Subaru Impreza STI EJ25
Our specialty, boxers... whether they are 4 or 6 cylinders we get involved!
On this car we wanted to enhance the mid-range torque without compromising reliability and mileage. The engine currently has more than 30,000km on it with 430hp and 600nm of torque, now we will show you the workmanship in detail:
To strengthen the block as much as possible we opted for a closed deck solution. In this case the ports around the water passage cylinder are reduced to allow higher turbo pressures. An excellent solution for maximum power at the expense of cooling, in fact in this way the water passage is reduced and the radiator must be enlarged to allow for greater heat exchange
The crankshaft is the load-bearing element, we used a reinforced version, as well as H-shaped connecting rods dedicated to minimizing possible bending due to other pressures
Lubrication is important, especially on boxer shorts which tend to leak easily. In this case we use a bulkhead that conveys the oil into the sump together with the killer oil sump B to minimize the possibility of missing draft in curves with high G forces
Variable pulleys? Yes. On the intake side the variation is managed by the standard AVCS which, based on the oil pressure, move the camshafts ensuring an optimal air flow, while on the standard exhaust side they are fixed. To give it the maximum emptying effect of the cylinders we adjust the pulleys to improve the response of the engine when exiting corners over the entire rpm range
To conclude, the Kevlar timing belt, so as to reduce elongation under stress, not only that, the wrapping of the manifolds allows for a smoother exit of the exhaust gases and less passage of hot air near sensitive elements such as belt covers and gaskets, a very delicate element on the boxers given by the presence of the manifolds on the lower part of the engine
The turbo, a fundamental element for pushing this engine to the maximum! Obviously it has been increased, a modification allows for low torque and a high spool without sacrificing power at high rpm and maintaining a constant pressure from 1.5 to 1.9 bar
It's there but you can't see it, the lightened flywheel combined with the single-disc copper clutch complete this preparation on the engine side, let's now see what was done to the chassis:
The chassis has undergone various modifications. First of all, an adjustable structure in compression, extension and height, so that it can be set to the best in every situation. The braking system was subsequently revised, DBA discs with sports pads to always have the best possible braking. Last but not least the general reinforcement used Cusco bars so as to have a precise frame to control the power of this fantastic ej25!
