GMPP Stage 1 - Turbo more audible?
03-11-2013, 04:08 PM
#11
Senior Member
Join Date: 07-05-2008
Location: Akron Ohio
Posts: 5,464
First off lets make this clear the Turbo upgrade does not make it louder!
Two issues are in play here. This engine and set up is similar to what GM is going to use in most of their cars in the future. The average buyers does not get a hard on if he hears the noise. For the most part owners of the Malibu and ATS Cadillac are not after noise or additional noise.
The second issue at hand is drive by noise levels that the government mandates on most cars. That is why most stock turbo systems are pretty quiet and why we do not get cold air intakes from the factory. This is also why the Camaro and Vette have a two stage muffler with a by pass. It gets them past the noise regs.
Note even many tires will make the cars fail a drive by noise test.
The one thing you will get is the pop off valve may pop more since you will be playing with more boost and it spools up faster. I also notice the noise is louder outside than inside too on the pop off valve.
But all things as they were noise does not make me faster so I could really care less about making a lot of noise. But that is just me. Now if it were a built V8 with a good cam I could enjoy some noise but with the small engines the more quiet the better for me.
Two issues are in play here. This engine and set up is similar to what GM is going to use in most of their cars in the future. The average buyers does not get a hard on if he hears the noise. For the most part owners of the Malibu and ATS Cadillac are not after noise or additional noise.
The second issue at hand is drive by noise levels that the government mandates on most cars. That is why most stock turbo systems are pretty quiet and why we do not get cold air intakes from the factory. This is also why the Camaro and Vette have a two stage muffler with a by pass. It gets them past the noise regs.
Note even many tires will make the cars fail a drive by noise test.
The one thing you will get is the pop off valve may pop more since you will be playing with more boost and it spools up faster. I also notice the noise is louder outside than inside too on the pop off valve.
But all things as they were noise does not make me faster so I could really care less about making a lot of noise. But that is just me. Now if it were a built V8 with a good cam I could enjoy some noise but with the small engines the more quiet the better for me.
03-12-2013, 04:10 PM
#15
Senior Member
Join Date: 07-05-2008
Location: Akron Ohio
Posts: 5,464
I had a buddy with a 69 GP with a 428. It had a real whine to it and many though he had some kind of under hood supercharger on it since it was fast.
Truth was it has a bad pump on the tranny and sounded like supercharger.
I have owned loud cars at times and some sound fine but I refuse to open the exhaust up on the SS as it just does not sound good.
It is difficult to make many smaller engines sound good. The one exception is my Fiero V6. The 60 degree engine in it and the exhaust Pontiac used has a very 308 Ferrari sound to it. I get many people who have a hard time believing that my exhaust is not only stock but is also 28 years old on that car. Stainless is our friend.
We sell at work a lot of timing gears with noise when you can get the quiet ones that work just as well. I never understood that. Many have issues on new cars where the gears will set off knock sensors and kill their performance.
Truth was it has a bad pump on the tranny and sounded like supercharger.
I have owned loud cars at times and some sound fine but I refuse to open the exhaust up on the SS as it just does not sound good.
It is difficult to make many smaller engines sound good. The one exception is my Fiero V6. The 60 degree engine in it and the exhaust Pontiac used has a very 308 Ferrari sound to it. I get many people who have a hard time believing that my exhaust is not only stock but is also 28 years old on that car. Stainless is our friend.
We sell at work a lot of timing gears with noise when you can get the quiet ones that work just as well. I never understood that. Many have issues on new cars where the gears will set off knock sensors and kill their performance.
03-13-2013, 03:03 AM
#17
Senior Member
Join Date: 11-08-2009
Location: Los Angeles, Dallas, New York
Posts: 220
Not amazingly great but deep and throaty at idle, if you run higher rpm on the road (like in 3rd) it sounds not real loud but audible. In 4th it's quiet.
The front of the car (especially at warm up sounds like a tractor).
My Regal GS with a more modern version of our SS motors sounds better at the front end, but is too quiet in the back. So quiet that if you shift in manual matic mode you have to watch the tach as you can't really hear the motor for the inside of the car.
The drive by noise thing you mentioned I don't understand as I've heard new Masteratis that are loud at any speed passing.
Now if I could get any noise from the HHR it would the the sound from a Lotus Elise at full song.
Been passed by two that were fly on the 10 fwy. and they screamed, literally screamed as they sounded like an F-1 car, but coming from a 4 cyl.
Also my EVO with a stock muffler at idle and full tilt makes a nice mechanical and semi-bold noise.
I'll record my SS's sound if I get time because it sounds pretty good (from the rear).
03-13-2013, 03:32 AM
#18
Senior Member
Join Date: 08-07-2011
Location: Montebello, CA
Posts: 553
On a similar note I decided to test out the whole air lid off thing again, ive done it before but not now that I have a K&N intake. after driving it today i can say for sure the K&N sounds better and louder the stock intake with the lid off, and alot more audible turbo noise. So maybe not the GMTU but the K&N full intake especially with the lid off makes the turbo more audible
03-13-2013, 05:45 AM
#19
Senior Member
Join Date: 07-05-2008
Location: Akron Ohio
Posts: 5,464
KNN system remove most of the sound baffling and it sounds like an old carburetor.
The MFG's have to put that noise in as one many buyers would complain but also they would not pass the Government regs. This is why they will dealer install a cold air package but not factory install.
This is what killed the functional Trans Am Shaker scoops in the 70's.
The MFG's have to put that noise in as one many buyers would complain but also they would not pass the Government regs. This is why they will dealer install a cold air package but not factory install.
This is what killed the functional Trans Am Shaker scoops in the 70's.
03-13-2013, 05:51 AM
#20
Senior Member
Join Date: 07-05-2008
Location: Akron Ohio
Posts: 5,464
I had two small custom magnaflows put on my HHR SS and it sounds good.
Not amazingly great but deep and throaty at idle, if you run higher rpm on the road (like in 3rd) it sounds not real loud but audible. In 4th it's quiet.
The front of the car (especially at warm up sounds like a tractor).
My Regal GS with a more modern version of our SS motors sounds better at the front end, but is too quiet in the back. So quiet that if you shift in manual matic mode you have to watch the tach as you can't really hear the motor for the inside of the car.
The drive by noise thing you mentioned I don't understand as I've heard new Masteratis that are loud at any speed passing.
Now if I could get any noise from the HHR it would the the sound from a Lotus Elise at full song.
Been passed by two that were fly on the 10 fwy. and they screamed, literally screamed as they sounded like an F-1 car, but coming from a 4 cyl.
Also my EVO with a stock muffler at idle and full tilt makes a nice mechanical and semi-bold noise.
I'll record my SS's sound if I get time because it sounds pretty good (from the rear).
Not amazingly great but deep and throaty at idle, if you run higher rpm on the road (like in 3rd) it sounds not real loud but audible. In 4th it's quiet.
The front of the car (especially at warm up sounds like a tractor).
My Regal GS with a more modern version of our SS motors sounds better at the front end, but is too quiet in the back. So quiet that if you shift in manual matic mode you have to watch the tach as you can't really hear the motor for the inside of the car.
The drive by noise thing you mentioned I don't understand as I've heard new Masteratis that are loud at any speed passing.
Now if I could get any noise from the HHR it would the the sound from a Lotus Elise at full song.
Been passed by two that were fly on the 10 fwy. and they screamed, literally screamed as they sounded like an F-1 car, but coming from a 4 cyl.
Also my EVO with a stock muffler at idle and full tilt makes a nice mechanical and semi-bold noise.
I'll record my SS's sound if I get time because it sounds pretty good (from the rear).
Too often I see people mess up though and add too much noise. Also with some engines like the 90 degree V6 engine the firing order makes it difficult to improve some sound with these engines. A lot of it has to do with the timing on the cranks. Most 60 Degree V6 do not have this issue.
Some 4 cylinder cars here sound like Motorcycles at high rpm which is fine if you like that noise but it is just not my cup of tea.