I am trying to understand a condition/symptom that my new GT3 exhibits, and I've received several opinions as to what engaging the SPORT mode button does. The owners manual says "when the Sport mode is switched on, the exhaust gas back pressure in the lower and middle ranges is reduced in the variable exhaust sytem. This serves to produce a marked increase in torque in the engine speed range from approx. 3000 rpm and 4000 rpm. The best values for vehicle acceleration and low-end torque are achieved when the Sport mode is switched on." The manual makes NO mention of the Sport mode in the GT3 making changes to the throttle response, ECU changes, etc. as I believe (and could absolutely feel immediately) was the case in my 997 Turbos. In the GT3 - which is consistent with what the manual states - I believe the only change that occurs is with the two exhaust diaphragms that are activated by vacuum..which deepens the exhaust tone when the Sport mode is activated at idle and other position changes as it states in the 3000 - 4000 RPM ranges. Here is what I call Condition 1 (which I like and it seems normal): If I activate the Sport mode button immediately upon starting the car (but BEFORE it is driven), a noticeable change in the idle exhaust tone deepens, and when I accelerate moderately to aggressively between gears or staying in a gear at the 3000 - 4000 range the exhaust 'howls' in response to what I suspect are further changes within the exhaust diaphragms...the sound is intoxicating. Condition 2: If I wait to engage the Sport mode button until the car is driven - whether that is 100 yards or 10 miles or more, the exhaust does deepen in tone and sounds the same at idle as condition 1, but it will NOT produce the evident change/howl in the 3000 - 4000 range....but rather stays a constant deep tone, but nothing like the very noticeable on/off howl...clearly something is not changing like it does in Condition 1. I spoke with the tech today who did my PDI and I have no confidence he fully understands my concerns or symptoms (he is three hours from me, so a drive by will have to come later). Alex at SHARKSWERS spoke with his tech, but was told the Sport mode changes throttle response, ECU mapping, etc. which I do not believe is the case in the GT3 (again, NO evidence such is happening and if true, I would suspect the owners manual would mention more than changes to the variable exhaust. Sorry to go on and on...this is driving me crazy. Knowledgeable replies would be most appreciated.

 

I have noted the same thing as you in my 2010. I do not notice any change in subjective apparent torque response, but the audio signature is exactly as you describe. Sometimes the howl is more evident at 3-4k rpms.

I have read everywhere, including PCNA manual, etc., that the car only opens exhaust baffles. I have never seen mention of ECU / throttle remapping in sport mode. I had a 997.1TT and this did occur as you note. Both the ECU and TCU remapped.

See what you get at 6-8k in both modes. It is noted somewhere, if I recall correctly, that the diaphragms open under aggressive driving even if sport mode is off. I often feel the car sounds the same in or out of sport mode in higher rpms.

What do you think?

My final analysis is this is the most incredible handling, sounding, and ergonomic 911 ever made. I hear the notes of the 3.2L Carrera air-cooled whine from 0-3,500 rpms, after that it is drowned by a modern symphony of howling glee that sounds like a 997.2 Cup Car being swallowed by Godzilla.

My poor neighbors.

 

Neuroguro - thank you for your thoughts and experience. Allow me to re-emphasize/clarify again what I am experiencing. In both examples I offered, the car is driven exactly the same with the SPORT mode on, but depending on when I turn it on - meaning either immediately after I start the car and before it is driven, or whether I wait to turn it on after it has been driven even the shortest distance, I get two difference results...i.e. my car will NOT produce that 3000 - 4000 howl if I wait to turn on SPORT mode after the car has been driven. It will only produce that sound at the 3000 - 4000 range if I turn on the SPORT mode immediately after starting the car and before it is driven. That makes NO sense to me, i.e. if the SPORT mode is on - regardless of when it is activated - I would expect to hear that wonderful howl at the 3000 - 4000 range. I'd so appreciate it if you could test your car in those two scenarios. As to 6000 - 8000 RPMS, I admit and make no apologies for breaking in the car the way Porsche engineers recommend, i.e. nothing above 4200 RPM for 2000 miles...with just 600 miles on the car, it will be a while before I experience the upper limits - but I can't wait!.

 

Interesting.......I'll give it a try as well.

 

What happens when you drive it without Sport Mode activated?

 

Without the SPORT mode activated, there is no 'howl' at the 3000 - 4000 range, and since that's been my RPM limit during break-in, I don't know what it would do beyond that. As the owners manual says, the SPORT mode engages the variable exhaust - hence howl - and I would not expect it to do that in the non-Sport mode. One last tidbit....if I am in the Sport mode (engaging it immediately after starting which will produce the 'howl' when aggressively accelerating between 3000 - 4000 once underway), it will NOT produce the howl if the rpms are brought up slowly between that range...apparently no vacuum 'signal' to activate the diaphragms is created with slow build of the RPMs in that range. I'm OK with that...just thought I'd provide that further detail in this already confusing story!

 

Here are some notes that I saved back from 2007. I believe it was posted here on 6Speed.

Sport off: idle - 4K RPM, the exhaust flows through all three mufflers. Above 4K RPM, the exhaust bypasses the two side mufflers and flows through the rear muffler only.

Sport on: at idle, the exhaust flows through rear muffler only. Above idle - 3K RPM, the exhaust flows through all three mufflers. Using light throttle from 3K - 4K RPM, the exhaust will continue to flow through all three mufflers. Apply moderate - heavy throttle above 3K RPM and the exhaust flows through the rear muffler only. Above 4K RPM, the exhaust flows through the rear muffler only.

Sport off/Sport on/Plug pulled: same sound over 4K RPM.

Sport off/Sport on: same sound 'just above idle' - 3K RPM.

Plug pulled: valves are open from idle - redline. The exhaust flows through rear muffler only. It is louder than either Sport-off/Sport-on in the 'above idle' - 3K RPM range. It's a purer sound.. no valves opening or closing, so no sudden changes in volume/tone. There is resonance/drone from 2K - 3K RPM, however.

 

Chardonet - very helpful accounting of what happens when with the 'variable' exhaust system. The events you describe (from your 07 model year) swould appear the same design/process as the new GT3 like mine. What remains elusive in all of this - and the real object of my initial post - is to understand why what you describe (and what I experience if I immediately engage the SPORT mode upon starting the car - will NOT happen if I wait to engage the SPORT mode after I have begun driving the car. Still no answers on this, and I am anxious with someone with a 2010 or 2011 GT3 to try my SPORT on before driving, and then SPORT on while driving to see if they too find that in the later example the wonderful 'howl' is obtainable.

 

tssci,

I have a 2011 GT3 and have done exactly what you describe on a few occasions, the "howl" as you mentioned, is there whenever I have the sport button turned on and it doesn't matter if I turn it on at start up or if I turn it on some time later while driving.

Since I love the howl it's mostly on as I leave the garage, my Spyder has the EOM sport exhaust so I'm in the habit of turning the sport button on in both cars upon start up.

I did Laguna Seca this summer with the exhaust valve bypassed to meet sound check, it's not the same car without that growl.

 

Quote:

Plug pulled: valves are open from idle - redline. The exhaust flows through rear muffler only. It is louder than either Sport-off/Sport-on in the 'above idle' - 3K RPM range. It's a purer sound.. no valves opening or closing, so no sudden changes in volume/tone. There is resonance/drone from 2K - 3K RPM, however.

Only way to go, the rest sounds crappy or artificial. I hear no drone?!
I did this both on my MKI and MKII at the dealership. Zip tied and duct taped.

 

in my 08 GT3, the suspension setting is changed with sport mode on, its harder than normal mode, but softer than with PASM activated.

about the howl, it does not matter if you turn it on before or after driving the car.

 

So would we all agree that SPORT on immediately puts a $hit eatin grin on your face?

(Now you have me wondering. I remember in the C2S, not so much when you activated SPORT but, when turned off, you could immediately feel the remap take place....... instant decrease in power)

 

I didn't know that the Sport button changes the sound of the exhaust (since I always drive it above 4000 rpm as soon as the engine is warmed up). I always thought the main function of the Sport button in the newer GT3's is to select the shock damping of the PASM for driving on track or on roads. The Sport button in turbos and 997s serve a different function in cars with the optional Sports Chrono package whereby you get performance gains in torque/HP mapping etc. in addition to firming up the shocks, etc.

 

Suspension changes (aside from PASM) have their own button (icon of a shock absorber) on the GT3 (at least my 2011). The SPORT button is - as the owners manual says (and only says) to activate the 'variable' exhaust feature.

 

I spoke to one of my friend/co workers at my Porsche store who also spoke to a tech and it should work the same regardless of when you turn on sport mode. The button only changes the variable exhaust and does NOT change any suspension settings. I would have a tech go for a drive with you while you drive to show him your concern. When moving for some reason it may not be turning the valve for the variable exhaust. I would have it looked at and until then remember to turn it on everytime you get in the car before you begin moving. Hope this helps.