Thread: exhaust leak / apexi ws2

Originally Posted by bubbadanger

before putting a 4-1 header on my car with the stock exhaust i thought it would be loud and sound bad, after i got it on it actually sounded pretty stock, i was suprised. it stayed that way for a few days then today i took it out and beat on it some.. on the way home it got alot louder and sounded really bad all of a sudden, could this be an exhaust leak or is the header finally "worn in" or something?

i was gonna wait til after winter to replace the exhaust, but since i can stand the sound ill be doing it sooner than i thought.. im interested in the apexi ws2 catback. i see that only the tip is stainless, will the rest of it rust out? i think it said it was treated with something but wasnt sure what it meant. also id like to get a flexpipe, would i have to order that seperatly or does it come with the kit, and does a flexpipe replace the midpipe? sorry for any dumb questions lol

well, about the header, what is the noise like? does it sort of sputter? because that could be a leak. if so, just look around the donut gasket at the bottom or at the head for leaks. i think the donut gasket is kind of prone to leaks if you dont replace it.

as for the exhaust, i dont think it should rust out. i personally dont have one, but if its treated with something, i dont think it should rust at all. maybe someone with the WS2 can chime in on that?

and the flexpipe comes separately, so you'd have to find one with the right inlet/outlet sizes. but the flexpipe is something that typically goes onto the midpipe to prevent the exhaust from breaking in places. it does not replace the midpipe though. you weld it onto the midpipe itself, but you wont need to add one if you dont replace the midpipe.

I have a ws2 and it's still shiny.

the sound is kind of a sputter like your were saying, sounds like its the worst back by the muffler. and sorry i wasnt clear but i was talking about the ws2 exhaust piping itself not just the muffler. id like to replace the midpipe too, but does the flex pipe have to be welded on or could it bolt on? i dont have access to a welder and i was hoping i could do all this at home without having to take it somewhere

Originally Posted by bubbadanger

the sound is kind of a sputter like your were saying, sounds like its the worst back by the muffler. and sorry i wasnt clear but i was talking about the ws2 exhaust piping itself not just the muffler. id like to replace the midpipe too, but does the flex pipe have to be welded on or could it bolt on? i dont have access to a welder and i was hoping i could do all this at home without having to take it somewhere

oh, its further back? well, i'd check where the flanges are first to see if the gasket may be shot, but if its not there, i'd try to spray something on the pipes. if you see bubbles, thats where your leak is.

and the midpipe, you can find any on ebay for pretty cheap, but the flex pipe has to be welded on. it shouldnt be too expensive to have it welded on at any muffler shop. everything else can be done at home with no problems though

ok ill try that in a little while, would i need a high flow cat welded onto the midpipe? i dont really want any check engine lights

you have to buy a midpipe if you have a 4-1. It doesn't come with the cat back. And yes, if you get an aftermarket midpipe it won't have a cat. You won't throw a code though as long as your second 02 is far enough back.

And the piping of the ws2 isn't polished but it doesn't turn to rust. just looks like metal.

ok thanks for that, would a highflow cat (ex. magnaflow) help with sound? i dont mind it being loud as long as its not raspy or annyoing. this is what ive come up with, if somethings not right let me know

flex pipe welded to front of the midpipe (so the flex pipe is connected to the 4-1)
high flow cat welded to back of midpipe (connecting it to the catback)

if what i have above is right, would it be possible for me to run the midpipe, flex pipe, and high flow cat to an exhaust shop and have them weld it all together then come home and bolt it up to the 4-1 and catback, or would they need to look under the car or weld something else?

if anyone got a pic of under there car of how it would look with this setup it would probably be easier for me, my old car had a 4-2-1 so i didnt have to do all this


i just went out and started it up, sounded normal again? hmm

Originally Posted by bubbadanger

ok thanks for that, would a highflow cat (ex. magnaflow) help with sound? i dont mind it being loud as long as its not raspy or annyoing. this is what ive come up with, if somethings not right let me know

flex pipe welded to front of the midpipe (so the flex pipe is connected to the 4-1)
high flow cat welded to back of midpipe (connecting it to the catback)

if what i have above is right, would it be possible for me to run the midpipe, flex pipe, and high flow cat to an exhaust shop and have them weld it all together then come home and bolt it up to the 4-1 and catback, or would they need to look under the car or weld something else?

if anyone got a pic of under there car of how it would look with this setup it would probably be easier for me, my old car had a 4-2-1 so i didnt have to do all this


i just went out and started it up, sounded normal again? hmm

That sounds good except you will probably want to add the cat in the beginning of the cat back because some mid pipes have a small resonator, and there is more room in the beginning of that cat back.

welding a cat on should help with sound a little.

And yes, as long as they are adding the same amount of material they cut out it should just bolt right up. Pretty easy to do in your driveway.


pics of mine. looking towards the back of the car. the end of the megan mid pipe on the right. see the small resonator. the start of the cat back. I have a muffler welded into where you are looking to put your cat.

thanks for the pics, about how much would a flex pipe, mid pipe, and high flow cat cost me? and what sizes would i need for those 3 things if i plan on running a 2.25" exhaust? for example ive found a megan midpipe/down pipe for 170 something shipped (is that a fair price?) but its 2.5", would it be compatible with 2.25" exhaust or would i end up loosing power since theyre different sizes

try to make it the same size throughout. my ws2 is 2.5. you can get a high flow cat for 100. flex pipe will be cheap, 10-15.

ok, one last question. i think i read somewhere the ws2 comes with a resonator on it, and so does the megan midpipe right? wouldnt 2 resonators do more harm than good as far as restriciting it

the resonators shouldnt do any harm to the flow of the exhaust. im almost positive they are straight through type of resonators, so they shouldnt cause any restriction in flow whatsoever

ok cool, thanks again for your help. when i get everything situated ill try to get some pics and let u know how it goes

well im back cause i ran into a little problem, the ws2 exhaust im lookin at is 60mm. i found a megan midpipe thats 2.5" with 2.25" inlet, would that work? im not sure about the 60mm. and about the flexpipe/high flow cat, would i be looking for 2.25" inlets or is 60mm too big/small for 2.25". also mtrapuzz, where did u find a 2.5 ws2? i can only seem to find 60mm

Originally Posted by bubbadanger

well im back cause i ran into a little problem, the ws2 exhaust im lookin at is 60mm. i found a megan midpipe thats 2.5" with 2.25" inlet, would that work? im not sure about the 60mm. and about the flexpipe/high flow cat, would i be looking for 2.25" inlets or is 60mm too big/small for 2.25". also mtrapuzz, where did u find a 2.5 ws2? i can only seem to find 60mm

be careful with which of the megan products you order. megan calls our midpipe a downpipe and the midpipe they sell is a catback minus an axle-back. and i did some searching, and i cant seem to find a 2.5 WS2 either.
but for your flexpipe/cat, you want to get the same diameter as your piping to avoid bottlenecking.

Sorry I know this is the wrong section but wanna ask a ? I want something quiet and have a 08 spec v. Could I do the down pipe and mid pipe with still keeping the stock muffler and gain anything?

ya i seen the whole megan downpipe/midpipe mixup on another thread. heres the one i found on ebay, is that price reasonable?

MEGAN MID-PIPE 02 03 04 05 06 NISSAN SENTRA SE-R/SPEC-V: eBay Motors (item 150478737040 end time Sep-09-10 21:01:40 PDT)

i finally made up my mind (i think) lol. if that midpipe is worth it im gonna buy that and a good sounding muffler and just have the exhaust shop who did my last exhaust do a custom 2.5 since the midpipe is 2.5, i could ask him to make a custom midpipe i guess but idk how much he would charge and wouldnt he have to weld the flanges on by the header? i can get a high flow cat from him but would u have any suggestions on any brands or types?

Originally Posted by bubbadanger

ya i seen the whole megan downpipe/midpipe mixup on another thread. heres the one i found on ebay, is that price reasonable?

MEGAN MID-PIPE 02 03 04 05 06 NISSAN SENTRA SE-R/SPEC-V: eBay Motors (item 150478737040 end time Sep-09-10 21:01:40 PDT)

i finally made up my mind (i think) lol. if that midpipe is worth it im gonna buy that and a good sounding muffler and just have the exhaust shop who did my last exhaust do a custom 2.5 since the midpipe is 2.5, i could ask him to make a custom midpipe i guess but idk how much he would charge and wouldnt he have to weld the flanges on by the header? i can get a high flow cat from him but would u have any suggestions on any brands or types?

That seems like a resonable price. thats typically what those go for, so yeah.
honestly, i think you could just get a random ebay catback (OBX is a Greddy EvoII knockoff but seems and looks good) for cheaper, buy two resonators, and have them welded in for cheaper, but i dunno if thats the route you'd want to go?

as for the midpipe, you could have it made. every place probably has different rates, so you're gonna have to go to him and ask for a quote and decide from there. and yes, he would have to weld a flange to have it bolt up to the header.

as for the suggestion on the high flow cat...i think it'd be best for someone who's used one to give a suggestion. just make sure its the same diameter as your piping!

Originally Posted by blueis300

Sorry I know this is the wrong section but wanna ask a ? I want something quiet and have a 08 spec v. Could I do the down pipe and mid pipe with still keeping the stock muffler and gain anything?

Im sure you should make more hp. muffler's typically give 1 hp, if that. but it might sound kinda crappy.