The September 2002 model IMPREZA STI was given a big upgrade & improvement. With the introduction of the twin scroll turbo charger & all stainless steel equal length exhaust manifold. With the high performance potential of the new exhaust manifold it was said that development of an exhaust manifold that could surpass the standard type was impossible.
However we at TOMEI challenged that claim and we persistently tried to make that claim false. With over 10 new samples, we extensively put every single model through its paces and thoroughly tested them. At last, finally we completed the TOMEI EXPREME exhaust manifold which has surpassed the standard model.
Unfortunately the distance of the exhaust manifold from the engine to the turbo charger is far on the IMPREZA due of the nature of the boxer turbo engine layout. Therefore the response is greatly affected if the exhaust pipe diameter is enlarged. So here at TOMEI we tested all various types of exhaust pipe diameter combinations & found the best combination of 38mm (pre gathering section), 42.7mm (post gathering section), 42.7mm (support pipe).
We didn’t only focus on the pipes diameter but also the design layout for the exhaust manifold. By reducing the sharp curves (at the gathering section) & long straight sections, helps minimize exhaust resistance & to increase the exhaust efficiency at higher RPM ranges.
The whole kit with the support pipe weighs in at the combined total of only 8.5kg!!
Dry Racing Sound
The SUS304 stainless steel brings out the sharp racing sounds.
The SUS304 stainless steel is strong, robust and has superb rust resistance.
Equal Length Design
The original STD equal length design was adopted as it was the best for minimizing exhaust interference.
Thermo Bandage Included
Bonus thermo bandage included in the kit! [50mm wide- 15M long].
Dual Support Pipe Included
The SUS304 stainless steel support pipe [ö42.7] is also included in the kit.
Comaptible with STD ECU & TOMEI ECU
The potential is greatly enhanced even with the use of the STD computer unit. But even more potential is attainable with the use of the TOMEI ECU.