Notices
991 2012-2019
Sponsored by:
Sponsored by:

Sport exhaust backfiring and farting

Thread Tools
 
Search this Thread
 
Old 11-09-2017 | 10:25 AM
  #106  
gbree's Avatar
gbree
Racer
 
Joined: Dec 2014
Posts: 369
Likes: 31
From: Texas
Default

I cant comprehend why some people dont like the backfiring. I've considered going with AWE to make it even louder. I want it to sound like the civil war when I'm driving down the road.
Old 11-09-2017 | 11:16 AM
  #107  
Needsdecaf's Avatar
Needsdecaf
RL Community Team
Rennlist Member
 
Joined: Jan 2013
Posts: 8,947
Likes: 2,631
From: The Woodlands, TX.
Default

Originally Posted by gbree
I cant comprehend why some people dont like the backfiring. I've considered going with AWE to make it even louder. I want it to sound like the civil war when I'm driving down the road.
1. I don't want it to sound like the Civil War when I'm driving down the road 99.9% of the time. Yet I drive in Sport as soon as the car is warmed up, and I'm not in my neighborhood.

2. The big pop I get when I shift from 2nd to 3rd on anything more than a light pull sounds like the car just grenaded the engine.

3. To most people, it sounds like the car is broken. Often to me too.

4. It's contrived and fake, and that by itself just annoys me. I am not one for theater just for the sake of it.
Old 11-09-2017 | 12:33 PM
  #108  
Code's Avatar
Code
Three Wheelin'
 
Joined: Feb 2013
Posts: 1,406
Likes: 51
From: San Diego
Default

Originally Posted by gbree
I cant comprehend why some people dont like the backfiring. I've considered going with AWE to make it even louder. I want it to sound like the civil war when I'm driving down the road.
Amen to that!
Old 11-09-2017 | 12:44 PM
  #109  
Needsdecaf's Avatar
Needsdecaf
RL Community Team
Rennlist Member
 
Joined: Jan 2013
Posts: 8,947
Likes: 2,631
From: The Woodlands, TX.
Default

Forgot to mention, Matt (Money2536) Moreman's GT3 with dundon race headers and side muffler delete sounded absolutely glorious to me. Was loud and nasty with no rasp or drone.

And no pops.

That's what I want to hear. Not looking for quiet. Looking for real.
Old 11-09-2017 | 01:39 PM
  #110  
Archimedes's Avatar
Archimedes
Race Director
 
Joined: May 2015
Posts: 13,162
Likes: 3,886
Default

Originally Posted by Needsdecaf
Forgot to mention, Matt (Money2536) Moreman's GT3 with dundon race headers and side muffler delete sounded absolutely glorious to me. Was loud and nasty with no rasp or drone.

And no pops.

That's what I want to hear. Not looking for quiet. Looking for real.
Same here. The exhaust on the Spyder is a little too backfirey on the decal, though it's not as bad on my current one than it was on my first one. Love the exhaust sound on the gas, but could do without the phony backfires on decel. Often, when I'm slowing to turn past one of the local car/moto hangouts, I'll actually keep the clutch in to keep it from making all the noise.
Old 11-09-2017 | 02:14 PM
  #111  
mb1's Avatar
mb1
Rennlist Member
 
Joined: May 2006
Posts: 1,138
Likes: 233
From: chicago
Default

Originally Posted by Needsdecaf
Forgot to mention, Matt (Money2536) Moreman's GT3 with dundon race headers and side muffler delete sounded absolutely glorious to me. Was loud and nasty with no rasp or drone.

And no pops.

That's what I want to hear. Not looking for quiet. Looking for real.
I don’t think that any of the sounds that any of these cars make are “real”. I suspect that there are large groups of engineers at every manufacturer manipulating the sounds to make them most appealing to most people, but are not, in fact, any more genuine than the overrun popping in the current PSE.
Old 11-09-2017 | 02:30 PM
  #112  
Archimedes's Avatar
Archimedes
Race Director
 
Joined: May 2015
Posts: 13,162
Likes: 3,886
Default

Originally Posted by mb1
I don€™t think that any of the sounds that any of these cars make are €œreal€. I suspect that there are large groups of engineers at every manufacturer manipulating the sounds to make them most appealing to most people, but are not, in fact, any more genuine than the overrun popping in the current PSE.
There's a big difference between the natural sound the motor makes, tuned with an exhaust, and shooting fuel directly into the exhaust to create artificial explosive sounds.
Old 11-09-2017 | 03:40 PM
  #113  
Mr. Big's Avatar
Mr. Big
Instructor
 
Joined: Oct 2017
Posts: 232
Likes: 16
From: Parts Unknown
Default

Originally Posted by Archimedes
There's a big difference between the natural sound the motor makes, tuned with an exhaust, and shooting fuel directly into the exhaust to create artificial explosive sounds.
OK, let me jump in here with a bit of Auto Shop 101. It's my understanding that the burble sound comes from more oxygen being injected into the combustion chamber to burn off any residual fuel to help emissions, and not more fuel being injected. Most cars do make that bubble sound, but it's being masked by the muffler. You'll notice that kids put those big fart cannons on their cars because they like that burble. They've done nothing to the air/fuel mixture, they've simply eliminated the muffler so you can hear the car fart like a fat man eating beans. So bottom line here is that fuel is not being wasted, it's just that the exhaust valves are open when put in Sport mode allowing the burble sound to come forward.
Old 11-09-2017 | 11:28 PM
  #114  
ipse dixit's Avatar
ipse dixit
RL Community Team
Rennlist Member
 
Joined: Sep 2005
Posts: 17,330
Likes: 12,277
Default

Originally Posted by gbree
I cant comprehend why some people dont like the backfiring. I've considered going with AWE to make it even louder. I want it to sound like the civil war when I'm driving down the road.
Because it's not natural.

Burbles, pops, backfire gurgles are engineered by throwing excess gasoline into the chamber.

Listen to a Porsche engine not tuned to play to the Pavlovian lemming-like masses, such as the powerplant in a 991 GT3 or RS, and you'll understand the difference.

It's like staring at the cleavage of a beautiful woman wearing Triple D cups, except she has breast implants.

Personally, I'd rather just admire natural beauty with natural, harmonious proportions.

Yes, I know. I'm weird that way.

Carry on.
Old 11-09-2017 | 11:34 PM
  #115  
Needsdecaf's Avatar
Needsdecaf
RL Community Team
Rennlist Member
 
Joined: Jan 2013
Posts: 8,947
Likes: 2,631
From: The Woodlands, TX.
Default

Originally Posted by Mr. Big
OK, let me jump in here with a bit of Auto Shop 101. It's my understanding that the burble sound comes from more oxygen being injected into the combustion chamber to burn off any residual fuel to help emissions, and not more fuel being injected. Most cars do make that bubble sound, but it's being masked by the muffler. You'll notice that kids put those big fart cannons on their cars because they like that burble. They've done nothing to the air/fuel mixture, they've simply eliminated the muffler so you can hear the car fart like a fat man eating beans. So bottom line here is that fuel is not being wasted, it's just that the exhaust valves are open when put in Sport mode allowing the burble sound to come forward.
You are incorrect.

There is the burble of the engine on the overrun, and then there is what we have which definitely is fuel injected to create artificial pops. This has been confirmed by Porsche.
Old 11-09-2017 | 11:35 PM
  #116  
Needsdecaf's Avatar
Needsdecaf
RL Community Team
Rennlist Member
 
Joined: Jan 2013
Posts: 8,947
Likes: 2,631
From: The Woodlands, TX.
Default

Originally Posted by ipse dixit
Because it's not natural.

Burbles, pops, backfire gurgles are engineered by throwing excess gasoline into the chamber.

Listen to a Porsche engine not tuned to play to the Pavlovian lemming-like masses, such as the powerplant in a 991 GT3 or RS, and you'll understand the difference.

It's like staring at the cleavage of a beautiful woman wearing Triple D cups, except she has breast implants.

Personally, I'd rather just admire natural beauty with natural, harmonious proportions.

Yes, I know. I'm weird that way.

Carry on.
Lol, love the analogy.
Old 11-09-2017 | 11:56 PM
  #117  
Dennis C's Avatar
Dennis C
Rocky Mountain High
Rennlist Member
 
Joined: Aug 2007
Posts: 17,710
Likes: 1,602
From: Colorado
Default

Perhaps I dont understand it correctly, but i thought that real overrun chatter like you hear from race cars was caused by advancing the timing to allow for better performance at higher RPMs, as seen on the race track. The advanced timing results in a very small amount of unburnt fuel being ejected into the exhaust system, resulting in overrun noises. These noises are certainly heard in race cars, including at the very top level in Formula 1 cars.
Old 11-10-2017 | 12:41 AM
  #118  
ipse dixit's Avatar
ipse dixit
RL Community Team
Rennlist Member
 
Joined: Sep 2005
Posts: 17,330
Likes: 12,277
Default

Originally Posted by Dennis C
Perhaps I dont understand it correctly, but i thought that real overrun chatter like you hear from race cars was caused by advancing the timing to allow for better performance at higher RPMs, as seen on the race track. The advanced timing results in a very small amount of unburnt fuel being ejected into the exhaust system, resulting in overrun noises. These noises are certainly heard in race cars, including at the very top level in Formula 1 cars.
Nope. You are absolutely correct.

Overrun chatter is a natural consequence of engine operation. At the top end of the RPM range (as you correctly note).

What's not natural is overrun at low-end RPM, or when you lift-off just tooling around town.
Old 11-10-2017 | 07:13 AM
  #119  
See U n RearView's Avatar
See U n RearView
Instructor
 
Joined: Oct 2014
Posts: 165
Likes: 12
From: Bay Area, CA
Default

Originally Posted by Needsdecaf
Only on .2's. .1's have it on both.
Yes that is my experience as well in testing due to this thread...lol

On my 2015 991.1 GTS CAb, I have the crackles and pops on both the Sports mode and the Sports + mode's.

I have not tested whether or not either mode has more or less or the same crackles and pops.

It is really nice having the option to tailor our sound with the PSE...
Old 11-10-2017 | 11:05 AM
  #120  
Dennis C's Avatar
Dennis C
Rocky Mountain High
Rennlist Member
 
Joined: Aug 2007
Posts: 17,710
Likes: 1,602
From: Colorado
Default

Speaking from the perspective of a TT owner, I find the pops and burbles to be very controllable. The TT engine muffles the effect considerably, but it’s still there. I’m running an aftermarket muffler on my car, and it makes things much louder. If I’m pushing the car in sport mode, it sometimes makes pops that sound like shotgun blasts. Sometimes, that’s fun. If I’m driving with my wife with the top down, I can put the car in normal mode and put the PDK system in auto mode, and the car is hardly louder than it was with a stock muffler, and there are no pops or gurgles. It really is a Jekyl and Hyde personality for the car, and I love that.



Quick Reply: Sport exhaust backfiring and farting



All times are GMT -3. The time now is 07:50 AM.