stock exhaust modification.

[CyFi6]

I have a stock exhaust on my 87 na and i see that after the cat theres two mufflers. I was looking for an exhaust tone a little beefier than how it is stock, and i was wondering how it would sound if i deleted the first in-line muffler or replaced it with a strait through magnaflow i have sitting around. I want to keep the stock look of the muffler at the very back but want it to sound a little different. Let me know if any of you have experimented with this, i have to pull the exhaust down to fix a leak anyways so i thought i might work with it now if i ever will.

 

[cuel]

The one before the rear wheels is a resonator. I cut mine out, put a Magnaflow glass pack there, and a 2 chamber flow where the stock muffler goes with 2.5 pipe

 

[Rennat]

A nice mod to the exhaust, is to gut the cat, it'll add more power, and should make it louder... at least thats what im doin. haha.

 

[BlackMKIII]

Gut the cat, replace the rest with a 2.5" setup finishing with a magnaflow muffler and basic tip

/thread

 

[CyFi6]

cat has got to stay lol. Need to pass emissions and i dont have a spare good cat. as for the exhaust if i just delete the resonator how will it affect the sound?

 

[suprarx7nut]

no resonator = louder. AFAIK, the resonator is simply there to lower the volume of the exhaust.

 

[Frank Rizzo]

You will notice the biggest difference without a cat. Even with bone stock exhaust piping and muffler/resonator. Do yourself a favor and don't gut it, just buy a $40 test pipe.

At least, if you do gut it, salvage the precious metals inside.

 

[Rennat]

OR do what i did, buy a gutted cat from somebody. haha. cost me $19 shipped. hell of a deal if you ask me, and it'll look stock when the cops look. but i'll keep my oem cat for smog reasons of course.

 

[MA70 Ed]

i've been told that it will still pass emissons, because it has 2 cats. am i right?

 

[suprarx7nut]

Cali-spec N/A's have two cats and two O2 sensors. Unfortunately I am familiar with this fact.

Turbo's have two as well, but since this is in the N/A section, I'm assuming you're N/A.

I would think just the one cat would still pass emissions outside cali, but I'm not sure. I may try it out next year. I'll be getting rid of one of the cats for sure.

 

[CyFi6]

im a cali car and i only have one cat. i dont even think it has a downstream 02 sensor, correct me if im wrong

 

[Frank Rizzo]

N/A non-cail = 1 main cat, no pre cat. 1 O2.
N/A cail = 1 main cat, 1 pre cat. 2 O2's and an EGR temp sensor.

Turbo (all models) = 1 main cat and 1 pre cat. 1 O2.

You will pass emissions if you just delete the precat. No vehicle will pass emissions without a main cat. You will fail all visual inspection if you are missing ANY cats.

Car had to be sold in cali when it was first purchased to classify it as a "cali" car. You can live in cali and not own a cali car.

 

[MA70 Ed]

oh damn so that means that right now i have no cat... no wonder it's so loud.

 

[MA70 Ed]

anybody have a cat they wanna sell? >_<

 

[BorHor]

Not all cali NA cars have 2 cats. I think it was after 88 or 89. My car has always been in cali and it has one cat. I have seen other 87 NA cali cars that had one cat as well.

 

[suprarx7nut]

Not all cali NA cars have 2 cats. I think it was after 88 or 89. My car has always been in cali and it has one cat. I have seen other 87 NA cali cars that had one cat as well.

Does your hood say California Catalyst on it?

Maybe they never needed to do extra emissions shit on pre 89 cars? :dunno:

Unless you know the exact purchase history, i would think it could be possible for someone to buy it elsewhere and move into cali and have it pass smog with just the one.

Idk, just hypothesizing.

But mine has a sticker on the underside of the hood that states CALIFORNIA CATALYST. I think its the vacuum diagram sticker. Though it may be a separate one.

 

[BorHor]

I know the history. It has been with in a 50 miles its whole life. And I think i remember seeing cali cat under the hood. I remember discussing this a few times so a quick search should come up with the proper dates and answers.

 

[CyFi6]

Mine is like that also, one cat, no downstream 02

 

[Frank Rizzo]

I'm sorry, my mistake, forgot to mention cali cars are 89+.