cat converters

[Toyota 4 life]

I just put on a magnaflow cat back exhaust system. Does anyone know if you can eliminate the cat converters? I have heard that Toyota's need the back pressure to run correctly. I really want to get rid of my cats. Any help would be great.

 

[sharp4runr]

Why do you need to eliminate the CATs? The performance gains will be minimal.

 

[Toyota 4 life]

I was told by an exhaust company that eliminating the cats would give me a noticeable difference in performance. Which it is true in my friends new Chevy truck. He did a way with his cats and the gains were definitely noticeable. His truck ran like crap until he got a programmer to equal out the air-fuel ratio. Don't you think that having 3 cats is alot of restriction?

 

[sharp4runr]

The CATs enable the 4Runner to get an ULEV (Ultra Low Emissions Vechicle) rating. Removing your CATs would fail your truck for emissions testing. I'm not a tree hugger, but I don't see the benefit...

 

[BROOKLYN]

DO YOU NOTICE A DIFFERENCE IN SOUND

 

[Toyota 4 life]

Passing emissions is not a big deal for me. I live outside of the DEQ limits. I am not worried about passing emissions. Just want to know how my 4runner will run without any back pressure. Are there any good chips out there besides JET?

 

[Toyota 4 life]

Hey Franco- Are you wanting to know if there is a difference is sound from the Magnaflow cat back? I highly recommend Magnaflow. It sounds deep and throaty without spending 800-1000$.

 

[Koz]

If you remove the cats and get caught there is a EXTREMELY steep fine.

Koz

 

[00328]

Maybe you should look into a hi-flow or flow-thru cat.

 

[savagebeast]

You could remove the cats and replace the with "Test Pipes"
Not sure if they manufacter them for 4 runners though.
Performance gain would be minimal though.
And just a side note if you ever decide to sell the vehicle or trade it in you will have to disclose that they were removed even if you put them back on...

 

[mole177]

the cats may not be the problem, its the Y pipe no ??

 

[Spider5]

A little off subject but I installed the magnaflow exhaust last weekend and noticed that only three of the four cat's had heat shielding on them. The one under the passenger seat did not. Is it missing on my Runner or is this normal?

 

[sharp4runr]

Here is a picture someone recently put up:

<img src="http://www.toyota-4runner.org/attachment.php?s=&postid=134226">

Looks like it is suppose to be that way for some reason...

 

[Spider5]

Strange but thanks for the reply.

 

[OUTRNNR]

A little off subject but I installed the magnaflow exhaust last weekend and noticed that only three of the four cat's had heat shielding on them. The one under the passenger seat did not. Is it missing on my Runner or is this normal?

4 Cats? The 4Runner only has two right? Aren't the other "bulges" resonators?

 

[00328]

I believe it has three cats. A small one on each header pipe and then one bigger one in front of the muffler.

 

[rolla_dink]

The 03 and up 4Runners have three CATs. Two pre-cats off each header and the Main CAT where the two pipes eventually go into. Removing the two pre-CATs would be ideal in the event you want to upgrade your headers and have some substantial gains. Just getting different headers like the JBA if they even make them for the 03 and up 4Runners is not IMO worth the $/hp on such a large displacement engine. You would need to get two O2 simulators to keep from throwing a code. Technically you will still retain the Main CAT.

The other option and I have explored this is to have the two Pre-CATs moved back as far away from each header as possible. This gives you a long-header effect for the exhaust gases and will yield some gains.

Anyway I know this is one of my first post, but I been modestly modify for some time now. I've pretty much finished my Corolla and I'm working on my 4Runner. I'm sure you guys will see more of me around!

 

[Koz]

I had seen an article somewhere that showed good hp gains from replacing the OEM cats with Magnaflow's HP High Flow replacement cats. Seems like the cost and work involved might not be worth it, but it might be worth researching!

Koz