DIY Exhaust Mod – Gain of 10+ HP!!!

[chipmunk]

Last stage of the test complete. I had 15mm holes and it sounded OK - quite raspy though. I increased the size to 20mm and then to 25mm. Big difference. At 15mm you could hear it at idle and a little over that. At 25mm you hear all the time. Much deeper sound and louder.

I have updated my video (apologies for the sound of rain in the background in the last 2 tests) but I think the camera toned the sound down so if you listen to all 5 x recordings they sound the same loudness. In fact, the last one is at least twice as loud as the first.

Porsche Boxster 986 Crios Mod 2 - YouTube

[jdlmodelt]

Originally Posted by chipmunk

Last stage of the test complete. I had 15mm holes and it sounded OK - quite raspy though. I increased the size to 20mm and then to 25mm. Big difference. At 15mm you could hear it at idle and a little over that. At 25mm you hear all the time. Much deeper sound and louder.

I have updated my video (apologies for the sound of rain in the background in the last 2 tests) but I think the camera toned the sound down so if you listen to all 5 x recordings they sound the same loudness. In fact, the last one is at least twice as loud as the first.

Porsche Boxster 986 Crios Mod 2 - YouTube

Excellent comparisons. I liked the throaty sound at 25mm. However, from some of your newer posts, you indicate 25mm is too much volume.

[chipmunk]

Originally Posted by jdlmodelt

Excellent comparisons. I liked the throaty sound at 25mm. However, from some of your newer posts, you indicate 25mm is too much volume.

No, the volume is fine - not loud, more like a background purr that you can hear through the rev range. When you open it up it's almost a little disappointing as you don't get the corresponding increase in exhaust note - primary because the higher the engine speed, the more exhaust gas passes along the original route, rather than out the drilled holes.

My only concern was the introduction of a little drone at 2800rpm - nothing like aftermarket exhaust however something to consider. On the flip side, the exhaust sounds like you would expect a sports car to sound.

I will put together a "driving video" when the weather warms up a little. It's a bit too cold at the moment to put the roof down!