I just finished installing a Magnaflow 16612 SI/SO exhaust on my 05' 5.4

Fit and finsish top notch, instalation easy but,

I get a little backfire when I let off the throttle after I rev it up.

Even if it is just up to 2200 RPM.

Havent had a chance to test drive just yet, will get some seat time this weekend.

Just worried about this, is it normal?

 

Are you sure it's backfire and not just lack of back pressure in the exhaust system? My mustang's exhaust poped a lot after I installed an off road h-pipe on it. Anyone else experience something like this?

 

I asked a similar question before, but didn't get any reply. I thought lack of back pressure is what causes backfire? Anyway, I installed the Corsa and mine does the same thing. Every sound clip I have heard does the same thing too. I think this is normal, but it doesn't happen if you have it in gear and are driving around. I think it is normal.

 

curious how the corsa sounds on your f? i know it doesn't have 4 cats but the corsa sport si so- dual tip on my buds 04 avalanche 5.3 is the best sounding 70's big block sounding exhaust i've ever heard on a truck- even towing 6k lbs no drone!-phil

 

I am very happy with it. I got the si/so w/dual tips, also. It makes noise when you are gettin off the line or downshifting, but I think it is quieter than stock, if you are cruising in OD on the freeway.

Now all i need is an intake that fits. Got it half-breathing anyway

 

Some popping is normal but alot of popping or backfire is probably due to an air leak in the exhaust system. Air entering the exhaust can cause any unburned fuel in the exhaust to ignite and backfire.