Full exhaust System for NA yaris

[t0m4s]

Originally Posted by CASTREX

The DC header mentioned above is actually a 4-1 design. There is only one 4-2-1 header available for the Yaris and is from Weapon R.

In theory a 4-1 will provide a better gain and higher rpm while a 4-2-1 will provide better gains at the mid range. The problem is that by design the Yaris header is so short that I doubt there is much difference between any of the current model available. So I would tell you to choose the one that fits your budget!

If you want the ultimate set up and still keep it legal for emission testing I will tell you to get a high flow cat Only one or at least remove the secondary cat leave the primary cat. You already have a bolt on muffler so you just need the mid pipe.
If you can get mandrel bent tubing go for 2" pipe if you can't get it, then go for 2.25" pipe.
If you want it civil, snap a round mufller/resonator in the middle in place of the OE resonator and ou are good to go!

And the header will make some difference as long as you work out the rest of the muffler. Not much gain by mating a header with a stock exhaust.

i've heard that seddan 08 has 2 cats and there are 2 air sensors after each cat, when you do that mod above what r u gonna do with the sensors? it will not give u CE light?
i'm asking cuz i wanna do a mod almost like this

[CASTREX]

Originally Posted by t0m4s

i've heard that seddan 08 has 2 cats and there are 2 air sensors after each cat, when you do that mod above what r u gonna do with the sensors? it will not give u CE light?
i'm asking cuz i wanna do a mod almost like this

Sedan = Liftback. The only difference is the axleback section. In the sedan is a little longer.

Both models come with 2 cat converters. First one just after the exhaust manifold and the other one a few inches after.
The car has 2 sensors on the exhaust the first one and the most important is in the header. You can not mess with that one. Then there is a second sensor right after the first cat. The function of that one is monitoring the functionality of the Primary (first) cat. That one can be easily tricked if you plan to go catless. There is no sensors after the second cat. Therefore you can remove that one if you want and your car won't even notice it.

[t0m4s]

Originally Posted by CASTREX

Sedan = Liftback. The only difference is the axleback section. In the sedan is a little longer.

Both models come with 2 cat converters. First one just after the exhaust manifold and the other one a few inches after.
The car has 2 sensors on the exhaust the first one and the most important is in the header. You can not mess with that one. Then there is a second sensor right after the first cat. The function of that one is monitoring the functionality of the Primary (first) cat. That one can be easily tricked if you plan to go catless. There is no sensors after the second cat. Therefore you can remove that one if you want and your car won't even notice it.

so when i change the header i just need to leave the sensor where it is and replace the header?

[CASTREX]

Originally Posted by t0m4s

so when i change the header i just need to leave the sensor where it is and replace the header?

Yes. You just need to unplug the sensor on the stock exhaust manifold. Take the manifold out and install the header and finally put te sensor back on the header. It should have a bung for the sensor. Pretty simple