Installed pypes cut and clamp X-pipe now i have a intermittent popping at idle

[moooosestang]

I have not actually timed it, but it is a good 10 seconds between pops i'd say. It might just be random and not rythmic. it really sounds like expansion of the exhaust, but it's at operating temp. It also seems to make more popping sounds when it's off and cooling. maybe i bound up the collector/cat pipe during the install? Maybe this is just normal with an X pipe and new SS exhaust. I had to loosen both cats from the manifolds to get them to line up with the x-pipe. I can't hear any popping inside the car, just at idle and nothing when accelerating. I'd expect an exhaust leak to be faster, but who knows. I'm going to be installing bbk shorty headers next week so this post is probably mute or maybe i'll be getting more random pops, lol!

 

[moooosestang]

Got under the car and didnt see any leaks where the x pipe bolts up. I used so.e exhaust pipe sealer and that stuff gets hard as a rock when it cures! Hope I can still line it up when I go to install these. Bbk welds are thick af! I went at them with a dremel and carbide bit. They are almost perfect now. Wish I had a dyno to see if these actually make power.

 

[JC SSP]

I alway say my shortie BBK gave me 5HP… maybe more but that’s what I am sticking with being optimistic.

 

[moooosestang]

I alway say my shortie BBK gave me 5HP… maybe more but that’s what I am sticking with being optimistic.

5hp peak is what bbk's dyno shows on a NA car so you probably ain't lying. I have a whipple on mine so i'm going to say 10hp peak. I'm going to go back over them with the dremel and make each pipe perfect. I should have done a before and after pic. the amount of weld overhang into the pipe was not what i expected from a name brand header. Maybe from an ebay special.

 

[moooosestang]

Tried to capture it on my phone. technically my wifes phone so i made her a youtube channel. it's every 20 seconds, not exactly 20 seconds every time, but pretty close. wtf is that? i'm going to try to listen through a long pipe and pinpoint it. i swear it started or at least got noticeably louder after i was yanking on the exhaust.

 

[EBABlacknChrome]

Interesting noise for sure. It sounds like the a/c or fan trying to turn on but can't.

Sent from my SM-G996U using Tapatalk

 

[JC SSP]

Sounds like creaking due to heat expansion, but from what? How old are the cats? Could be a cracked honey comb?

Are those cast iron exhaust manifolds with an S/C?

Put it on a lift and get under it... if it the cats you will hear it better.

 

[moooosestang]

Interesting noise for sure. It sounds like the a/c or fan trying to turn on but can't.

Sent from my SM-G996U using Tapatalk

i don't have AC and the fan comes on at 200F, it wasn't quite there yet. it also starts soon after i start the car.

 

[moooosestang]

Sounds like creaking due to heat expansion, but from what? How old are the cats? Could be a cracked honey comb?

Are those cast iron exhaust manifolds with an S/C?

Put it on a lift and get under it... if it the cats you will hear it better.

those are the stock headers, stock cats and midpipe. Car has just under 60k miles, most of that with the supercharger. It sounds like it's coming from the front of the motor, but not internal. I try getting under the car though. i tried pinpointing it yesterday, but it was being aloof. I revved the engine and it went away for several minutes. I swear it wasn't there or at least wasn't nearly as loud before the X pipe install. The inside of the cats looked fine. Installing shorty headers on Thursday/friday so we'll see. it does sound like expansion.

 

[moooosestang]

Going to try loosening the midpipe nuts at the header and start it up tomorrow before i begin my header install. Maybe i over torqued those nuts. whatever it is it starts very shortly after startup so if it's thermal expansion it has to be the header or cats, something that gets hot fast. If it were anything else i'd expect a more consistent timing, lol!

 

[moooosestang]

I couldn't loosen the nuts on the cats without spraying pb blaster on them so i didn't want to start it after that. I went ahead with the shorty install, started it up and no more popping. i think i just over tightened those nuts and they had no room to stretch when heating up or i had the midpipe in there all cockeyed somehow causing the popping. Everything went back together very easily.