hey im new here and i have a 92 camaro with 2.25 exhaust with out the cat and that goes to a 3" pipe that goes over the axle to the flowmaster then dual 2.5 tail pipes. this was done before i bought the car.My question is, when i rev it past 2500 rpm then let off it will pop. i was wondering how to get rid of that poping sound?

my guesses would be:

1. you are running rich, and with the cat removed, the unburnt gas is still in the exhaust and self-igniting when you let off the gas.

2. going from 2.25 to 3 to 2.5 is going to make your airflow screwy and also trap that unburnt gas listed above, giving it a place to pool up and self-ignite.

solutions:

1. fix the running rich problem
2. Reinstall the cat to burn off the excess unburnt fuel
3. Replace your exhaust system headers back running all 3 inch "you can run straight pipe from the y to the existing 3inch, then change the 2.5 to 3 with new mufflers" which will better your exhaust flow. this will increase HP Potential since your engine can now exhale better, and will help stop unburnt gas from pooling up to self-ignite.