I have a 3.4L 04 taco in California. The truck has two catalytic converters. I am wondering if the converters are the bottleneck in the exhaust path. I ordered headers and cat back but now I wonder if they will matter with the CA catalytic converters sitting between them??? any thoughts?

 

If you are not supercharged removing the cats will not make that much difference. Removing them will not be worth the costs involved or the smog hassle or having to put an O2 simulator in so you won't have to stare at a check engine light. JMHO

 

Probally wont hurt much, if you want to; carsound makes hi flow cats you could put in. They are priced very well.

 

its not that I want to remove the converters, Im just wondering if they will negate all of the positive affects of the headers and exhaust? In my mind, the headers and cat back are like the top and bottom of an hour glass and the catalytic converters are the pinched section in the middle. But I don't know about flow ratings and such of the converters.

 

certainly not, you will still flow better. The header and exhaust will still flow more than the cats, and I would consider two new hiflow cats, but?? Another question, is there a o2 sensor aft of the 2nd cat?

 

On his truck----yes.

 

never mind the test pipe for emmissions then....

 

I just put on the cat back last night and it sounds nice, haven't noticed much difference in power but I still have headers and a supercharger sitting in my garage waiting to be installed. Just based on the looks of things, I am going to have to cut and weld the catalytic converter to attach it to the headers. Someone else stated that only 4runners have this issue. What is the truth about this. I have an 04 prerunner in CA with two cats.

 

You DO have to cut and weld a new flange on the first cat. I had to do it on my 04 Tacoma. As far as I know all 3.4s have to have this done with the TRD headers.