revoltingasp

05 WRX STI STRAIGHT PIPE Questions

Recommended Posts

Hey guys!

(new to the forum so sorry if anything is misleading)

 

I currently have a stock 05 WRX STi apart from a Muffler delete. Looking at getting a straight pipe on my STi. Talked to my local Pitstop who told me he is unsure about how the "secondary 02 sensors will cope and that due to this I cannot get my cat removed". Looked online and apparently after a straight pipe you need to get an ECU tune done so that the 02 sensors dont freak out. Can anyone shed some light on what I should do in a step by step for a straight pipe so I dont mess anything up as this car is my pride and joy. Also does anyone know any good ECU tuner's in AUCKLAND as thats where im based! cheers guys and gals!! :)

Share this post


Link to post
Share on other sites

hey man,

 

have done that to the same model as u

you can remove the cat and get a straight through turbo back exhaust

a tune really livens up the car.

Pm me and we can have a further chat

 

  • Like 1

Share this post


Link to post
Share on other sites

It will be obnoxiously loud, at least put a resonator in, unless you like yarning with policemen and little green windscreen stickers.

  • Like 3

Share this post


Link to post
Share on other sites
26 minutes ago, Loren said:

Why not just share the info here?

need to know what all is on the car and what all is planned as part of the ball of mods

plus some people prefer different things (power,spool, loud noises...) - no single answer fits all hence we always do custom maps only ..

 

and agreed with Boon - straight pipe will be LOUD and announce your car when you enter your street ... and needs a wof time plan as well cos will be above the DB reading if they test

 

  • Like 1

Share this post


Link to post
Share on other sites
7 hours ago, Pappu1 said:

... and needs a wof time plan as well cos will be above the DB reading if they test

A straight pipe is illegal even if it is under the DB level.

 

From the VIRM:

Reasons for rejection:

1. A vehicle is not fitted with an exhaust system that includes a means of sound reduction (Note 1) (Note 6).

....

Note 1:

Exhaust system means a pipe assembly through which the engine exhaust gases pass to the atmosphere and includes some means of sound reduction such as a silencer or resonator.

 

Note 6: (external wastgate stuff)

 

https://vehicleinspection.nzta.govt.nz/virms/in-service-wof-and-cof/general/exhaust/exhaust-system

 

 

A stock 05 STi is a tidy car, a turbo back straight pipe would be one hell of a way to change that. Just my 2c.

  • Like 5

Share this post


Link to post
Share on other sites

Hey all! 

 

Thanks tons for the info! Im probably just going to go with a resonator delete as this car is fully stock and I still want to keep the reliability and "stockness" of the car as I still even have the full factory exhaust in my garage :) I just want to have the iconic subie rumble which HOPEFULLY I can achieve w/out  getting tunes done etc. (however ill be making sure whatever I do wont damage the car etc) Awesome feed back from all of you guys im extremely impressed with all the honesty from your comments. So thanks tons! 

Share this post


Link to post
Share on other sites

I hate to break it to you but no matter what exhaust or tune you put on it you won't get any rumble. The 05 STI has equal length headers, so they don't rumble, period.

  • Like 4

Share this post


Link to post
Share on other sites

Ffs I’m an idiot I’ve got so much work to do. 😡 Im used to subies having unequal headers so idk how it slipped out of my mind (rough couple months blah blah) Got a resonator delete today and the previous owner has removed the cat which I didn’t realise until the resonator was gone so now I have a bloody 3 inch straight pipe which just rapes people’s ears. Sounds like a bloody loud honda now! been told if I remove cats I need to get a tune for the secondary 02 sensor however I’m the second owner of this Subaru and there’s no warning lights etc but he’s certain he DIDNT get a tune after removing cats. He also mentioned he turned up the boost to 20-22 psi and when I’m on the motorway in 5th at about 4k rpm and I ease my foot I can feel the boost cutting in and out so would this back up his point of “20-22psi” don’t know where to go from here I’m fully lost with what’s true and what’s not .just want my car to be a reliable and fun car to drive!! What do I do!?!???

Edited by revoltingasp

Share this post


Link to post
Share on other sites

im an amateur so there may some some unnecessary and/or missing things but if it was me i would:

  • get a diagnostic scan done check for any particular error codes. You can actually do this yourself using FreeSSM software. I'm pretty sure these vag com kkl cables work fine https://www.trademe.co.nz/motors/car-parts-accessories/tools-repair-kits/meters-testers/listing-1767032299.htm
  • check all vacuum lines look ok
  • do a smoke test and check for any intake leaks
  • make sure all your servicing is up to date and no gaskets are leaking
  • get a new boost control solenoid if it hasnt got one already
  • get a new fuel pump if it hasnt got one already
  • put a resonator in the midpipe
  • do anything else you want to do before getting a tune
  • get a tune.

Dave at tune technic did mine - I highly recommend him if you are out west. Very professional, knows his S***. The best thing to do is contact a tuner now as well, you can get their opinion on what changes to make before tuning - this is their job!

 

  • Like 1

Share this post


Link to post
Share on other sites

Hey mate, 

 

When I brought my car it had been tampered with and had loooots of issues but that is another story :P . best bit of advice I can give is drop the car to a known mechanic / tuner in your area and just foot the bill to have it sorted. gives you piece of mind knowing its healthy and on a safe tune rather than the thought some backyard mechanic may have tried to toy around with it. 

  • Like 3

Share this post


Link to post
Share on other sites

yeah thanks guys! Yeah I’ll probs revert to a resonator and muffler just because I’d rather it sound all right then wanna be in equal headers 😂. Once that’s done Ill look into tuners. Are tourque performace out west any good? They would be my local tuners

Share this post


Link to post
Share on other sites

Before I make any decisions are there any exhausts out there that you guys reckon sound good for a EQUAL HEADER STi? seen the Tomei exhausts but not really sure

Share this post


Link to post
Share on other sites
2 hours ago, Loren said:

Just get it running right and stop worrying about the sound.

Yeah I’m still going to get a diagnostics on it but as the cars on 43,000 original k’s the  previous owner took the cats off after 700 k’s so the cars been running like that since. I’ll still get a diagnostics done tho!! 

Share this post


Link to post
Share on other sites
16 hours ago, revoltingasp said:

Ffs I’m an idiot I’ve got so much work to do. 😡 Im used to subies having unequal headers so idk how it slipped out of my mind (rough couple months blah blah) Got a resonator delete today and the previous owner has removed the cat which I didn’t realise until the resonator was gone so now I have a bloody 3 inch straight pipe which just rapes people’s ears. Sounds like a bloody loud honda now! been told if I remove cats I need to get a tune for the secondary 02 sensor however I’m the second owner of this Subaru and there’s no warning lights etc but he’s certain he DIDNT get a tune after removing cats. He also mentioned he turned up the boost to 20-22 psi and when I’m on the motorway in 5th at about 4k rpm and I ease my foot I can feel the boost cutting in and out so would this back up his point of “20-22psi” don’t know where to go from here I’m fully lost with what’s true and what’s not .just want my car to be a reliable and fun car to drive!! What do I do!?!???

hey man,

strictly speaking - the cat delete does NOT need a tune in this model ecu

But the higher flow it allows will be best to get a tune so you dont run into fueling issues etc

 

the boost may be raised due to the higher flow and thats where the issue is: it may not be fueling right for that flow since 22psi was never a stock option on that model.

Also, how did he turn the boost up? is there a boost controller in the car? maybe turn is down for now?

 

Confirm as per above :

no vac lines are leaking

what fuel pump you running

 

if you are ok to make a trip to South Auckland, then i would recommend @Subirex Automotive for any maintenance that needs to be done.

diagnostics can be done there and also tuned for the ball of mods you have

 

Share this post


Link to post
Share on other sites
1 hour ago, Pappu1 said:

hey man,

strictly speaking - the cat delete does NOT need a tune in this model ecu

But the higher flow it allows will be best to get a tune so you dont run into fueling issues etc

 

the boost may be raised due to the higher flow and thats where the issue is: it may not be fueling right for that flow since 22psi was never a stock option on that model.

Also, how did he turn the boost up? is there a boost controller in the car? maybe turn is down for now?

 

Confirm as per above :

no vac lines are leaking

what fuel pump you running

 

if you are ok to make a trip to South Auckland, then i would recommend @Subirex Automotive for any maintenance that needs to be done.

diagnostics can be done there and also tuned for the ball of mods you have

 

Hey man! He said you can turn the boost up from behind the glove box? Or something like that. As far as I’m concerned the fuel pump is still OEM but when I did the full service aka compression test, exhaust leak check rady ra they said I’d need to get a new fuel pump eventually however atm it’s still fine. (Bit of a dummy) ahaha

Share this post


Link to post
Share on other sites

nothing behind the glove box that turns up the boost - unless its a hidden boost controller setup there

from factory there is no wiring there to do any boost changes.

 

the pump change is just a safety measure and also means after a tune you will not be potentially running out of fuel pressure etc..

 

check the boost solenoid and see if its still stock and maybe peek behind the glove box in case it does have a hidden unit

 

for the sound - ur stuck with the twin scroll sound but with the right muffler it does sound pretty nice (i somewhat prefer it over the traditional one actually - the x-force mufflers seem pretty good but im sure there are others)

 

what was the result of the compression test?

 

  • Like 1

Share this post


Link to post
Share on other sites
On 9/20/2018 at 0:05 PM, Pappu1 said:

nothing behind the glove box that turns up the boost - unless its a hidden boost controller setup there

from factory there is no wiring there to do any boost changes.

 

the pump change is just a safety measure and also means after a tune you will not be potentially running out of fuel pressure etc..

 

check the boost solenoid and see if its still stock and maybe peek behind the glove box in case it does have a hidden unit

 

for the sound - ur stuck with the twin scroll sound but with the right muffler it does sound pretty nice (i somewhat prefer it over the traditional one actually - the x-force mufflers seem pretty good but im sure there are others)

 

what was the result of the compression test?

 

Hey man ill have a little look but I might just go straight to either torque performance or the tuner you recommended. I got the muffler put back on as I failed my wof and it sounds really good for a equal header so luckily that’s one problem Gone. The compression tests cane back really good (as in even) I’m just at work at the moment but when I get home I’ll try post a pic of them. 

Share this post


Link to post
Share on other sites
On 21/09/2018 at 2:17 PM, revoltingasp said:

Hey man ill have a little look but I might just go straight to either torque performance or the tuner you recommended. I got the muffler put back on as I failed my wof and it sounds really good for a equal header so luckily that’s one problem Gone. The compression tests cane back really good (as in even) I’m just at work at the moment but when I get home I’ll try post a pic of them. 

 

Hahaha even taking it for a WoF with a straight pipe is pretty brave of you :P 

  • Like 3

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.