My friend who was behind my car when I turned it on noticed a popping sound from the exhaust similar to those cars with modified exhaust system. Even when I rev the car, a bit of popping is heard from the exhaust.
P.S: My car is all stock.

 

Dude it's normal. That is what we call "backfire", which is caused by unburnt fuel. This is normal for our GCC Spec cars which run rich A/F ratios below 9.

Alot of US members may tell you its not normal, but their cars are not detuned like ours, and I'm pretty sure their A/F ratios are within normal parameters ( between 11 and 13 )

Backfires are very normal when cold as well. I get backfires when shifting, especially when cold.

 

Afa, was hoping for something new from the dealership

 

what kind of power would our cars make with a normal af ratio

 

The GS460 is advertised by Lexus as having 342hp at the crank. While our cars here in the Gulf are advertised to have 322hp at the crank.

I dynoed my car and got 255whp with an AF ratio of 9. I would love to see a US based member dyno a GS460 so we can compare not only the output, but also the AF ratio.

As per my results, I refuse to believe that a 67hp drive train loss is normal. It must be due to the rich AF ratio.

 

I don't think 20% drivetrain loss for an auto is out of line. I've seen numbers as high as 23% listed.