The intake air system sounds simple — suck air from outside, feed it to the engine. In reality, it's a carefully calibrated component. Flow velocities, pressure loss, temperature rise, and water separation are all engineered. Modify any of them, and you risk emissions compliance, or worse, engine damage from water ingestion.
What Cannot Be Modified
INEOS does not provide an approved pathway for modifying the clean air side or maintenance indicator connection. The clean air side is the intake path from the exterior air opening to the engine. The maintenance indicator is the visual cue for a clogged filter.
Intake System Constraints
- Flow velocities: Must not be increased in intake area or duct
- Cross-section: Must not be constricted
- Pressure loss: Must equal factory air intake
- Temperature: Intake must not exceed ambient by more than 10°C
- Water separation: Even minor modifications near intake opening require departmental approval
- Emissions: Attachments changing air intake size may affect emissions type approval and require re-certification
Water Ingestion and Splash Protection
Water must not flow directly past the intake point from body runoff, splash, or car washing. If your bodywork channels water toward the intake opening, you've created a water ingestion risk. In deep water fording, water flows directly into the engine, hydrolock occurs, and the engine seizes.
The intake temperature must not exceed ambient by more than 10°C. A partition between the engine interior and intake point is essential for maintaining proper air temperature and preventing thermal stress on components.
Dust Protection and Filter Maintenance
Increased dust pickup shortens air filter maintenance intervals. To reduce dust, place the engine air intake as dust-protected as possible. In dusty environments or for extended off-road use, consider supplementary dust management strategies.
INEOS offers the Raised Air Cyclone Pre-cleaner (part number GRA-0B14-009860) as the approved dust solution, available via the INEOS Aftersales portal accessory section. This device pre-separates dust and water before the air filter, extending filter life and improving intake performance in challenging conditions.
| Parameter | Requirement |
|---|---|
| Flow velocity | Must not exceed factory specification |
| Cross-section | Must not be reduced below factory dimension |
| Pressure loss | Must equal series air intake |
| Max temperature rise | 10°C above ambient |
| Water exposure | No direct flow past intake from any source |
| Approved pre-cleaner | INEOS Raised Air Cyclone (GRA-0B14-009860) |
Emissions Compliance and Type Approval
The detachable pieces of the air intake represent a certified condition with regard to emissions. Attachments or conversions that change the size of the air intake may result in the emissions type approval of the base vehicle no longer being valid.
The body manufacturer must ensure compliance with certified limits and associated approval requirements if modifications are made in the intake area. This means any changes to the intake system require engineering review and potential re-certification testing. Plan accordingly if your build specification includes intake modifications.
Snorkel vs. Raised Air Intake: A Critical Distinction
This is one of the most misunderstood topics in the Grenadier community. The terms "snorkel" and "raised air intake" (RAI) are used interchangeably, but they are fundamentally different things with different implications for your emissions certification.
The INEOS Raised Air Intake (RAI)
INEOS offers a factory Raised Air Intake option that repositions the air inlet higher on the vehicle's A-pillar area. Critical point: the RAI is not sealed against water ingress and does not increase your wading depth. It is designed to draw cleaner, cooler air above the dust cloud during off-road driving — nothing more. The RAI bolts on to the existing intake system and can be switched back to the standard configuration.
Because the RAI is an INEOS factory option, it does not affect your emissions certification. It maintains the factory air path geometry and pressure characteristics — the intake volume, cross-section, and pressure loss remain within the original type-approval parameters.
Aftermarket Snorkels
A true snorkel is a sealed intake system that routes air from roofline height through a sealed pipe to the engine. Several aftermarket manufacturers now offer snorkel systems for the Grenadier — typically aluminium construction, requiring drilling and cutting for installation, with installation times of 4–5 hours.
Here's the emissions problem: an aftermarket snorkel changes the intake air path entirely. It modifies the clean air side, alters flow velocities, changes the cross-sectional area of the intake duct, and may affect the pressure loss characteristics. All of these parameters are part of the original emissions type-approval testing. Changing them technically requires re-certification — which is effectively impossible for an individual owner.
The Practical Reality
Most aftermarket snorkel manufacturers don't provide emissions re-certification documentation. They sell the hardware; the certification question is left to the owner. In many jurisdictions (particularly EU and Australia), this creates a grey area: the snorkel may trigger a compliance issue at registration renewal or during roadside inspection, even if it functions perfectly well from an engineering perspective.
If you're in a jurisdiction that strictly enforces emissions type-approval (most of the EU, parts of Australia), installing an aftermarket snorkel may technically void your vehicle's type-approval for the intake system. If you're in a more permissive jurisdiction (much of the US, parts of Africa and the Middle East), enforcement is less likely to be an issue.
Sealed Airbox Systems
Some aftermarket solutions go further than a simple snorkel — they replace the entire airbox with a sealed unit and aftermarket pod filter. These systems change even more of the intake path: the filter element, the airbox volume, the seal integrity, and often the filter maintenance indicator connection. From an emissions certification standpoint, a sealed airbox replacement is the most significant modification you can make to the intake system.
The Pre-Cleaner Option
For owners who need better dust management without the certification risk of a snorkel, the INEOS Raised Air Cyclone Pre-cleaner (part number GRA-0B14-009860) is the approved solution.
How It Works
The cyclone pre-cleaner sits upstream of the main air filter. Incoming air enters the cyclone chamber, where centrifugal force separates heavier particles (dust, sand, insects) from the airstream before it reaches the paper filter element. Pre-separated particles are ejected through a one-way valve at the bottom of the cyclone housing.
Why It Matters
| Benefit | Detail |
|---|---|
| Filter life extension | Cyclone pre-separation removes 80–90% of coarse particulates before they reach the main filter, extending filter service intervals significantly in dusty conditions |
| No emissions impact | The pre-cleaner sits upstream of the factory air filter and does not change the clean air path, cross-section, or pressure characteristics |
| Approved part | Available through the INEOS Aftersales portal — it's a factory-sanctioned accessory that maintains your warranty and type-approval |
| Reversible installation | Can be removed and the standard configuration restored without permanent modifications |
For most owners driving in dusty environments (outback Australia, North African trails, American desert Southwest), the cyclone pre-cleaner provides the practical benefits they're looking for — cleaner air, longer filter life — without any of the certification complexity that comes with modifying the intake path itself.
What Owners Are Actually Experiencing
Based on community discussions and forum reports, here's the practical landscape for Grenadier intake modifications:
The RAI Retrofit Question
Many owners who didn't spec the Raised Air Intake at build time want to add it later. The good news: the RAI is a bolt-on/bolt-off system that can be switched between standard and raised configuration. Some owners have sourced the RAI parts through dealers and installed it themselves. The bad news: INEOS doesn't officially treat it as a standalone accessory — it was originally a build-time option. Availability through dealers varies by market.
The "I Need a Snorkel for Water Crossings" Misconception
The Grenadier has a factory wading depth of 800mm. The RAI does not increase this — it's not sealed. An aftermarket snorkel may provide sealed air intake at a higher point, but the wading depth is also limited by other factors: door seals, electrical components, breather hoses, and body drain plugs. Raising the air intake alone does not make the vehicle safely wadeable beyond 800mm. Several owners have learned this the hard way when water entered through other unsealed pathways despite having a raised intake.
The 10°C Temperature Rule in Practice
The Body Builder Guide specifies that intake air temperature must not exceed ambient by more than 10°C. In practice, this rules out any intake routing that draws air from the engine bay (where under-hood temperatures can exceed 80°C). It also means that a snorkel routed close to the exhaust manifold or turbocharger area during its path through the engine bay would violate this constraint — even if the snorkel inlet itself is at roofline height.
Snorkels, Pre-Cleaners, and What the Community Is Learning
The Grenadier's raised air intake (RAI) is already positioned higher than most vehicles, but owners heading into deep water crossings or extremely dusty environments often want more. Here's what's technically at stake.
The Snorkel Question
Aftermarket snorkel systems for the Grenadier are now available, but installation involves significant engineering considerations:
- Sealed airbox requirement: The factory airbox isn't fully sealed for snorkel use. A proper snorkel installation requires a sealed airbox system to prevent unfiltered air from entering through the original intake path.
- Crossover pipe: The snorkel must connect to the engine bay intake without introducing leaks or restrictions. The path through the engine bay must avoid exhaust manifold and turbocharger heat zones (where temperatures can exceed 80°C).
- Drilling and cutting: Snorkel installation requires cutting the fender — this is irreversible and must be accompanied by proper corrosion treatment of all exposed metal edges.
- Emissions impact: If the snorkel system changes the intake air temperature, volume, or filtration characteristics, it can affect the engine management calibration and potentially void emissions certification.
Pre-Cleaner and Dust Filtration
Before considering a snorkel, many owners address the factory RAI's dust ingestion issue first:
- Factory cyclonic separator: Available as an INEOS option for the raised air intake — centrifugally separates heavy dust particles before they reach the main filter
- Aftermarket pre-filter socks: Foam or mesh covers that fit over the RAI inlet to catch coarse particles. Effective in light dust but can restrict airflow in heavy conditions.
- Sealing the RAI: The factory raised air intake has known sealing issues where it meets the fender. Dust enters through these gaps before reaching the filter.
What Owners Are Experiencing
"Did you realise our raised air intake sucks in a lot of dust where it enters the fender? I could drastically reduce dust in the filter with taping the outer seam. The sealing there begs for improvement."
— Owner discovering RAI sealing issues, The INEOS Forum, May 2024
"I found this issue last week after having an annoying knocking sound. The raised air intake has become separated from the body. There is effectively no sealing from the exterior. The failure occurred from highway driving — there has not been any contact or impact with the air intake."
— Owner reporting RAI detachment, The INEOS Forum
"With all of the aftermarket products rolling out, I'm a bit surprised not to have seen a sealed system yet."
— Owner noting the gap in aftermarket solutions, The INEOS Forum
"A cyclonic separator is offered as an INEOS option for the raised air intake."
— Forum member highlighting the factory pre-cleaner option, The INEOS Forum, November 2023
The Emissions Certification Risk
Any intake modification that changes the following parameters risks voiding your emissions certification:
- Air filter type or efficiency: The factory filter is calibrated for specific flow rates and particulate capture. High-flow aftermarket filters may allow particles that damage the MAF sensor or turbine blades.
- Intake air temperature: Snorkel routing near heat sources changes the density of intake air, affecting the air-fuel ratio and potentially increasing NOx emissions.
- Intake restriction: Too much pre-filtration (stacking pre-cleaners on pre-cleaners) can increase intake restriction, reducing power and increasing fuel consumption — which in turn affects emissions output.
- Airbox volume: The factory airbox acts as a resonance chamber. Replacing it changes the intake acoustics and can affect low-RPM torque delivery.