Fabricating cold air intake inlet
#21
10-08-2007, 04:19 PM
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RE: Fabricating cold air intake inlet
If you study the efficiency tables from the manufacturer
for any given turbocharger
you will see that going from inlet air with 404 inches of water pressure
(normal atmosphere also equal to 14.7 psi or 30 inches Hg barometric pressure)
at the turbo inlet
to a higher 404+8=412 air pressure at inlet
pays off handsomely in more boost downstream of the turbo.
for any given turbocharger
you will see that going from inlet air with 404 inches of water pressure
(normal atmosphere also equal to 14.7 psi or 30 inches Hg barometric pressure)
at the turbo inlet
to a higher 404+8=412 air pressure at inlet
pays off handsomely in more boost downstream of the turbo.
#22
10-09-2007, 07:55 AM
RE: Fabricating cold air intake inlet
I am saying there would be a slight gain if the intake opening is at the spot on the vehicle where a measurement finds the highest air pressure.
This might allow you to win a drag race by a slight amount.
Personally I don't think that someone using a truck for truck-like duty gains anything from such a mod.
If you test the Cummins Ram when it is standing still on a rear wheel dyno and all the filters are brand new
( the magazine author is not being paid money is some way...typically a 'rental' for use of the vehicle by the aftermarket CAI manufacturer)
then the standard air box does not show any great design defect:
http://www.dieselpowermag.com/tech/g...ers/index.html
but note in above test the effect of 'Ram Air' would never show up
Ram Air is a modest effect at speeds below 80 mph.
See details in old post below:
------
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%
Want a challenge?
Consider your tires.
Some strange facts:
At 70 mph the center of your tire is moving 70 mph.
The bottom of your tire where it 'grabs' the pavement is moving at 0.1 mph
The top of your tire is moving forward at 140 mph.
If you could put a 'Ram Air' inlet right at the top of the tires (where it is
horribly dirty and wet) you could get a significant air pressure boost.....
This might allow you to win a drag race by a slight amount.
Personally I don't think that someone using a truck for truck-like duty gains anything from such a mod.
If you test the Cummins Ram when it is standing still on a rear wheel dyno and all the filters are brand new
( the magazine author is not being paid money is some way...typically a 'rental' for use of the vehicle by the aftermarket CAI manufacturer)
then the standard air box does not show any great design defect:
http://www.dieselpowermag.com/tech/g...ers/index.html
but note in above test the effect of 'Ram Air' would never show up
Ram Air is a modest effect at speeds below 80 mph.
See details in old post below:
------
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%
Want a challenge?
Consider your tires.
Some strange facts:
At 70 mph the center of your tire is moving 70 mph.
The bottom of your tire where it 'grabs' the pavement is moving at 0.1 mph
The top of your tire is moving forward at 140 mph.
If you could put a 'Ram Air' inlet right at the top of the tires (where it is
horribly dirty and wet) you could get a significant air pressure boost.....
#23
10-09-2007, 03:37 PM
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#24
10-09-2007, 04:16 PM
#25
10-09-2007, 08:45 PM
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RE: Fabricating cold air intake inlet
If the hose clogs with snow the hole in the fenderwell will still supply air. I can tell a significant difference towing in heavy pull in 2-3 gear at high RPMs.
Charts and investigations or what ... the turbo will act better if a large volumn of free air is available.
Charts and investigations or what ... the turbo will act better if a large volumn of free air is available.
#26
10-10-2007, 07:59 AM
RE: Fabricating cold air intake inlet
Will there be a test?
Sad to say
in the past there was a test for engine knowledge
it was called
"War"
and if you did not acquire the knowledge
there was a lot of death.
Got a diesel?
Imagine that you are the engine officer
either on a **** sub in the Atlantic
or equally true
on a USA sub in the pacific.
The captain has just said to you:
"You know our major chance of death is when we are on the surface
and if you could find a way to run the diesel and charge the batteries
faster, every minute you save is a life or death deal. Got any ideas?"
What do you reply?
It is a shame
that information past generations died getting
is not picked up and held
but those too lazy to read.
Don't think this applies today?
The remotely controlled spy planes
watching for IED's in Iraq
stop doing their job
when they have to refuel.
Some may be too lazy to do anything about that,
but other Americans are still working hard
to improve the situation with new ideas
like totally eliminating piston rings:
http://www.newscientist.com/article.ns?id=dn8658
Sad to say
in the past there was a test for engine knowledge
it was called
"War"
and if you did not acquire the knowledge
there was a lot of death.
Got a diesel?
Imagine that you are the engine officer
either on a **** sub in the Atlantic
or equally true
on a USA sub in the pacific.
The captain has just said to you:
"You know our major chance of death is when we are on the surface
and if you could find a way to run the diesel and charge the batteries
faster, every minute you save is a life or death deal. Got any ideas?"
What do you reply?
It is a shame
that information past generations died getting
is not picked up and held
but those too lazy to read.
Don't think this applies today?
The remotely controlled spy planes
watching for IED's in Iraq
stop doing their job
when they have to refuel.
Some may be too lazy to do anything about that,
but other Americans are still working hard
to improve the situation with new ideas
like totally eliminating piston rings:
http://www.newscientist.com/article.ns?id=dn8658
