Cold air feeds - closed or open???

[clio-lane]

While searching a related topic I read that Andy at GDI recommends not connecting your CAF up to the filter (gaining <5bhp), but to leave it open and feed the area around the filter. So rather than the have the air forced in to the filter, the induction kit actual sucks in the air. I would imagine that an open system is also louder too.
What are your thoughts, as I'm about top change the positioning of my feed???

 

[Neil G]

Not sure about this one

My opinion is if it aint broke don't fix it (or f**k about with it)

I'm running the OE box and feeds with Green Panel filter...car is plenty punchy/torquey so I'm happy.

 

[thedoc]

I'm running original airbox with green panel filter too, and I'm happy with it. I'm also too tight to spend £200+ on a viper though.

 

[biojo]

the idea behind it is when theres air rushing through the pipe at say 60mph , it isnt forced into and through the firster but the only the air that is needed is puled though , personally alls u need is a hole or 2 in the inlet pipe then it wont do it

 

[rmccardal]

Andy has the opening to his behind the headlight though as his battery has been relocated.I dont think it would help having it sat open and behind the radiator.

...get a maxogen

 

[Neil G]

I'm running original airbox with green panel filter too, and I'm happy with it. I'm also too tight to spend £200+ on a viper though.

Yep

Half these induction kits are crap anyway.....more show/noise and less go.

 

[MarkM]

I have my viper open (no cold air feed) pointing at the back of my radiator.

I have been to GDI today and went out with Andy to do some road mapping of my Omex ECU. You can see various real time parameters being read from sensors on the car one of which is air intake temp, read at the manifold I think.

With an outside temp of about 10degC the intake temp was around 25degs when driving normally. When driving the car harder this temperature rose to 36degs proving there is a very big effect with the filter open in this position.

Under normal driving more then double outside temp and nearly four times when driving hard. I imagine in the summer sat in stop start traffic these temps could get very high.

I have had my battery relocated today so I will be able to move my viper down behind the headlight. It will be interesting to see what this does to intake temps but hopefully they will be alot lower and remain at a more consistent level.

 

[clio-lane]

Cheers for that info Mark. It's good to have hard evidence to work from. Is it also the case that the length of the feed should ideally be as short as possible, as it's easier to suck up a short pipe than a long one. Therefore, and not for the purists, would a bonnet vent, feeding the filter be a good option, rather than a long length of ducting from the bottom of the car??

 

[lee_cup]

Yep

Half these induction kits are crap anyway.....more show/noise and less go.

true in some aspects, but some induction kits i.e viper, bmc etc are actually very good imo... but wayyyy to expensive!

 

[miketheman2k]

Not sure about this one

My opinion is if it aint broke don't fix it

Who told you that?

 

[MarkM]

Cheers for that info Mark. It's good to have hard evidence to work from. Is it also the case that the length of the feed should ideally be as short as possible, as it's easier to suck up a short pipe than a long one. Therefore, and not for the purists, would a bonnet vent, feeding the filter be a good option, rather than a long length of ducting from the bottom of the car??

Length of the feed is not an issue more the fact the feed has to be forced through various restrictions in the engine bay causing pinched sections in the tube with a smaller diameter which decreases the air flow.

A bonnet scoop would be the best solution but who wants a chavvy bonnet scoop? If you are willing to cut a hole in your bonnet you might as well get your battery moved.

Andy, GDI, made a brilliant job of doing mine very tidy and you would be amazed at how much space it frees up. I will post a pic up of it whan I get home.

I will also check the intake temp readings when I move it see if it makes a big difference or not.

 

[Neil G]

Who told you that?

I did

The last thing I want to see when I open my bonnet is some roachy cone filter sitting there covered in filth and making lots of noise while making the car less drivable.

Enclosed kits may be good but are just way too expensive

 

[Lunner]

Yes because i can see how you woudl gain 5bhp by not having a direct cold air feed *rolls eyes*

 

[clio-lane]

Hi Mark,
I'm new to this car game, but have read as much as I can get my hands on and I could be completely wrong here. From my understanding an IK is supposed to work by sucking in air, rather than having it rammed at/into it by a closed feed. Ok the closed feed is keeping the air cooler. Looking at the new pipercross design, I'm guessing that the closed box causes a reduction in the force of the air around the filter intake allowing it to suck the air in, while maintaining the cooler feed?
As for sucking, it takes more effort to move something a greater distance. So surely a long feed causes the IK to work harder than a short feed??
If I'm anywhere near to the mark I can understand why a closed induction kit doesn't work well 1)air rammed at it and 2)too long a feed
I also seem to remember reading that the inlet for the IK should be mounted in the wheel arch. Here I could see that the air is at a lower pressure and a fairly short distance from the filter, allowing it to work more easily.
Or am I talking b:quiet:llox

 

[clio-lane]

....looking forward to your pics.

 

[Andy GDI]

Yes because i can see how you woudl gain 5bhp by not having a direct cold air feed *rolls eyes*

you dont gain it.... you just dont loose it

adding 3 ft to the induction length with lots of bends in it does not seem to help these cars....

to clarify what mark saw on the temp gauge when we were out in his car.

when we were going slowly (sub 40mph) the temps were approx 35 deg, when the car was going faster they dropped to 25 deg..

moving the filter to point behind the headlight or giving the area where the filter is a cold feed (NOT connected) is IMO the best way.

 

[Andy GDI]

Hi Mark,
I'm new to this car game, but have read as much as I can get my hands on and I could be completely wrong here. From my understanding an IK is supposed to work by sucking in air, rather than having it rammed at/into it by a closed feed. Ok the closed feed is keeping the air cooler. Looking at the new pipercross design, I'm guessing that the closed box causes a reduction in the force of the air around the filter intake allowing it to suck the air in, while maintaining the cooler feed?
As for sucking, it takes more effort to move something a greater distance. So surely a long feed causes the IK to work harder than a short feed??
If I'm anywhere near to the mark I can understand why a closed induction kit doesn't work well 1)air rammed at it and 2)too long a feed
I also seem to remember reading that the inlet for the IK should be mounted in the wheel arch. Here I could see that the air is at a lower pressure and a fairly short distance from the filter, allowing it to work more easily.
Or am I talking b:quiet:llox

about right.

 

[clio-lane]

Thanks sir:approve:

 

[BenR]

With the viper it seems to be more of an issue with the entry cross sectional area since it is so small with the top hat thing for the cold air feed on, and the entry profile is just rubbish.

The viper is a positively teeny filter with a very low bhp rating, so you need to help it out as much as possible.

 

[Andy GDI]

yup..

we found recently that a CDA thingy on that audi s3 could not handle over 300 bhp.... took it off and 20 bhp extra.... its was just strangling the engine.

 

[Andyman]

yup..

we found recently that a CDA thingy on that audi s3 could not handle over 300 bhp.... took it off and 20 bhp extra.... its was just strangling the engine.

What did you put back on in its place to give the 20 bhp extra?? The standard air box ??

 

[Mike T]

Thats why I run two of them - and forced cold air is always best - look at it as an assisted suck!!!!
Only two things to worry about - air density (cold air) means you can put in more fuel = more bhp if mapped correctly and volumetric effeciency which can be imapcted upon ( in a very very small way) by a ram air system.
Worry about the temps as this is where the noticable gains can be made - plently of comments on here about enhanced winter performance, all down to cold air

mike

 

[Andy GDI]

What did you put back on in its place to give the 20 bhp extra?? The standard air box ??

larger filter that could handle the required airflow

Mike, I agree...... forced is good...

BUT!

in the 182 etc its hard to find somewhere there is a good flow to the filter...

a shorter rad etc and a direct feed from the front, that is not long with bends etc would certainly be better.

 

[MarkM]

Battery move pics.
Just need to reposition the viper next. I may buy an itg filter and sell my viper, they do a cone shaped one that would fit nicely behind the headlight.

 

[clio-lane]

Cheers Mark, looks very neat. Is the battery relocated to the boot? Where is your Omex mounted?

Andy - how about a custom rad with a chunk cut out of it to fit a more direct CAF?

 

[portal172]

I removed my fog lights and the valve, then just ran the hose straight to the filter. A 70mm hose works best, as it fits perfectly and doesn't get squashed.

 

[George k]

Cold air is what it is all about. There is an equation which will show the increase in density and hence oxygen and the improvement is quite significant. Interestingly enough when checking the pressure drops down a standard intake system, the smallest drop is across the panel filter (even paper if clean) so it is the other obstructions that matter. also the position of the air intake does matter as it could be in a stagnation point which will reduce pressure to below atmnospheric. I am sure that Andy can check for this. Last but not least the problem with ram systems is that the ram effect is proportional to speed and so varies in each gear, which could make mapping difficult - I would guess that this is why Andy prefers to keep them separate.

 

[clio-lane]

Can't help feeling that the ideal solution for this problem is some form of bonnet vent - SHOCK HORROR. If it's done for a useful purpose, would that be more acceptable to the cliosport purists?

 

[Lunner]

Can't help feeling that the ideal solution for this problem is some form of bonnet vent - SHOCK HORROR. If it's done for a useful purpose, would that be more acceptable to the cliosport purists?

f**k what people think lol, if you want to put a bonnet vent in put a bonnet vent in, can't live your life worrying about what other people think lol

 

[Andyman]

Some idea's on getting cold air in:

Bonnet on this one looks pretty cool but not a clue who makes it !!

Not sure if these vents on these replacement front wings would be affective enough

 

[clio-lane]

Ha ha Lunner - That was said tongue in cheek. I don't give a monkey's what people think.

I'm thinking of relocating the battery and having the IK (where the battery normally is) pointing towards the wheel arch with a side mount bonnet vent feeding the open IK. What do you guys think, on a functional basis?

 

[Lunner]

Certainly on teh mk1 clios you can relocated the IK down behind the front bumper.

The vents int eh wings will only work of you relocate teh filter inot the wing, whcih isn't a bad idea, although i can't see the need for the vents in the wing if you do that.

On the mk1 clio again hill power have a kit whihc relocates the filter to where the washer bottle is

 

[MarkM]

Cheers Mark, looks very neat. Is the battery relocated to the boot? Where is your Omex mounted?

Andy - how about a custom rad with a chunk cut out of it to fit a more direct CAF?

Battery is in the boot.
The omex is the silver box with the DIN socket on the top, mounted behind the siemens ECU.


custom rad will cost alot of cash.

 

[Gaz_]

i have a viper, and initially i had the caf connected straight to the filter housing... (force fed from the fog light) but imo i found the throttle response alittle 'slack'. I have now pulled the caf about 2-3" away from the filter,(pointing at it) and imo it works much better, the response now feels much better

 

[EVOgone]

you dont gain it.... you just dont loose it

adding 3 ft to the induction length with lots of bends in it does not seem to help these cars....

to clarify what mark saw on the temp gauge when we were out in his car.

when we were going slowly (sub 40mph) the temps were approx 35 deg, when the car was going faster they dropped to 25 deg..

moving the filter to point behind the headlight or giving the area where the filter is a cold feed (NOT connected) is IMO the best way.

So is what your saying is just buy a Maxogen and dont connect the origional air feed ?? Just have it pointed at it ?

 

[Andy GDI]

that would be my option yes. or move the battery....

 

[Andy GDI]

Alloy Rad, shortened, direct replacment.

better cooling than std one is

£650 + vat

although we are looking to get this price down.