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Dogegg1280

Quiet Induction Kits???

11 posts in this topic

Hi all, I'm in now way a boy racer for starters. I have recently become interested in improving the shed of a focus (mk1 Zetec SE, Lefthand drive) I've been driving for the last two years. In this time it has never been serviced, passed 2 MOT's and noticed it was getting horrible to drive. I decided to look at how to make it a little better and over the last few days I've changed the oil, oil filter, air filter and spark plugs. This was all after changing the bonnet as the paint had been ruined by bird crap while the car was sat in Rome for three months under a tree.

Now the car is running a lot smoother and seems to be doing better on fuel, I am looking at other ways to improve performance without it sounding like a typical boy racer car. I've looked at air induction kits as they seem to say they improve performance throughout the RPM range and as long as you don't drive like a boy racer it's good for fuel consumption.

Is there such thing as a quiet induction kit? They all seem to say they give a louder throaty sound and I'm kind of trying to avoid that. Also if anyone has any advice on how to improve performance in general it would be much appreciated.

Cheers, Mike.

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You could purchase a K&N or Pipercross replacement panel filter and the air intake assembly (that takes the air from the front grill to the air box) from a 2.0 litre automatic.

The performance air filter just replaces your standard air filter. The intake on the 2.0 litre automatic is larger than the standard and allows a little more air in to the air filter box and can be bought from a main dealer relatively cheaply.

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A decent set of tyres can make a big difference to a car, even a pair of tyres, tyre pressures - try higher pressures (eg 38psi all round)

Reduce weight - if its difficult to raise the power to improove the power to weight ratio and a turbo or a V8 are out of the question, - get a big box and fill it with all the junk you have been hauling around you don't need, replace your spare tyre/ jack with a can of tyreweld

sounds like you don't want to spend too much money on the car and probably want to get rid of it and get a better one

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Induction kits always result in a louder engine note and unless positioned very carefully result in heat soak which can actually reduce performance.

Unless you use heat shields and a very low or un-interrupted front air inlet you will get heat soak.

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Old thread I know but does "heatsoak" affect diesels too?

Thinking of installing a k&n or similar....

Would I see any MPG gains??

Mike.

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Old thread I know but does "heatsoak" affect diesels too?

Thinking of installing a k&n or similar....

Would I see any MPG gains??

Mike.

Yes - turbo cars (Petrol or diesel) are usually affected worse by heatsoak because the turbo compresses the air resulting in higher post -compressor air temps.

As Stoney has said (and most experts i the field agree) fitting an open cone filter under the bonnet will result in a power LOSS

Cooler air into the air intake = denser air = more oxegen per cc = more power

the air intake needs to be isolated from the underbonnet heat - with things like fully encapsulated filters, (BMC CDA or Pipercross venom) cold air feeds, etc

Often the way to go is fit a panel filter/ replacement "performance" filter (K&N/ Pipercross etc) to the stock airbox

There are other things that can be done - gas flowing - de-webbing the stock airbox/ fitting bigger/ extra feeds etc

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Yes - turbo cars (Petrol or diesel) are usually affected worse by heatsoak because the turbo compresses the air resulting in higher post -compressor air temps.

As Stoney has said (and most experts i the field agree) fitting an open cone filter under the bonnet will result in a power LOSS

Cooler air into the air intake = denser air = more oxegen per cc = more power

the air intake needs to be isolated from the underbonnet heat - with things like fully encapsulated filters, (BMC CDA or Pipercross venom) cold air feeds, etc

Often the way to go is fit a panel filter/ replacement "performance" filter (K&N/ Pipercross etc) to the stock airbox

There are other things that can be done - gas flowing - de-webbing the stock airbox/ fitting bigger/ extra feeds etc

Thanks for the detailed response! :)

I just wanted to replace to stock paper filter within the airbox with a more free-flowing aftermarket filter within the airbox.

I didnt realise that i could suffer from "heatsoak"? I thought the existing design of the feed to the airbox would be enough to provide plenty of cold air so it just shows how much I know! LOL

You see, I dont want to go all out fitting cold air feeds etc etc as it just isnt what I am after at the moment (although that may change in the future).

Think I may just leave the stock filter in.........

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Thanks for the detailed response! :)

I just wanted to replace to stock paper filter within the airbox with a more free-flowing aftermarket filter within the airbox.

I didnt realise that i could suffer from "heatsoak"? I thought the existing design of the feed to the airbox would be enough to provide plenty of cold air so it just shows how much I know! LOL

You see, I dont want to go all out fitting cold air feeds etc etc as it just isnt what I am after at the moment (although that may change in the future).

Think I may just leave the stock filter in.........

When "a k&n filter" is mentioned - it normally refers to a k&n cone filter - not a panel filter (unless specified)

So when i was talking (writing) about heat soak - i meant when using an open "k&n type" cone filter under the bonnet/ in the engine bay - not a panel filter

The stock airbox feed acts as as a cool air inlet - its just not normally very big/ a large diameter

A stock or mildly modified car probably does not need a (panel) filter upgrade but it won't do any harm - for years i just fitted a cheap stock pattern paper filter (£6!) but changed it every 6 months

When i went to get the car dynoed i fitted a fresh cheap pattern airfilter the week before - the 115ps Mondeo measured 162ps with it fitted (there are a lot of other modifications)

I am researching filters at the moment - hoping to increase power a little

exponential likes this

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When "a k&n filter" is mentioned - it normally refers to a k&n cone filter - not a panel filter (unless specified) So when i was talking (writing) about heat soak - i meant when using an open "k&n type" cone filter under the bonnet/ in the engine bay - not a panel filter The stock airbox feed acts as as a cool air inlet - its just not normally very big/ a large diameter A stock or mildly modified car probably does not need a (panel) filter upgrade but it won't do any harm - for years i just fitted a cheap stock pattern paper filter (£6!) but changed it every 6 months When i went to get the car dynoed i fitted a fresh cheap pattern airfilter the week before - the 115ps Mondeo measured 162ps with it fitted (there are a lot of other modifications) I am researching filters at the moment - hoping to increase power a little

Yeah, sorry. That was my fault for not explaining myself properly in the first place pal.

Ive done a bit of digging on youtube and apparently, like you have said, you see no benefit at all (infact, a decrease in BHP) in fitting an aftermarket panel filter.

I watched an investigation by a couple of aussie car tuners who took a stock 200SX and dyno'd it using various methods of induction and every time, the stock panel filter got the best gains or should I say, fitting any other method of induction actually decreased BHP!!

I definately did not expect that at all!

Just looked at your sig and your mods list is very impressive!! :)

FOCA likes this

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Thanks! - yes, i saw the youtube "mythbuster" video, too

There is a lot of conflicting information on the web about air filters -

Years ago manufacturers' stock filters were poorly designed and sticking a K&N cone filter or similar made a big improvement

Nowadays the stock air filter & induction systems are carefully designed, - it has to be quiet, withstand high tempratures/ deserts, torential rain, artic conditions, etc etc

The filter has to last a fairly long time without needing to be changed and the car maintaining good economy and emmisions and filter out most harmful dust

Most modern induction systems have cool air inlets - the system is often matched to the engine -the airbox often has a "resonant frequency" where it boosts torque at low revs - there is a formula for working out the volume of the airbox depending on the capacity of the engine - often replacement/ aftermarket induction systems / cone filters are not "resonated"/ are not matched to the engine so do not boost the torque

A paper filter (stock) works well at filtering even tiny dust particles, many performance filters let a lot of these particles through - so there is a balance/ compromise betwen flow and filter efficiency - the more effective a filter is at cleaning the air - the more restrictive it is

A paper filter (stock) flows (fairly) well when it is new/ clean, over time the tiny airholes get clogged, once it is clogged it is much more restrictive than when it is new,(it depends on the conditions - if it is a dusty enviroimant it gets glogged quicker) a paper (stock) filter with frequent changes offers good protection and reasonable performance for a stock or mildly tuned car -

A K&N flows well (better than a same- sized paper- filter) when new - it does not offer the same filtration, though, as it gathers a layer of dust/ dirt, it filters better, but the fow goes down, but over a longer period than the paper filter - a typical K&N costs between 3 times to 7 times as much as a stock/ pattern paper filter, though - EG - i can get a pattern filter for my Mondeo - i can have a new, fresh (pattern) filter (£5) every 6 months for 2-1/2 years for the same price as a (£35) K&N (panel) filter - the paper filter offers better filtration/ engine protection than the K&N, and maintains its flow because it is frequently changed

I was thinking of getting a high-flow but poor-filtration filter for special occasions - to put in for dyno runs/ drag racin etc - (and keep the high-filtration/ protection stock filter in for normal use) but i could just remove the filter completely for that anyway

The actual air filter element may not be the most restrictive part of the induction system - all the pleats/ folds in the filter increase its surface area - if its streched out it can be as big as a manhole cover - in other parts of the induction system, there may be small tubes/ pipes that restrict the airflow more than the lilter does - so you buy an expensive panel filter and it does not increase performance - but just allows more dust/ dirt into the engine - see above

Often, a new performance panel filter is bought and an immedeate, improvement in performance is noticed - this may be because it replaced an old and clogged filter, not because it actually increases the performance compared to a new/ clean stock filter

"Fast car" did a roundup of different filters - they tested all the filters on a flow rig - it reccomended ditching the stock filter/ airbox but because this tested flow only and did not take resonant frequency or heatsoak into account its conclusion/ can be mostly rejected - a flow rig is not an engine - it is different also, the amount of air a real engine requires is only a fraction of the flow rates they measured

Often a car with an open cone filter (K&N etc) is tested on a dyno with the bonnet open and a massive fan/ blower to force cool air in - obviously this is not the same as having the bonnet closed in "real life" conditions - (unless you drive with it open but visibility and aerodynanics could be a problem! ) - you are liable to loose power due to heatsoak with the bonnet closed and an open filter - this will not show up with the bonnet open

Moral - the filters have to be tested in, or close to "real life" open bonnets and flow rigs are no good or only tell part of the story at best - the filters have to be tested on the engine its used on, in the conditions it is to be used

A turbocharged car is all about the turbo - the turbo compenseates for restrictions by working harder - so, you put a new, clean filter in, as time goes on, the filter gradually gets clogged the turbo just works harder (the ECU compensates) and (up to a point) no performance is lost = likewise, if a (panel) filter is fitted that actually increases airflow, the ECU compensates for this too, so often, it makes no difference at all, the engine may be more responsive to the throttle, and it picks op better from low revs though (this is because the filter flows better before the turbo spools up, once the turbo spoots up it is just the same - with the same power, in "real life" and measured on a dyno)

The larger the surfaca area the more air the filter can flow - it is therfore possible to have a massive filter that flows better than a typical cone (K&N etc) filter but also filters out most of the dirt/ dust (that K&Ns don't) - basically the bigger the filter the better

It is also possible to have multiple filters to increase the total surface area

Im continuing to aquire data and my own research on the subject

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Thank you FOCA for that incredibly detailed post!!

Im still undecided on whether to install a k&n (or similar) panel filter.

I am blanking my EGR this weekend (weather permitting) and having the DPF deleted and remapped in the next couple of weeks so maybe after having that done, I might fit one but at £60+, its a tricky decision!

Please keep us posted on your research.. :)

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