cold air feeds and rain

[franx]

agree it does help, but "ramair" does not occur until silly speeds

exactly.. what works for race cars cannot be compared to/for roadcar usage

Clio's and silly speeds do'nt go together.

When i still had my Saxo, i did the caf change to foglight because i was desperately trying to make my expensive Viper-superduperairintake work... nothing happened

In a couple of minutes i'll be outside under the bonnet putting my original filterhousing back.
Somebody on here mentioned pulling the lower caf off the housing and aiming towards the 50mm hole from which it was taken.
This i've also already tested (well i just completely removed this caf) and it definately worked best for me !
You get a bit of induction noise, my throttleresponce was right there and smooth power all the way up the rpm range, car pulls like a train !

Also Chris on here strangely enough had LOWER airtemp readings on his RStuner kit with both the Cafs removed, getting air from the engine bay...

It's actually quite fun to spend a day removing/changing cafs and the take the car out on a run to see the differences !

 

[Dash]

It's so easy really. What you need is a water repellent expandable throttle body.

 

[LeeP86]

i reckon get rid of the bodies all together and use a couple of twin webers lol

 

[franx]

turbo

 

[LeeP86]

f*** the engine off, hole in floor, legs down, flintstone style DONE!

 

[franx]

yesss

i can outrun any 172 from 0 to 7 , not a prob...

 

[Neil G]

its not bs and not marketing rubbish it works v well granted not at below about 30mph but above there it gives the engine more and colder air which then gives the engine slightly more power. if you look on nearly every single seater race car there is an air intake above the drivers head. i have spoken to all of my collegues and other people in my line of work including one of the chief mechanics for wsr/team RAC and all of them agree with me that having a cold air feed helps the cars performance.

The word race car being the defining factor

For road going clios it is marketing BS...next thing you know they'll be people telling you can get 10bhp by removing the acoustic valve and installing an electric 'turbocharger' off ebay.

I think fiddling around with CAFs is fun and we've all done it but these days I know it's going to make so little difference I just leave the setup standard (bar green panel filter)

 

[Olly1.216v]

Engines done suck air, its because the atmospheric air in the cylinder is small then outside the cylinder so it rushes in to fill the space were there is no air. It is not the engine its self sucking the air in.

Its like if you suck a lemonade bottle people think its the sucking thats crushing it, but its actually the air outside crushing the bottle.

Lol really confusing but i also always say the engine can suck more air in if you do this ect as its just eaiser to explain

 

[Andyman]

its not bs and not marketing rubbish it works v well granted not at below about 30mph but above there it gives the engine more and colder air which then gives the engine slightly more power. if you look on nearly every single seater race car there is an air intake above the drivers head. i have spoken to all of my collegues and other people in my line of work including one of the chief mechanics for wsr/team RAC and all of them agree with me that having a cold air feed helps the cars performance.

The word race car being the defining factor

For road going clios it is marketing BS...next thing you know they'll be people telling you can get 10bhp by removing the acoustic valve and installing an electric 'turbocharger' off ebay.

I think fiddling around with CAFs is fun and we've all done it but these days I know it's going to make so little difference I just leave the setup standard (bar green panel filter)

Marketing tool :S

Who's exactly marketing cold air feeds? Last time i looked they were mostly home made jobs......

 

[franx]

The word race car being the defining factor

For road going clios it is marketing BS...next thing you know they'll be people telling you can get 10bhp by removing the acoustic valve and installing an electric 'turbocharger' off ebay.

I think fiddling around with CAFs is fun and we've all done it but these days I know it's going to make so little difference I just leave the setup standard (bar green panel filter)

Marketing tool :S

Who's exactly marketing cold air feeds? Last time i looked they were mostly home made jobs......

think he meant pointing cafs toword the front for forced intake

 

[fuzzi]

though this was a really interesting read, just in th eprocess of putting mu caf to my fog. hope im making the right desision lol

 

[Eckascliovalver]

i would say yes, my inlet is now cold since putting on my CAF to the lower grill, surley this is better that having a warm inlet when the standerd box was on and a buring inlet when i had my open filter on CAF to the front of the car ftw

 

[fuzzi]

woop woop lol

 

[sammyhale22]

Don`t Ford connect their intake to the front grill on the Focus range, they use a small scoop that sits behind the grill? My 91 suzuki swift Gti used the wheel arch induction style! I think they are both just different designs and probably do the same job of making the air cooler!

 

[Rob 88]

'Ram air' for a standard road car engine is bo**ocks. The engine has to be designed for this and cold air feeds are for cool air, so your viper does'nt turn into a K&N. Agree with standard set up and panel filter for road cars

 

[cleo]

I thought the fact that rolling roads used big fans was to simulate the air you would be facing driving fast? (ie if they suck and dont have any gain from a front facing CAF, wouldnt it just be the same as having no fan on the rolling road, and the engine would just suck in what it needed)?

 

[Rob 88]

I thought the fact that rolling roads used big fans was to simulate the air you would be facing driving fast? (ie if they suck and dont have any gain from a front facing CAF, wouldnt it just be the same as having no fan on the rolling road, and the engine would just suck in what it needed)?

The fans only there to stop you cooking your engine

 

[Jimbo_924]

'Ram air' for a standard road car engine is bo**ocks. The engine has to be designed for this and cold air feeds are for cool air, so your viper does'nt turn into a K&N. Agree with standard set up and panel filter for road cars

I have to say the last two post from Rob, have been spot on.

RAM effects in engine inlet tracts are a very important parameter to tune when designing a car, it is a very complex procedure !!

Such as: Inertia RAM effects, yes you may not think that air weighs very much, however at inlet gas speeds of around 80-120 m/s (Racing cars are around 140m/s) it has a considerable inertia (it'll help if you think of it as momentum). This can then mean that in fact even while the piston has reached BDC (bottom dead centre) and is on its way back up more air can flow in (hence inlet valves stay open past BDC). Improving volumetric efficiency. Equally while the valve is closed this builds a positive pressure (above atmosphere) behind the valve, meaning when it reopens this air forces inself into the vacum of the cyliner even faster. This inertia effect then depends massively on the size of the pipes as they affect the amount of air in the inlet tract.

This is one of two main reasons (other being Wave RAM effects, that I won't go into as I've just realized how geeky I've become) why many aftermarket induction kits can reduce engine power as they do not have the money to properly develop their products. Which isn't their fault, working for an OEM I am well aware of the money needed to properly develop engine breathing.

SKIP TO HERE IF YOU DON'T WANT TO READ ALL THAT:

So as far as aftermarket CAF's go (as properly tuned CAF's work very very well! Ie: race cars), if they aren't integrated into the manifold (as in a gap between the filter or airbox and the end of the CAF pipe)(if they are integrated then without exact instructions from the engineer there next pointless) they do assist in bringing cooler air through without many down sides. OEM's normally don't fit them however as they are expensive when trying to build thousands of cars and are often very hard to engineer for NVH (Noise Vibration and Harshness).

Altho the down sides are that positioning them in the air flow around the car can be difficult, my advise being put them as close to half way up the bumper as possible. (As here (or at the best guess without having wind tunnel data) there is a stagnation point where the air is slowed to a stop and the pressure rises dramatically).

Not too sure where in the wheel arch people are talking about though?? As there are some high pressure rejoins there too.

Positioning the other end is best kept4-5 inchs away from the filter, pointing directly at it.

Phewww, that was long, sorry !
Don't really want to proof read it, so if you think there are any mistakes let me know!

 

[Cue]

Jimbo's correct, of all the posts in this thread this is the one that's actually correct.

Having tested air pressures to the front of a 182 I can say that the fog light is a pretty poor area for a caf for engine use, it's fine for brake cooling but it a fairly low pressure area.

Best place would be at the top of the bonnet just below the windscreen - although it would be difficult to engineer it and would look silly. Second would be not far off where the Reno badge is. Difficult to engineer again as the radiator is in the way...

Easiest visual way to tell is look at where all the flies collect on the front of the car after a spirited drive - they hit the bodywork at high pressure points. How many times do you see a large collection on the fog lights when the bumper or number plate is clear?

For a more scientific approach you'll need to do what I had to do - when reno refused to give me the info (still don't understand why they wouldn't) Get an air pressure sensor - strap a small tube to it - and fix the other end of the tube to various points on the front of the bodywork.

You can then use the reading to map out the high and low pressure areas of the front of the car

 

[steve32c]

Ok I've read the arguements back and forth, one question what does a turbo do?

It's all about RAMJET theory (trumpet on front of car anyway) the more air you can force in the denser it is increasing pressure aswell as oxygen so to a degree the outside temperature arguement is reduced at speed as more air is being forced in to the engine than would be normally and have you felt the temperature inside you wheel arch after a run. Moving parts cause friction which produces heat so on a long journey your wheel arch isn't the best place to fill your cars lungs from.

At low speeds the engine will 'suck' in what it needs and then as you speed up your just helping it out (cheap turbo if you like) and you will have a bit more oomph when needed.

As for water ingress don't drive through rivers your front bottom grille is a good 6" from the road and the vertical climb up to your filter will stop all but a few drops unless you submerge at speed......... Puddles deeper than 6" avoid.

 

[steve32c]

Use a big funnel affair to increase the pressure rather than those trumpets all they do is make the end of the tube look nice.

 

[Jimbo_924]

Ok I've read the arguements back and forth, one question what does a turbo do?
.

A Turbo is all based around pressurising the air in the inlet (ie: Boost pressure). Both turbo chargers and superchargers simply use either Exhaust gases or crank power respectively to up volumetric efficiency. Clearly with the extra air it is important to get the fueling correct in order to achieve the correct mixture.

How ever there are ways of charging the air without them, Wave theory and Inertia theory as mentioned earlier. However obviously no way near the same extent as a turbo.

Induction on road cars however has many more considerations such as cost, NVH (noise vibration and harshness) and packaging. So some aftermarket systems will indeed increase power as they don't really care about how much noise it makes or how much they charge you. But they are generally in the minority as these companies haven't got the money to burn using expensive CFD software.

Got a bit of the turbo topic there, sorry !

 

[Yellow Dave]

What a debate over such a little topic. :S

As far as water going into the engine, it won't unless you drive through a flood that you really shouldn't be! I had mine fitted in the foglight surround and drove in heavy rain down the motorway with a lot of spray coming up of the road. when I stopped I checked the airfilter out of curiousity and it was dry.

A CAF is purely for supplying cold air to your intake, which having it sat in the bumper is an ideal place than having it take it from the engine bay/ wheel arch. Having the so called ram affect will slightly aid this by marginally pressurising your airbox but not enough for anyone to really notice and certainly not before about 60mph.

Motorbikes have been using the ram air design for a long time on the intake systems. by doing this they add a slight positive pressure within the airbox aiding the flow into the cylinders. When they were first testing this on dyno's, bikes weren't making the reported power figures claimed. once the dyno kit was wired upto the bike and taken for a real ride it made the power figures purely down to the ram air design.

Theres my pennys worth anyway

 

[Andyman]

Whats all this rubbish about ram effect??

I bet ram never even crossed 99% of folks minds who have fitted a cold air feed!

Folk fit cold air feed just to get a bit more errmm cold air in the direction of the IK, Air box or what ever your using ... and why not? it aint gonna hurt is it plus is a good little DIY and costs pennys

 

[Christophe]

do what i've done. get the caf to go down to the bottom of the car and poke out at a slight angle. that way there is also less bends

 

[Neil G]

The word race car being the defining factor

For road going clios it is marketing BS...next thing you know they'll be people telling you can get 10bhp by removing the acoustic valve and installing an electric 'turbocharger' off ebay.

I think fiddling around with CAFs is fun and we've all done it but these days I know it's going to make so little difference I just leave the setup standard (bar green panel filter)

Marketing tool :S

Who's exactly marketing cold air feeds? Last time i looked they were mostly home made jobs......

K&N, Piercross etc....always banging on about it. If people have enough time to waste f**king about with air feeds then that's their problem! Original setup designed for the car FTW

 

[Andyman]

Standard set up is rough, twisty and very restrictive. If you dont think that can be improved upon, you cant have opened the bonnet

 

[RBHynes]

Put simply your car would have to be travelling at approx 1900MPH to generate 1bar of pressure in the inlet, so 1900MPH = a doubling of atmospheric pressure, now given that a typical turbo increases the pressure between 1-2bar, can you see how little effect the "ram air" principle has on a 140mph hot hatch? The biggest advantage is to supply cold air to the engine, this makes a tangeable difference, the location of the intake does not - hence why they are all called Cold Air Feeds....

 

[Neil G]

Put simply your car would have to be travelling at approx 1900MPH to generate 1bar of pressure in the inlet, so 1900MPH = a doubling of atmospheric pressure, now given that a typical turbo increases the pressure between 1-2bar, can you see how little effect the "ram air" principle has on a 140mph hot hatch? The biggest advantage is to supply cold air to the engine, this makes a tangeable difference, the location of the intake does not - hence why they are all called Cold Air Feeds....

Agree

Tinkering for the sake of tinkering....engine can get enough air with stock setup