Im running my 350 with an Invidia midpipe and F Sport exhaust. It backfires a lot as some of you may know.

How can I fix this? Any chance getting headers would fix / make this worse?

Thanks!

 

Yikes! I never knew the invidia had a chance to make the car backfire!

Besides the OP's question let me pose another question. Why would it cause your car to backfire?

 

Is the backfiring on deceleration or during acceleration? Maybe not enough (or too much) backpressure is causing it? Have you checked for leaks too?

 

Isn't back-firing caused by unspent fuel exiting the CC and igniting somewhere along the exhaust causing the "popping" sound? Probably caused by mods without a perfect A/F adjustment via the OE ECU causing a rich condition or a small timing issue. Prehaps a cleaning of your MAF would help? Where is the IAT in our 350s; in the plastic manifold perhaps?

 

Adding headers would only make it worse. I deleted my secondary cats, resonators, and mufflers and my IS350 backfires so loud, people slam on their brakes whenever they hear it. I honestly like the backfires. It never happens under acceleration but when letting the car roll for a few seconds and I hit the gas, it backfires loud and when coming to a stop, it backfires.

The car probably backfires already but with the stock resonators and mufflers, they pretty much get dampened and we hear nothing.

 

Maybe the fact he's 30,000 miles past due to change his spark plugs is contributing

 

This is common with the Invidia Midpipe / F-Sport Exhaust combo. It happens to me quite often. The backfire seems to occur randomly on deceleration. Sometimes it is a little pop, and other times it sounds like a gunshot. I have found that I can make the car backfire by tapping the gas during deceleration.

 

is the problem the combination of the midpipe and exhaust? Do people with just the exhaust experience this problem?

thanks

 

Mine after fired from new with the OE HKS catback, just not as loud as it is now with the Nvidia mid pipe. My son thinks is cool

I need to change the cone gasket at the axle connection 'cause I saw some leakage there and check the other two connections before the mufflers,...but it's normal.

Most modern day fuel injected cars turn off the injectors on deceleration, ours is just very aggressive with a very sharp cut-off and turn-on.

 

i believe its the invidia and fsport combo. i have the same setup on my 2011 with only 10k. i actually the backfire.

OP: i think the only was to get rid of it is to put the stock mid pipe back on or maybe a different axleback

 

invidia with stock exhaust... no backfires for me. if that helps narrowing it down

 

chi123 you are right on it! When I don't step on the gas for a second, then I touch the gas pedal I can hear it, and when I come to a stop SOMETIMES i can hear it.

Kurtz LOL haha maybe Im lucky my car even turns on in the morning

And for those that are asking, it's because you now have only the PRIMARY cat, and no secondary. This causes it to backfire. Perfectly normal, there are no leaks, just an effect of taking out the SECONDARY cat

 

Hmm... no backfiring for me, PPE headers (no primary cats), and PPE high flow cats in my JoeZ racing exhaust. Must just depend on the combo and 250/350.

 

PPE Headers + Fsport exhaust here and no backfiring.

So your saying IF I wanted it to backfire all you have to do is remove the 2ndary cats?

 

Well see, you removed your primary cats no? I dont know how that set up is, thats why I asked in my first post. If I could get rid of the backfiring by getting PPE headers, I would