Ok, so I got a new muffler this weekend, the Dynomax Superturbo. I instantly noticed a couple of things. First that it really did improve the acceleration from off the line to highway cruising (It's not CBR 600 RR, but that's not what i want in a truck anyway) and second that there is this horrible rattling when I give it the gas, that I've narrowed to the Catalytic Converter.
You would think that the guy at the muffler shop would have said something, but whatever. I need a new CC and I've been looking around here and I have narrowed it to a high-flow CC (probably dynomax) but here are my questions that I couldn't answer:

Do I have an O2 sensor on the CC?
What size intake and output pipes do I have? (I'm pretty sure it's 2.25 out)
Are the universal CC's one size fits all?

Thanks,
Adam

 

I forgot to mention that it's a 92 4runner 3.0L 2WD..sorry

 

Your 02 sensor is right before the cat.

Your pipe diameter should be 2" in and out, unless it's been changed.

Just find a converter that has a 2" inlet and outlet and have it welded on.

Are you dead set on a dynomax? I could be wrong, but when I was looking, the only reason for getting a dynomax is for the bling bling chrome look. If you wanna save some money, get a CarSound. They're high flow, as are any and every aftermarket replacement catalytic converter.

 

Are you positive the cat is bad?

 

Thanks, for all your help guys. I'm not positive its the CC, but I talked to the guy who sold me the 4runner and he said it has never been changed. So I figure that it probably needs it anyway.

So, I found this CC on ebay, do you think it will work? I emailed the seller, but no responce...http://cgi.ebay.com/ebaymotors/ws/eB...tem=2468263218

 

I'm running that muffler as well and I love it...

AgRunner06 is runnin the same muffler and has a high-flow cat on his and I think he likes it...PM him and see what he says.

Good luck,

Fink

 

Ok, I found out that the pipe on either side of the CC is 7.5 inches...by my ruff calculations that's about 2.25 inches in diameter (inside the pipe)...right? It's been a long time since I needed to figure this stuff out. Anyway...I found some on Ebay for around $60 shipped.

Now, if it isn't the right size, can the muffler shop do anything like narrow the pipes?

Thanks
Adam

 

They can, but it wont be optimal. If you are going to replace the cat, you need to know the exact size. It will just work better that way.

I vote for a Carsound cat.

 

Are you sure about the diameter? I might be wrong but I thought Toyota didn't offer any pipes over 2". Other than that, the cat you picked out looks good.

When you get it, look through it and then look through the one you had on it. You'll be amazed.

 

Yeah the piping is 2", I put a 2.25" tip on it though...it just took a lot more welding.

Fink

 

Ok, I'll crawl under her again and look. The pipe might be tapered off before it goes into the cat.

Just a curiosity question...what's that piece of sheet metal that is right above the cat? It's only attached to the left (driver) side? It's about an 8th of an inch thick; I can't imagine what it might be for...

 

You mean the heat shield? It prevents the floorboard from melting.

 

It's a pretty flemsy heat sheild, then, I wonder why it's only connected to one side.

 

Heat shields do not have to be thick. If it was thick it would be a heatsink. The heat shield is 1/8" thick so it doesn't absorb and retain the heat, airflow around the heatshield disapates the heat. It is only attached to one side to allow for expansion when it heats up. Basic properties of metals, you need some way for the metal to grow (and it does) when it gets hot. Did I loose you yet?

 

I think you lost me right after "heat"...LOL

It makes sense, when you put it that way.

Thanks

 

just order a dynomax highflow cat from summit racing. i just put a dynomax super turbo muffler and the dynomax cat with all 2 1/4" piping. sounds great and the high flow cat is only $55 from summit, and their shipping is free i think. you wont be dissapointed.

 

I just ordered a carsound from ebay for $45 and $10 shipping. I got the 2" in and out. I love the muffler! And now I have something to put in my signature..woohoo

 

the heat sheild is the source of you rattle. the heat shield is spot welded on it should be attached at the four corners,at the flat tabs on the cat. I cured this rattle by drilling pilot holes then using four short #8 sheet metal screws. Guess this reply is a little late since you already bought a new cat.

 

That's ok, I think I'm going to need it sooner or later anyway. Thanks for your reply I'll ask the guy who installs the CC to take a look at it and maybe tack it on for me.

Adam