Air filters straight from turbos

[apeman69]

Been mulling over this for a while. I'm running a MAP2 & using MAP sensor. From those who have already done it, how easy is it to run air filters (e.g. Apexi Power Intake) straight from each turbo. I assume much intake pipework can be removed along with the airbox and my hollowed-out MAF in order to create some space.
I don't want to move battery to boot. Is it doable and any ideas, thoughts, experience, pics would be great.
I want a bit more power and I'm guessing my intake setup is restrictive. I appreciate the MAP2 would need tweaking.

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[Gowf]

You can, but the best place to put them is where the battery is Alan. Then you can have a decent cold air box. If your not going down that route, you would struggle to find somewhere suitable for them, they could go where your standard airbox is, and use that as a cold air feed I guess, but the pipework would be a little bit more involved. I didnt do mine that way, but no reason why it wouldnt work

[Nick Mann]

It's definitely do-able. Gareth had done it (but I think with battery to the boot too) and Kieran found a kit a while back to do the same.

All you need are some pipes the right diameter to come from the tubs to the filters.

[Nick Mann]

Oops! Delay between typing and pressing submit!

[apeman69]

I was also thinking of 2 of those BMC CDA jobbies fed from the grille. I think the bigger ones are good for 300BHP, smaller ones less BHP but it would be one to each turbo. A bit pricey still... for 2! Heat shouldn't be much of a problem as the carbon is supposed to keep the air cool and, in theory, they could therefore be placed wherever space would allow.
What do you reckon folks?

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[Ghost_2008]

As long as the air supply is freeflowing, cold and sealed up the air filters properly you should be fine.... however if the air filter is sitting in the engine bay it will need to be boxed in with a cold feed otherwise you will pull in a lot of hot air which will be detremental..... having said that at speed the air will be replaced in the engine bay very quickly, probably stopping the heat build up..... when sat in traffic, at lights etc is when the heat really builds.......

[Nick Mann]

If you really wanted a cold air box, why not just make something custom to fit where all the pipework you are losing is?

[apeman69]

So would pipes off the turbos and 2 air filters give a performance increase over standard air box & Ralliart filter, if done right and using std turbos? I know you did it, Gareth, with the bigger turbos but why was this? Std setup no good for your expected power, wanted to do something different or is it just 'better' all round?
What sort of intake setup does anyone who's using MAP instead of MAF have now as I don't remember seeing much other than 'std airbox is better than pod'?
If 2 filters is better than 1 for cars not running the MAF then how come nobody's developing kits or bolt on solutions? The cost can't be so restrictive for a few pipes and a couple of bits of metal sheet. I suppose it's down to volume of people going MAF elimination and the battery position.
In the Skyline world it's a given that the std airbox will be ripped out, replaced by cone then a remapped ECU. I guess their AFMs aren't so choosy concerning air flow characteristics.
In terms of 'heat soak' then surely the panel filter in a std air box is still going to suffer as it's only encased in a tight fitting plastic box. Couldn't I hollow out and reshape the std airbox to house 2 filters if space allows? I think I need to actually open the bonnet and have a look!
In real terms would the 'heat soak' have any significant effects that would outweigh any benefits of what I'm contemplating. At a standstill it could be more prevalent than when moving and you can't drive very fast when you're stopped! Would it be much of a big deal anyway? Anyone got any real world experience of this or is it just theoretical?
Keep the comments coming... I like to think stuff through.

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[Gowf]

The reason I did it was quite simple on mine. As I was putting different turbo's on, the standard stuff wouldnt fit. So then it was simply a case of running pipework to them and having the filters as far away from the heat as possible (where the battery was). It also means that you can not run a recirc dump valve. The most simple way to think of it is this:
the maximum airflow you induce into your turbos (and hence engine), ignoring all the boost side of things, is controlled by the size of the turbo inlet. Hence why GpN rally cars have a 32mm restrictor and GpA have a 34mm. You want this to be as big as possible for the size of your impeller (no point having a 10" inlet on a 1" impeller). The standard setup, although it does start the same size at the turbo's, goes through so many bends and reshaping of the pipes that you will have tremendous drag inside the pipes, not to mention various restrictions due to odd changes in diameter. Giving this a smooth path to flow to your air filter is the best way to minimise these losses and thus increase the flow to your actual inlet.

Ideally you would want a trumpet and a recovery cone but then you don't have any filtration (although you can bolt filters onto them but this is just for best case scenario) and you would also suffer issues with the back one sucking in pretty hot air.

You're right on the bolt on kit idea. The cost of developing a generic product for the few people that have these cars, and the fewer that have an ecu capable of allowing the map to be binned, far outweighs what you would get back. Its just not a financially viable thing to do.

[Ghost_2008]

Having two filters essentially allows for free'er flow of air, this may not increase power by itself but will improve response.......

As above, you want the most straight and direct path for the air to travel, the main issue being the rear turbo which sits where the still air is hottest...... The new GTR has a brilliant layout for what your trying to achieve, because the engine is orientated the otherway, the turbos fit either side of the engine allowing for individual filters to be fitted directly to the turbos away from the heat......

The problem we have is limited space under the bonnet to place stuff, if all the pipework was removed and redesigned you might buy back some space but it would be difficult. I would also suggest that the pipework to the turbo's tries to be "simetrical", reason being is if one turbo flows better than the other you will have one working harder...... only a consideration......

The standard air filter and the housing may get warm/hot sitting in the engine bay, but the air flowing through it will be cool as it's being pulled in from outside, the problems occur when the air from the engine bay is pulled into through the air filter, not the filter itself becoming warm.....

[apeman69]

Thanks boys.
I know what you're saying about the std piping taking some weird paths and size changes.
Ideally I'm thinking:-
as equal length pipes as possible with a filter on each (or sealed BMC filter type thing),
within a sealed heat controlling box of some sort located centrally as the pipes from turbos will allow,
this box with filters inside to be fed with air from outside the engine via sealed piping/trumpet/snorkel type device. This way there will be no sucking of existing air from inside the engine bay as everything will be enclosed and fed from outside. Any air within the box will be constantly replaced by ambient air.
Hmmm... where the hell is the battery gonnna go in my boot?

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[ILLEGAL]

how are you finding the mapecu2? you just running stock fuel system?

[apeman69]

AFPR, std pump hotwired, 530cc injectors. The MAP2's alright. If I was to start afresh I'd go for the total control of a Vipec or if I was in the market for a piggyback I think I'd go for an E-Manage Ultimate.
If I was to have the MAP2 done again I'd use an EBC rather than the MAP2's boost control. Dunno what it is but it just seems different somehow. Maybe the use of my right leg's deteriorating with the onset of old age
Biggest booboo in my mind is the MAP2's inability to effectively control anything below 1000rpm. A bit strange these days when most cars idle and can tootle about below that. I guess it's been designed primarily for cars other than a quiet and smooth to drive family estate.

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[Gowf]

Having two filters essentially allows for free'er flow of air, this may not increase power by itself but will improve response.......

There is a simple rule of thumb, More air = more power! if you have a less restrictive flow you WILL make more power (all other things being equal)

The problem we have is limited space under the bonnet to place stuff, if all the pipework was removed and redesigned you might buy back some space but it would be difficult. I would also suggest that the pipework to the turbo's tries to be "simetrical", reason being is if one turbo flows better than the other you will have one working harder...... only a consideration......

The pipework to the turbos is nowhere near symetrical! Have you seen the black pipe that sits on top of the gearbox? If 1 turbo is flowing better than the other, then 1 turbo will be flowing more than the other... What you find in that case is that the turbo's fight and then the loser has boost passed back through it. This will happen regardless of the setup from the inlet and is a result of unequal wastegates/actuators.

The standard air filter and the housing may get warm/hot sitting in the engine bay, but the air flowing through it will be cool as it's being pulled in from outside, the problems occur when the air from the engine bay is pulled into through the air filter, not the filter itself becoming warm.....

Yes and No. It all depends on the velocity of the flow as to the level of convective heat transfer along with obviously the temperature of the solid body. I can see what you are saying with the standard airbox as it potentially will not conduct as much heat as a metal one, however if you are talking panel filters or any filter for that matter, the temperature of the filter is what truly matters. If that is kept cool by keeping it in a box, all the better

[Ghost_2008]

It will allow for the potential of more power, you would have to remap the fueling etc to achieve power increases, if you have the same set up but with a less restictive filter all you will achieve initially is more response. You may see minor improvements in power but nothing to write home about. For example a panel filter alone will not give BHP gains, but with a less restrictive exhaust you may see a couple of pony's but your responsiveness will improve, your still running the same boost the volume air hasnt increased....

I know the current system isnt symetrical, but if your replacing turbos and pipework then surely it makes sense to try and ensure that the turbos are flowing as equally as possible? If you have one turbo working harder to acieve less boost then your system isnt very efficient and you could have long term issues with one turbo dying and possibly reduced power as your not making full use of both the turbo's potentials.

So if you have a cold air feed, the air being pulled through under boost rushes through the filter, if the filter is encased and therefore unable to pull warm air in, the fabric of the filter will be cooled very quickly. The outter edge may retain some heat close to the edges which are exposed to the heat source, Im not convinced that a filter will retain heat if air is being pulled through especially under boost.

[Nick Mann]

TBH with the amount of air movement in the engine bay when the car is moving, plus the much greater amount of air being sucked into the engine at high revs, I doubt whether the cold air box would have as much effect as an easy breathing system.

And as for power increases with a less restrictive air flow - I thought that the lack of restriction would effectively give a larger air throughput - therefore more power?

[ILLEGAL]

get a air filter like mine i found it has the best flow.. not sure how good it filters out small animals and children though.

http://www.youtube.com/user/localres.../5/_ghu8wJ19VA

[apeman69]

I'd need 2 of those though and 1 is hard enough to find! Must have been expensive, what with it being made of invisible material :-)

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[psbarham]

and Kieran found a kit a while back to do the same.

you mean the kit i have sat in my workshop doing nothing?

[apeman69]

Tell me more and pics please

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