CoolHandLC21

I'm planning on going the I/H/E route and know that I want the Injen intake, DC Sports Header and Exhaust. I've been reading through the threads and see complaints about the rasp caused by the header and the resonator to fix it. What else will I need to have the full cat-back exhaust as far as mid-pipe, s-pipe, etc goes?? I'm trying to learn everything I can before I do my setup.

Thanks

tC9o9

dont get the DC headers if you dont want rasp.

Mightygnu

What exactly is your goal? eventually going to go FI? just want I/H/E for a little extra gain?

amdforever

x2 on those questions

I have the Injen CAI, DC header, Invidia s-pipe with CEL fixer, Magnaflow Cat-back. Get a lot of rasp when its cold, kinda mellows a little when the pipes are warmed up be the rasp is still there. I'm going to get 1 or 2 of these http://www.aeroexhaust.com/aero_resonator_ar25.html and then have the whole thing welded up. I know I've posted this in atleast 3 other threads now But yeah, I'm doing this setup b/c I want a little fun now til I build my engine and turbo setup in a yr or 2 from now. Header and rasp practically go hand and hand really. The resonators are there to prevent/dampen it. Like I told others, got questions about mine just shoot me a PM :D

CoolHandLC21

I'm just looking for a lil' HP gain and a nice sound. What would I gain from just the exhaust+CAI? What do the s-pipe/mid-pipe do as far as the exhaust is concerned?

Mightygnu

Not that much from just the CAI + axleback... the larger spipe and midpipe create more airflow, hence making a little bit more power.

CoolHandLC21

If I were to install both pipes would I see a gain even without the header?

Mightygnu

yes, but the header would give a little bit more gain, it all depends on what you want, and your spending budget...

CoolHandLC21

Just to get it straight. If I were to buy a DC Sports exhaust and the invidia s-pipe and "x" mid-pipe would I be replacing/eliminating the catalytic converter(s)?

amdforever

Ok so are you talking about getting Injen CAI and the Magnaflow Catback? If so it will sound nice and you will notice more pulling power in the 3.5k + range. Pretty much it transfers a little lower end torque into higher end HP. It does that b/c you are reducing the restriction/backpressure in the exhaust. Now if you added the spipe that would help you out too as the stock spipe is really restrictive. Having a complete setup of CAI, header, spipe, catback will yield roughly 20whp. I havn't dynoed mine yet but that seems to be about what people have been gaining I do believe. Axle backs aren't going do anything for you performance wise. If your plan on going F/I later then spipe and cat back is the way to go b/c most turbo kits are fine with 2.5inch exhaust. Even if your not going F/I 2.5 would be ok, you just don't want it to be too big, like 3inches, because the exhaust gasses will cool too fast and make the engine work harder to push them through the piping. The s-pipe is literaly a pipe that is shape like a s to go over the front axle. the mid pipe is just that, its the pipe in the middle of the car and the stock one has a big resonator and the small main cat on it. The magnaflow cat back exhaust system will remove the big resonator. Doesn't hurt any until you put on a header. That's when people buy new resonator(s) to be welded into the mid pipe to get rid of the rasp.

amdforever

What would you be replacing the stock mid pipe with...which you allocated with "x" And yes you would be. The main cat converter on our car is the small thing located on the mid pipe towards the front axle. The long thing after it is the stock resonator. If you went with Magnaflow cat back, you cut the stock mid pipe 3 inchs after the main cat and it replaces everything back from there so you will loose the stock resonator which is fine since it will give it deeper tone and you wont have any rasp. Before I put my header on last weekend I had a slight rasp about 2.5k in the mid pipe section due to one of my bolt on clamps not tightening the pipes together right. So when the pipes are warm they expand and seal themselves and the rasp went away. No biggie if yours clamps right and/or you have it totally welded if you don't get a header.

Mugetsu

this is a misconception born from MOST other models/cars.
the "main" cat on the tc is in the HEADER/exhaust manifold this is the large cat metered by both O2 sensors.
the second bulb cat in the pid-pipe is the secondary cat, its main purpose is/was for the S/C so that it could be installed with no further modifications to the exhaust. this small cat is unmetered...

kuo34

I've found that since I've removed the DC sports header on my car I've got more low end torque (at least perceived). The header rattles everything as you bring the clutch out. I'm guessing it's because there aren't any other mounting points other than the engine while the OEM header has the two lower mount points.

If I'm reading the above post correctly then a n/a tC should be 100% emissions okay without the midpipe secondary cat right?

amdforever

If thats a misconception then why would my dealership have it listed as a precat? and the second one as a main cat!

Mugetsu

well you will pass the actual test but not the VISUAL inspection, were the second cat sits is were the cat on every other model has for years, if they don't see it they will ask then look it up then realize the tc comes with 2 and see you removed a cat and you will fail and maybe get a hefty fine in the process...

also yes, aftermarket headers are the biggest killers of low end TQ on tcs , thats not to say they are bad, people just need to understand that there is more to performance tuning than 1. brand name 2. public opinion 3. peak HP!! it all has to do with what exactly you wanna tune your car to do...

i over did it

Mugetsu

[quote="amdforever"]because dealer ships are dumb, and thats just how toyo/scion USA got the specs from japn and because thats were the main AND ONLY cat sits on most every other car...

remove the bulb cat and your tc will never miss a beat, remove the stock manifold and see what happens...its not just "because its an after market header that it throws a CEL" its because you are removing the cat the car recognises as its main emissions device...what the hell is wrong with this post? every time i try to edit it frags up...

amdforever

Hmm, that makes sense. I mean it was explained to me that you get the CEL b/c the second o2 sensor is getting more airflow and thinks the "precat" or "main" cat is not there and throws the light, so you use the antifouler mods to get it out of the main airflow. But yeah, it would make more sense for that to be the main one sense it's bigger...but what is the function of the second one? To catch stuff the first one misses aka, doesn't convert? If so I guess mines pulling overtime now

Mugetsu

well a tiny lil cat is better for the environment than no cat at all!

saying that the CEL is being thrown because of increased flow is a partially true over simplified reason.
its more than that, the second O2 is sensing an increase in just about every thing the cat cleans up.
if you were to extend the second O2 behind the bulb cat, you would throw a cel that claims "catalyst efficiency dropped or below normal" can you figure out what this means..?

the second bulb cat in the pid-pipe is the secondary cat, its main purpose is/was for the S/C so that it could be installed with no further modifications to the exhaust. this small cat is unmetered...

2fast4you

So the tC can meet Ultra Low Emissions Vehicle (ULEV) standards.

Mugetsu

yeah i keep forgetting to add that, but ULEV is such an ugly word...

one last thing, I was running my EVO2 with the stock manifold and a custom 2.5 mid-pipe with a magnaflow highflow cat and my car was so damned ULEV compliant that the inside of the EVO's tip did not even blackened it was still shinny polished stainless showing through...i bet if you tried to kill yourself by huffing the exhaust it would prob take you 2 days to do it... ...j/k...