cenzo86

Chevy calls it a Dual Mode Exhaust.

threefirs

There is also a difference in the software - PE cars have a difference in their ECU. That's why you can't slap an aftermarket exhaust on and get the same quality of burbles and overrun as a PE car.

ASH_C43

There's no proof that the ECU of the C43 cars with PE are tuned differently than the ones without. Yes, there's a setting/flag in the ECU that say whether PE is installed on the car, however, nobody knows whether it indicates that ECU parameters are different or it's only there for interoperability with the HU/COMAND.

I've asked both the performance shops and the dealerships and they don't know the answer. In fact, most people think the tunes are the same.

C63, on the other hand, may have a different story as it has an extra valve in the mid-section of the exhaust that is controlled by the engine rpm/etc.

threefirs

Why don't you just ask a tuning company? They are different, ECU data can easily be compared. There are no performance gains as far as anyone knows, but the burbling and overrun is definitely controlled by the ECU - which means yes, the ECU has a different configuration on PE cars.

ASH_C43

I do agree with you that 'performance' wise there's not much gain if any at all. However, Performance Exhaust (U78) is a different configuration than the Sport Exhaust (U21). PE has a dual-pipe setup from the mid-section to the mufflers. This creates a difference in the tone of the exhaust. Not saying if it's better or worse. I'm just saying it's a bit different. And of course, the additional valves in the mufflers, can make its sound louder and audible.

threefirs

The burble and overflow is definitely ECU. It's pulling back on timing and dumping fuel into the exhaust. Doesn't just happen with a change of exhaust.

ASH_C43

I have asked as I mentioned. And they said they don't know if it has affected any of the parameters. They only see the option there (they can't change it either).

Burble/overrun might be ECU driven but the ECU tune is not different between the two cars because of the exhaust, IMHO.
A car without PE makes a lot of it too when in Sport+. In a car with PE, it's definitely more noticeable because of the valves and perhaps more importantly the fact that PE is a dual-pipe configuration and has a different mid-section/resonator altogether.

threefirs

What does "ECU driven" mean? lol. It's in the ECU tune - the tune impacts all parameters, including the timing and fuel which is what causes the burble!!!

I don't know who you spoke to but you should probably not allow that person to touch your ECU, lol.

sean1.8t

Yes and no. There is a software difference but it's not mutually exclusive to the PE. It's either the same thing, or at least similar, as to what I get in my 450. In E, C, and S modes, I only get a tiny bit of 'pop-pops'. But when it's in S+, it's a completely different story. Like said in another post, those noise charactaristics are created at the motor, so the more free-flowing the exhaust, the louder those pops will be. Since I removed my cats, they became crazy intense. Pedestrians close by duck and cover haha

ecmexchange

Now that is a good one. May I put it in my repertoire?

susman@eurogermantown.com

night package is good, but the mirrors and trim will be black anyways.. just the rear diffuser and exhust tips and the front lip is black. I like ordering black cars without the night package and I order the rest with it (not always on the brilliant blue).

synergize

Absolutely.