Fan-assisted air box: another home-made mod.
11-05-2007, 09:01 PM
#1
Fan-assisted air box: another home-made mod.
In an unrelated thread, I spoke about increasing air flow to the throttle as a way to improve performance. Originally, I needed a connection in the engine bay that is "hot" only when the engine is turned on. So far, all of the leads I found are "hot" all the time (fuse box included).
The idea was to put a small, but powerful computer case fan inside the bottom half of a stock airbox next to the air intake. This fan would draw in
more cool air.
Anyway, for the time being and for testing purposes, I ran a wire from the airbox fan into the cabin, and attached the free end to a standard cigarette lighter plug.
This is no ordinary computer case fan. It is THE most powerful fan for its size (about 3 1/8" square x 1 1/2 thick). How powerful is it?
Until recently, I thought that the Vantec Tornado was the most powerful case fan around, delivering a constant 84 CFM (Cubic Feet per Minute) in air flow.
But this Delta fan I got this week literally blows the Vantec away with 107 CFM! Not only is it more powerful than the Vantec, it is also $10.00 cheaper.
Here's a picture of the fan:
Here's a picture of the fan inside the bottom of the air box. Currently, the fan is fastened in place by two 10/24 bolts and double-sided tape.
OK, so what does it do?
First off, when I turned it on, it sounded like a mini turbo spooling up. However, the fan motor cannot be heard over the sound of a running engine.
Next, you can feel the difference on take-offs -- they are quicker, smoother, and require less pedal input. In-town gas mileage has also improved by 2-3mpg.
Before I put in the fan, the car had a small but annoying delay on take offs (except when launching with power braking).
Now, with the fan, there is no hesitation at all. It seems to smooth out power at the lower end, and maybe add a few horses
No, It won't increase air pressure the way a blower or turbo does, so it's not a cheap replacement for them.
It does what it is designed to do, which is to increase the flow of cool air into the intake (as mentioned above).
And, you can get one for less than the cost of four gallons of gas. it's definitely worth the investment.
The idea was to put a small, but powerful computer case fan inside the bottom half of a stock airbox next to the air intake. This fan would draw in
more cool air.
Anyway, for the time being and for testing purposes, I ran a wire from the airbox fan into the cabin, and attached the free end to a standard cigarette lighter plug.
This is no ordinary computer case fan. It is THE most powerful fan for its size (about 3 1/8" square x 1 1/2 thick). How powerful is it?
Until recently, I thought that the Vantec Tornado was the most powerful case fan around, delivering a constant 84 CFM (Cubic Feet per Minute) in air flow.
But this Delta fan I got this week literally blows the Vantec away with 107 CFM! Not only is it more powerful than the Vantec, it is also $10.00 cheaper.
Here's a picture of the fan:
Here's a picture of the fan inside the bottom of the air box. Currently, the fan is fastened in place by two 10/24 bolts and double-sided tape.
OK, so what does it do?
First off, when I turned it on, it sounded like a mini turbo spooling up. However, the fan motor cannot be heard over the sound of a running engine.
Next, you can feel the difference on take-offs -- they are quicker, smoother, and require less pedal input. In-town gas mileage has also improved by 2-3mpg.
Before I put in the fan, the car had a small but annoying delay on take offs (except when launching with power braking).
Now, with the fan, there is no hesitation at all. It seems to smooth out power at the lower end, and maybe add a few horses
No, It won't increase air pressure the way a blower or turbo does, so it's not a cheap replacement for them.
It does what it is designed to do, which is to increase the flow of cool air into the intake (as mentioned above).
And, you can get one for less than the cost of four gallons of gas. it's definitely worth the investment.
Last edited by dr-rjp; 11-05-2007 at 09:39 PM.
11-05-2007, 09:38 PM
#5
Tell me that's not bolted right up before the maf...? If it were just pulling cold air into the airbox, that's one thing. But, if that is right on the front of the maf, all air going into the engine will have to go thru that fan. Sure it might flow enough for just off idle, but at high rpms, your engine will suck more air than that fan could dream about! imo, that just added restriction more than anything.
edit: now I'm seeing that its not in front of the maf, but at the entry of the airbox. still same effect tho, all air going into the intake will have to go thru that fan...
so basically you have like...2 electric superchargers?
edit: now I'm seeing that its not in front of the maf, but at the entry of the airbox. still same effect tho, all air going into the intake will have to go thru that fan...
so basically you have like...2 electric superchargers?
Last edited by mowgli29; 11-05-2007 at 09:46 PM.
:
11-05-2007, 10:34 PM
#12
CPU fan FTL
Leafblower FTW
http://videos.streetfire.net/Player....AD23CA9564&p=0
(music in the video FTL)
Leafblower FTW
http://videos.streetfire.net/Player....AD23CA9564&p=0
(music in the video FTL)
11-06-2007, 03:59 AM
#16
Member
Join Date: Apr 2006
Location: MD
Posts: 42
Oh know, what did you do!! 
I think the fan would only be a restriction buddy. In theory it adds more cfm and the specification numbers rock!! but in reality, its nothing. Try getting a 3in pipe thats 1.5-2 feet long, and put the fan on the other end, if you felt anything, its little to none.... now imagine that same pipe with ridges all around and mutiple bends on the pipe, its not happening. Atleast you tried, but this idea has been around as long as civics has been around. And all that improvement, I think its a placebo.. but everyone feels different so... nice try though! 
but if you are dynoing, definately interested to see what the changes are! (good or bad)
I think the fan would only be a restriction buddy. In theory it adds more cfm and the specification numbers rock!! but in reality, its nothing. Try getting a 3in pipe thats 1.5-2 feet long, and put the fan on the other end, if you felt anything, its little to none.... now imagine that same pipe with ridges all around and mutiple bends on the pipe, its not happening. Atleast you tried, but this idea has been around as long as civics has been around. And all that improvement, I think its a placebo.. but everyone feels different so... nice try though! but if you are dynoing, definately interested to see what the changes are! (good or bad)
Last edited by h22enjen; 11-06-2007 at 04:02 AM.
11-06-2007, 06:11 AM
#17
Tell me that's not bolted right up before the maf...? If it were just pulling cold air into the airbox, that's one thing. But, if that is right on the front of the maf, all air going into the engine will have to go thru that fan. Sure it might flow enough for just off idle, but at high rpms, your engine will suck more air than that fan could dream about! imo, that just added restriction more than anything.
edit: now I'm seeing that its not in front of the maf, but at the entry of the airbox. still same effect tho, all air going into the intake will have to go thru that fan...
so basically you have like...2 electric superchargers?
edit: now I'm seeing that its not in front of the maf, but at the entry of the airbox. still same effect tho, all air going into the intake will have to go thru that fan...
so basically you have like...2 electric superchargers?
Well, it immediately stalled out my car. I reported the results on the Forum as well.
Then I thought, "What if I were to put it in the bottom half of the box?"
I really expected it to do absolutely nothing, or maybe stall out the car or make it run crappy.
No such luck. It actually does something useful.
Yes, all incoming air is going through that fan...BUT...at a much faster rate than one could get without it. If all it did was to cool off the incoming air, it would still be useful.
I have an old write-up on here where I used a hot wire anemometer (bascially what an MAF is) placed where the fan is now to determine both air volume and temperature. I was comparing a stock air scoop to my modded air scoop (aka scoop extender).
At 60mph, air coming in the modded scoop measured 43 CFM as compared to the stock's 39 CFM. Temperature for the stock setup was 82 degrees, and 78 degrees for the modded setup. (Outside air temperature was 76 degrees)
First of all, the volume of air entering naturally into a stock air box is not that great to begin with, and it turns out that it's much lower than the volume produced by the fan.
No dreaming here. Strictly empirical testing.
Now, if the fan was not running, then it would impede air flow. But it's running all the time and drawing only 1.8 amps in the process, so no big woof as far as being a power drag.
When I get to Orlando, I will put my car on a dyno, and get some numbers to go along with my mods. Up here they charge $100 for 3 runs, and that's way more than I can afford right now.
In the meantime, if anyone has a stock air box and $12 to spare, they can try what I did.
If they don't like it, they can always take it out, attach a base to it and a 12v adapter, and have a powerful, compact desk fan.
Make sure that the base is heavy, though, because this fan scoots across a table like an RF airplane on a runway.
11-06-2007, 07:23 AM
#21
everything I've ever read on any forum has said that anything like this would be more restrictive and it's not something I would do but your logic seems interesting. It's hard to argue with results, so hit the dyno and see what you come up with.
Wonder if you'll get a CEL too.
Wonder if you'll get a CEL too.
11-06-2007, 07:34 AM
#23
Originally Posted by merlin2375
everything I've ever read on any forum has said that anything like this would be more restrictive and it's not something I would do but your logic seems interesting. It's hard to argue with results, so hit the dyno and see what you come up with.
Originally Posted by merlin2375
Wonder if you'll get a CEL too.
11-06-2007, 07:42 AM
#24
Originally Posted by dr-rjp
I have an old write-up on here where I used a hot wire anemometer (bascially what an MAF is) placed where the fan is now to determine both air volume and temperature. I was comparing a stock air scoop to my modded air scoop (aka scoop extender).
At 60mph, air coming in the modded scoop measured 43 CFM as compared to the stock's 39 CFM. Temperature for the stock setup was 82 degrees, and 78 degrees for the modded setup. (Outside air temperature was 76 degrees)
At 60mph, air coming in the modded scoop measured 43 CFM as compared to the stock's 39 CFM. Temperature for the stock setup was 82 degrees, and 78 degrees for the modded setup. (Outside air temperature was 76 degrees)
Or more specifically: http://forums.maxima.org/showpost.ph...70&postcount=1
11-06-2007, 08:31 AM
#26
As noted above, I used a hot-wire anemometer (about the size of a large, cigarette lighter) positioned in the air flow, directly in front of the air inlet side of the air box, and held in place with tape and a sturdy, L-shaped bracket.
(BTW, I did take pictures of the setup at the time, but my camera's SD card became corrupted and I could never recover them).
The MAF is. in fact, a hot-wire anemometer that is cooled by the airflow around it: the faster the air flow, the more the hot-wire cools. Also, the colder the air flow, the more the hot-wire cools. The main difference is, of course, that the MAF only outputs changes in voltage corresponding to changes in temperature.
The hand-held anemometer I used (borrowed from an HVAC technician, as it costs well over $500), has a digital readout that inputs the temperature changes to the hot-wire element and automatically computes a wide range of variables including flow rate (CFM, CMM), air pressure (KG/CM2), and air temperature (DEG. F/DEG. C).
It also stores in memory the highest and lowest readouts for each variable (which can be individually reset).
The only downside is that I did not have a special cable that would have allowed me to connect it to a remote display and get real-time readings. What I had to do instead was to lift the hood and airbox after each run to see the readings.
Basically, what I did was to
1. Bring the car up to operating temperature
2. Zero out the anemometer's memory
3. Run the car at a fixed speed for 10 minutes.
4. Pop the hood and airbox.
5. Read off the minimum & maximum values for each variable
then repeat #2 thru #5 for a total of three sets of baseline readings.
Next, I would install my mod and repeat #2 thru #5 for three sets of modded readings.
Lastly, remove my mod and repeat #2 thru #5 for two final baseline readings.
What I reported was the average maximum baseline readings versus the average maximum modded readings for both CFM and temperature. The reason I used maximums is because they would not be affected from opening up the hood and air box, whereas minimums would.
(BTW, I did take pictures of the setup at the time, but my camera's SD card became corrupted and I could never recover them).
The MAF is. in fact, a hot-wire anemometer that is cooled by the airflow around it: the faster the air flow, the more the hot-wire cools. Also, the colder the air flow, the more the hot-wire cools. The main difference is, of course, that the MAF only outputs changes in voltage corresponding to changes in temperature.
The hand-held anemometer I used (borrowed from an HVAC technician, as it costs well over $500), has a digital readout that inputs the temperature changes to the hot-wire element and automatically computes a wide range of variables including flow rate (CFM, CMM), air pressure (KG/CM2), and air temperature (DEG. F/DEG. C).
It also stores in memory the highest and lowest readouts for each variable (which can be individually reset).
The only downside is that I did not have a special cable that would have allowed me to connect it to a remote display and get real-time readings. What I had to do instead was to lift the hood and airbox after each run to see the readings.
Basically, what I did was to
1. Bring the car up to operating temperature
2. Zero out the anemometer's memory
3. Run the car at a fixed speed for 10 minutes.
4. Pop the hood and airbox.
5. Read off the minimum & maximum values for each variable
then repeat #2 thru #5 for a total of three sets of baseline readings.
Next, I would install my mod and repeat #2 thru #5 for three sets of modded readings.
Lastly, remove my mod and repeat #2 thru #5 for two final baseline readings.
What I reported was the average maximum baseline readings versus the average maximum modded readings for both CFM and temperature. The reason I used maximums is because they would not be affected from opening up the hood and air box, whereas minimums would.
11-06-2007, 09:05 AM
#27
There is a device on the market, called the NITROD VPM-100G, that sells for $275 and measures Mass Air Flow along with a ton of other stuff including:
Fuel Consumption
Fuel System Status
Boost gauge
General System Display
Factory Wide Band O2 Sensors (A/F - Lambda)
Air Intake Manifold Pressure (Vacuum/Boost)
Engine Coolant Temperature
Air Intake Temperature
Narrow Band O2 Sensors
Battery/Alternator Voltage
Tachometer & Vehicle Speed
Spark Advance
Long- and Short-Term Fuel Trims
Throttle Position
Engine Load Value
-and-
Elapsed Time for: 1/4 mile, 1/8 mile, 60 ft, 0-60 mph ...
Maximum Horsepower
Cornering, Braking & Accelerating g-force
11-06-2007, 10:33 AM
#28
Hmm, I didn't know all that, really. 
I need to word myself a little differently around you.
I'm interested in what the MAF/ECU is seeing with respect to the changes (before and after) you made, (gm/s data).
I need to word myself a little differently around you.
I'm interested in what the MAF/ECU is seeing with respect to the changes (before and after) you made, (gm/s data).
11-06-2007, 10:37 AM
#30
Just another damn OBD-II gauge mixed with a G-Tech. Boost gauge, fuel consumption, factory wideband, etc don't/won't work on the A32.
11-06-2007, 11:00 AM
#31
Not advocating this device, but do you know anyone who's tried it? Why wouldn't it work on an OBD-II compliant A32?
What low-cost devices on the market will at least measure MAF output?
On the other hand, I could hook up the test probes of a multimeter and check the MAF readings directly. But, I would need some freakin' long probe wires, too!
11-06-2007, 11:04 AM
#32
Not advocating this device, but do you know anyone who's tried it? Why wouldn't it work on an OBD-II compliant A32?
What low-cost devices on the market will at least measure MAF output?
On the other hand, I could hook up the test probes of a multimeter and check the MAF readings directly. But, I would need some freakin' long probe wires, too!
What low-cost devices on the market will at least measure MAF output?
On the other hand, I could hook up the test probes of a multimeter and check the MAF readings directly. But, I would need some freakin' long probe wires, too!
We aren't factory F/I, nothing in the ECU to use for a 'boost gauge'. I don't imagine the A32 ECU could show fuel consumption, and our stock O2 sensors are narrowband.
Any OBD-II scanner will show MAF g/s.
11-06-2007, 12:41 PM
#35
I know the A33 and A33B have the IAT built in to the MAF, as your I30 probably does.
11-06-2007, 01:01 PM
#36
Licensed to Spell
iTrader: (12)
Join Date: Feb 2001
Location: Murrieta (southern California)
Posts: 4,521
I like your creative thinking. I too have a bag of computer fans sitting in my garage, but for a slightly different reason. I was going to put a big one right in front of my Air/Water aftercooler's heat exchanger. Then stratigically place the others throughout the engine bay for cooler engine temps. Maybe aim one right at the supercharger. I'll probably hook the power up to a WOT switch so the fans aren't sucking any power/voltage under WOT. If you are looking for a switched power source under the hood, I used the windhsield wiper motor. PM me for pics/detailed description if you are truly interested. Is your air filter able to fit in place with the fan installed? I know some people claim your fan is a restriction, and it might be, but at least it's active unlike a passive device (read: The Tornado). Good job.
In an unrelated thread, I spoke about increasing air flow to the throttle as a way to improve performance. Originally, I needed a connection in the engine bay that is "hot" only when the engine is turned on. So far, all of the leads I found are "hot" all the time (fuse box included).
The idea was to put a small, but powerful computer case fan inside the bottom half of a stock airbox next to the air intake. This fan would draw in
more cool air.
Anyway, for the time being and for testing purposes, I ran a wire from the airbox fan into the cabin, and attached the free end to a standard cigarette lighter plug.
This is no ordinary computer case fan. It is THE most powerful fan for its size (about 3 1/8" square x 1 1/2 thick). How powerful is it?
Until recently, I thought that the Vantec Tornado was the most powerful case fan around, delivering a constant 84 CFM (Cubic Feet per Minute) in air flow.
But this Delta fan I got this week literally blows the Vantec away with 107 CFM! Not only is it more powerful than the Vantec, it is also $10.00 cheaper.
Here's a picture of the fan:
Here's a picture of the fan inside the bottom of the air box. Currently, the fan is fastened in place by two 10/24 bolts and double-sided tape.
OK, so what does it do?
First off, when I turned it on, it sounded like a mini turbo spooling up. However, the fan motor cannot be heard over the sound of a running engine.
Next, you can feel the difference on take-offs -- they are quicker, smoother, and require less pedal input. In-town gas mileage has also improved by 2-3mpg.
Before I put in the fan, the car had a small but annoying delay on take offs (except when launching with power braking).
Now, with the fan, there is no hesitation at all. It seems to smooth out power at the lower end, and maybe add a few horses
No, It won't increase air pressure the way a blower or turbo does, so it's not a cheap replacement for them.
It does what it is designed to do, which is to increase the flow of cool air into the intake (as mentioned above).
And, you can get one for less than the cost of four gallons of gas. it's definitely worth the investment.
The idea was to put a small, but powerful computer case fan inside the bottom half of a stock airbox next to the air intake. This fan would draw in
more cool air.
Anyway, for the time being and for testing purposes, I ran a wire from the airbox fan into the cabin, and attached the free end to a standard cigarette lighter plug.
This is no ordinary computer case fan. It is THE most powerful fan for its size (about 3 1/8" square x 1 1/2 thick). How powerful is it?
Until recently, I thought that the Vantec Tornado was the most powerful case fan around, delivering a constant 84 CFM (Cubic Feet per Minute) in air flow.
But this Delta fan I got this week literally blows the Vantec away with 107 CFM! Not only is it more powerful than the Vantec, it is also $10.00 cheaper.
Here's a picture of the fan:
Here's a picture of the fan inside the bottom of the air box. Currently, the fan is fastened in place by two 10/24 bolts and double-sided tape.
OK, so what does it do?
First off, when I turned it on, it sounded like a mini turbo spooling up. However, the fan motor cannot be heard over the sound of a running engine.
Next, you can feel the difference on take-offs -- they are quicker, smoother, and require less pedal input. In-town gas mileage has also improved by 2-3mpg.
Before I put in the fan, the car had a small but annoying delay on take offs (except when launching with power braking).
Now, with the fan, there is no hesitation at all. It seems to smooth out power at the lower end, and maybe add a few horses
No, It won't increase air pressure the way a blower or turbo does, so it's not a cheap replacement for them.
It does what it is designed to do, which is to increase the flow of cool air into the intake (as mentioned above).
And, you can get one for less than the cost of four gallons of gas. it's definitely worth the investment.
11-06-2007, 01:10 PM
#37
This Delta fan is slightly larger than the Vantec, and one corner of it does touch the filter, but I had no trouble fitting the filter on it or closing it up. Thanks for the offer (of pics).
I think that everyone would be freaked out by how powerful is this 3" square fan. I know when one thinks of a computer case fan, they think about this quiet, little device to move the air around. Those type of fans rarely go above 25CFM. This one does 107 CFM and is loud as hell.
Seriously though, if you hold it between your thumb and forefinger, and turn it on, it will twist right out of your grip.
As long as its running, there won't be any impediments to air flow.
I think that everyone would be freaked out by how powerful is this 3" square fan. I know when one thinks of a computer case fan, they think about this quiet, little device to move the air around. Those type of fans rarely go above 25CFM. This one does 107 CFM and is loud as hell.
Seriously though, if you hold it between your thumb and forefinger, and turn it on, it will twist right out of your grip.
As long as its running, there won't be any impediments to air flow.
11-06-2007, 02:25 PM
#38
Newbie - Just Registered
Join Date: Nov 2007
Posts: 1
delta makes bigger fans. big following in pc cooling.
http://www.delta.com.tw/product/cp/d...cfans_main.asp
i might have to try this. nice work
http://www.delta.com.tw/product/cp/d...cfans_main.asp
i might have to try this. nice work
Last edited by cwolv; 11-06-2007 at 02:31 PM.
11-06-2007, 04:07 PM
#40
Um.
Alright, first of all, I can see how this could help out for low-load situations. But at 60mph your VQ is under what, 40hp of load? So some ricer math will give us 40CFM ~= 40hp. Now what happens when you try and use all 190hp? Fan is a big bottleneck, not to mention the extra turbulence it's creating (admittedly possibly negligent). I get that a 2 amp fan flowing 100CFM is nothing to sneeze at, throttle response would be improved, etc, but any improvement under WOT would certainly be low-end only.
That said, kudos for trying it out and I'd be interested to drive your car and mine back-to-back, as well as read a dyno chart.
Alright, first of all, I can see how this could help out for low-load situations. But at 60mph your VQ is under what, 40hp of load? So some ricer math will give us 40CFM ~= 40hp. Now what happens when you try and use all 190hp? Fan is a big bottleneck, not to mention the extra turbulence it's creating (admittedly possibly negligent). I get that a 2 amp fan flowing 100CFM is nothing to sneeze at, throttle response would be improved, etc, but any improvement under WOT would certainly be low-end only.
That said, kudos for trying it out and I'd be interested to drive your car and mine back-to-back, as well as read a dyno chart.