so i just put a LS in to my civic (98 sedan) and i have a few issues/concerns

first is that i didn't have the cash to get a full b-series exhaust so they just connected it to what was left of my old y7 exhaust. so now im wondering if the old d-series exhaust will effect my LS? like if it will restrict flow or to much back pressure and possibly harm my engine in anyway?

and between 2500 to 3000 rpm their is a weird rattle that sounds exactly like a fart can but is only for that specific rpm range then it goes away and the engine sounds normal? i think this issue is probably a loose exhaust flange or bolt or something like that, but if someone has any other troubleshooting ideas im up for it.

just working out the kinks of my first swap any ideas/tips are greatly appreciated thanks for any help guys

 

It definitely won't hurt anything, a better exhaust might get you a couple horsepower though. And you're probably right about there being a leak somewhere in your exhaust system.

 

getting a healthy engine is what im shooting for right now, power will come this spring, i just wanted to be sure the motor wasn't getting congested with exhaust fumes.

yea i think its a leak to but the fact that it only happens at a specific rpm range is what worried me i've got all day tomorrow to find it tho ish

 

Your fart noise is probably vibration of heat shields or baffles in the muffler.As for back pressure being destructive, it is possible if you have other modds.I have a b18b in my eg and switched back to stock exhaust temperaley to pass an inspection test because of the man hassling me and it busted up the honeycombs in my converter.Or at least that is what i am blaming it on.The converter was from a supercharged frontier and should of be fine for years.

 

Might be the o2 sensor mine makes that same noise at 1500 rpm

 

Yeah the little ring comes loose near the wire entry.That is a possibility.