Hello everyone,
First time posting on this or any other forum.
I recently purchased (my wife’s vehicle) a 2021 GMC Yukon Denali with the 6.2 V8. It was a little sluggish for a 6.2 and so I wanted to free it up a little. My daily driver is a 2019 Silverado with the 6.2. So, I have an idea how much more power it should have. Yesterday 7/25/23 I took it to a local muffler shop and had a Borla ProXS (40359) muffler welded in, the resonators and cats and everything else are still there. (NOT a full cat back exhaust). At the same time my CAI (K&N 63 series FIPK 63-3110) arrived and I installed that as well. I’ve done this to almost every truck or SUV I’ve owned. Including my current Silverado. Side note it sounds awesome and is much more responsive, unlike all the 5.3s I’ve had where I’ve hardly noticed a difference in performance…
What’s strange is after test driving it, it seems like when I come up to a red light or stop sign and let off the gas to start to slow down (from about 20-30mph) the engine goes completely quiet (as though the auto stop feature has engaged but, that’s not supposed to happen until you come to a full stop). The tachometer still shows around a 1,000 rpm. Now, it could be that it’s in v4 mode and it’s just idling so low that it sounds like it’s not running but, it sure sounds eerily quiet. I mean I can’t hear any engine noise, at all. As soon as I touch the gas I can instantly hear the exhaust note again. I can’t tell if it’s starting or if it’s just reengaging the additional 4 cylinders. Since the vehicle is moving, the wind noise and/or road noise is loud enough that I can’t tell if the engine is starting again or if it’s running the whole time. Like how you can hear it start when you let off the brake after being completely stopped. I pushed the button to disengage the Auto Stop feature and no change, the engine is still so quiet (while coasting/braking to a stop) I can’t hear if it’s running or not.
Has anyone else experienced this? Am I just imagining this? Is there some reason why the Auto Stop feature would engage while the vehicle is still in motion now that I’ve altered the exhaust and intake? Or is it actually just running so quietly that I really just can’t hear it at all (immediately after installing a much louder muffler)?
First time posting on this or any other forum.
I recently purchased (my wife’s vehicle) a 2021 GMC Yukon Denali with the 6.2 V8. It was a little sluggish for a 6.2 and so I wanted to free it up a little. My daily driver is a 2019 Silverado with the 6.2. So, I have an idea how much more power it should have. Yesterday 7/25/23 I took it to a local muffler shop and had a Borla ProXS (40359) muffler welded in, the resonators and cats and everything else are still there. (NOT a full cat back exhaust). At the same time my CAI (K&N 63 series FIPK 63-3110) arrived and I installed that as well. I’ve done this to almost every truck or SUV I’ve owned. Including my current Silverado. Side note it sounds awesome and is much more responsive, unlike all the 5.3s I’ve had where I’ve hardly noticed a difference in performance…
What’s strange is after test driving it, it seems like when I come up to a red light or stop sign and let off the gas to start to slow down (from about 20-30mph) the engine goes completely quiet (as though the auto stop feature has engaged but, that’s not supposed to happen until you come to a full stop). The tachometer still shows around a 1,000 rpm. Now, it could be that it’s in v4 mode and it’s just idling so low that it sounds like it’s not running but, it sure sounds eerily quiet. I mean I can’t hear any engine noise, at all. As soon as I touch the gas I can instantly hear the exhaust note again. I can’t tell if it’s starting or if it’s just reengaging the additional 4 cylinders. Since the vehicle is moving, the wind noise and/or road noise is loud enough that I can’t tell if the engine is starting again or if it’s running the whole time. Like how you can hear it start when you let off the brake after being completely stopped. I pushed the button to disengage the Auto Stop feature and no change, the engine is still so quiet (while coasting/braking to a stop) I can’t hear if it’s running or not.
Has anyone else experienced this? Am I just imagining this? Is there some reason why the Auto Stop feature would engage while the vehicle is still in motion now that I’ve altered the exhaust and intake? Or is it actually just running so quietly that I really just can’t hear it at all (immediately after installing a much louder muffler)?