Looking for an exhaust that can deliver unrestricted performance, yet being able to behave mannered when required to? GMS 3'' Dual center out valved rear silencer is the way to go. Starting car on a cold morning in a quiet neighborhood, passing authority controls or passing noise limitations on the track is not an issue anymore. Drone in the interior is gone and conversation at normal levels on a long joy ride is now actually possible.
Pair this puppy to full 3" decat and you get a wolf in a sheep's clothing. On idle, with valve closed, it's pretty much impossible to tell whether it's stock or not. Keep the valve closed and you can make it to the track and back without headache even with decat, while the 200 cell cat is perfectly suitable for daily use, without major performance impact. More subtle than OEM race, yet significantly less restrictive. Open valves and send it and it sounds mean. With the revised GMS Stage I ECU tune with raised and hard cut rpm limiter along with GMS carbon CAI, it's another world compared to OEM. Probably one of the best sounding 4-pot bangers out there. I think this is where we can pull the line on the exhaust system. I believe we got what we needed.
With valve closed, the exhaust flow is routed through baffled chamber to greatly reduce sound levels and interior drone. With closed valve, on wide open throttle (WOT), you can hear the turbo compressed air rushing through the exhaust pipes, but engine sound is greatly reduced compared to an open valved situation.
With valve opened, there are no restrictions in the exhaust path to achieve minimum backpressure and deliver maximum engine performance. Engine sound becomes much more notable, from the very moment the engine is started. On cold start and idle, this exhaust system with opened valve delivers the signature 1.75 TBi deep growl tone. With revs increasing the sound becomes more and more aggressive, with dB peaking out at around 102 dB when pops and bangs or hard cut limiter take action.
dB levels comparison closed / opened (w/ 3" GMS Dowpipe + 3" GMS 200 cell cat + 3" GMS midpipe). Measurements taken with dB meter at height of the exhaust tips, 45°, 500mm distance.
- Cold start - static - 90 dB / 102 dB
- Idle - static - 82 dB / 90dB
- Steady throttle @ 2000rpm - static - 85 dB / 92 dB
- Steady throttle @ 3000rpm - static - 91 dB / 102 dB
- Max est. noise - static - 105 dB / 115 dB (7200 rpm, hard cut)
- Idle 59 dB / 67 dB
- Steady throttle @ 2000rpm - static - 65 dB / 72 dB
- Steady throttle @ 3000rpm - static - 69 dB / 77 dB
Lightweight (6.490g) vs. stock (7.820g + 500g bracket) vs. stock race (4.200g + 500g bracket), TIG hand welded and back purged T304 stainless steel. GMS unique, pie cut design, for one of a kind look, unmatched flow and significant weight reduction.
This is silenced, resonated and valved version of the exhaust suggested for street, track or race use with dB limitations. For louder, unrestricted, superlight and the meanest version, you can choose dB unlimited GMS 3" Dual center out non resonated exhaust.
ALFA ROMEO - 4C - 3'' Dual center out valved rear silencer
- Lightweight (6.490g) vs. stock (7.820g + 500g bracket) vs. stock race (4.200g + 500g bracket)
- Plug and play
- 3'' / 76mm diameter
- Unrestricted performance w/ open valve (76dB idle, 102 dB max)
- Mannered sound levels w/ closed valve (69dB idle, 92dB max)
- Remotely controled valve system
- Significantly decreased drone levels
- Smart and minimalistic mount with rubber damping to prevent exhaust vibrations and cracking
- Backpurged TIG welded
- Quick release V-band clamps for easy installation
- T304 Stainless steel
- Laser engraved GMS logo
- Requires GMS 3'' Midpipe