flowmasters

[bad 71 chevy]

i have a set of 40 flows with 2.5" dual exust and headers
hear is the deal every time i let off the gas they pop and is kind of anoying what should i do i have heard of geting an x pipe or a y pipe or even an H pipe but i dont know what is the best thing to get rid of the poping thanks

[orange72]

i honestly didnt think they would pop.. mine never have until recently when i about broke my headers... how do you got em ran.. out the back??

[Zurbo]

Are they popping like an oversized oil can? (the kind that pop when you squeeze the bottom) Or is it more like a soft backfire?

If the first is true there could be a loose baffle. The old turbo muflers were bad about that. More than likely, you are just getting the typical unspent fuel pops while the engine is winding down. Something that the crossover will not eliminate.

In your case though, an H pipe would make the sound much nicer. I just done Dynomax 88022 long tubes, 2.5" duals with balance pipe and Flowmaster 40's on my 72.

It has never sounded better!

[68 with 350 TPI]

You are hearing a little backpressure and some unburnt fuel.

Most people will call it "burble" now if its a loud POP it could be something else like a small exhaust leak somewhere throwing the system out of a perfect balance of flow/backpressure.

Kinda like a bum-de-dum-bum-bum is normal when you let off the gas and your in gear.

[lukecp]

I have had that problem with my Flows before, but it has never been the mufflers. First, check for exhaust leaks. A leaky header gasket will cause the same thing. Check for problems in the igniton system. Mine was popping when i let off the gas about a month ago, and after i gave it it's yearly tune-up (new plugs, wires, cap, rotor), it dosen't pop anymore.