Page 53 - Fast Car (March 2020)

2 PANEL FILTERS upgrade to make the most of the extra flow. All

Performance panel filters are so easy to fit, it’s filters work like this (at least on modern fuel-

probably a little patronising to tell you how to injected cars) and it’s the reason why massively

unbolt an airbox lid. These simply replace the increasing the airflow with a huge cone filter
stock paper filter (which can be a cone shape won’t always provide the optimum gain without

or more often a flat panel), so instead of talking supporting software. Conversely, you can get to

about the physicality of plonking in the new one, the stage where a panel filter in the standard

we’ll look at how they work, and why (contra airbox can’t flow enough air to make use of
to popular belief) they can often be more the software. Like so often in tuning, it’s all a
beneficial than a full-on induction kit. balancing act.

All performance filters flow more air than

the stock item. They also direct this air past the
AFM (Air Flow Meter, sometimes referred to as
the MAF, MAS, AFS or all sorts of other weird
acronyms). Which is basically a sensor used to
tell the ECU how much is going in. The ECU then
matches this increased flow with more fuel and

you get more power. Magic!
Except of course, there are limits. The ECU can
only push the timing and fuelling parameters so
far, and after that you’ll be needing a software
3 HEAT PROTECTION
The real problem though comes with heat and a more open setup like you’d find with a large

more specifically a filter sucking in loads of cone filter. In this way it’s not only a question

hot air. Hot air is less dense than cold air so of the tuning level you’re after, but of real-world
it contains less oxygen to burn for any given application, too.

volume. Even if you have more air flowing, a
relative lack of oxygen in a load of hot air verses
less volume but denser cold air, will often sap
car performance.
In many situations – you may have an
extremely tight engine bay, or spend a lot of

time sitting in traffic – it can be more viable

to install a performance panel filter protected
from heat by the standard airbox, rather than
4 INDUCTION KITS
Induction kits are designed to replace the whole pipework all the way to the throttle body (or nowadays will have a separate cam breather,

airbox. Just like performance panel filters, you turbo), or simpler items that simply fit to the or extra sensors fitted to the original airbox, so

can achieve good gains up to a point on most AFM housing. The clue is usually in the word ‘kit’. these will need to be taken care of. An induction
cars, but others will need a software flash In many cases it’s all the other stuff that comes kit designed for your car specifically will provide

to make the most of the extra flow. In some with the filter that proves invaluable. Many cars a solution (a separate connector, breather filter

cases (New Age Scoobys spring to mind here), or extra mounting hardware), where a universal

an induction kit can actually lose you power, cone won’t. Usually you’ll find a whole load of

because the ECU will think something is wrong brackets and fittings designed to bolt them in,
and will back off to safeguard the engine. and if heat shielding or ducting is needed on

For this you will definitely need to factor in a that particular car, these will be included too.
software tweak. Most of all though, it pays to go

for a trusted brand of filter, so you know the kit
has been developed properly.
The cone filter found in most kits will provide

a far larger surface area over a flat panel filter

for the maximum airflow. This may become

important for any future tuning. Think about
what’s next after the filter: will a panel be

enough or are you planning on going further?
Anyway, induction kits come in all shapes
and sizes. They can be full-on intakes with new
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