duct and helps 'supercharge' your

engine a bit. ?

Well, at 'typical' street speeds the effect is very very small.

The formula for that is:

Inches of water pressure from Ram Air = (mph) times (mph) divided by 2025.

So at 70 mph the ram air effect is:

(70 mph) times (70 mph) divided by 2025 = 2.4 inches of water.

So the very best possible air inlet tube designed for Ram Air would actually

have a positive pressure of 2.4 inches of water.

How much pressure is an inch of water ?

One psi of pressure is equal to about 28 inches of water.

You can get this by dividing the cubic inches in one cubic foot ( 12 x 12 x

12 ) by the weight of one cubic foot of water ( 62.4 lbs).

The air pressure around us is averages about 14.5 psi at typical heights above

sea level.

So another way of looking at it is that the air pressure around us is about

400 inches of water. ( 14.5 x 28).

So the best Ram Air system at 70 mph gives you a boost of about 2/400 or one

half of one percent. Small.

Ram air started in airplanes where it means more. An airplane going 300 mph

gets a boost of:

300 x 300 divided by 2025 = 44 inches

This is a percentage boost of 44/400 or about 11%".

fubar569

04-02-07, 10:17 PM

OK, I found this in doing some research. Found it in a discussion forum about "ram Air". Not my calculations, but I think it proves my point.

"So the less restriction and the more booste = MO POWER. And the size of the hole does not put a cap on the amount of air that can be pushed through. Example - A water faucet... more pressure, more water.

ummm boost is restriction, boost is the measurement of air you do not use. Also just because you have more pressure, does not mean that you have more volume. All it means is that you have more of a restriction.

I have posted this before but, I thought it was appropriate for this discussion.

Hmmm I was in a coma like state earlier today ( sitting through a four hour training lecture at work). Anyway I was wondering how fast the air in a 3" inlet pipe to the turbo would be traveling if 800 cfm of air was going into the turbo. So when I came up with my answer it woke me up enough to ask my buddies at work to calculate it for them selves and see what they came up with. I didnt tell them how I went about calculating it to avoid getting them started on the wrong foot incase I was wrong. They came up with the same results as I did. When I asked them how they went about calculating it they had approached it the same way I did.

here is how I did it:

1) I'am going to use standard temp and press for the air

2) area of 3" pipe = pi * radius squared

3.14 * 1.5in * 1.5in = 7.07 in2

3) Inside volume of pipe = area * length

I wanted to know how long a piece of 3" pipe had to be to half an internal volume of 1 cubic foot. I rearanged the equation:

length = volume / area

length = 1 ft3/ 7.07 in2 = 1 ft3 * 144in2 / 7.07in2 = 20.4 ft

4) OK now I know that 1 ft3 is the volume of a 20.4 ft long piece of 3" pipe. I also know that Iam looking for 800 ft3/min. so this is next:

Speed of the air in the pipe (mph) = (800 * 20.4 * 60) / 5280

800 is cfm (ft3/min)

20.4 (ft of pipe for one cfm)

60 (convert from minutes to hours)

5280 (convert from feet to miles)

ANSWER: 185.45 mph!!! Air speed in a 3" pipe with 800 cfm of air moving through it. Makes me shake my head but it appears to be right. I also calculated for a 4" pipe and the speed dropped to 104 mph.

There is no intended point of this. I was just kind of suprized by my answer and thought I would pass it along. BUT....it does make me wonder how much ram effect some of these late model cars get at 60 mph or even 80 mph with the little factory snorkels. Maybe they're just fancy looking cold air induction set ups? it does not ram air.

This is why I don't think ram air works. it might be a cold air intake but it is not ramming the air in the engine."

And this from Wikipedia.

"However, Fluid Dynamics can support claims that only 3 % higher volume of intake air is accomplished at speeds attainable by high performance and race cars (and an intake on the side reduce the volume by 3 %). Forcing a large volume of air into a cone by motion alone is only possible at supersonic speeds (below that it reduces the volume)"

And then there is this.

"Heard of the 'Ram Air' effect where the speed of the air hitting the vehicle

builds up pressure in a forward facing air duct and helps 'supercharge' your

engine a bit. ?

Well, at 'typical' street speeds the effect is very very small.

The formula for that is:

Inches of water pressure from Ram Air = (mph) times (mph) divided by 2025.

So at 70 mph the ram air effect is:

(70 mph) times (70 mph) divided by 2025 = 2.4 inches of water.

So the very best possible air inlet tube designed for Ram Air would actually

have a positive pressure of 2.4 inches of water.

How much pressure is an inch of water ?

One psi of pressure is equal to about 28 inches of water.

You can get this by dividing the cubic inches in one cubic foot ( 12 x 12 x

12 ) by the weight of one cubic foot of water ( 62.4 lbs).

The air pressure around us is averages about 14.5 psi at typical heights above

sea level.

So another way of looking at it is that the air pressure around us is about

400 inches of water. ( 14.5 x 28).

So the best Ram Air system at 70 mph gives you a boost of about 2/400 or one

half of one percent. Small.

Ram air started in airplanes where it means more. An airplane going 300 mph

gets a boost of:

300 x 300 divided by 2025 = 44 inches

This is a percentage boost of 44/400 or about 11%".

the math does check out...so basically at street speeds the effect is so minute no one would notice...and at race speeds the most to be gained is a couple pecent...

guess that busts the myth?

"So the less restriction and the more booste = MO POWER. And the size of the hole does not put a cap on the amount of air that can be pushed through. Example - A water faucet... more pressure, more water.

ummm boost is restriction, boost is the measurement of air you do not use. Also just because you have more pressure, does not mean that you have more volume. All it means is that you have more of a restriction.

I have posted this before but, I thought it was appropriate for this discussion.

Hmmm I was in a coma like state earlier today ( sitting through a four hour training lecture at work). Anyway I was wondering how fast the air in a 3" inlet pipe to the turbo would be traveling if 800 cfm of air was going into the turbo. So when I came up with my answer it woke me up enough to ask my buddies at work to calculate it for them selves and see what they came up with. I didnt tell them how I went about calculating it to avoid getting them started on the wrong foot incase I was wrong. They came up with the same results as I did. When I asked them how they went about calculating it they had approached it the same way I did.

here is how I did it:

1) I'am going to use standard temp and press for the air

2) area of 3" pipe = pi * radius squared

3.14 * 1.5in * 1.5in = 7.07 in2

3) Inside volume of pipe = area * length

I wanted to know how long a piece of 3" pipe had to be to half an internal volume of 1 cubic foot. I rearanged the equation:

length = volume / area

length = 1 ft3/ 7.07 in2 = 1 ft3 * 144in2 / 7.07in2 = 20.4 ft

4) OK now I know that 1 ft3 is the volume of a 20.4 ft long piece of 3" pipe. I also know that Iam looking for 800 ft3/min. so this is next:

Speed of the air in the pipe (mph) = (800 * 20.4 * 60) / 5280

800 is cfm (ft3/min)

20.4 (ft of pipe for one cfm)

60 (convert from minutes to hours)

5280 (convert from feet to miles)

ANSWER: 185.45 mph!!! Air speed in a 3" pipe with 800 cfm of air moving through it. Makes me shake my head but it appears to be right. I also calculated for a 4" pipe and the speed dropped to 104 mph.

There is no intended point of this. I was just kind of suprized by my answer and thought I would pass it along. BUT....it does make me wonder how much ram effect some of these late model cars get at 60 mph or even 80 mph with the little factory snorkels. Maybe they're just fancy looking cold air induction set ups? it does not ram air.

This is why I don't think ram air works. it might be a cold air intake but it is not ramming the air in the engine."

And this from Wikipedia.

"However, Fluid Dynamics can support claims that only 3 % higher volume of intake air is accomplished at speeds attainable by high performance and race cars (and an intake on the side reduce the volume by 3 %). Forcing a large volume of air into a cone by motion alone is only possible at supersonic speeds (below that it reduces the volume)"

And then there is this.

"Heard of the 'Ram Air' effect where the speed of the air hitting the vehicle

builds up pressure in a forward facing air duct and helps 'supercharge' your

engine a bit. ?

Well, at 'typical' street speeds the effect is very very small.

The formula for that is:

Inches of water pressure from Ram Air = (mph) times (mph) divided by 2025.

So at 70 mph the ram air effect is:

(70 mph) times (70 mph) divided by 2025 = 2.4 inches of water.

So the very best possible air inlet tube designed for Ram Air would actually

have a positive pressure of 2.4 inches of water.

How much pressure is an inch of water ?

One psi of pressure is equal to about 28 inches of water.

You can get this by dividing the cubic inches in one cubic foot ( 12 x 12 x

12 ) by the weight of one cubic foot of water ( 62.4 lbs).

The air pressure around us is averages about 14.5 psi at typical heights above

sea level.

So another way of looking at it is that the air pressure around us is about

400 inches of water. ( 14.5 x 28).

So the best Ram Air system at 70 mph gives you a boost of about 2/400 or one

half of one percent. Small.

Ram air started in airplanes where it means more. An airplane going 300 mph

gets a boost of:

300 x 300 divided by 2025 = 44 inches

This is a percentage boost of 44/400 or about 11%".

the math does check out...so basically at street speeds the effect is so minute no one would notice...and at race speeds the most to be gained is a couple pecent...

guess that busts the myth?

clarkz71

04-06-07, 02:10 PM

Good info Larry.

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