Overview
The GR86 is already a highly entertaining back to basics sports car which is a huge amount of fun to drive. The engine has a good torque curve and the rpm’s build progressively to the red line.
However, it does lack something and this is evident from just hearing the engine under normal driving and looking under the engine bay.The intake sound is mostly artificial being driven into the car by the speakers and it is very small with a series of Helmoltz resonators which quieten the induction sound.
There is also a distinct hesitation at the lower rpm’s (not the mild torque dip).
Our aim was to vastly improve the intake with a full redesign to give faster throttle response, improved torque under both partial load and full load and most of all more induction sound.
The Toyota GR86 is the least powerful car we have ever developed an intake system for but it’s been the most rewarding.
Development Process
During the development process we created multiple prototypes. The initial prototype used a straight venturi tube feeding into a large airbox which took it’s air from the stock OEM area with an enlarged area with an additional air feed on the opposite side which is very small.
The idea was that the additional air feed would help in increasing available airflow. However this design failed to give the desired results both on the dyno testing and on the road with no difference in power. CFD analysis showed vast amounts of turbulence in front of the air filter.
The OEM system bends towards the right hand side of the engine bay with the air filter inline with the air feed giving the most direct path for the air to flow.
We decided to create a system which followed the same path with the single feed but with the following major changes:
1 – Double the cross sectional area of the front inlet feed giving more a more than adequate increase on available air for the FA24
2 – Extend the snorkel towards the front and incorporate a bell mouth to smooth the air flow
3 – use a significantly larger air filter housing and the largest possible venturi inlet tube.
After some iterations this method gave the best air flow under CFD analysis showing less turbulence than the OEM system with vastly increased airflow.
The results on both the dyno (see below) and road driving were excellent. Vastly improved throttle response, low end torque response improvements with all of the hesitation now absent. At mid-higher rpm heavy load driving a clear gain in performance noticed.
Under normal but spirited driving the engine feels even more eager to accelerate in the 2000-4000rpm range required with more torque.
Final Product
Dual Feed Prototype
Air Intake Temperatures & Heat Soak
Intake temperatures were tested on the stock intake system by placing thermocouples before the air filter on both the OEM and Infinity systems.The OEM system manages ambient temperatures as low as 20mph and immediately under full load. Under full load high rpm acceleration the ambient temperatures remains at ambient. In terms of temperature, the OEM system sets the benchmark.WIth the Infinity intake fitted without the front snorkel intake temps are consistently + 5-10 degC higher than OEM. With the snorkel fitted, the air air is being taken from the exact same area as OEM and therefore the Infinity system matches the OEM efficiency.
Air Filtration
Within the beautifully shaped carbon shaped enclosures sits our bespoke short stack high surface area filter larger than any cone filter design currently on offer on the market with a huge opening of 170mm (6 3/4″) and is designed to take full advantage of the intake tubes by altering the direction of the airflow towards the outer walls.
By placing the air filters in front of the inlet tube we achieve the largest velocity stack ever seen for the FA24 engine and which also has the best laminar flow. It is important to note that we have painstakingly opted for the largest possible air filter for a various number of reasons. Not only does a larger air filter allow for more air flow and therefore power but it also does not block up for longer and continues to be efficient at it’s main purpose which is to filter the air of harmful elements.
Dyno Testing - +10-12HP | +5-10lb.ft
Dyno tests were performed under strict controlled conditions on an independent Maha MSR500 dynamometer in order to show a true and realistic result.
The stock car made almost exactly what the manufacturer quotes with 228 BHP and 179 lb.ft torque with a perfect power curve.
After fitting our intake system the peak power went to 240 BHP and 184 lb.ft torque.
A significant and clear gains of 12 BHP and 5 lb.ft torque peak.
From 2000-3000rpm a torque increase of 10 lb.ft was gained which is a significant gain.
From 6000rpm onwards the FA24 engine gains significant HP and torque to the red line.
Run down losses remains identical between the two tests as did the ambient temperature.
Both sets of tests were carried out with identical starting oil and coolant temperatures.
Dyno Line Key:
Solid Blue line / Dotted Blue Line – WHEEL HP
Solid Green Line / Dotted Green Line – Drivetrain Loss
Solid Red Line / Dotted Red Line – Flywheel Calculated HP (wheel + loss)
Solid Yellow Line / Dotted Yellow Line – Flywheel Calculated Torque
Specifications
1 x Inlet Tube with integrated CNC MAF Boss
1 x Air Filter Housing / Inlet Duct
1 x Inlet Snorkel
1 x Bespoke Infinity Design Air Filter
1 x black metal clamps
1 x EPDM Flexi hoses with clamps
1 x Bracket
1 x Fitting Kit
