Exhaust Problem

[dj_004]

Hey was up people? :chainsaw: im new around here but so for i like the forum!! I have a 87 Accord LX 5spd and i just put a new Magnaflow Muffler on it and when ihave it put on I told the guy to take off the Catalick (spelled wrong) converter and just put a 2.25 pipe on it all the way back and then weld the muffler on. Which was only 50$! It sounds good (expacially at full throttle!!:super: ) but when i let off the gas or i go down a hill it pops rapidly:wtf: so can someone tell me what this is and how to fix it... its not that bad but its just irratating! But someone did tell me that it was just the excess gas being burned off...? is that true?

[NXRacer]

You most likely have holes in your piping somewhere. Whoever did the exhaust job didnt do a good job of welding around the pipes on all the welds. Another thing might be that you have a hole in your exhaust manifold. I'd take a good look at all the new exhaust piping and see if you can see any holes. Even the smalles hole will cause it to pop like that.

Taking off the catalytic converter will make it so your car won't pass DEQ smog inspections (if you have them in your area).

[dj_004]

no i dont have emission test in my area. beside taking off you cat will give you extra hp

and i could start off by replacing the manifold guasket right?
but i might have to take it back to the guy who put it on and have him look at it

[NXRacer]

its not necessarily the gasket. Sometimes because of the hot/cold changes, the manifolds tend to crack therefore causing holes. Its most likely holes in the piping. I'd check that first.

[dj_004]

and could it be the excess gas burning off?

[dj_004]

well when the engine is cold i can tell a difference in the sound of the exhaust

[dj_004]

oh and what kinda lip is that on your accord? its pretty straight!!

[A20A1]

It could be from a hole in the exhaust... but remember you're letting off the accelerator and closing the throttle but the engine rpm is still high. At the high rpms he engine is trying to suck in more air, but it can't because the throttles closed... so it starts sucking air from the exhaust end as well, or it just sends out weak pulses thru the exhaust because of the lack of air.

Just throwing out a few theories there... :D

Also the increase in pipe diameter, affects the exhaust pulses.

[krott5333]

eh, mine makes popping sounds ever since I ripped the tailpipe off, I think it might be normal.. but better get a second opinion.

[NXRacer]

With a straight pipe, it will pop a little because of what A20A1 said. If the popping is really bad then there are holes somewhere.

I don't think its excess gas buring. Don't quote me on the since i'm no pro about those things.

My front clip is a 99 civic Wings West Avenger kit.

[pimp86LX]

i was always told that when you change your exauhst you have to adjust the carb, I did this on my bike and never had any exauhst troubles. I've changed the exauhst setup of EFI vehicles and never had a problem, but carb'd farts and farts. Could that be it?

[dj_004]

but if i get bigger pipes wont it change the exhaust sound?

[wprocomp]

yes it will,but don worry...the sound is normal,its just back pressure,mine does it alot and I have from header,cat,to muffler and its all new.

[Darkside]

Also you could get a blaster coil and gap your sparkplugs slightly larger thus making the spark slightly cooler but for a longer duration end result it better burns the fuel and then less poping. I have a weberon and the poping went a way and now I shoot a flame out the back when I shift. I'm running pretty rich. Just a thought.Darkside

[NXRacer]

Bigger pipes = better sound! (usually anyway)

[Jims 86LXI HB]

You can have good sound and tune things right by using the correct pipe diameter. 2.25 makes sense in terms of exhaust gas volocity for these cars. We don't have the tuning or rev range needed to benefit from a larger pipe size than that.

[dj_004]

am i able to gap the plugs larger and still use my stock ignision?

[infecto]

What a waste to take off the cat. doesn't do much for performance and pollutes like hell with it off.

[dj_004]

dude your crazy!! every time a volcano erupts it put out more pollution than the world does in one year!! its true you can look it up! and it does give you more power! maybe 3 or 4 hp or more...... but every little bit helps.

[NXRacer]

it can give you way more hp then 3-4. my friend has a CRVTEC in his civic and he had a bad cat and when he punched it out he got a HUGE increase in HP. of course, thats a little diff then our cars, but still i would expect more then 3-4.

[pimp86LX]

a volcano is a natural geological occurance. All your sayin is that humans pollute an insane ammount.
:flip:

[dj_004]

we dont live forever

[rocky2]

Look at your exhaust manifold for a pipe...disable it (Plug it) see it that works........it sends air into the manifld under high vacum to reduce emissions

[dj_004]

what do you mean??? what pipe?..... the EGR pipe?

[A20A1]

the air suction pipe... It uses the exhaust scavanging effect to suck in air from the air cleaner... disable the air suction valve by unplugging the vacuum line and plugging the port for the vacuum line where it connects to the hard line... there is no need to plug the valve itself.
Actually though the valve only works untill about 3,000 rpms anyways, or untill manifold vacuum runs out and the valve closes.

the EGR recirculates the exhaust gas... I suppose manifold vacuum assists in drawing out the exhaust gas, but I'm guessing it's under some pressure as well. i have no idea at what Rpm range the EGR work at.

[Neuspeed007]

look into ur vacume lines around ur carb. my system did that for a while until i found a line that wasent plugged.

[Neuspeed007]

haha mike beat me to it

[Elijah]

My car doe's the same thing and I have msd coil and the sci box.I like the sound so it don't bother me.The V8 cars do the same when they put a little work in to them.I beleive it's just loss of back presure.