bubbly exhaust?

[peanotation]

not actual bubbles, but if you put your hand or leg right up next to the muffler, you can feel the exhaust coming out. on my car, it feels like there's 2 different pressures, and the car is switching back and forth between them. this is hard to explain. like, slowly breath onto your hand so you can feel your breath, then cough, then keep breathing normally without inhaling again. thats what i feel, but really fast back and forth between the "coughing" and normal breathing.

is something wrong with my valves? or is it just my rough idle from all my unstopable horsepower.

[josh_877]

i have the exact problem, i guess its just the horsepower, LOL
naw but i think it is the rough idle, i also get a weird noise when i step on the gas and rev it to like the 4k it makes like a rattle noise(hard to explain)

[Import_Beast]

i also have the same noise...and when i get up to 4k rpm it sounds like a weed wacker

[peanotation]

hm, for you guys it seems different. for me it's only at idle. anywhere after that it sounds/feels great.

[josh_877]

no at idle too, it feels just like yours, like weird wind/pressure

[Import_Beast]

yea i get the same thing u described at idle too...and it sounds and fells great too when im driving except for at 4000 rpm for some reason only at 4k when i pass 4k all i hear is the engine and no rattle and under 4k it sounds nice

[jusmills]

I could be wrong but isn't that how its supposed to be--when you think about it, your exhaust isn't one continuous stream, exhaust valve opens, exhaust out, then closes, creating a pressure gradient. You have four cylinders, so you would get high to low from 4 different cylinders, the low pressure end of 1 exhaust pulse creates a vacuum and pulls the high pressure end of the pulse behind it. In essence, you get a series of cough, regular, cough, regular...your RPMs will determine the frequency (or how fast you get cough, regular...etc). The thing is at high RPMs you'll never be able to feel it with your hand as the total pulse lenght is way too short, so you perceive it as a continous stream.

[peanotation]

<div class='quotetop'>QUOTE(jusmills)</div><div class='quotemain'>I could be wrong but isn't that how its supposed to be--when you think about it, your exhaust isn't one continuous stream, exhaust valve opens, exhaust out, then closes, creating a pressure gradient. Â*You have four cylinders, so you would get high to low from 4 different cylinders, the low pressure end of 1 exhaust pulse creates a vacuum and pulls the high pressure end of the pulse behind it. In essence, you get a series of cough, regular, cough, regular...your RPMs will determine the frequency (or how fast you get cough, regular...etc). Â*The thing is at high RPMs you'll never be able to feel it with your hand as the total pulse lenght is way too short, so you perceive it as a continous stream.</div>

yeah, that makes sense i guess. now i know an engine moves faster than this, but i'm just throwing it out there: maybe 2 of the valves are letting out the "cough" and 2 are letting out the regular streams. i dont know. if everyone else is sort of experiencing it then i'm not as worried, maybe it's just our engines.

i noticed the cough/normal flow out the exhaust became exagerated after i started spraying and the car also idled louder. hopefully all that n2o cleaned something out.

<div class='quotetop'>QUOTE</div><div class='quotemain'>yea i get the same thing u described at idle too...and it sounds and fells great too when im driving except for at 4000 rpm for some reason only at 4k when i pass 4k all i hear is the engine and no rattle and under 4k it sounds nice</div>

for the brief happy days i had my muffler completely disconnected, it was extremely loud/abnoxious, but when i would floor the car, after about 4.5K to 5K, the exhaust would almost completely cut out. it was almost all motor sound no exhaust sound. now with the OBX B1 muffler, it just screams under WOT through all gears. thanks to mindless for the muffler.