View Poll Results: What does everyone think about this cold air intake?
Good
1
1.72%
Sucks
50
86.21%
Maybe
6
10.34%
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1
1.72%
Voters: 58. You may not vote on this poll
*** JDM Cold air intake ***
#51
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Originally Posted by RotaMan99
Explain again. Why would you have to rev the engine to 4500rpm? There is a member that used a t2 hood on his n/a and made a functional ram air intake with it.
Really? Loose your low and part of the mid range power with them. The best intake for an series4 n/a is swapping on a series5 intake mani.
Really? Loose your low and part of the mid range power with them. The best intake for an series4 n/a is swapping on a series5 intake mani.
Or try this. Take the entire air box, intake tube, all that crap off all the way to the TB and then drive the car around the block.
Your definition of ram air is correct but you left out two crucial points. 1.) the intake tube needs to be as straight as possible to channel air into the TB. 2.) second the shorter the tube the smaller the amount of torque the engine will out put. ITBs are smaller in size but greater in volume, thats why you don't lose torque. The IM on an FC is right below the Tii hood scoop, and off center a few inches. How long can you make the tube and still keep it straight? Not very, which why you wont have a lot of torque. ITBs are also more efficient, as they are more precise. The only problem I see with an individual set up is the cost, as they are all custom made.
#52
Clean.
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11.5" water / ((12 inches per foot) * (2.31 feet per psi)) = 0.41psi lost
As a side note for comparision, I recently calculated <.05psi lost through the stock intake pipe. That's at WOT and high revs.
Air density is proportional to absolute pressure: 0.41psi/14.7psi (atmospheric pressure) = 2.8% drop in pressure, or a 2.8% drop in air density. That means 4HP on an s4. So, assuming a cone intake still has a little restriction, it probably nets 3HP to gain.
Of course, since a CAI gives 6-7 HP compared to hot air, you better have that cold air box. Assuming the stock intake is already cold air, you're losing 3HP with a cone intake. Assuming stock intake isn't 100% cold air, you could gain a little by converting it to cold air.
EDIT: That's the extra power from getting denser air into your engine. Kinda like having 0.41psi of boost. I also calculated another 0.5HP from not fighting against the restriction. But for 0.5HP, I'm not gonna go through the calcs here. Just figure out how to use power = pressure * flow if you're curious.
Last edited by ericgrau; 08-24-07 at 06:27 PM.
#53
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^^ that's what I was referring to. I don't know why I said ram air. I meant "short ram" which is still wrong, but is often used to describe what I'm talking about. Essentially just a cone sitting in the engine bay. This will guaranteed lose you power.
If you can make an intake that truly gets 100% cold air, and absolute minimum restriction, then you make out. Most people I've seen failed on one or both of these issues. I have almost never seen an insulated intake pipe either, so heatsoak is still generally worse.
I never said it was impossible to gain power, just that tons and tons of systems out there fail to, and that it really is more work than most think to do this right.
If you can make an intake that truly gets 100% cold air, and absolute minimum restriction, then you make out. Most people I've seen failed on one or both of these issues. I have almost never seen an insulated intake pipe either, so heatsoak is still generally worse.
I never said it was impossible to gain power, just that tons and tons of systems out there fail to, and that it really is more work than most think to do this right.
#54
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Numbers! Sweetness. Okay, time to go to work.
11.5" water / ((12 inches per foot) * (2.31 feet per psi)) = 0.41psi lost
As a side note for comparision, I recently calculated <.05psi lost through the stock intake pipe. That's at WOT and high revs.
Air density is proportional to absolute pressure: 0.41psi/14.7psi (atmospheric pressure) = 2.8% drop in pressure, or a 2.8% drop in air density. That means 4HP on an s4. So, assuming a cone intake still has a little restriction, it probably nets 3HP to gain.
Of course, since a CAI gives 6-7 HP compared to hot air, you better have that cold air box. Assuming the stock intake is already cold air, you're losing 3HP with a cone intake. Assuming stock intake isn't 100% cold air, you could gain a little by converting it to cold air.
EDIT: That's the extra power from getting denser air into your engine. Kinda like having 0.41psi of boost. I also calculated another 0.5HP from not fighting against the restriction. But for 0.5HP, I'm not gonna go through the calcs here. Just figure out how to use power = pressure * flow if you're curious.
11.5" water / ((12 inches per foot) * (2.31 feet per psi)) = 0.41psi lost
As a side note for comparision, I recently calculated <.05psi lost through the stock intake pipe. That's at WOT and high revs.
Air density is proportional to absolute pressure: 0.41psi/14.7psi (atmospheric pressure) = 2.8% drop in pressure, or a 2.8% drop in air density. That means 4HP on an s4. So, assuming a cone intake still has a little restriction, it probably nets 3HP to gain.
Of course, since a CAI gives 6-7 HP compared to hot air, you better have that cold air box. Assuming the stock intake is already cold air, you're losing 3HP with a cone intake. Assuming stock intake isn't 100% cold air, you could gain a little by converting it to cold air.
EDIT: That's the extra power from getting denser air into your engine. Kinda like having 0.41psi of boost. I also calculated another 0.5HP from not fighting against the restriction. But for 0.5HP, I'm not gonna go through the calcs here. Just figure out how to use power = pressure * flow if you're curious.
Although, I lost you when you starting talking about loosing 3hp with a cone filter, you must mean with the filter in the bay without heatshielding right?
One thing I always wondered, is how much restriction a K&N filter drop in has compaired to your standard K&N cone filter. The surface area must be smaller unless you get a large cone filter.
^^ that's what I was referring to. I don't know why I said ram air. I meant "short ram" which is still wrong, but is often used to describe what I'm talking about. Essentially just a cone sitting in the engine bay. This will guaranteed lose you power.
If you can make an intake that truly gets 100% cold air, and absolute minimum restriction, then you make out. Most people I've seen failed on one or both of these issues. I have almost never seen an insulated intake pipe either, so heatsoak is still generally worse.
I never said it was impossible to gain power, just that tons and tons of systems out there fail to, and that it really is more work than most think to do this right.
If you can make an intake that truly gets 100% cold air, and absolute minimum restriction, then you make out. Most people I've seen failed on one or both of these issues. I have almost never seen an insulated intake pipe either, so heatsoak is still generally worse.
I never said it was impossible to gain power, just that tons and tons of systems out there fail to, and that it really is more work than most think to do this right.
Since we are on the same page about installing a cone filter on the AFM and leaving it in the engine bay to suck in hot air, I agree. Personally, I don't see why people convert to a cone filter in the bay without heat shielding, mainly its the new guys, which is ok since they are learning, but it really needs to be said more often to members wanting to build or buy a so called...cold air intake.
#55
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You don't completely lose low end, its just not there as much as before
the intake tube needs to be as straight as possible to channel air into the TB
second the shorter the tube the smaller the amount of torque the engine will out put.
#56
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Not as much as you think. 50mm and 55mm are th most common, but any size velocity stack can be used, and you can get them tapered, etc. The best thing about them is the COLLECTIVE intake effect, two heads> one. But don't think about just the intake side of the equation. More throttle bodies=more air=more fuel=great response+great power(when tuned right). Think of the 5 valve system Toyota applied to the 4AGE(?). 3 intake 2 exhaust. The three can cove more are collectively than the 2 on the standard engine making them more efficient and more powerful. That jump in intake design alone took those engines from 120(?)hp to 160(?)hp. Sorry for the question marks, I'm not a big Toyota fan and my knowledge is limited, but...ITBs remain the best in my opinion. I refuse to run anything but, and will until I can come up with something better or something just as good that costs less.
#58
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#59
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Why are people so obsessed with "Cold air intakezz"? WHy can't you stick with the stock box and duct since there's very little if any increase in efficiency (correct me if i'm wrong) with those "cold air intakez"? Mad koo filter in yo face, yo?
#60
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I forgot that. Short answer...No. Do the test I suggested to any car. ANY car.
Not to be a dick, I'm just curious, do you actually roll Rotas?
Not to be a dick, I'm just curious, do you actually roll Rotas?
Well if this is true, then getting rid of the AFM and airbox would make you loose torque. considering there is fractions of a difference between leaving the tube on and leaving the tube off considering the amount of CFM an engine on sotck ports can consume.
#61
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Not as much as you think. 50mm and 55mm are th most common, but any size velocity stack can be used, and you can get them tapered, etc. The best thing about them is the COLLECTIVE intake effect, two heads> one. But don't think about just the intake side of the equation. More throttle bodies=more air=more fuel=great response+great power(when tuned right). Think of the 5 valve system Toyota applied to the 4AGE(?). 3 intake 2 exhaust. The three can cove more are collectively than the 2 on the standard engine making them more efficient and more powerful. That jump in intake design alone took those engines from 120(?)hp to 160(?)hp. Sorry for the question marks, I'm not a big Toyota fan and my knowledge is limited, but...ITBs remain the best in my opinion. I refuse to run anything but, and will until I can come up with something better or something just as good that costs less.
#62
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Originally Posted by RotaMan99
btw thanks for the info
By Rotas, I meant the knock off brand wheel. I'm not a copyright ****, but I think making an unoriginal product, and making it cheaply is ******' dumb. Though not as dumb as the people who buy them and swear they're getting a good product.
Last edited by dial8; 08-25-07 at 11:18 AM. Reason: I forgot the IS. As in can you define what the word IS is?
#64
I have put a few k&n filter charger kits on my rx7's
I loved the way the car wanted to go to the redline. Thats my kind of driving. I live in a small town 1st and 2nd gear felt much better
I noticed the loss of some low end torque. Flooring the gas in 5th gear felt sluggish.
I'm very happy with my CAI ( if you can call it that)
I loved the way the car wanted to go to the redline. Thats my kind of driving. I live in a small town 1st and 2nd gear felt much better
I noticed the loss of some low end torque. Flooring the gas in 5th gear felt sluggish.
I'm very happy with my CAI ( if you can call it that)
#66
MAzda has some competition manuals online somewhere and it gives you detailed measurements on how to build a CAI system with the snorkel in the front end and ducting to the filter. Look into that instead of ebay.
You're itchy to waste money but you're looking in the wrong direction
The hood scoop Idea works but you're using the incorrect type. I'd look into Z3-like fender vents and rather than mount them as vents you'd mount them backwards so the air goes right where the CAI and airbox are (like in the picture from natey) so you don't add a piece that will increase drag and not be very functional.
You're itchy to waste money but you're looking in the wrong direction
The hood scoop Idea works but you're using the incorrect type. I'd look into Z3-like fender vents and rather than mount them as vents you'd mount them backwards so the air goes right where the CAI and airbox are (like in the picture from natey) so you don't add a piece that will increase drag and not be very functional.
#68
I had a cold air box on my car, but it wouldn't fit with my new TID. Before I took it off it did make a nice difference :-). Here's a picture of the box:
Installed pic (not my car):
I've got it for sale : https://www.rx7club.com/showthread.php?t=679393
Vince
Installed pic (not my car):
I've got it for sale : https://www.rx7club.com/showthread.php?t=679393
Vince
#70
Cake or Death?
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I loved the way the car wanted to go to the redline. Thats my kind of driving. I live in a small town 1st and 2nd gear felt much better
I noticed the loss of some low end torque. Flooring the gas in 5th gear felt sluggish.
I'm very happy with my CAI ( if you can call it that)
How can 1st and 2nd gear "feel much better" with less low end torque?
If it "wants" to go to redline more easily, why would accel in 5th feel sluggish?
You can call your intake anything you want ("CAI"?) but unless it's winter where you live I doubt there's anything "cold" about your intake air.
Where does the K&N kit pull air from?
#72
These sentences seem to describe two different cars.
How can 1st and 2nd gear "feel much better" with less low end torque?
If it "wants" to go to redline more easily, why would accel in 5th feel sluggish?
You can call your intake anything you want ("CAI"?) but unless it's winter where you live I doubt there's anything "cold" about your intake air.
Where does the K&N kit pull air from?
How can 1st and 2nd gear "feel much better" with less low end torque?
If it "wants" to go to redline more easily, why would accel in 5th feel sluggish?
You can call your intake anything you want ("CAI"?) but unless it's winter where you live I doubt there's anything "cold" about your intake air.
Where does the K&N kit pull air from?
What I was saying about 1st and 2nd gear was that The 7 pulled much harder to the redline. Engine could breathe much better.
While driving in 5th around 2800 rpm flooring the gas it felt sluggish. Meaning it didn't want to rev to the redline so fast. JUST my experience vs STOCK
This mod prob doesn't add any HP! It does change the CHARACTER of the car and that is my point.
If you ever get a chance go look at a stock S2000 intake. That might be the right way to go. Kinda combines both types of intake
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