d3vil0gy

Exhaust write up.(in pursuit of bopbopbop)(updated)

106 posts in this topic

For those who have known me, would know i change exhaust set up like changing clothes in search of the boxiest scream for the WRX.

So i've decided to contribute my experience so the rest of you bros can decide on an exhaust suitable for you and not waste so much money on labour in search of your music.

 

Ride: MY07 WRX EDM Spec

 

Exhaust components contain of:

1. Headers (aka extractors)

2. Up pipe (usually come together with extractors, but not all the time)

3. Down Pipe

4. Mid Pipe

5. Muffler

6. Open Pod (added this in as this does affect sound)

7. FMIC (does create a more deeper tone)

8. Turbo (more flow, more sound!)

9. Tune (aggressive tune, louder)

10. Cams (changes idling characteristics and scream on WOT)

 

Set up 1:

 

Stock extractors and up pipe

Stock downpipe (with cat)

Operated muffler

 

Sound and experience:

 

The sound is indeed louder, slight boxerish note. Very slight in fact. Sound at 2k RPM would sound like stock muffler revved till 4k RPM. Slightly bassy. Boost lvl upped by 0.1BAR. Faster spooler, better high end. By very slight significance.

 

 

Set up 2:

 

Stock Extractors and up pipe

Stock downpipe with cat

NO MUFFLER. (Note: rear muffler box removed)

 

Sound and experience.

Louder den 1st set up. Very boxerish. Not bassy. Loud. Faster spooling, good torque over the RPM range. Boost upped by 0.2 bar.

Note: The stock muffler is VERY restrictive.

 

Set up 3:

 

Stock extractors, uppipe and downpipe with cat.

Fujisubo cat-back (unoperated)

Sound and experience.

Mid lvl boxerish, Mid lvl bassy. Good mid end, not very great improvements in high end. Boost upped by 0.2 bar as well.

 

Set up 4:

 

Stock extractors, uppipe and downpipe with cat

STi rear muffler.

 

Sound and experience:

Muffled boxer. Slighty bassy. Lesser power and torque den set up 2. Boost up by 0.1 bar.

 

Set up 5:

 

Stock extractors, uppipe

DECATTED downpipe

Fujisubo (non operated)

 

Very bassy. Muffled boxer. Very good mid end to high end. Boost up by 0.3 bar.

 

Set up 6.

 

Stock extractors, uppipe

Decatted DP

OPERATED fuji

VERY VERY bassy. Slighty punchier boxer at idle. Spool rate comes fast.

 

*at this point i had a boost controller, can't see up boost by how much*

 

Max boost came in 400RPM quicker.

 

Set up 7

 

Tomei extractors, uppipe

Decat DP

OP fuji

 

With tomei extractors, i lost a huge amount of bass. Boxer had more punch, but less loud. From a burble in the boxer, to massively quick "burp burp burp" Overall sound decreased.

Torque came in 300RPM faster. Very hard punch from mid to high end.

dynoed at this point, compared to stock, there was an increment of 60whp at 0.8 bar. Dynoed came in at 230WHP at 1.3 Bar.

 

Set up 8

 

VF34 turbo.

Tomei extractors, upipe

SIDE PLANT

Blitz Open Pod

 

EXTREMELY loud. EXTREMELY boxerish. SLIGHT bassiness. Low end suffered like crazy. Super fast spool and extreme high end.

 

Dynoed at 330WHP at 1.4Bar

 

Set up 9

 

VF30 turbo

Tomei headers and uppipe

KAKUMEI 3" DP

HKS HI SILENT (Operated)

Blitz open pod

 

Personally, this is the set up i love the most.

Extremely boxerish when boost comes in. Punches harder than a trust. Bassy and NOT boxerish on idle. EXTREMELY loud during WOT. very beautiful exhaust tip.

Dynoed came in at 320WHP. A loss of 10WHP due to no sideplant.

 

Note: Sideplant is extremely free flowing.

 

Set up 10

 

VF34

 

Tomei headers and uppipe

Kakumei 3in DP

Fuji (operated)

Blitz open pod

 

Very bassy. Mid punch boxiness. Spools slightly slower than above. However high end abit better. Bassy boxer idle. Bop bop bop

Power wise, not much difference between operated HKS and operated Fuji, maybe 1-2whp at most, but high end wise, fuji takes the victory.

 

Didn't dyno this set up.

 

 

Setup11

 

VF30

Stock uppipe (pussy died)

Stock Downpipe (pussy died)

Apexi Open Pod

HKS Silent Hi Power CBE (Unoperated)

Extremely silent idle.

 

Bassy moving off

 

Sweet spot at 2.1k RPM (Bassy boxy)

Not as boxer-ish as Fuji

 

Sweet sound on WOT (merge a wrx and an evo together)

 

281whp @1.3bar

 

Sound level:

 

Idle - 79db/81db/78db (3 readings)

 

3,000rpm - 89db/90db/90db (3 readings)

 

 

Setup12

 

VF30

Stock uppipe (pussy died)

Stock Downpipe (pussy died)

Apexi Open Pod

HKS Silent Hi Power CBE (Operated full 3', along with full 3' midpipe)

 

I did both ways on above:

 

1. With muffler wool and resonator

 

2. Without muffler wool and just a 3' pipe

Only difference is that:

1 -> Very bassy and boxerish. Its a muffled boxer but very pronounced when wack on throttle

2 -> Helicopter choppy boxer. Extremely loud. Louder than a sideplant (I don't know why) Extreme boxer without the bass.

 

Butt dyno: Sluggish low end. Solid spool + mid to high end punch.

 

No official dyno figures, but butt dyno comparisons estimate a 1-5whp increment across the mid to high end range. 1.3bar

 

Setup13

 

VF30

Stock uppipe (pussy died)

Stock Downpipe (pussy died)

Apexi Open Pod

Apexi N1 Catback (Unoperated)

 

Butt dyno figures: Loss of high end power. Low end very solid. Strong mid-range pull.

Very bassy idle (not as loud as fuji, louder than un-op hks silent)

Not as boxerish as fuji (but more boxerish than un-op hks silent)

Better low end and mid end than unop fuji and unop hks silent)

High end lose to unop fuji, but win hks silent

Solid bassy growl upon WOT.

Mellowish boxer with bassy kick.

No droning.

 

No official dyno figures.

Idling - 80db/84db/82db (3 readings)

3000rpm - 90db/92db/92db (3 readings)

Manufacture's reading - 92db

 

IMHO - Apexi N1 has the best mix of boxer pur with mellowish bassiness amongst comparisons with the Fujisubo CBE, and HKS Silent hi power CBE, and easily the loudest on WOT. (Note: all being un-oped with the same setup)

 

 

Setup14

 

Blouch TD05-18G

Stock Sti uppipe (pussy died)

Stock Sti Downpipe (pussy died)

Stock Sti extractors

Apexi Open Pod

Turbo inlet hose

FMIC

Apexi N1 Catback (Unoperated)

 

 

Larger sized turbo brought up the roaring characteristic of the Apexi N1, almost like unleashing it and bringing the N1 to life.

Boxy Idle got louder. Idles like a Fuji with boxer note, but more mellow. N1 has a mid-range bassy boxy tune. (As loud as an unoperated Fuji. Louder than unoperated HKS)

WOT is heaven. Apexi N1 is a raw screamer. Boxer note roars and flutters in a very raw way. The scream from the tail pipe is like a V6 straight through kind of fluttering roar.

On stock extractors, uppipe and downpipe, N1 surprisingly can flow very well and does not choke. Can fully utilise the turbo up to 1.6bar. The scream at 1.6bar from the N1 is far different from Trust, Fuji, HKS. I would say the scream is the most raw, rude, in-your-face, loud uncivilised scream that is so addictive.

 

Till date, my favourite still N1 lol.

 

 

*note.

1: Turbo, open pod, inlet hose, fmic, tuning, displacement (2.0/2.5), JDM/EDM, Twinscroll/Singlescroll affects the sound. Therefore every rex may sound different.

2. Single Scroll gives the boxer note, twin scroll sounds like a hybrid evo/wrx together

3: Aftermarket extractors are less boxerish den stock ones, unless they are very unequal which in turn affects ur high end and spooling rate

4. JDM boxy beats are harder and pronounced compared to EDM

5. 2.0 is louder, boxer growls harder. 2.5 is tamer and slightly softer.

6. Some of the above modifications break the law. And contributes $500-750 to the government's pocket.

7. I am lta-friendly, and not in anyway encouraging anyone in trying to break the law

8. Stock is best.

 

Side note- Found out from STA that the loudest passing level for a WRX 2.0/2.5 is ----> 102DB!! Woohoo!

 

 

 

 

Other bros who have anything u wanna contribute, do add as well.

 

Cheers.

 

 

Some videos for reference (not my car);

 

Apexi N1 Catback

 

Fuji + decat

 

Trust/Greddy Pe-Tir w/o silencer

 

HKS Silent Hi Power with cats

 

STI exhaust vs Apexi N1 Catback

 

Open Downpipe (no exhaust)

https://www.youtube.com/watch?v=OOsn5O4f214

 

Side plant (open & close)

 

Wastegate scream

 

 

 

 

 

 

 

 

 

 

 

List of approved exhaust for the;

 

EDM 2.5l WRX(06/07)

 

Catback (Midpipe+Rear muffler)

1. Fujitsubo Catback (Most high end, middle sound)

2. Apexi N1 Catback (Most low end and mid end, most sound)

3. HKS Silent High Power (Strong all rounder, least sound)

4. Trust PE-TiR (Without silencer, best exhaust in the world)

 

Axle-back

None.

 

EDM2.0l WRX (02-05)

 

Catback

1. Fujitsubo Catback

2. Apexi N1 Catback

3. HKS Silent High Power

4. Trust PE-TI

5. Remus Titanium Catback (Rare)

 

Axle-Back

1. HKS Legamax

2. Supersprint

3. Remus

 

JDM Auto 2.0l WRX (06-07)

 

Catback

1. Fujitsubo (only 1st batch)

 

Axleback

1. HKS Legamax

2. Fuji Axleback

3. Supersprint axleback

4. Apexi N1 axleback

5. Prodive (Rare)

6. Remus Titanium Tip (Rare)

 

1.5 Hatchback (08 onwards)

 

Catback

 

Axleback

1. Tanabe

2. Supersprint

3. Remus

4. SYMS

 

 

2.0 S-GT (GH8)

 

Catback

1. Fujitsubo

2. HKS Silent Hi Power

3. JIC Magic

 

2.0 STI (GH8)

 

1. Corazon Catback

 

2.0RS (GH7)

 

1. HKS Silent Hi Power

2. Remus (Muffler)

 

 

- 9tro's awesome compilation for all makes and models:

 

http://www.9tro.com/news/lta-approved-exhaust

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Thanks for the comments bros.

 

OP fuji means operated fuji. Note this is highly illegal. But turns your restrictive fuji into a bassy boxier 3 inch straight through exhaust.

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nice info, an adventurous path you've been through icon_biggrin.gif

 

i'm on hks hi silent. any further comments abt how it'll sound after operating? heard it doesn't sound as bassy as unoperated?

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bryan your car is EDM not USDM lol

 

 

Oops!

 

Corrected, thx bro.

 

Coffee soon man. Heard someone did excellent timing in Sepang!

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nice info, an adventurous path you've been through icon_biggrin.gif

 

i'm on hks hi silent. any further comments abt how it'll sound after operating? heard it doesn't sound as bassy as unoperated?

 

 

Won't be as bassy as unoperated. But u'll get a very punchy burble of the boxer beats =) Alot more mid end power. It's louder den an operated FGK. Not very bassy though.

 

On full throttle, the sound is fantastic. It wraps around you in the tunnel at KPE =)

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Won't be as bassy as unoperated. But u'll get a very punchy burble of the boxer beats =) Alot more mid end power. It's louder den an operated FGK. Not very bassy though.

 

On full throttle, the sound is fantastic. It wraps around you in the tunnel at KPE =)

 

very good write up.

 

btw do u know if HKS hi power 409 got any silencer inside like the silent hi power?

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very good write up.

 

btw do u know if HKS hi power 409 got any silencer inside like the silent hi power?

 

hi bro, from what i know, hks hi power 409's are the ones used in US, Perth etc. , it doesnt has the silencer, but it does have a cat as the rear of the muffler. =)

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hi bro, from what i know, hks hi power 409's are the ones used in US, Perth etc. , it doesnt has the silencer, but it does have a cat as the rear of the muffler. =)

 

It's not a cat, just a resonator (like a n additional straight-thru muffler), not restrictive and not baffled icon_razz.gif

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It's not a cat, just a resonator (like a n additional straight-thru muffler), not restrictive and not baffled icon_razz.gif

 

ah.. i see =)

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just wondering.. how is tuning done with the sideplant?

 

i suppose it is done when the sideplant is fully opened but what happens to performance when it is closed?

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Unless you have an aftermarket ECU that allows switchable maps, you are really only limited to 1 effective tune, either with sideplant open or closed.

 

Theoretically, if your ECU is tuned with sideplant opened, when it is closed your car should be seeing a lot more exhaust backpressure, unstable boost, and possibly running very rich/lean (depending on what ECU you're using - ie. is it closed loop/open loop/adaptive/etc).

 

IMHO, if your car is tuned with sideplant open, you have to take it very easy when driving with sideplant closed, and vice versa. Too many factors and variables are changed when you go from short tract, unmuffled, unrestricted sideplant to long tract, mufflered, silenced, catalytic converted exhaust system, and vice versa.

 

In a simple analogy, you can dress for winter (exhaust), or you can dress for summer (sideplant). You can't expect to wear the same clothes for winter, AND for summer, unless you have 2 sets of clothes (maps) so you can change when seasons change.

 

If you wear winter clothes for summer, you will burnup and dehydrate, resulting in death (engine failure).

 

If you wear summer clothes for winter, you will become hypothermic, freeze and die (engine failure).
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What about Kakimoto? I getting my LGT 2.5 soon, thought the Kakimoto looks nice with the bluish tip. Anyone have experience with that?

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Unless you have an aftermarket ECU that allows switchable maps, you are really only limited to 1 effective tune, either with sideplant open or closed.

 

Theoretically, if your ECU is tuned with sideplant opened, when it is closed your car should be seeing a lot more exhaust backpressure, unstable boost, and possibly running very rich/lean (depending on what ECU you're using - ie. is it closed loop/open loop/adaptive/etc).

 

IMHO, if your car is tuned with sideplant open, you have to take it very easy when driving with sideplant closed, and vice versa. Too many factors and variables are changed when you go from short tract, unmuffled, unrestricted sideplant to long tract, mufflered, silenced, catalytic converted exhaust system, and vice versa.

 

In a simple analogy, you can dress for winter (exhaust), or you can dress for summer (sideplant). You can't expect to wear the same clothes for winter, AND for summer, unless you have 2 sets of clothes (maps) so you can change when seasons change.

 

If you wear winter clothes for summer, you will burnup and dehydrate, resulting in death (engine failure).

 

If you wear summer clothes for winter, you will become hypothermic, freeze and die (engine failure).

 

 

Agreed!

 

And also, there're automatic electronic side plants available in the market. They work like v-tecs/wastegates etc.

 

U can set it to open specifically at 4000RPM automatically. Anything less it will close. This sideplant opens and closes in a split second.

 

Tuning with this sideplant would be the safest, and the best bang for buck mod.

 

U're car would have the boxer beats, turbo spools, ,wastegate opening, bov, and best of all, boxer -v-tec.

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so in a scenario where the stock ecu is in play and tuning is done when the sideplant is open,

 

when closed, will the engine be running lean or rich?

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it will run rich bro. But its not the rich/lean that really matters, its the AFR(air fuel ratio).

 

and also, because the stock ecu is extremely smart, once u drive with the sideplant close, the stock ecu will alter a few parameters to

 

compensate the AFR. And trouble comes when u suddenly open the sideplant and floor it. The AFR will be screwed and the engine check light comes on. U'll have trouble during idling for a period of time till the stock ecu alters the parameters again.

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Updated: setup 11,12,13

 

 

Cheers

 

Bryan

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just chanced upon this. nice write up! btw, just wanna check the approved fgk exhaust on a atrex, isit the same one thats approved for the hawkeye spec c? both needs a axleback one isn't it? so are these the same? thanks in advance. icon_smile.gif

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