Subaru Impreza GC8 EJ25 for higher boosts on Sweden roads - Hard Core Racing

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Subaru Impreza GC8 EJ25 for higher boosts on Sweden roads

This is a project of Mattias, one of our clients from Sweden who had a desire to install a bigger turbo for higher cylinder pressure in his Subaru Impreza GC8 to aim for 500+wHp. For preventing common engine failures that can happen under the higher loads with original equipment manufacturer (OEM) block, he wanted its durability improvements, that no matter what he throws at it, it can take it without any problems and risk.

Good reviews from other customers who have used HCR services and the activities in social media, which was proving the quality of the work encouraged to contact with us and make some arrangements to improve a daily beater for higher power on Sweden roads.

Closed Deck and precise bore and hone was the answer. We sourced for EJ25 open deck block and let it through our machinist’s hands to do services that are suited for our client needs. We did:

1) Closed decking: stage 1
2) Line Boring
3) Block Deep Cleaning
4) Mains Pinning
5)Machining M14 threads for bigger studs
6)Cylinder bore and hone

The first step was deep cleaning of the block to remove oil, sand or sealant leftovers from previous use, make it look like new and well maintained and ready for further work.

The block of the engine was then closed decked for better cylinder wall support and prevention of cylinder cracking. This also prevents head gasket issues because of cylinder deforming under high power and boost applications.

M14 head stud threads were machined after the closed decking was done. Bigger studs eliminate the possibility of heads lifting in applications over 500 horsepower.

After closed decking and head stud threading cylinder boring and honing could take a place – all with torque plates torqued down to manufacturers spec. Cylinder liners are pre-tensioned to get the best result of the final roundness of the cylinder.

Next, we did a line boring and mains pinning, so the bearing clearances are perfect. This prevents the engine from so much heard Subaru bearing clearance problems that are actually caused by case warping.

After all HCR services were done, we packed and shipped Mattia’s new block safely to his doorstep where he was able to continue his build project, and after 3 to 4 months with a little help of a local company with balancing the crank Mattias was finally ready to flat out!

It's been over a year since his build project. He is able to run his GC8 with around 400whp safely. There haven’t been any problems, not even a single oil drop or coolant leak, in fact, he has now already got a new turbo and upgraded fuel system so he can achieve the planned 500+wHp.

We were excited to hear that even in -5C with 2618 pistons there is not a drop of piston slap, oil pressures are stable and he feels confident to throw much more to this setup and be sure it will hold it.

“I’m really happy how the engine turned out, lots of torque and its response immediately. I recommend HCR to everyone that wants a top-notch job, the service and machining are outstanding!” – Mattias.

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