If you want the exact same engine Element Tuning runs in our "Unlimited" Time Attack STi, then look no further. Whether you want to make 400 whp or 800 whp this will have the biggest and fattest powerband your Subaru can have. This motor is setup to maximize HP from 4000 RPM to 8500 RPM with the addition of our "Big Valve" head package. Custom piston top coatings, intake manifold, cooling system upgrades, oil pump upgrades, and other parts may be recommended by Element Tuning. Our Pro Comp Long Block starts with the Pro Comp Short Block and adds Element Tuning Competition Valve Springs, Cosworth Camshafts, Valve Covers, 11mm High Flow Oil Pump, and Element Tuning's Big Valve Head modifications.
Through years of testing on the track and on the dyno the key to maximum power is unlocking the potential within the Subaru heads. The first step in the process is to select a more aggressive camshaft set utilizing more lift and duration, but even then power is bottlenecked by the OEM intake and exhaust valves. Testing with a Garrett GT35R or the Element GT65 turbocharger results in a +100 whp gain with this head package and camshafts over a stock head package.
The key to this gain in the +1mm larger stainless steel intake and Inconel exhaust valves. Just camshafts alone are held back by over 40 whp when the heads are left with the OEM valves. Element Tuning has discovered that the majority of the gains from the Subaru head are attributed to the valve size itself and not the intake and exhaust ports. Often "Big Valve" heads can be $4000 plus dollars due to the labor required to port the heads. The modifications start with a 5 angle intake valve job and it finished off with a bowl blend to maximize the flow through the intake port to the larger valve. The stems of the valves are larger and stronger than OEM therefore a precision hone of the valve guides is performed.
Many may ask why don't you port the intake ports fully? We don't do this because almost 100% of the gain is realized by just fitting the larger intake valve and performing a bowl blend. (HP/value/compared to porting) On top of this the head retains 100% of it's reliability due to how thin the cast walls are. It's all too common to see highly stressed, high HP, road race engines blow through over ported head walls. On the exhaust side we also install a +1mm valve and hone the guide but a 2 angle with a radius valve job is performed. The exhaust port is again blended to maximize the potential of the larger exhaust valve. We are seeing +20% increase in flow on the exhaust side alone!
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