Air Filter

[mactell]

Hi there,

How easy is it to replace the air filter in a Ford Fiesta MK6.5? Where about's is it in the engine?

And would it increase power or acceleration for a 1.2?

Was thinking of getting a K & M or is it a waste of money?

[jamesm182]

The air filter should be relatively easy to get at.

K & N is a popular brand and they either do a panel filter (standard replacement that goes in the existing air box but made of a different material for less restriction) or a 57i induction kit (replaces/removes the standard airbox for your 1.25 fiesta with an open cone style induction kit and includes all brackets etc)

The panel filter is a simple and relatively cheap mod that allows the engine to breathe better and also is a lifetime filter (never needs to be changed only cleaned) but will probably not gain you more than a couple of horsepower and a little response

The induction kit will not gain much more horsepower either (maybe a couple more than the panel if you're lucky) but the main advantage if you like that sort of thing is a lot more 'induction' sound under hard acceleration.

Here are the listings on K&N's site for your car:

http://www.knfilters.co.uk/search/appsearch.aspx?type=auto&year=2008&make=FORD&model=Fiesta+VI&engine=1.25L

[mactell]

Ah okay. Anything else I could do jamesm182? I was thinking of a remap but i only get 3HP extra and it costs £250...

[jeebowhite]

For the sake of the K&N filter and a remap, you would gain about 5 bhp, if you then upgraded the exhaust, you could make that another 7 BHP in all.

I have to be honest though and say this, given the content of your other thread and the possibility of whats coming up, your much better saving the money to put towards the day just in case it doesnt work in your favour...

[jamesm182]

For the sake of the K&N filter and a remap, you would gain about 5 bhp, if you then upgraded the exhaust, you could make that another 7 BHP in all.

I have to be honest though and say this, given the content of your other thread and the possibility of whats coming up, your much better saving the money to put towards the day just in case it doesnt work in your favour...

I have to say I would be inclined to do the same. No point ploughing loads of money into performance mods if you won't be able to drive it. No harm in doing a few small mods though I guess.

Induction kit and a decent exhaust system/sports cat would liberate a handful of ponies and increase noise a little but in all honesty with a small naturally engine the only way to gain serious power would be an engine transplant to a 2.0 litre ST block or similar. This would probably make it difficult for you to insure though.

[D13 HPD 95]

Whats better k n 57i or j1 considering theres like £120 difference ??

[mactell]

How easy would it be to replace my engine with a ST engine block? And how much roughly with labour?

[btmaldon]

How easy would it be to replace my engine with a ST engine block? And how much roughly with labour?

I doubt it would be worth the effort or the cost as its not just a case of changing the block. It would be cheaper buying an ST and probably cheaper to insure it. If your under 25 most insurers wouldn't touch you if you had modified a car let alone dropped an ST lump and all the running gear in what was a 1.2.

[FOCA]

Cone filter - (eg - K&N)

The induction/ filtration systems in modern cars are carefully designed to work in all conditions, tempratures, etc and to have extended service intervals

they are often "matched" or "tuned" to the engine (a tuned length matched to a specific resonance frequency, that boosts power at certain revs or )and many actually boost the torque at low or medium revs or are specifically designed to remove "flat spots" or hesitation,

The intake of the stock induction system often draws air from a cool place (eg - behind the grill but in front of the radiator) so is like a cool air inlet on a performance car - this increses power compared to having the intake air being drawn from under the bonnet (which would reduce power) (cool air= more oxegen per volume= more power / warm air less qxegen per volume = less power)

So an open cone filter under the bonnet drawing warm air will loose power - a rally car would use a shielded / fully encapsulated one (eg - BMC, pipercross make one called a venom) as a heat shield or cool air inlet with an open filter is only partially effective

The reason some tuners still use open cone filters (eg K&N) is, they don't know any better/(the cars are often dynoed with the bonnet open, keeping it cool so the power loss with the bonnet closed as the temp rises in "real life" conditions is not measured) are stuck in the past when they might have beel actually better than stock induction systems, have not enough underbonnet room for a fully encapsulated filter, or have re-located the filter to a cooler place (like in the wing) or are using a seriously vented bonnet or extensive cool air ducts

Apart from the power loss there may be a reduction in MPG as well

The extra noise can gve the illusion of more power, they recon the sound is 50% of the "feeling of power/ acceleration/ speed"

if the K&N reduces the bottom end power,(see above about the stock induction system boosting bottom or midrange power) although the overal power/ acceleration would be reduced, knocking a bit of low or mid power off may give the illusion of more "top end" power, as you hit a little "power band"

So the stopwatch or the dyno (with the bonnet closed!) is the way to measure improvements,(or otherwise) as subjective tests can be deceptive

Panel fillter - (K&N, , green cotton etc (oiled cotton ) pipercross (foam))

Fitting a "performance" panel filter at least retains the advantages of the stock induction system, but even this has pitfalls -

An oiled cotton filter (K&N/ green cotton) filter, has been known to contaminate the MAF sensor, especially, if it is over-oiled by the user

K&N make rediculus claims about their filters lasting the lifetime of the car etc - they still need to be cleaned periodically,(the special cleaning fluid and oil needs to be used) which many owners forget to do, the filter gradually detariorates/ gets glogged up over time, untill a new stock filter woud (significantly) out-perform it

Cost - a stock or pattern paper filter could cost £6-£10 an aftermarket "performance" filter night cost £30-£50 that means the stock pattern filter could cost a sixth of the "performance" one, allowing you to change the paper one twice a year for 3 years for the same cost

Filtration - the paper filter (stock or parrern) is very effective at filtering dirt and dust particles (even tiny ones) even when the filter is new, the filter also flows quite well when it is new, but the tiny holes get clogged over time and the filter starts to restrict the flow of air, this can start to happen quite quickly, the bigger the surface area of the filter the less of a problem this is - the folds in the filter increase the surface area and a modern filter may be the size of a manhole cover or bigger when streched out

A K&N or oiled cotton filter allows (small particles of) dirt and dust through into the engine when it is new, as it gets older and the dust builds up it filters out dirt more effectively, it can last a bit longer and flow better / for a longer time than a paper filter

When you buy a New "performance" filter and fit it to your car, you might notice an inprovement in performance, as aftermanket filters may increase noise, this could simply be an illusion, (with the extra sound giving the impression of more power) or your old filter is dirty, (the dirt builds up gradually, so you don't notice) and is being replaced with a new, clean filter, which increases flow

Likewise if dyno tests are carried out - it has to be new-for-new / like for like (not showing an improvement because one new filter is being compared to an pld, dirty filter)

unless it is long- term tests showing the dropoff in performance as the filter gets clogged over time/ older

Flow tests done on filters that are not connected to are car are of limited use because they do not take things like heat soak, tuned length/ resonance etc ito effect (filters should be tested on the car as close to "real life" conditions as possibe - with the bonnet closed etc) - a filter/ induction kit (especially with an open cone filter) could test well (vastly outperforming the stock filter with flowing several times more than the stock filter/ induction system, or the engine needs ) on a flow rig (not connected to the car) and be worse than the stock filter when on the car, due to heatsoak, and the stock filters ability to increase power as it is "matched" - and the cone filter is not

Often, on some cars, the intake on the car/ induction system is more restrictive than the air filter element itself, in this case fitting a freer- flowing panel filter or even running without a filter will make no difference at all (compared to a new, stock filter)

on some turbo cars (petrol or diesel), adding a freer flowing filter makes no difference to the peak power/ torque at all, (as the boost/ therfore the airflow is controlled by the ECU) but the engine picks up better from very low revs before the turbo "boosts up" and the response/ lag is improved (and the turbo may not have to work quite so hard)

On some, (NA petrol) if the "performance" filter increases the airflow, it just makes the engine run lean, loosing power and increasing flat spots, and potentially damaging the catalytic convertor

On some NA petrol engines, where a performance filter actually increases the air flow, and the maf sensor/ ECU can detect this and increase the fuelling, maintaining the air-fuel ratio (dumb down version - the air is increased and the engine increases fuel, increasing power) - these are the engines that benifit from a freer- flowing filter, it may only be a small increase (1 or 2 HP) but this may be increased if coupled with other modifications, or help the engine rev a bit more at the top end (sometimes the improvement is only noticable near the redline)

I have done a lot of research on this subject and am still gathering data - and i will eventually put it all together in one place for future reference

So the conclusions are -

Every engine design is different, but

A performance filter may increase flow but at the expense of filtration, there may be a slight increase but you may not even notice the difference (you need a 10%+ power increase to notice a difference, typical power increases with a "performance" panel filter are 1 to 2% or nil)

It is difficult to significantly improve the power of stock setup, but easy to make more noise, you might as well save your money and just fit a stock paper panel filter regularily (every 6-months/ 6k,) at least it will filter the dirt/ dust better than a K&N panel filter, and won't contaminate the MAF sensor with filter oil

Especially if you have to inform your insurance that one is fitted, even though its an insignificant gain

,

[FOCA]

I have to say I would be inclined to do the same. No point ploughing loads of money into performance mods if you won't be able to drive it. No harm in doing a few small mods though I guess.

Induction kit and a decent exhaust system/sports cat would liberate a handful of ponies and increase noise a little but in all honesty with a small naturally engine the only way to gain serious power would be an engine transplant to a 2.0 litre ST block or similar. This would probably make it difficult for you to insure though.

Agreed, better to save the pennies for potential fines,future insurance increases and bus fares

[Corkin]

This fine for mk7.5 im assuming?

http://www.amazon.co.uk/33-2955-Performance-Filter-Fiesta-Mazda/dp/B002ASSWF0/ref=sr_1_1?ie=UTF8&qid=1443463875&sr=8-1&keywords=K%26N+air+filter+fiesta

[GingerFlame]

Hi there,

How easy is it to replace the air filter in a Ford Fiesta MK6.5? Where about's is it in the engine?

And would it increase power or acceleration for a 1.2?

Was thinking of getting a K & M or is it a waste of money?

The airbox on the duratec engines (2002-2008) has two bolts on top. Undo them then pull the airbox off( disconnect hoses)

Then flip the airbox and begin the long task of undoing all of the bolts that hold the airbox together.

[GingerFlame]

Ah okay. Anything else I could do jamesm182? I was thinking of a remap but i only get 3HP extra and it costs £250...

I got quoted £1000 for a custom stainless exhaust including 4-2-1 manifold & sports cat.

And a custom induction kit (the 57i doesn't have enough hosing to fit the non turbo engines)

This would have given me 20-25bhp.

Piper cams give about 10bhp

(approx £400)