Exhaust Modification - Advice Needed

[stutzedward]

I know this is a MLOC forum but since I am driving an Airtrek Turbo, the heart is similar to E7-GTA. Anyway, hope I can get some advice here as I don't get much reply from the Airtreker forum. Here goes:

I want to modify my exhaust but I have some concerns here. Need all the sifu's advice. Here are my choices:

A) Full 2.5" repiping, de-cat with new mid-box & HKS Silent HiPower muffler (or equavilent silent muffler) - cost Rm3K

OR

B) Decat with new mid-box, retain original piping & muffler. Will get a tatinum exhaust tip for look - cost Rm350.


I know the price difference is a lot but my concerns:

1) My financial minister disallow me to modify the exhaust and really hated NOISE! I travel long distance occasionally. Don't wanna deaf me and my family from that.
2) I want the look and I love the HKS Silent muffler a lot!
3) I do not want too much noise but I want a nice rumble tone. Will (A) be too noisy?
4) How about power improvement, is it significant with (A)?
5) How about fuel consumption?

My current FC is about 6.5km/L in KL City with 20% spirited driving. Car is stock standard except for K&N drop in, Iridium plugs, manual boost controller (upped 0.3 bar from standard), HKS intercooler piping and SQV.

Appreciate comments.. thanks!

 

[mizunori77]

there is a solution for you if your exhaust is loud. you can try using those sound proofing material that those car audio uses. then your cabin inside will be quiet and less noisy...

as for the exhaust, you may not gain any power with option B because the piping is still original. is option A custom piping or those off-the-shelf full set exhaust with muffler?

 

[stutzedward]

Option A will be custom piping. Don't think it's easy to find off-the-shelf pipes for Airtreks here in Msia.

I know B will not gain power, but that's wht my wife wanted cos she drives it too.

 

[basis]

Hi Guy
I;m running option B also for my hyundai matrix 1.8, slightly more deep bass because of the faster flow rates from de-cat n bigger mid box. One thing you notice the faster pickup ( my car is NA).If you want to use for daily driving i think is okie, and cheaper option, if the sound is too loud, get a silencer to be put in the muffler , able to reduce some noise because the silence restricted the flow rate a little bit.

Another option is to used the exhaust valve control system. where you can adjust the diameter of the exhaust output. Think is a vavle to control the flow rates, if u close the valve more , less gas go out less sound, if you open up all the way more gas go out more sound. But of course the power output might be change.

 

[mizunori77]

oh... if she also drives your car, then quite dangerous for you to choose option A coz she will notice the difference in acceleration... sure kena marah...

maybe u can go for option B and consider the sound proofing or add the silencer lor... :wavey:

 

[stutzedward]

Thanks for the replies. I guess B is to go for. Hoping de-carting will give a bit of omph n slightly louder tone. I don't mind tht.

 

[bnr32]

Id recommend de-catting and getting custom piping for your catback along with a new high-flow muffler. Then later when you have the funds you can get your front pipe and the rest of it done. It doesnt have to be noisy to get a power increase, you can get a 'kotak' muffler instead of a cannon which will keep things civil. You just need slightly larger piping, which will give you better flow plus a bit of extra boost from the decreased pressure in the system. The main difference in noise depends on your resonators or 'hot-dogs' and your muffler itself obviously.

 

[stutzedward]

I went for option B. Have not gotten a chance to test if there's any power improvement because of traffic jam.

Out the cat, in the straight flow mid-box.

4.5" dual layer stainless steel tip.

 

[egiewan]

stutzedward....you did the right thing. I think that is the best setup for airtrek and gta. I'm driving a GTA and I've tested with 5 sets of exhaust already. I think the stock system is the best. But you need to change the front pipe to 2.5inch and do a de-cat. Quiet and powerful :-) Dun mind me asking, where did you do your de-cat? Welds and workmanship looks horrid man.

 

[stutzedward]

Egiewan, thank you so much for your feedback and you are a good testimonial for me. I made the right decision then. I am also glad there are so many helpful ppl around here that is not selfish of sharing experiences and knowledges.

I have no plans to repipe it (eventho at first, I plan to) as the stock is 2.2 or 2.3. Is the difference drastic when upgarded to 2.5"?

I did it at a shop near my house, I think the welding is just 'okay' but since it can't be seen, I am fine with it. :)

Thanks for your comments again bro.

 

[egiewan]

Yes, if you change the front pipe...the throttle response will feel lighter. From the outside it looks like 2.3 inch but actually if u look at the stock front pipe carefully, there is one section where the pipe is 'dented' abit. Not sure if there is a ready made custom front pipe for airtrek...for evo got alot bro. Where are you staying bro? I can recommend to you a very good exhaust shop near my place :)

 

[stutzedward]

I see... Im staying at Old Klang Rd. Some update on the difference in performance.

I drove over 350km yesterday. A big difference was the boost, it starts spooling much earlier now. Before this, 2200rpm but now, even a gentle press on the throttle sees the needle swings to positive zone. Is this good or bad?

The car felt very much lighter n more willing. Acceleration was very brief, I must say its more powerful.

 

[bnr32]

As I said before, boost will be affected slightly. As long as it maintains its peak boost without spiking, then earlier spool up is a good thing :D

 

[stutzedward]

Thanks again for all who gave advises. Another update, I am already back in KL. The entire journey was very pleasant. The more I drive the car, the more I like the difference. The car felt much much lighter and very willing to go when I pedal down especially in gear accleration.

This is not the best part.... the best part was when I refueled the car. This is the first time I am getting 9.25km/L! All these while, the best I've got was 8.36km/L and this is a record FC!

Wow, I didn't expect decatting can be so much difference. Best of both worlds, more powerful and yet, better FC. :D

---------- Post added at 09:44 PM ---------- Previous post was at 08:53 PM ----------

Just sharing 2 videos of my exhaust tone (Option B setup) for those whose curious to know how it sounded like. :)

Exhaust tone, idling.
YouTube - Airtrek Turbo - Idling Exhaust Tone

Exhaust tone, revving.
YouTube - Airtrek Turbo - Revving Exhaust Tone

 

[Stormvolution 9]

stutzedward,

Hey, congrate tht u hv made a great move where u r very happy with the result!!! Hahaha... Oso welcome u to the modding world!!! Airtrek is a very good car, powerful, 4 doors n spacious!!!

Fyi, normally when the boost come early it will means FC will b heavier too!!! When boost goes up, fuel and air wil b increased too in order to give the engine/car more power! So it will b interesting for u to keep us update on yr FC, especially in city drive!!! Test few rounds n do a average count!!!!

Welcome u to MLOC forum, and yep, there r lotsa very frenly members here willing to share their experience with anyone looking for advises!!! Do stay tune n welcome to the modding world too!!! Hahaha... I bet now u find car modding is getting more n more interesting!!! Cheers mate!!! Happy modding too!!!

 

[kampoon]

stutzedward,

The next step is to change your extrator, get those nice nice titanum...banana hose.....
Should be same as those evo using .......for sure will increase your car performance without adding any extra noise....

 

[stutzedward]

stutzedward,

Hey, congrate tht u hv made a great move where u r very happy with the result!!! Hahaha... Oso welcome u to the modding world!!! Airtrek is a very good car, powerful, 4 doors n spacious!!!

Fyi, normally when the boost come early it will means FC will b heavier too!!! When boost goes up, fuel and air wil b increased too in order to give the engine/car more power! So it will b interesting for u to keep us update on yr FC, especially in city drive!!! Test few rounds n do a average count!!!!

Welcome u to MLOC forum, and yep, there r lotsa very frenly members here willing to share their experience with anyone looking for advises!!! Do stay tune n welcome to the modding world too!!! Hahaha... I bet now u find car modding is getting more n more interesting!!! Cheers mate!!! Happy modding too!!!

hey man, tnx so much for the warm welcome. I've been driving on NA all these while n hv zero knowledge in turbo cars. This is the first one. Yeap, a single tank of fuel can't determine the fc but it was surely surprising. Will keep y'all updated. :)

---------- Post added at 08:12 AM ---------- Previous post was at 08:09 AM ----------

stutzedward,

The next step is to change your extrator, get those nice nice titanum...banana hose.....
Should be same as those evo using .......for sure will increase your car performance without adding any extra noise....

Bro tnx for advise. Can I know if those banana can house the original turbine? AtrR uses td04 n I plan to get E7 or E8 together with the cams n valve spring, tht's where the diff is, compared to Evo's engine n the reason why it's 40hp n 40Nm lesser.

 

[Stormvolution 9]

But u hv to make sure u take good care of yr auto tranny when u do the engine upgrade ya!!! Its important to keep yr auto tranny healthy!!! Mayb a good tranny oil cooler will help much in the later stage!!! Cheerz!

 

[stutzedward]

yr not the first one who advised me to add on a oil cooler kit for the tranny. thanks, it's in my todo list... upcoming soon. :)

 

[basis]

Hi Guy
I also plan to add auto tranny cooler, any recommendation on the workshop and part staying around QUG , Kuchai Lama area.
Many thanks