HKS Exhaust Choices - Which one do I go with?

[Ashikabi]

Originally Posted by SuperTom

Yeah my Legamax premium came out higher pitched than I thought. Of course I have no cats just resonators taking place of them. Was thinking of having a high flow cat added in between the 2 resonators of the hks front pipe.


Or could go outside the box and have a cherry bomb welded in somewhere. That would give it a deep tone. But the louvers inside cause turbulence. My setup is 60mm piping all the way front to back for high velocity and no turbulence. ARRRRRRRHHHHHHHHHHHH! Looks like we cant have our cake with these cars

It's probably the high velocity causing the higher pitch

[SuperTom]

Originally Posted by Ashikabi

It's probably the high velocity causing the higher pitch

That's possible although I thought internal muffler design had the most to do with it. just read this article
http://www.gomog.com/allmorgan/exhaustbackpressure.html


Down-turned tips, particularly those that force the exhaust underneath the car, can deepen the exhaust note by bouncing sound off the ground and using the undercarriage as a resonator. The ground will absorb much of the annoying high-frequency sound from smaller displacement or more restricted engines.


So the legamax tips are slightly pointed up which doesn't help

[SuperTom]

Also read this deals specifically with Subaru engines. Basically saying a chamber style muffler will take highs off


https://www.physicsforums.com/thread...t-tone.723376/

[Ashikabi]

Originally Posted by SuperTom

Also read this deals specifically with Subaru engines. Basically saying a chamber style muffler will take highs off


https://www.physicsforums.com/thread...t-tone.723376/

My GReddy cans were deep as fuck. I miss that cold start...

[Sam.Vera]

Originally Posted by Clipdat

Those are some impressively fast shifts!

Thanks!

[Darkrune]

Originally Posted by SuperTom

Yeah my Legamax premium came out higher pitched than I thought. Of course I have no cats just resonators taking place of them. Was thinking of having a high flow cat added in between the 2 resonators of the hks front pipe.


Or could go outside the box and have a cherry bomb welded in somewhere. That would give it a deep tone. But the louvers inside cause turbulence. My setup is 60mm piping all the way front to back for high velocity and no turbulence. ARRRRRRRHHHHHHHHHHHH! Looks like we cant have our cake with these cars

I had this same issue, but I placed the stock fp on and it made it super tasty with uel headera.

Sent from my SM-G935V using Tapatalk

[SuperTom]

Originally Posted by Darkrune

I had this same issue, but I placed the stock fp on and it made it super tasty with uel headera.

Sent from my SM-G935V using Tapatalk

Yeah adding the Stock FP back in would take icing off the cake with the piping very small in some areas.


I have enough room on the HKS FPS to put a small cat in between the resonators. It looks like 60mm cats would have to come from overseas. Overnight parts from Japan!

[weederr33]

Curious if anyone here has the HKS catless EL manifold or the "super exhaust" linked below. I wonder how it performs compared to other equal length headers. It is neat how the super exhaust includes a front pipe.

https://www.hks-power.co.jp/en/produ...haust/db/15165

[SuperTom]

Originally Posted by weederr33

Curious if anyone here has the HKS catless EL manifold or the "super exhaust" linked below. I wonder how it performs compared to other equal length headers. It is neat how the super exhaust includes a front pipe.

https://www.hks-power.co.jp/en/produ...haust/db/15165

If money was no issue that would be a good path as that front pipe comes with a cat. Not sure why they don't sell that front pipe separate.


The dual resonated FP has a good sound but you still get some unpleasant smell. After driving a few thousand miles + a tune the sound has gotten deeper and that initial off the line high pitch is gone. Setup Gruppe-S UEL + Overpipe, HKS DUAL resonated FP, HKS Legamax Premium Catback.

[weederr33]

Originally Posted by SuperTom

If money was no issue that would be a good path as that front pipe comes with a cat. Not sure why they don't sell that front pipe separate.


The dual resonated FP has a good sound but you still get some unpleasant smell. After driving a few thousand miles + a tune the sound has gotten deeper and that initial off the line high pitch is gone. Setup Gruppe-S UEL + Overpipe, HKS DUAL resonated FP, HKS Legamax Premium Catback.

I do wish that front pipe was available. It would be great with the ace header. I'm still debating which set up.

[SuperTom]

Originally Posted by weederr33

I do wish that front pipe was available. It would be great with the ace header. I'm still debating which set up.

The JDL ultra quiet front pipe is probably the quietest with a cat and resonator. I think mine is second with the 2 resonators. Also saw Hooker has a front pipe with a cat & and Helmholtz pipe which could work as well.


It sounds like the FP's with just a cat and no resonator are still very loud and raspy.

[weederr33]

Originally Posted by SuperTom

The JDL ultra quiet front pipe is probably the quietest with a cat and resonator. I think mine is second with the 2 resonators. Also saw Hooker has a front pipe with a cat & and Helmholtz pipe which could work as well.


It sounds like the FP's with just a cat and no resonator are still very loud and raspy.

It appears the hks has a muffler too. So yeah. Another concern is how the exhaust would pair with a supercharger. In another thread it was said the hks didn't see many gains. So not sure. Either way the sound is amazing.

[Ashikabi]

Originally Posted by weederr33

It appears the hks has a muffler too. So yeah. Another concern is how the exhaust would pair with a supercharger. In another thread it was said the hks didn't see many gains. So not sure. Either way the sound is amazing.

I've heard exhaust doesn't make much for gains on the FRS(not counting headers) obviously forced induction could change that

[weederr33]

Originally Posted by Ashikabi

I've heard exhaust doesn't make much for gains on the FRS(not counting headers) obviously forced induction could change that

Let me rephrase that. I meant could the exhaust support the flow from a supercharger. I ask since it's only 60mm vs 63.5mm. Though I am very tempted to get it considering the ACE header is super expensive.