Exhaust June 12, 2007
As soon as I got home with the new Apexi GT Spec exhaust installed, I plugged it with the Apexi Active Tail Silencer:
The ATS was developed as a high performance evolution to the standard tail pipe silencers available in the market today. While many people enjoy the power gains of a racing exhaust on the track, often times these systems require a silencer to be installed in the tip for use on the street. While sound output can be dramatically lowered using a non-adjustable silencer, unfortunately response and power tend to suffer due to increased exhaust gas restriction. The ATS (Active Tail Silencer) uses the same active valve technology as the PS Revolution exhaust system. The spring loaded valve is engaged and disengaged based upon exhaust gas pressure. This allows for effective sound suppression for the street, without the power loss under high load. Dyno tests have proven power levels to be nearly identical to an exhaust using no silencer at all.
I’d tried a traditional silencer with my old Helix exhaust and the car drove like it’s balls had been cut off. With the ATS I’ve noticed no difference in performance, with the caveat that I haven’t gone anywhere near full-throttle yet. The exhaust is pretty quiet at idle and at speed on the highway.
But there’s a downside: it muffles out the “boxer rumble” that Subaru engines are so well-known for. At first I wasn’t sure if the ATS was the offending part, I’ve got aftermarket headers as well, but this afternoon I removed the ATS (no easy task, ended up using my tow straps!) and the rumble was back.
Not sure what to do. I like the loud, but quiet is nice sometimes. Installing and removing the ATS is a bit of a pain so it’s not practical to use only when I want peace and quiet. Apexi has another product, an Exhaust Control Valve, that is cockpit-adjustable but I’ve found very few user reports on it.
Another option would be to go with a quiet cat-back and a QTP downpipe with electronic cut-out.
- Posted in : Uncategorized
- Author :tby
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