Budget Performance mods that aren’t noisy?

[ZDan]

Originally Posted by Dyniek

What about a catted header? Would it increase performance? I’m just trying to get more torque at the 3-4k and get more linear torque.

And how much did the sound increase in your opinion from catless header? I can’t stand my car’s noise at 90mph, and it’s only a catback.

Also, is the torque difference noticeable a lot? Like for example do you fell being pushed into the seat when accelerating?

I think the big advantage of catless is that you can lengthen the runners a lot, you wouldn't be able to do that with a catted header as obviously they have to merge at the cat. I could be wrong but I would guess that midrange gains with a catted header are going to be pretty limited.

For noise, with the ACE-350 header and front pipe, factory mid/catback, noise is slightly louder than stock from idle, on the highway it's not a whole lot louder, barely competing with road and wind noise.

[Dirty Harry]

Originally Posted by Dyniek

What about a catted header? Would it increase performance? I’m just trying to get more torque at the 3-4k and get more linear torque.

And how much did the sound increase in your opinion from catless header? I can’t stand my car’s noise at 90mph, and it’s only a catback.

Also, is the torque difference noticeable a lot? Like for example do you fell being pushed into the seat when accelerating?

I got the HKS GT-Spec catted header, with a custom dyno tune and noticed a significant increase in mid range torque and 11.4kw (15hp) increase at the wheels at the top end. Catless gives you roughly 5hp more from what I’ve read on here. Not much noisier than stock, sounds better though, a bit more “angry” if that makes sense. Changing the headers you definitely notice it more in the mid range, which is where the car needs it most I guess.

[Dirty Harry]

Originally Posted by ZDan

I could be wrong but I would guess that midrange gains with a catted header are going to be pretty limited.

I think it depends on the type of cat in the header, the HKS header uses more purification materials but a lower cell count, so it has less resistance and still passes JDM exhaust emissions, pretty much why I bought it. But agree, pure performance, catless headers will get you more gains overall.

From the web.

Brand: HKS
Product: Super Manifold with Metal Catalyzer GT-Spec - BRZ ZC6 86 ZN6
Part Num: 33005-AT007

SPECIFICATIONS:
Series: GT-Spec
Material: Stainless Steel (SUS304)
Layout: 4 -> 2 -> 1
Piping Diameter Size (mm): 60
Catalyzer Cell Count:
-HKS: 150
-OEM: 600

Stock exhaust manifold has a catalyzer and it's causing a resistance for exhaust output that make the engine to perform poorly. HKS SUPER MANIFOLD with CATALYZER GT-SPEC for ZN6/ZC6 uses a compact and high cleaning capacity catalyzer, still it has a low resistance which passes Japan Exhaust Gas Regulation.

[FR-S2GT86]

Originally Posted by Dyniek

So I would like to increase power a little bit in my car, but I’m not sure where to start.

I don’t want to get a turbo or a supercharger because it’s too expensive and I don’t want to risk blowing my engine.

Many people say to get a catless header, but I’ve a TRD edition with TRD catback and it’s already pretty noisy, and the noise is really loud when going on a highway. Also I would like to pass an inspection.

So, are there any other mods that I can make to increase power even if it’s just a few horsepower? Thanks!

Surprised nobody has mentioned this to you yet.



Yes it's a bit old school, and not too many people here have experimented with it, but it remains a viable alternative in your case. Of course a bottle doesn't last very long, but if you're only wanting a small increase, then you can design a low horsepower boost by choosing the right nozzle sizes and make it last longer. Just a thought.

[alex87f]

Shorter FD is probably not a solution if noise is a concern, will make the engine spin too fast on the highway.

Would advise getting a catted header + tune, panel filter and calling it an expensive day