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Product Spotlight: The benefits of our Auxiliary Cold Air Intake (ACAI)

  • 4 min read


£190.83 Ex. VAT | £229 Inc. VAT

Our new Auxiliary Cold Air Intake (ACAI) has proven extremely popular with owners of Mk8 Fiesta ST wanting to optimise their cold air induction setup - and for good reason, but there's plenty more to our ACAI. It forms an integral part of a modular suite of both existing and future performance upgrades that have been engineered to work together in perfect harmony.

Before we get into that though, let's take a look at the OE setup and see how and why the ACAI improves performance on its own.

The OE deflector can be seen above and directs cold air in through the openings on either side of the assembly; you can clearly see that the bulk of the airflow is being channeled through the radiator as the top edge forms an enclosure against the rear of the bumper.

Once the air enters the OE side channels it's deflected through 90º upwards and then another 90º across into an area that loosely feeds the two OE entry points for the cross-car cold air feed (where the top two arrows are pointing).

It's important to remember that all of this is going on with the bumper in place creating pockets within these various sections. It's also important to notice that as soon as the air enters these frontal openings on either side, whilst 'guided', there are plenty of low-pressure areas in front of the headlights and next to the cooling pack where air can - and will, easily diffuse away from the OE air intake points.

This also means that whilst visually an option that some owners will certainly appreciate, adding scoops or 'nostrils' to this area alone is as equally ineffective, as the issue hasn't been addressed and the air can still easily dissipate.

So how does the ACAI differ and what benefits does it provide straight out of the box? Quite a few as it happens.

Firstly, being made of aluminium, the ACAI will not distort or sag down like the OE version is known to do, it also installs in exactly the same place and with the same fixings as the OE unit, so other than removing the front bumper (which is easy after you've done it once), the rest is a doddle to fit yourself.

You'll notice that the left-hand section is blanked off - the reason for this is to both ensure airflow is only going where it is needed (who needs to cool a headlight anyway?) and because as you can see from the top image on this article, the washer fluid reservoir is also on this side of the vehicle, so there's little to gain by opening this out - we wanted as much cold air as possible both feeding the intake and keeping the radiator operating efficiently.

What you'll also notice is our twin deflector scoops across the leading edge. These have been carefully optimised to deflect more air than the 1.5-litre Dragon engine could ever likely consume, straight into the section feeding the dual OE air entry points. No twists and turns and no diffusion and lost efficiency.

Whilst bigger is normally better, we also wanted to ensure that unlike some other individual scoops available, that the radiator's cooling surface area would remain largely unaffected, ensuring maximum performance - particularly useful for those taking their cars on track in the summer months, or that like to exploit their Fiesta's abilities and that live in warmer climates.

Equally, for those that do use their cars in particularly cold climates for prolonged periods, we've ensured that a build-up of snow wouldn't become an issue either, so striking the right balance of performance versus size has been essential.

Even at this stage without any other features, the ACAI is providing less inhibited cold air straight into the factory airbox feed (which is also used by other aftermarket induction kits), so you're getting a gain regardless of whether you are running a standard airbox, the mountune airbox or a third-party induction kit. But we weren't done there...


We've also added an auxiliary air feed which can be used in a number of ways to suit owner's requirements, thanks to the supplied porous hose and billet joiner:

  • To direct additional cold air into the bottom of our induction airbox kit (as currently used with our m235 power upgrade) by neatly joining the lower porous hose supplied with that kit - shown above.

  • To direct additional cold air to our forthcoming cone filter induction kit (more details on that will be revealed soon).

  • To direct additional cold air to a third-party induction kit (you may require your own expansion hose).

  • To direct additional cold air to our forthcoming inner-wing-mounted oil cooler kit.

Hopefully you can see the ACAI is a standalone upgrade that warrants consideration on its own merits, but if you already have, or you're planning on upgrading to our current, or future induction kit offering, it adds additional benefits - it even gives extra options for those running third-party induction kits, too.

It's also been engineered to work in perfect harmony with our high-performance intercooler solution. We've extensively tested intercooler options in an environmental test laboratory and the data collected confirmed that our intercooler performs on par with a lot of full-height units out there, without the lag and pressure-drop issues associated with a full-height unit and such a relatively small displacement engine and turbocharger. To that end, it's important to make sure owners realise that the ACAI is not compatible with any full-height intercoolers currently available.

It's probably worth adding at this point that if you want to maximise your airflow and cooling performance by fitting both the ACAI and our intercooler at the same time (well, the bumper will be off after all), you can save 10% on the pair when you use code GOWITHTHEFLOW at the checkout.

Another question we've been asked that we really wanted to cover within this article is what the ACAI looks like once it's fitted, which we can confirm looks a lot like this...

Finally, we couldn't leave it there as some of you will have taken the time to read all of this article and would've noticed we did mention our forthcoming wing-mounted oil cooler upgrade. We'll put together another article covering that in due course, but for now here's a teaser of that and a further demonstration of the modular nature of the ACAI - thanks for reading!

What owners are saying about the ACAI: