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BmxBandiT

Dyno Tuning after complete exhaust replacement

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Hi. I was hoping someone or several people could suggest or tell me their experiences that follow an exhaust upgrade . I have a 2009 wrx sti Hatch. 2.5litre. I have just purchased an Invidia Cat Back exhaust system including a invidia Downpipe. Dyno Tuning is rec commended.  Has any one done this sort of upgrade? Does the engine light come on due to catalytic converter removal? How much is a dyno tune?  Please help with any advice . 

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If you do the down pipe then you’ll need a tune.

either it’ll over boost or the lack of cat will throw error codes.

tune is somewhere around $1200 depending on what else is going on.

Make sure the car is all serviced and not leaking etc. hub dyno make sure you have the locknuts tool for the wheels is out ready if you have them.

 

more time effort if you swap to 3 port solenoid or intake etc at the same time. 

 

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Car is mint condition absolutely untouched . This exhaust system is all I plan to do. I didn't realise a dyno was needed but it sure is lol. Possum Bourne Motorsport recommended SAS... to do tune . Just exhaust upgrade shouldn't cause any other issues? Other than catalytic removal causing dash lights.  Its Sooooo bloody expensive for the tune . 

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The lack of s*** factory cat converter makes the turbo spool easier so the ecu needs to let the wastegate work early to keep the boost levels the same. 

mine was 24psi spikes and then it’d go into limp mode. 
 

Add the intake pipe at the same time so you don’t retune twice. 

Edited by Gripless

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Hi Gripless...thanks for ur input and advice . Can I ask if u have personally done what I am doin ? Totally original factory 2.5 litre sti? I'm not very motor jargon savvy. I know enough to  change my own oil air filter etc. Lol. So....intake pipe ...my new exhaust....iz it REALLY gonna need to have all thesectrickle down effect upgrades?  Remember..this is a untouched car. And I will keep it that way because in my 20 plus years and legacy 1.8 manual... 2003 wtx manual... 2litre non turbo l99 legacy wagon....1.5 litre 2008 Impreza....and now my fave off all 2009 2.5 litre sti....all those vehicles....never a break down. Nothing mechanical except clutch replacement in th 03 wrx...no problems. I believe because I A: never screwed a vehicle lol B: changed oil without fail..C: NO MODIFICATIONS  other than an after market exhaust on the 03 wrx. This exhaust upgrade should be simple non invasive and yet over $1000 I didn't count on to tune lol. Do...intake pipe ? Why do I need to do this ? Air filter upgrade too ? Where does it stop? 

1 hour ago, Gripless said:

The lack of s*** factory cat converter makes the turbo spool easier so the ecu needs to let the wastegate work early to keep the boost levels the same. 

mine was 24psi spikes and then it’d go into limp mode. 
 

Add the intake pipe at the same time so you don’t retune twice. 

 

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Gripless.. is ur experience with an sti? Not a,wrx...an sti? From untouched to exhaust upgrade ? 

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Yip mine is 2008 sti 2L version. Was fine until down pipe done then needed tune. 
Was still stock everything else even intake.

With the cat back you have no need to tune. 
 

the intake is the only other big gain item before turbo and lots of money. But that also requires a tune as the airflow meter gets all screwed up. Hence the best time is with the downpipe and exhaust. 
that ends the cheap upgrades. 

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By intake..please excuse my lack of knowledge . I feel embarrassed but that's y I joined this forum. I want to. And I really  appreciate your patience . Intake...u mean air filter ...I hope lol. I'm getting the r400 Invidia.. but now I'm concerned cos the downpipe  says it's for NZ and Aust. new 2.5 litre. Mine is  Jap import . Does that matter lol ? Again...thanks fir your patience   . 1st hand owner knowledge beats all. Intake kit 700$ not too had .  

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You might not like that exhaust, it's what I have in mine and it is super loud and droney. That downpipe should be fine. The 2.5’s all use the same exhaust flange and it is for RHD so no issues there.

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You don't need a tune... just make sure it's not over boosting too much... if it is, get an aftermarket boost controller.

 

Havig said that... if you are going to be beating on it at a track day or something... a dyno check before hand is advisable.

Edited by Loren

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Hi Andy mac ...Loren...thankyou  . I definitely wont be track bound. I cruise . Take it easy . Never thrash   ..not ever   ..maybe the odd go cart simulation round the hills where I live. Thanks for info. It's a nice system. I think it's good quality.  If I DONT need a dyno then best not to upgrade intake air filter . I watched a Invidia company spokesman say if u go from standard to a new downpipe with exhaust system you should definitely dyno tune lol. So.....guess I will wait and see. Thanks guys . Another opinion is great  . It's the only thing I want to change on my car..the exhaust.  Let her breathe! 

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You get over boost at low rpm in high gear going up hills. In an auto you have that occur a lot. 
 

you can do the cat back only and it’ll sound good and not drone. The cat and factory down pipe with big exhaust gives a nice bark. 

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The r400 still drones a lot with the factory downpipe, some don't seem to care so maybe I'm just picky but it really bothers me.

It's actually worst when taking it easy at around 3krpm while giving a small amount of throttle. 

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For noise, here's a few sound clips from our 2011 STI, it's a 2L, but the noise volume should be about the same for a 2.5L. 

We started with just an R400, cat-back. Then later on went with a cat-less down pipe, we never did get a CEL from that. 

We had it tuned, as we also did an after-market intake system.

Tuned at SAS as recommended by PBMS and CroweSport, think it was around $700 for the tune.

 

Just the R400 exhaust:

 

R400 + cat-less downpipe:

 

 

 

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