AK-3 Engine

The LP400R is powered by a 2.5L turbocharged engine, from our series of forged engines (AK-series). In addition to being equipped with piston rods and forged , it is equipped with a forged and balanced crankshaft. The new engine (AK-3) design provides increased reliability. 

Forged piston set

The piston is one of the most important components within the engine. It can be subjected to directional change up to 285 times every second and must withstand acceleration forces of 8500g. Cosworth high performance forged pistons are designed and engineered to withstand this type of punishment and still perform. All Cosworth pistons are manufactured using the same methods as our Formula One pistons and include features such anti scuff skirt coating, ulta-strong pins, polished top and patented anti-detonation bands. Additionally, each application uses a unique forging to minimize weight and ensure the strongest possible piston design.

Forged connecting rods

These are manufactured from 4340 alloy forgings. They are fully machined, heat treated, stress relieved, shot peened, and magnafluxed. They also are built standard with 3/8" ARP 2000 bolts.

Forged / balanced crankshaft

The original crankshaft is not able to withstand the added stress when you have many updates. There is a balanced forged crankshaft in the AK-3. It is stronger and provides better lubrication.

Bearing set

Engine bearings are one of the most vital components within an engine and are often overlooked when considering high performance upgrades. Performance engineered, multi-layer bearings generate less heat than normal bearings by reducing friction. Race bearing sets feature a unique combination of design, metallurgy and engineering to deliver performance in extreme conditions.

Subaru EJ25 STI Engine case

Each AK2 short block is built with a new Subaru EJ25 STI engine case

AK-Heads Stage 2

The team of Lachute Performance with their partners have developed a series of ultra high performance cylinder heads for 2008-2015 & 2004-2007 Subaru STI. Optimize your HP and torque gains with new cylinder heads AK-Heads 

Visit the website: http://www.lachuteperformance.com/ak/ej/ak-heads

The machining accuracy is important

At the Shop, the heads go through rigorous measurements and verifications to be sure the process is applied within our specs. And the magic is done with the 5 axis CNC machine.

Machined with precision to improve the exhaust flow.

Blended to better fill the exhaust manifold and ultimately the turbocharger, the exhaust ports are calibrated to match each pairs in velocity and ultimately volume.

The intake ports have been completely machined accurately to improve the air flow.

Internal work is also done to different parts of the head, like the guides: machined and tailored for flow and strength.

The intake ports

The intake ports are matched to the manifold according to our application and use, smoothed and blended for a perfected flow.


Combustion chambers

Verified for volume and matched, the combustion chambers keep the mix in check when the spark comes ticking.

Stainless valves

A match of stainless valves is used for a better flow pattern and efficiency to fill the cylinders.


Exhaust valves treated with nitrate.

Nitrated on the exhaust, our stainless provide a better flow at all lift points versus the stock profile.


Titanium retainers

Valves retaining discs are made of titanium. This material is used for its hardness and its lightness, eliminating the losses caused by the heavier materials.



Tailored to the cam profiles, boost and rpm use, our springs keep everything together nicely for your use.


Performance camshafts

The AK-Heads Stage 2 cylinder heads are different from stages 1 because they are equipped with high performance camshafts. Optimize your performance with AK-heads Stage 2.

Headers and Up-Pipe

Handmade in our workshops according to our high quality standards, the Lachute Performance headers is made of 304 stainless steel.

All flanges were laser cut and welded TIG on both sides to provide optimum performance.

We designed an innovative system of "Slip-Joint" to allow the expansion of the part during temperature changes.

We use this headers on all our race cars.

It is definitely one of the most resistant on the market.

Lachute Performance Up-pipe & Tial external wastegate

Improve control of your "boost" and your performance with the Lachute Performance up-pipe with external wastegate.

The design promotes the flow of the exhaust gas and allows better control of the "boost" with its external wastegate.

The up-pipe is made of stainless steel 304 and is hand assembled in our workshops. It is strong and durable.

Lachute Performance Downpipe

Without any question, one of the best flowing down pipes on the market. For ultimate performance and trouble free installation, this down pipe speaks for itself. Fully made out of 304L stainless steel tubing and flanges this down pipe also features an extra bung for tuner easiness at plugging their wide band.

Lachute performance catback

Lachute Performance is proud to offer its LP400R special edition cat back exhaust system. This exhaust system from the downpipe to the muffler tips is entirely made of 304 Stainless Steel. Flanges, brackets, and pipes of .125 gauge wall tubing. All flanges have been laser cut and tig welded on BOTH sides to provide optimum performance, durability and flow.


The LP400R is equipped with a new turbo that is perfectly suited for use on the race track. This turbo developed by Lachute Performance, provides optimal performance, quick response and increased power that is felt also in the middle and high RPM.

Turbo Inlet Hose

The PERRIN inlet hose is perfectly smooth on the inside and has a significantly larger internal diameter than the OEM part. The increased air flow by removing the pleats found in the OEM hose makes more horsepower, decreases turbo spool time, improves acceleration and increases throttle response. The PERRIN inlet hose is reinforced with a stainless steel support wire that is embedded within the silicone layers. The support adds rigidity to the hose and prevents collapse when used with restrictive filter elements and large turbo applications running extreme amounts of boost.

Lachute Performance short ram air intake

This air intake increases air flow to the turbocharger for increased horsepower.

TGV Delete

TGV deletes are the easiest ways to eliminate the OEM tumbler generator valves (TGV.  This removes the turbulence caused by them. Thus improving the air flow.

Injectors & fuel pump

A good flow of fuel is critical, especially when you replace the turbo with a bigger turbo. The LP400R is fitted with larger injectors and better fuel pump to provide an ideal fuel supply for all of the improvements made to the car.

Lightened crank pulley

This newly design aluminum crank pulley is approximately 4 pounds lighter than stock.

Aluminium radiator

Controlling the coolant temperature is critical during track days. We grafted the LP400R, a large capacity radiator and it's more efficient than the original one.

Oil cooler

The LP400R has an additional oil cooler This improvement comes directly from our research and development performed on our racing cars. This piece will keep a stable engine oil temperature even during long sessions on track.

Twin plate racing clutch

The LP400R is equipped with a twin plate racing clutch. 

Differential & cover

The rear differential of LP400R allows tight corners and come out quickly with maximum traction because it eliminates the "wheel spin" that we could meet with the stock STI differential.


Programming with the EcuTeK software, allows our expert programmer to communicate with the car's computer and change some parameters such:  air / fuel, "boost", "timing". The LP400 has a custom mapping.

Engine spécification


Entre 480HP et 515HP

(Indice d'octane: 94)


Subaru symmetrical AWD system with electrical DCCD


Subaru 6 speed gearbox