Making an airbox for a cone filter

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57
Location
England
Car
celica gt4 st205
Hi, basically I fitted an induction kit to my suzuki swift but of course its just open and I have felt it after a drive and it is very warm so obviously it is sucking in a load of hot air.
I am thinking of making a bit of a cone that is open at both ends, I will put this over the filter to act as a heat shield and air box and then put quite a few air feeds at the front/underneath, this should give good flow to the filter and protect it from the hot air.
Now my main question is what kind of gap should I leave between the filter and the air box I will be making, will about an inch be enough to ensure it is not restricting the amount of air around the filter and making it struggle slightly.

IMG_20151013_184659443.jpg
This is a pic of the engine bay, this is when I first fitted it, only a week ago, basically now I have made two brakets on the side and underneath the filter to hold it in place properly, I have spun the throttle cable holder a little so it is not pushing down on the pipe, I have cut down the rubber hose so that it sits flush inbetween the battery and the side of the engine and not nearly touching the battery, I have also put a small length of silicone tube to fix the filter to the pipe properly rather than is just being held on by gaffa tape, I have also spun it around so you can't see where I crushed it trying to force it onto the pipe :D

I am just looking for a bit of advice on my idea about the airbox and if it is worth it and if it is a good idea, thanks in advance
 
Hi, basically I fitted an induction kit to my suzuki swift but of course its just open and I have felt it after a drive and it is very warm so obviously it is sucking in a load of hot air.
I am thinking of making a bit of a cone that is open at both ends, I will put this over the filter to act as a heat shield and air box and then put quite a few air feeds at the front/underneath, this should give good flow to the filter and protect it from the hot air.
Now my main question is what kind of gap should I leave between the filter and the air box I will be making, will about an inch be enough to ensure it is not restricting the amount of air around the filter and making it struggle slightly.

View attachment 7070
This is a pic of the engine bay, this is when I first fitted it, only a week ago, basically now I have made two brakets on the side and underneath the filter to hold it in place properly, I have spun the throttle cable holder a little so it is not pushing down on the pipe, I have cut down the rubber hose so that it sits flush inbetween the battery and the side of the engine and not nearly touching the battery, I have also put a small length of silicone tube to fix the filter to the pipe properly rather than is just being held on by gaffa tape, I have also spun it around so you can't see where I crushed it trying to force it onto the pipe :D

I am just looking for a bit of advice on my idea about the airbox and if it is worth it and if it is a good idea, thanks in advance
 
Sorry I'm a touch confused all I'm seeing on my phone is a quote of my original post but not reply from you, is my phone not showing it?
sorry i just joined, just wrote a really long response and then the site sai it could not be submitted!

the long and short of it was, that for the work you will do and the quality of materials you will need to actually insulate the cone filter, you will prob end up spending 100 quid and a good 3 or 4 hours fabricating it...

cone filters are unfortunately more show and very little go, so if i were you i would buy a cold air induction kit with cold air feed, the pipercross venom is a very well made unit, top materials and 183quid from deamon tweaks, and you can fit it in an hour with just a few basic tools.

also i know from experience that if any na car is making 100hp or more then a unit like this will def give at least 5bhp more, and the more power you already have the more this increases. hope this helps,

if you do still want to adapt what you already have, then i will post it up tommorrow as need to go to bed and its a long winded explanation or you could call me tommorow in the day if you want mate. 07404599196 Mark
 
cone filters are unfortunately more show and very little go, so if i were you i would buy a cold air induction kit with cold air feed, the pipercross venom is a very well made unit, top materials and 183quid from deamon tweaks, and you can fit it in an hour with just a few basic tools.

also i know from experience that if any na car is making 100hp or more then a unit like this will def give at least 5bhp more, and the more power you already have the more this increases. hope this helps,

I am impressed that you are able to gain 5% increase with just an air induction kit. Could you please post the dyno sheets, or any other documentary evidence, confirming this increase? Although you have yet to reach the miminum posts to allow this I will authorise the post as I am sure there are many members who would be interested to see them.
 
I'm not a great fan of cone filters. They make more noise than a conventional panel filter but there's not a huge performance increase on offer, if indeed any.

Panel filters were preceded by round ones, which did indeed present airflow restrictions.

You've hit the nail on the head regarding intake temperature though.
 
I am impressed that you are able to gain 5% increase with just an air induction kit. Could you please post the dyno sheets, or any other documentary evidence, confirming this increase? Although you have yet to reach the miminum posts to allow this I will authorise the post as I am sure there are many members who would be interested to see them.
dont have any evidence except my own experience, but that was 10 years ago on a renauult clio 1.8 16valve, and i did have the dyno run print out which showed 137bhp before and 143bhp after fitting an appollo cold air induction kit with cold air feed cut into the bumper, so compleately un heated air was going in. thats 6bhp. on a more modern car with an exhaust and re map, the same kit would give around 10bhp increase as i was told by the guys at the tuning centre.
 
sorry i just joined, just wrote a really long response and then the site sai it could not be submitted!

the long and short of it was, that for the work you will do and the quality of materials you will need to actually insulate the cone filter, you will prob end up spending 100 quid and a good 3 or 4 hours fabricating it...

cone filters are unfortunately more show and very little go, so if i were you i would buy a cold air induction kit with cold air feed, the pipercross venom is a very well made unit, top materials and 183quid from deamon tweaks, and you can fit it in an hour with just a few basic tools.

also i know from experience that if any na car is making 100hp or more then a unit like this will def give at least 5bhp more, and the more power you already have the more this increases. hope this helps,

if you do still want to adapt what you already have, then i will post it up tommorrow as need to go to bed and its a long winded explanation or you could call me tommorow in the day if you want mate. 07404599196 Mark

haha fair enough
Well I already have the sheet steel and heat reflective tape and heat wrap so I have plenty to actually stop the air box itself warming up too.
I don't mind spending time on stuff like that I love fabrication :D
Yeah true they are more show but it's a little too late now :rofl:
To be honest at the moment there isn't a noticeable difference it just makes a much better sound and looks better.
But yeah I still want to make it, don't know when I will get around to it but hopefully soon :)
 
I'm not a great fan of cone filters. They make more noise than a conventional panel filter but there's not a huge performance increase on offer, if indeed any.

Panel filters were preceded by round ones, which did indeed present airflow restrictions.

You've hit the nail on the head regarding intake temperature though.

Yeah thats true it is more sound unless I do some serious modifications, but I will probably only do some serious modifications when I get a better car that has more parts available, cheapest performance camshaft is about £800 for my swift :eek:
 
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haha fair enough
Well I already have the sheet steel and heat reflective tape and heat wrap so I have plenty to actually stop the air box itself warming up too.
I don't mind spending time on stuff like that I love fabrication :D
Yeah true they are more show but it's a little too late now :rofl:
To be honest at the moment there isn't a noticeable difference it just makes a much better sound and looks better.
But yeah I still want to make it, don't know when I will get around to it but hopefully soon :)
ok well if your doing it, fabricate a cold air feed pipe and route it through the bumper, and try to move the cone to a lower cooler part of the engine bay by extending the ducting from inlet manifold to cone.

dont forget to put a good gauze/mesh over the opening of the cold air feed so you dont suck up debris and insects into the filter! good luck mate
 
basically at the front grill if I remember correctly the radiator only takes up about 3/4 of the grill and there is blanking plastic over the grill, I think thats just to stop water splashing onto the exhaust manifold, and so hopefully I will be able to just put a nice large intake there, maybe another on the lower grill, I am thinking around the fog lights too, either cut a hole in the plastic next to the fog light and put a cold air feed there or maybe take the fog light out and put a cold air feed there OR take the whole plastic bit out and put another big 'un there.

I am talking about the fog lights lower down on the bumper either side
 

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basically at the front grill if I remember correctly the radiator only takes up about 3/4 of the grill and there is blanking plastic over the grill, I think thats just to stop water splashing onto the exhaust manifold, and so hopefully I will be able to just put a nice large intake there, maybe another on the lower grill, I am thinking around the fog lights too, either cut a hole in the plastic next to the fog light and put a cold air feed there or maybe take the fog light out and put a cold air feed there OR take the whole plastic bit out and put another big 'un there.

I am talking about the fog lights lower down on the bumper either side
if there is space behind the radiator grill to run a pipe, i would do it there, if not, cut a hole in the grill below the reg plate, but as high up in it as you can, any lower on the front of the car (fog ligh level) and you risk sucking up water if you hit any puddles.... or just be very careful to avoid standing water.

either way, i would nt cut into any body colour plastic, it will look like a bit of a botch boy racer type job if you do stick to cutting into one of the grilles. will keep it looking standard
 
dont have any evidence except my own experience, but that was 10 years ago on a renauult clio 1.8 16valve, and i did have the dyno run print out which showed 137bhp before and 143bhp after fitting an appollo cold air induction kit with cold air feed cut into the bumper, so compleately un heated air was going in. thats 6bhp. on a more modern car with an exhaust and re map, the same kit would give around 10bhp increase as i was told by the guys at the tuning centre.

That's a shame. Figures without documentary evidence are just that, figures.

If you remappped a modern car, you will get more than 10bhp without changing the intake. Who is this tuning centre?
 
Don't make the air intake opening too big. You are looking to create as much pressure as possible at the filter. The bigger the intake opening the lower the pressure at the filter. It's the same principle as that used to calulate radiator grill openings. You need to build as much pressure as possible at the filter/air interface.
 
if there is space behind the radiator grill to run a pipe, i would do it there, if not, cut a hole in the grill below the reg plate, but as high up in it as you can, any lower on the front of the car (fog ligh level) and you risk sucking up water if you hit any puddles.... or just be very careful to avoid standing water.

either way, i would nt cut into any body colour plastic, it will look like a bit of a botch boy racer type job if you do stick to cutting into one of the grilles. will keep it looking standard

Yeah that would be the best place at the grill
I won't cut into any body colour plastic, I'm taking about the black plastic fog light surrounds and possibly cut a hole next to the fog light or take the bulb and lens out and use the predrilled hole for that
 
Don't make the air intake opening too big. You are looking to create as much pressure as possible at the filter. The bigger the intake opening the lower the pressure at the filter. It's the same principle as that used to calulate radiator grill openings. You need to build as much pressure as possible at the filter/air interface.

Really? I thought if I had a huge one that let's plenty of air in then into a smaller pipe that will them lead into the air box that will make more pressure as you are forcing much more air into a small pipe than you would with a smaller inlet
 
That's a shame. Figures without documentary evidence are just that, figures.

If you remappped a modern car, you will get more than 10bhp without changing the intake. Who is this tuning centre?


that is very dependent on the engine. you cant just claim a remap will give more than 10bhp on any modern car, this simply is not true. remap gains can only be accurately predicted in terms of %increase on standard power.

for example if you remapped a na petrol engine with 90hp standard you would only get 5-9bhp increase.

na petrol gives 7-13% which i ve found to be directly linked to engine capacity
charged petrol gives around 20%
and tdi gives 30+%

so no if your na petrol motor with 100hp or less will struggle to achieve 10bhp with a remap.

The tuning centre i had my clio 16valve done at was k tec (the best renault tuners in the country) was done about 12 years ago.

dont know what your qualifications/experience are like, but i have allot of experience with induction, remapping and exhaust flow upgrades.

been running a seat toledo 2002 v5 20valve with cold air feed induction, full straight through exhaust with de cat pipe and a remap. have found that larger capacity na petrol engines especially 5 and 6 cylinder 20/24valvers respond very well to letting them breath well and remapping.

it was 167hp standard and after all the mods, it was pushing 210 hp at the wheel

unfortunately i passed the dyno print outs on to the guy i sold the renault to. they obviosly wanted proof of the power i claimed in tha ad...
 
Really? I thought if I had a huge one that let's plenty of air in then into a smaller pipe that will them lead into the air box that will make more pressure as you are forcing much more air into a small pipe than you would with a smaller inlet

you only want to increase the diamiter of the intake pipe if you are also fitting a high flow exhaust system and remapping it otherwise you will loose engine compression and therefore power as the motor cannot suck air in any fater if it cant exhaust it any faster
 
you only want to increase the diamiter of the intake pipe if you are also fitting a high flow exhaust system and remapping it otherwise you will loose engine compression and therefore power as the motor cannot suck air in any fater if it cant exhaust it any faster

Ahh ok fair enough
Also about the pressure thing I was actually thinking of just leaving the back open as I was more thinking of just making sure the filter is protected from hot air and has a nice supply of fresh air passing over it
At the moment (possibly later on) I don't have an exhaust or anything else so if I start seriously shoving air into the intake isn't it possible that fuel system can't keep up as well as the exhaust
 
that is very dependent on the engine. you cant just claim a remap will give more than 10bhp on any modern car, this simply is not true. remap gains can only be accurately predicted in terms of %increase on standard power.

for example if you remapped a na petrol engine with 90hp standard you would only get 5-9bhp increase.

na petrol gives 7-13% which i ve found to be directly linked to engine capacity
charged petrol gives around 20%
and tdi gives 30+%

so no if your na petrol motor with 100hp or less will struggle to achieve 10bhp with a remap.

The tuning centre i had my clio 16valve done at was k tec (the best renault tuners in the country) was done about 12 years ago.

dont know what your qualifications/experience are like, but i have allot of experience with induction, remapping and exhaust flow upgrades.

been running a seat toledo 2002 v5 20valve with cold air feed induction, full straight through exhaust with de cat pipe and a remap. have found that larger capacity na petrol engines especially 5 and 6 cylinder 20/24valvers respond very well to letting them breath well and remapping.

it was 167hp standard and after all the mods, it was pushing 210 hp at the wheel

unfortunately i passed the dyno print outs on to the guy i sold the renault to. they obviosly wanted proof of the power i claimed in tha ad...

I was generalising as most modern engines produce more than 100bhp, which equates to around 10bhp on an NA lump with a remap depending, as you say, on the engine. My point is that you can get around 10bhp from an NA engine with 100bhp without messing around with the intake system. If it is turbo'd then you are looking at around 20-25% and a TDi can see near 40%.

My son remaps cars as an agent for Celtic Tuning.

I have been messing around (tuning and modifying) with (mainly British) cars for around 45 years so have picked up the odd snippet of info in that time, one of them being don't believe anything a tuner or seller of snake oil go faster bits tells you - especially air filter and cold feed intake peddlers :-)
 
Really? I thought if I had a huge one that let's plenty of air in then into a smaller pipe that will them lead into the air box that will make more pressure as you are forcing much more air into a small pipe than you would with a smaller inlet

No, the exact opposite will happen! Simply having a bigger inlet will not force more air in (you need a compressor to do that) and will not increase pressure. As the diameter of the intake reduces the velocity of the air increases and the pressure decreases - basic fluid mechanics (air behaves like a fluid in these situations).

Keep the intake cross sectional area smaller than the air box CS area and totally enclose the filter so the air cannot escape. This should result in an increase in pressure in the air box which is what you want.
 
No, the exact opposite will happen! Simply having a bigger inlet will not force more air in (you need a compressor to do that) and will not increase pressure. As the diameter of the intake reduces the velocity of the air increases and the pressure decreases - basic fluid mechanics (air behaves like a fluid in these situations).

Keep the intake cross sectional area smaller than the air box CS area and totally enclose the filter so the air cannot escape. This should result in an increase in pressure in the air box which is what you want.

Oh ok fair enough
I just thought that an intake with a bigger surface area would let more air into it and then if it is continuously forced into a smaller pipe that would increase the pressure as oppose to an inlet that is the same size as the piping afterwards
So basically does that mean make sure that the intake should be smaller than the air box
 
Can I just check I've got my head around this

Big intake to small pipe = higher velocity low pressure
Big intake to big pipe = large volume but low pressure high velocity?
Small intake small pipe = low velocity high pressure low volume?
Small intake big pipe = i would've thought that's low everything but then pressure and velocity adversely affect each other so what would this be
Just want to check I've got my head around it

Thanks for the help everyone by the way :)
 
I was generalising as most modern engines produce more than 100bhp, which equates to around 10bhp on an NA lump with a remap depending, as you say, on the engine. My point is that you can get around 10bhp from an NA engine with 100bhp without messing around with the intake system. If it is turbo'd then you are looking at around 20-25% and a TDi can see near 40%.

My son remaps cars as an agent for Celtic Tuning.

I have been messing around (tuning and modifying) with (mainly British) cars for around 45 years so have picked up the odd snippet of info in that time, one of them being don't believe anything a tuner or seller of snake oil go faster bits tells you - especially air filter and cold feed intake peddlers :)


yeah, on modern cars, cold air induction feeds dont do much unless coupled with high flow exhausts and remaps, but the late 80s and early 90s hot hatches which had much simpler engines seemed to benefit much mor from cold air feed induction.

you can actually get upto 50% power increase from just remapping a tdi, however mpg and reliability will both basically dissapear!

a remap can be set any what way you want, most of the figures we are discussing are a happy balence between power, reliability and mpg. my mate heaviley mapped his wrx turbo to 680hp, and could empty a full tank of fuel in 45 miles! but he did have all the uprated suspension brakes clutch and gearbox exhaust and turbo so nothing would break! it was a monster, you could spin all 4 wheels from 50mph right up to 120mph. very funny to see the looks on porsche turbo and ferrari drivers faces when they were left in a cloud of tyre smoke wondering what they had spent £80000+ on haha!
best part was the only give away was the huge brake discs and callipers and exhaust. oh and the noise once he did open it up.... he kept everything as oem looking as possible
 
Air is very difficult to compress and simply reducing the size of the pipe won't do it, a very common misconception.

Yes. Make the air box as big as possible.

Notice the size of the intake on this F1 car, not exactly cavenous :-)

 
Can I just check I've got my head around this

Big intake to small pipe = higher velocity low pressure
Big intake to big pipe = large volume but low pressure high velocity?
Small intake small pipe = low velocity high pressure low volume?
Small intake big pipe = i would've thought that's low everything but then pressure and velocity adversely affect each other so what would this be
Just want to check I've got my head around it

Thanks for the help everyone by the way :)

If the cross sectional area for a given amount of moving air increases then velocity drops and pressure increases. This is what you want to achieve.

If the CS decreases then velocity increases and pressure drops.

For a radiator, the ratio is around 1:3 ie the grill needs to be around a third of the area of the radiator. This is, however, a big generalisation as every setup is different so experimentation would be required to establish the correct ratio for a particular car.

Same with the air filter. 1:3 to 1:2 would be a good starting point.

PS. Ram air is pointless below around 100mph, and even then might be worth 1/2 to 1%. So having a cold air intake at the front of the car will supply cooler air (keep it at least 250mm above the ground as air near to the ground is warmer) but there will be no 'ram air' effect.

You can keep the pipe the same size as the intake opening and just increase the size of the filter box.
 
If the cross sectional area for a given amount of moving air increases then velocity drops and pressure increases. This is what you want to achieve.

If the CS decreases then velocity increases and pressure drops.

For a radiator, the ratio is around 1:3 ie the grill needs to be around a third of the area of the radiator. This is, however, a big generalisation as every setup is different so experimentation would be required to establish the correct ratio for a particular car.

Same with the air filter. 1:3 to 1:2 would be a good starting point.

PS. Ram air is pointless below around 100mph, and even then might be worth 1/2 to 1%. So having a cold air intake at the front of the car will supply cooler air (keep it at least 250mm above the ground as air near to the ground is warmer) but there will be no 'ram air' effect.

You can keep the pipe the same size as the intake opening and just increase the size of the filter box.

Ok awesome thanks that's exaclty what I wanted
 
Ram air is pointless below around 100mph, and even then might be worth 1/2 to 1%. So having a cold air intake at the front of the car will supply cooler air (keep it at least 250mm above the ground as air near to the ground is warmer) but there will be no 'ram air' effect.

You can keep the pipe the same size as the intake opening and just increase the size of the filter box.


Example


Fed via custom ali ducting from vent in front valence . Bonnet closes and seals box at top which is vented through inner wing . Seems to work for me.
 
Are you agreeing with me? Looking at the photo I reckon so :-)

Why is the air box vented through the wing (if I read that correctly)?
 
And yeah I already knew about ram air not having an effect at lower speeds

So 1:2 to 1:3 is that the airbox is 3 times bigger than the intake?

Bearing in mind this very emperical as each car/engine combination is different then, for example, if you have a 100mm diameter feed pipe, in order to increase the cross sectional area by 3 times, the box containing the filter needs to be at least 175mm diameter or 150mm square and long enough to contain the filter. However, you need to have at least 25mm gap around the filter.
 
Actually does just one more thing does the distance from the filter to the MAF sensor matter?
I know the actual position of the MAF sensor is important but would it make a big difference if I cut down the metal tube a bit as that would give me a bit more space around the filter for the airbox
 
Sensors aren't my strong point (not sure what is) but and inch or so shouldn't make any difference, IMO.
 

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