ToxicDK

What exhaust setup is this + The crackles?

I was looking into armytrix, but I saw they don't provide them currently.

Didn't think this car could sound that good.

Any guesses?

Thanks!

Sasnuke

I'm not sure what exhaust it is, but a couple comments on the vid.
First, it looks like a valved exhaust..note when he rev's it at 0:01-0:02 and then the difference at 0:06 when he rev's it again. It was likely valved closed the first time and valve open the second.
Second, at the end they show the laptop screen...which would indicate the crackles are likely a 'pop and bang' tune instead of being caused by the exhaust.

The 'pop and bang' tune will definitely ruin an engine.

paulmantis

those crackles sound so obnoxious

TLeexus

first of all ... your posts are always quality.

dumb noob question ... what exactly causes the popcorn noise?

Sasnuke

The engine is basically creating the 'pop and bang' (popcorn noise, burble, etc.) through the combustion process.
What the tune is adjusting is what happens when you take your foot off the gas pedal.
Usually when you lift off the accelerator, the throttle body closes and the injectors stop injecting...some refer to this as fuel cut. No air or fuel is going into the engine.
In most vehicles when you are in fuel cut, this is when the exhaust valves are open, to let the already combusted air/fuel mixture out of the engine down the exhaust pipe. (remember this)
This allows the car to start slowing down and gives you better fuel economy.
What the tune does is start up the injectors again, and retard the ignition timing. The goal is to create a lean combustion by opening the injectors (slightly) under fuel cut and igniting it with the late (retarded) ignition timing, WHILE the exhaust valves are open.
This gives you the 'pop and bang'/'popcorn' noise as well can produce flames out the tailpipe. The hotter the exhaust is the more amplified the entire effect is.

Because this combustion process is happening when the exhaust valves are open, it creates a few undesirable scenarios for the engines life span.
First, the cat's are being subjected to this violent explosion they were not designed for...second, as this is an unanticipated time of combustion in the engine, it puts added stress on the pistons at a time where there should be no stress...or no additional stress.