Dual mode exhaust calibration

[Glava2876]

I’m bringing my 2025 AT4 6.2 to get the revised dual mode exhaust calibration -to get a little louder.

I do like the existing sound in sport, so I’m hoping it only gets better.

Has anyone else done this yet -and if so what do you think of it?

Edited July 1, 2025 by Glava2876

[tbarn]

Hmmmm. haven't heard of that availability. Keep us posted.

[redwngr]

This has been around for since the 2024 model year

 

 

 

 

This optional item is new for 2026 model year

 

[Glava2876]

7 hours ago, redwngr said:

 

 

This optional item is new for 2026 model year

 

This is what I’m adding

[Glava2876]

4 minutes ago, Glava2876 said:

This is what I’m adding

So I ordered it and you get a sheet with a code sent to you.

Then called the dealer. To set up the time for the reflash, which they have to coordinate with GM tech.

it cost $395.00, but I used the GM site 20% off and had some rewards points ended up costing me $300.00.

ill try to remember to do a before and after

[tbarn]

I found it. Works on model year 2025 and up.

[Bikerjon]

On 7/2/2025 at 7:21 AM, Glava2876 said:

So I ordered it and you get a sheet with a code sent to you.

Then called the dealer. To set up the time for the reflash, which they have to coordinate with GM tech.

it cost $395.00, but I used the GM site 20% off and had some rewards points ended up costing me $300.00.

ill try to remember to do a before and after

Let us know how this works out for you. I really want to get that done to my truck.

[Glava2876]

Got the install Monday.

Biggest notice is that after the start up, the exhaust stays louder. It seems to have a little more burble to it too, but no drone on the highway.

Took a before and after, but the site says they are too long?

[redwngr]

2 hours ago, Glava2876 said:

Got the install Monday.

Biggest notice is that after the start up, the exhaust stays louder. It seems to have a little more burble to it too, but no drone on the highway.

Took a before and after, but the site says they are too long?

Try posting video to youtube and posting a link to it

[newdude]

The deets on the calibration. 

 

Part No. 85822149 - ZR2/AT4X Spec Active Exhaust Calibration

• Designed specifically for your vehicle to enhance the driving experience
• Activated during Sport mode, allowing a wider range of aggressive exhaust sounds
• At startup and when in Sport Mode, the calibration allows the valve to open up to 35% more for a sporty, more aggressive exhaust note
• While cruising at 1200-1500 rpm, valve opens up to 10% more
• Quicker valve-open response under wide-open throttle
• Compatible with 2025+ models with 6.2L V8 engine
• Installation by an authorized Chevrolet/GMC Dealer is required

Edited July 10, 2025 by newdude

[Glava2876]

6 hours ago, newdude said:

The deets on the calibration. 

 

Part No. 85822149 - ZR2/AT4X Spec Active Exhaust Calibration

• Designed specifically for your vehicle to enhance the driving experience
• Activated during Sport mode, allowing a wider range of aggressive exhaust sounds
• At startup and when in Sport Mode, the calibration allows the valve to open up to 35% more for a sporty, more aggressive exhaust note
• While cruising at 1200-1500 rpm, valve opens up to 10% more
• Quicker valve-open response under wide-open throttle
• Compatible with 2025+ models with 6.2L V8 engine
• Installation by an authorized Chevrolet/GMC Dealer is required

Yes that’s the one. 

[Bikerjon]

On 7/10/2025 at 7:22 PM, Glava2876 said:

Yes that’s the one. 

This calibration is now on backorder. 

[tbarn]

How the hell does gm backorder a software update?

[Bikerjon]

On 7/12/2025 at 6:51 PM, tbarn said:

How the hell does gm backorder a software update?

I know. I don't get it but i tried to order it and their website says backordered.

[newdude]

8 hours ago, Bikerjon said:

I know. I don't get it but i tried to order it and their website says backordered.

 

 

Was it from the Chevrolet Accessories website?  If so that will pull from dealer inventory levels.  If the dealer it was ordered from has none in stock it will email you backordered if it had to be ordered.  If it was from one of those "online GM parts" sellers (GMPartsDirect for example), it likely said backordered because they don't have it in stock and have to order it. 

 

Otherwise, that "part" 85822149 calibration isn't on backorder.  Lots of stock available.