The short answer
On a turbocharged car, a bigger intercooler is the single most worthwhile bolt-on you can buy. On a naturally aspirated car, an induction kit mostly buys you noise.
Both parts do the same job from different ends: get more air, and colder air, into the engine. Cold air is denser, dense air carries more oxygen, and more oxygen means more fuel can be burned.
See the range in OMI Performance.
Why cold air matters at all
Air at 20°C is roughly 10% denser than air at 50°C. Same volume, 10% more oxygen.
That is the whole principle. Every induction kit, every intercooler, every charge cooler and every high-flow radiator exists to keep the air going into the engine cooler and moving more freely.
It also works the other way. Feed an engine hot air and a modern ECU pulls timing to protect itself, so you lose power you already paid for. A lot of what these parts do is stop you losing power rather than finding new power.
Cold air induction kits
A cone filter on a pipe, replacing the airbox, usually with a heat shield or a feed from outside the engine bay.
On a turbo car
Genuinely useful. The turbo pulls hard through the intake, so restriction there costs real power. A good kit frees that up, and on a mapped car the gain is measurable. Expect single-digit percentages on a standard car, more once remapped.
On a naturally aspirated car
Be realistic. The factory airbox on a modern NA engine is usually not the restriction. A kit will make the car sound considerably better — induction roar on throttle is exactly why most people fit one — but the power gain is often within measurement error.
That is fine, as long as you are buying it for the noise and not expecting 15bhp. We would rather say so.
The heat shield matters more than the filter
An exposed cone filter in a hot engine bay can be worse than the standard airbox, because it sits in 70°C air. The kits worth having either shield the filter or duct cold air to it. Ignore any kit that is just a filter on a pipe.
Intercoolers
Only turbocharged and supercharged engines have one. Compressing air heats it — a turbo can deliver air at well over 100°C — and the intercooler takes that heat out before the air reaches the engine.
Why a bigger one helps
A standard intercooler is sized for standard power and normal driving. Drive hard, and it soaks up more heat than it can shed. Inlet temperatures climb, the ECU pulls timing, and the car gets slower the longer you push it.
That is heat soak, and it is why a car can feel strong on the first run and flat on the third.
A larger core holds more and sheds more. The gain is not usually a bigger peak figure — it is the same figure, repeatedly, instead of fading.
Front mount versus top mount
- Front mount (FMIC): sits behind the bumper in clean air. Best cooling. Needs longer pipework, which adds a little lag.
- Top mount (TMIC): sits on the engine, short pipework, sharp response. Sits in engine heat, so it soaks faster. Common on Subaru.
- Charge cooler: water-to-air, used on many modern turbo engines. Very compact, very good at short bursts, and the usual upgrade is a bigger charge cooler radiator rather than a new core.
Bigger is not always better. An oversized core in front of the radiator blocks airflow to the radiator and can raise coolant temperature. Size it to the power you actually make.
Radiators and cooling
Often overlooked and sometimes the thing that is actually limiting you. If coolant temperature climbs on a hot day or during sustained hard driving, a higher-capacity alloy radiator does more for consistency than any intake part.
This matters most on older performance cars, anything with the original radiator still fitted, and anything used on track.
What order to do things in
- Fix what is worn. Tired plugs, a split intake hose or a blocked filter will undo everything that follows.
- Cooling. Intercooler, charge cooler radiator or radiator. This is what lets the rest work repeatedly.
- Intake. Induction kit, properly shielded.
- Exhaust. Let the air out as freely as it goes in.
- Remap last. Map the car as it will be driven, with all hardware fitted. Mapping first and adding parts after means paying to map twice.
People routinely do this backwards, remap a standard car, then wonder why bolt-ons afterwards feel like nothing.
Common questions
Will an induction kit fail my MOT?
An intake change is not an MOT item on a petrol car, provided the car still passes its emissions test. Removing or defeating emissions equipment is a different matter and is not road legal.
Do I need to tell my insurer?
Yes. Intake and intercooler changes are declarable modifications. Most insurers charge little or nothing for them. An undeclared modification gives them a reason to question a claim.
Will a bigger intercooler cause lag?
Marginally, because there is more volume to fill. On a road car the difference is far smaller than the gain from stable inlet temperatures.
How much power will I actually gain?
On a standard turbo car, an intercooler alone often shows little at peak but holds power far better on repeated runs. Combined with intake, exhaust and a map, meaningful gains are realistic. On a standard NA car with just an induction kit, expect noise and very little else.
Does a cone filter need cleaning?
Yes. Most are washable and reusable — clean and re-oil roughly every 10,000 miles. Over-oiling a filter can foul the airflow sensor and cause rough running, so use the right amount.
Related reading
If brakes are next on the list, our guide to drilled, grooved and hooked brake discs covers what each pattern does. More power deserves brakes that match it.
And if the front of the car is coming apart for an intercooler, it is the natural moment to look at grilles and alloy wheels.
Tell us the car
Send the make, model, engine and year to sales@omiwheels.com, message OMI on WhatsApp or call 028 6625 1123, and say what you want from the car. We will tell you what is worth fitting and what is not.
We ship from Enniskillen, Northern Ireland, so orders to Ireland and the EU arrive with no customs declarations and no import duty.