Brand: Forge Motorsport

Toyota Yaris/Corolla GR Upper Airbox Induction Kit

Product code: FMINDK43

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More info The Toyota Yaris GR Inlet Duct allows you to add an aesthetically pleasing carbon fibre part to your Yaris GR's engine bay and help keep your inlet temperatures down during spirited driving and whilst on the track or rally stage. - Read More
More info FMTIA8 is the turbo inlet adaptor for the Toyota Yaris GR with a smooth and free flowing path thus creating the highest possible flow rate - Read More
More info Toyota Yaris GR Dump Valve - Read More

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Product Description

  • Gains of 13bhp
  • Peak torque gains of 8nm
  • High quality carbon fibre
  • Pleated performance air filter
  • No engine management check lights (EML) 
  • Increased air flow  
  • Lifetime warranty*

The Toyota Yaris GR has proven itself to be a fantastically capable vehicle since its release, and the development team at Forge Motorsport have been able to work their magic once again to find further improvements. The next instalment, is the release of FMINDK43 the new upper airbox for the Yaris GR.

After continued testing and discussions with owners of Yaris GR’s, the stock airbox has proven itself to function well, especially with the stock map. However, the weakness in the airbox is most definitely the quantity and directional flow of the air. As such, we explored several different avenues, before settling on a replacement upper airbox that mounts to the stock lower. When used in collaboration with the Forge Motorsport Inlet Duct (FMINLD1) performance car part, it ensures a consistent cold feed of air into the lower airbox that can then be delivered into a refined upper airbox. The increased diameter from 80mm of the stock inlet pipe to 89mm produces a volumetric increase of around 20% in just the connecting pipe from turbo inlet adapter to the airbox alone. After running data and tests it was decided that we would not use a panel filter, but instead a cone filter as shown in the CAD below. 3D scan data was utilised to ensure that the cone filter would fit in the optimum position inside the lower airbox, not just for ease of fitment but also to allow for optimum flow into the inlet tract.

Due to the sensitivity of the MAF and stock map of the Yaris, a lot of testing was required to ensure that performance was gained without inflicting the driveability of the car - especially as we were changing from a panel filter to a cone filter and an increased diameter. To test this in real world conditions, we created a modular design that was 3D printed and allowed for different variations of MAF position, diameter, and airflow to be tested on road and the dyno. After finding the optimum design, we then reprinted the full prototype and left this on the vehicle. This allowed us to continue our testing to prove out the performance repeatability in real world driving conditions. We also noted at this stage that there is a small gain in induction noise.

This product works extremely well when collaborated with existing Forge Motorsport performance products for the Toyota Yaris GR. With the release of our turbo inlet adapter (FMTIA8) we were able to increase the volumetric capacity over the stock inlet by 53%. Once coupled to this intake we have been able to ensure a smooth airflow from filter to turbo with minimal restrictions by continuing the 89mm diameter for a large proportion of the inlet tract. It is designed in a similar way to a conventional velocity stack by routing the air more directly into your turbo charger and allows more air to be compressed due to its larger capacity. This can have a positive effect on acceleration after long deceleration or in between gear changes due to more air being kept within the intake system.FMINDK43 is part of our acclaimed Hi Flow range and will ensure that your vehicle is getting critical cold air.

Not only are Forge Motorsport performance parts a better option for an improved drive, but carbon fibre car parts really help give an engine bay some character. The high-quality carbon fibre is prepreg 2x2 twill formed in an autoclave from billet tooling and finished with an anti UV gloss gel coat.

Dyno Results

We found that FMINDK43 with the stock turbo inlet produced peak gains on average of 13bhp at the wheels and peak torque gains of 8nm.

The dyno graph below shows a comparison between the stock airbox, the 80mm prototype and 89mm prototype. We ran a total of 8 different prototype variations of MAF height, MAF distance from entry and inlet diameter to ensure that the best solution was used. You can see how sticking to the stock size diameter and MAF position with the cone filter produced a slight improvement to the wheel horsepower, however when increased to 89mm we were able to produce some fantastic gains from such an easy to install bolt on modification.

Another important observation to note is where the power is delivered. As you can clearly see on the dyno graph that the engine produces a much higher power earlier into the rev range. From 2000rpm to 3600rpm the lower flap in the airbox is opened via a solenoid, and the dyno graph shows that at the same rpm there is an increase of around 15- 20nm of torque with FMINDK43 installed compared to stock. This figure is noticeable when driving, and you can feel that the vehicle picks up much better than in stock form.

It’s worth remembering that this is with a stock ECU and no tune, so we would expect to see mapped cars returning even greater yields of power as they will be able to utilise the increase of airflow.

The performance part kit comes complete with everything you need for installation, which can be carried out in around half an hour, including a set of full colour instructions.

Our Toyota Yaris GR performance parts will help improve both the look and drive of your car.

*Please note - the filter is excluded from the Forge lifetime warranty 


Complimentary Products

After discussions with many GR Yaris owners about airbox modifications, Forge Motorsport are proud to present the Toyota Yaris GR Inlet Duct. The Forge inlet duct allows you to add an aesthetically pleasing carbon fibre part to your Yaris GR’s engine bay and help keep your inlet temperatures down during spirited driving and whilst on the track or rally stage. This part really works well in combination with the intake.

The FMTIA8 is the new turbo inlet adaptor for the Toyota Yaris GR. Throughout the development process we have strived to improve the efficiency and performance of the Yaris GR’s engine and for this product we felt we would offer the whole inlet pipe work as one complete package. FMTIA8 consists of a billet machined turbo adaptor, two 5 ply silicone hoses and mandrel bent alloy hard pipe.

It is recommended for any vehicle where the boost pressure has been increased by an ECU software upgrade and for unmodified vehicles operating in warmer climates, as a solution to the many failures that have occurred. The Forge motorsport valve solution is available in either atmospheric where a noise is heard when the throttle is lifted or the factory type non noise recirculating valve.


Please Note: In line with our policy to constantly review, revise, and improve our product range, the appearance of the product you receive may differ from the one advertised.

Product Reviews

Product Reviews from on Sep 18th 2023
Increased induction noise and nice carbon look, all that I can ask for.

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Compatible Vehicles




Toyota Yaris/Corolla GR Upper Airbox Induction Kit


Warranty Infomation

All Forge Motorsport products come with a limited lifetime warranty. All warranty claims must be accompanied by the original proof of purchase to enable us to help you. Failure to supply this proof will result in your claim or enquiry being denied.

For further information, please call our customer service team on +44(0)1452 380999 or email

Do not use aggressive (acidic) car cleaning products, particularly traffic film remover solutions or shampoos to clean your intercooler, radiator or oil cooler. The use of these products can damage Forge Motorsport cooling systems and invalidate your warranty. These are often found at car washes. A light, warm, soapy solution (free of harsh acidic cleaning compounds) should be used to clean you cooler and thoroughly rinsed away. We recommend that you should inspect your product on a regular basis for bent and/or crushed fins. Any bent fins should be carefully straightened to allow ambient air to pass through the core face. At the time of installing your Forge radiator, an approved coolant must be used and added to the coolant system. Be sure you never mix coolant and always use distilled water.



USA Deliveries

All Deliveries are sent via Fedex. We cannot guarantee delivery timelines as all orders are up to shipper schedules and routes.  Delivery fee is a Flat Rate of $20 fo all orders over $20. Orders below that value are costed out based on weight. Signature required may be added to your package. Orders can not be re-directed, held, or re-scheduled.

Shipping outside of the Lower 48- Duty Charge Information

All Forge products are sold with a Delivery Duty Unpaid (DDU) status and an import tariff may apply to your order. Customers will be contacted by the Customs and Excise authority in the destination country regarding payment prior to delivery, and it is important that correct contact telephone number and email information be submitted with the order to facilitate this part of the delivery process. 

Our shipping methods ensure safe and timely delivery of your new Forge products. For further information on cost and delivery times, please contact Forge using the email address if you require any more information. We reserve the right to change the delivery service and company at any time.

***Once a product has left our warehouse and is in the possession of the shipping company, any claims must be made directly with that shipper however we can assist with most cases.