Help me choosing between these two manifolds

[norcalpb]

I have the HKS header and it is surprisingly heavy for what it is, but I do like how it’s styled after the OEM header minus the cat.

[gpvecchi]

Originally Posted by weederr33

Well the top one is HKS and it's a decent header. I'm not familiar with the bottom. But I'm sure either or will only net very little difference.

Nope, the top one is not HKS...

[NLSP]

Depends on your goals/priorities. Recognizing both headers...

Header 1 would be the better daily driver. Comes with a catted and resonated front pipe that's known for keeping almost stock noise levels. And as you mentioned, has better low-end torque.

Header 2 seems to be more track oriented given the company's background and as you mentioned, produces more power in the higher RPM. I predict this unit will be louder. Comes with a strange catted HALF front pipe; you chop the OEM front pipe in half and keep the resonator side, then use a slip joint/clamp to connect them. The dinky OEM front pipe resonator isn't the best at keeping noise/drone down, especially compared to the larger resonator that comes in the front pipe of Header 1.

[gpvecchi]

Exactly what I needed, thanks! You discovered the brands, I see... The half front pipe, is for japanese laws, if you replace the resonator of the front pipe, you need to get the homologation for the full exhaust, or you'll have to keep stock cat back.
I'll go with the first one, that's Apex'i. The second one is Revolution Garage.

[KillerBMotorsport]

Bottom header will perform better IMO. Neither are great, but if you HAD to pick based on design appearance potential, the bottom one has more aspects that would lend it to make better power.

[86TOYO2k17]

Longer front runners 4-1 or 4-2 increase power at the top end
Shorter front runners 4-1 or 4-2 increase power at midrange
Longer 2-1 runners increase mid range,
Shorter 2-1 runners increase top end.

[gpvecchi]

Originally Posted by KillerBMotorsport

Bottom header will perform better IMO. Neither are great, but if you HAD to pick based on design appearance potential, the bottom one has more aspects that would lend it to make better power.

I wouldn't say that Revolution headers aren't great: all the dynos I found of Revolution headers, Revolution/Gruppe M intake, 70 mm throttle body and Revolution/Revotec remap are around 220 HP and 24 Nm torque (japanese premium fuel)...

[FSFRS]

Originally Posted by norcalpb

I have the HKS header and it is surprisingly heavy for what it is, but I do like how it’s styled after the OEM header minus the cat.

I recently took off my stock header (didn't have shields either) and was surprised how similar it looked to the 1st image.

[churchx]

I wouldn't consider similarity to stock as any kind of pro, rather opposite, as stock header for several prioritized reasons, like emissions, mass production cost, clearance, might be more compromised then aftermarket parts with performance as main goal.
Characteristic subaru-ish UEL was not put there on many subbies for specific sound. Design was chosen such to reduce material used and cut costs, with worse performance compensated with more boost. I'm sure, that there are many compromises with stock twins header aswell, such as below optimal runner lengths, too wide merge angles and such. Different priorities.

[tomm.brz]

actually stock headers perform quite good if decatted, very similar to hks el
>17 stock headers are better because they are real EL and a bit bigger.. with good fuel you get basically the same performance as hks El, they also fill the dip quite good

[Brz-123]

Originally Posted by tomm.brz

actually stock headers perform quite good if decatted, very similar to hks el

>17 stock headers are better because they are real EL and a bit bigger.. with good fuel you get basically the same performance as hks El, they also fill the dip quite good

That's news to me. Did they change exhaust headers/ manifold in 2017+ MY? I thought they changed the intake manifold from black plastic to red aluminium which added 5 HP but did nothing on the exhaust side.

Sent from my SM-G781B using Tapatalk

[tomm.brz]

the red aluminum manifold doesn't really add anything, also it heat-soaks and transfers heat more easily to the charge compared to the plastic one
The exh header changed a bit and that's also why has more HP
We in Europe didn't get it

/OT

[Brz-123]

Originally Posted by tomm.brz

the red aluminum manifold doesn't really add anything, also it heat-soaks and transfers heat more easily to the charge compared to the plastic one
The exh header changed a bit and that's also why has more HP
We in Europe didn't get it

/OT

Thank you for that. Now I know why I don't know as it didn't happen in Europe. The 2022 / new GR86 header will be even better as per the videos from Stratfield and their dyno runs.

Sent from my SM-G781B using Tapatalk

[KillerBMotorsport]

Originally Posted by gpvecchi

I wouldn't say that Revolution headers aren't great: all the dynos I found of Revolution headers, Revolution/Gruppe M intake, 70 mm throttle body and Revolution/Revotec remap are around 220 HP and 24 Nm torque (japanese premium fuel)...

I didn't say any were bad, just based on appearance one has a better design. I've designed a LOT of headers over the years, many for Subaru engines, and tested/compared Subaru headers, more than I can count. Appearance is a horrible metric to judge a header by though. Testing rules all, regardless of what anyone might think.

4-2-1 is not ideal from a performance optimization standpoint. A 4-1 will always perform better, unless the design envelope causes a poor layout, which is almost always why a 4-2-1 version is used. A header is further down the road on our project list, but we will test everything first to know where the bar sits performance wise. I'm more concerned about price point where there must be a cat included TBH.