routier1642
Member
- Joined
- Feb 19, 2014
- Messages
- 320
- Reaction score
- 3
- Points
- 18
- Age
- 64
- Location
- Australia
- Members Ride
- 2005 Adventra LX6
Just sharing an experience....
I fitted a Growler CAI, and the Mace Engineering 12mm Intake Manifold Insulator, and trying to get just a little more efficiency, I replaced the stock Alloytec 190 intake tube, which has 2 resonator tubes, with one from an Alloytec 175, which lacks them ($20 from the wreckers - cheapest mod I've done yet).
Although the car now has more grunt down low, and performance has improved across the board, I didn't like the induction noise I was getting.
The Alloytec can produce some harsh notes, and with the noise reduction gear gone, even the normal engine noise grated on the ears a bit.
Some hoony sound is OK, but this was (1) too loud and too often, and (2) really crackly, tinny, and unpleasant and not classy at all.
We tend to think of intake systems as being one-way, but sound comes back through the intake system when the valves close - it's a reverse pressure wave that happens many time per second. These sound waves bounce around the airbox, making noise, and also exit through wherever the air comes in. Seeing as the Growler is faced on 3 sides with the natural metal wall of the engine bay, I could see this making the sound even tinnier.
Today, I solved that by lining most of the inside of the Growler box and the bottom and side walls of the engine bay where the box attaches, with Acoustic Foam from Clark Rubber. This is the stuff with the bumps all over it, specifically designed for noise absorption.
I cut pieces to size, and attached them with very strong double-sided tape (so strong you don't want to make a mistake). I was careful not to cover the places where the air enters the box, and to leave a clear path to the large conical filter. I also made sure that the areas that the sound waves would hit directly when coming back through the filter were all insulated.
I thought this might soften the harsher, higher frequency notes in particular. I had no illusions about getting a nice V8 rumble - this is a V6 Alloytec after all - but I thought it might be an improvement.
Well, it seems to have worked. I drove around under various conditions today, and the harsh sounds I was getting when doing normal driving have gone, and though the dramatic induction sound when you put the foot down is still there, it now lacks the higher frequencies that made it sound tinny and harsh, and sounds much better. Performance, as measured by instruments and feel, doesn't seem to have been affected.
It's no V8 sound, but I'm pretty happy with the result.
I fitted a Growler CAI, and the Mace Engineering 12mm Intake Manifold Insulator, and trying to get just a little more efficiency, I replaced the stock Alloytec 190 intake tube, which has 2 resonator tubes, with one from an Alloytec 175, which lacks them ($20 from the wreckers - cheapest mod I've done yet).
Although the car now has more grunt down low, and performance has improved across the board, I didn't like the induction noise I was getting.
The Alloytec can produce some harsh notes, and with the noise reduction gear gone, even the normal engine noise grated on the ears a bit.
Some hoony sound is OK, but this was (1) too loud and too often, and (2) really crackly, tinny, and unpleasant and not classy at all.
We tend to think of intake systems as being one-way, but sound comes back through the intake system when the valves close - it's a reverse pressure wave that happens many time per second. These sound waves bounce around the airbox, making noise, and also exit through wherever the air comes in. Seeing as the Growler is faced on 3 sides with the natural metal wall of the engine bay, I could see this making the sound even tinnier.
Today, I solved that by lining most of the inside of the Growler box and the bottom and side walls of the engine bay where the box attaches, with Acoustic Foam from Clark Rubber. This is the stuff with the bumps all over it, specifically designed for noise absorption.
I cut pieces to size, and attached them with very strong double-sided tape (so strong you don't want to make a mistake). I was careful not to cover the places where the air enters the box, and to leave a clear path to the large conical filter. I also made sure that the areas that the sound waves would hit directly when coming back through the filter were all insulated.
I thought this might soften the harsher, higher frequency notes in particular. I had no illusions about getting a nice V8 rumble - this is a V6 Alloytec after all - but I thought it might be an improvement.
Well, it seems to have worked. I drove around under various conditions today, and the harsh sounds I was getting when doing normal driving have gone, and though the dramatic induction sound when you put the foot down is still there, it now lacks the higher frequencies that made it sound tinny and harsh, and sounds much better. Performance, as measured by instruments and feel, doesn't seem to have been affected.
It's no V8 sound, but I'm pretty happy with the result.
