Engine Help with my 2003 corolla 'S' muffler situation

Unless you're going with forced induction, 3 inches is a bit much. You're going to lose some low end power.

3" inch is going to be a big no no. the only reason to get your pipe done in 3" would be for a turbo aplication. You engine is NA and needs a certain amount of backpresure to run properly. even if you went S/C'd 3" wouldn't help that much. I would go 2.5 that would work fine and you would see the best results.

Help with my 2003 corolla 'S' muffler situation

NOTE THE ABOVE POLL LEFT OUT : Leave the resonator in and go with the 3 inch.

VOTE FOR #3 IF THIS IS YOUR CHOICE. IT IS MY CHOICE!

So, I finally purchased the muffler I wanted. I went with the magnaflow 14803 seen here Image 1 | Image 2 | Image 3 | Image 4

It sounds very nice, but I have 2 VERY IMPORTANT questions I would like you all to help me answer before Saturday.

1. I am considering going with 3 Inch exhaust from the header back. I have a buddy who owns a muffler shop and will do it for a case of beer. Will this affect gas mileage, vvti, are there any NEGATIVE affects.

2. I am also considering removing the resonator. It sounds decent right now, but I think with 3 inch and no resonator it would scream. I dont want ricey, I like the sound now, I just want more volume.

I am trying to attach a poll here.

Should I,

1. Just remove the resonator and leave the stock exhaust piping

2. Leave the resonator in and go with the 3 inch

3. Go with the 3 inch and take the resonator out

Thanks for your help. I have 24 hours to decide

Yea, after doing some research 2.5 is the way to go I think. I think I will also leave the resonator in.

Here are the results of my muffler expedition this weekend. I decided to go with the 2.5 from the second catback. Also, because there are two cats, you can safely remove the resonator without having to worry about the ricey sound, as long as you buy the right muffler. I am very happy. Once the muffler gets worked in I will let you know how it sounds. If my wife likes it, that is usually a good indicator that I will not be waking up the neighborhood as I head for work. She likes it...

you have two cats?

I believe the 03+ rollas has 2 cats..

The WRX has 3 cats.. in a few yrs the whole exhaust system will be nothing but cats attached end to end..

damn tree hugging air nazis!

There are definitely two cats and a rather long resonator. These rollas are some of the cleanest burning car in the world... and they look good too

I thought 03 had 1 cat, and 2 resonators... i went with 2¼ pipe...

with the 2007 the first 2 are cat's and the third is the resignator? just a question. and can i remuve the resignator? what will that affect?

You better keep both the cat and resonator. Like rollatuner110 said, it's gonna be really really loud if you delete both of them.

an oil change has nothing to do with your exhaust. the problem is your ECU is flipping out over the lack of cat.

yeah i only have one cat with my custom catback exhaust and trd muffler and its really loud. i just ordered a footlong resonator (vibrant resonator) and hopefully installed by next week.

Hello, im new here...wanted to share my experience. I have a 2006 rolla S. I took out the cat and went 3 in. straight pipe all the way from the exhaust manifold.

Problems...........

1. "maintenance required" light has been on since {even after oil change}

2. car in INSANELY LOUD!!!!!!!! too loud for comfort...in cabin is WAAAAAAYYYYYY too loud for anyone to even have a decent conversation without having to yell.

3. I am very UNHAPPY with this setup....DO NOT TRY AT HOME!!!!!!

4. terrified of getting tickets even during a school zone!!!!!!!!

5. sounds MEAN but is DEFFINING

6. car is LOUUUD!!!!!!!!!!!!

7. car is too LOUUUUUD!!!!!!!!!!!

8. HATE IT HATE IT HATE IT!!!!!!!!!!!!!!!!!

Hope this helps with any curious ppl thinking how it would be...will he upgrading to a sick system and will be posting a video as proof....of how LOUD it is now...

I already explained this partially. Removing the cat is NEVER a good idea. You don't gain much if any power unless you have a high horsepower setup which still doesn't justify it's removal. Removing the resonator will only make your car unbearably loud. However, replacing the resonator with an aftermarket one will flow better. You can also replace the stock cat with a high flow one. But you should NEVER simply delete it. Either of these ways are not cost effective ways for more power. Stick with simple bolt ons such as a CAI, header, cat back exhaust, etc.

post some videos of the car, and also what are the disadvantages of removing the catalytic convertor vs the resanator?
Im lookin to add some umph to the car, what would be the cheapset but correct way?

THANKS EVERYONE FOR THE PROMT FEEDBACK

I know that the oil change has nothing to do with the exhaust, just wanted to clerify any doubt i had to why it was on....

Now, I know i didn't think about it before i did it, but now i know, FIRST HAND!

My new setup consists of DC HEADERS, HIGH FLOW CAT, and Greddy SPL 2 CAT BACK EXHAUST.................will this be aggressive and pleasing or just annoying and loud??? does anyone have any ideas of how loud it will be period???

AND....does anyone know if a 2000 celica 1zz's parts can be used on my 06 1zz? because i want an adjustable exhaust cam but can't find for rolla, so celica is a maybe, maybe???

It'll be louder but not obnoxious. MonkeyWrenchRacing has 1zzfe adjustable cams.