[vtirocz]

Originally Posted by TRZ06

I will be the opposite.

The LS/LT motors sounds great when timing isn't pulled, but here in CA, we only get 91 octane and unless you are mixing with 100 race fuel, the conservative timing parameters makes the exhaust sound like shit sometimes. These cars are tuned for 93 octane from the factory.

You can hear when it does it too. The exhaust note takes on a muffled sound and doesn't sound as clean and sharp. It is even more apparent when you have an exhaust system on like I do.

I had the same issues with my C5 and C6 Z06's as well. It really does suck.

I am not a fan of GM's conservative timing mapping.

The GT4 on the other hand, sounds amazing, especially past 4K even with the stock system. No, it is not as loud, but I love the tonality much more and it is consistent.

The GT4 is almost certainly tuned/optimized for 93 octane and will adjust spark timing for lower octane levels. Can’t say you will “hear” this happening, but likely some level of reduced performance vs 93 octane.