Impreza exhaust
Discussion
Could someone advise me please.
Dad has a 2003 Impreza WRX which he had rebuilt and tuned by API (not too sure exactly what work was done). They fitted a Scoobysport exhaust (manifold and cat), along with an STI turbo i believe.
The cat has failed, so needs to be replaced (he wants to replace the cat and silencer).
He's after a quiet exhaust, but something that still allows him to run the full power (he was told 330bhp, but a recent rolling road showed only 260bhp with 1 bar of boost). So a remap will be in order soon!
Subsequently, he has found out that it isn't a sccobysport exhaust, so we are not sure what it is, hence changing the full exhaust (cat and silencer).
Does anyone have any idea of a full, but quiet system (3 inch i guess?).
How about the Prodrive exhaust, is that any good?
Also, are there any recommendations for garages in the South East that could fit the exhaust and map the car correctly?
Apologies for the ramblings, but i don't know a great deal about the world of Subaru.
Many thanks
Chris
Dad has a 2003 Impreza WRX which he had rebuilt and tuned by API (not too sure exactly what work was done). They fitted a Scoobysport exhaust (manifold and cat), along with an STI turbo i believe.
The cat has failed, so needs to be replaced (he wants to replace the cat and silencer).
He's after a quiet exhaust, but something that still allows him to run the full power (he was told 330bhp, but a recent rolling road showed only 260bhp with 1 bar of boost). So a remap will be in order soon!
Subsequently, he has found out that it isn't a sccobysport exhaust, so we are not sure what it is, hence changing the full exhaust (cat and silencer).
Does anyone have any idea of a full, but quiet system (3 inch i guess?).
How about the Prodrive exhaust, is that any good?
Also, are there any recommendations for garages in the South East that could fit the exhaust and map the car correctly?
Apologies for the ramblings, but i don't know a great deal about the world of Subaru.
Many thanks
Chris
Do you know which cat has failed (Impreza has 3: uppipe, downpipe and centre)?
I'm sure that other, far wiser souls will be along shortly to assist, but AFAIK a 3" system is unnecessary unless you're after lots of power, the standard system is 2.5".
Removing cats will make the car louder; for 'quieter' backboxes I'd suggest either the Prodrive, Scoobyworld Racebox or perhaps Milltek. I test drove a WRX with PPP (inc. Prodrive backbox), and had a Racebox fitted to my WRX, and they were both a lot louder than standard, but neither was offensive.
I'm sure that other, far wiser souls will be along shortly to assist, but AFAIK a 3" system is unnecessary unless you're after lots of power, the standard system is 2.5".
Removing cats will make the car louder; for 'quieter' backboxes I'd suggest either the Prodrive, Scoobyworld Racebox or perhaps Milltek. I test drove a WRX with PPP (inc. Prodrive backbox), and had a Racebox fitted to my WRX, and they were both a lot louder than standard, but neither was offensive.
You have a number of options. But you need to know what CAT has failed first.
There are 3, the 1st one in the uppipe, the 2nd in the downpipe and the 3rd final one just before the mid pipe in the exhaust.
If you buy a WRX Prodrive exhaust Turbo Back this will not include the Prodrive sports CAT. The WRX Prodrive pack only replaced the 3rd CAT with a Bypass Pipe..
The main CAT in the downpipe was only replaced on the STI PPP Pack.
Once you know which CAT has Failed i would get a HAyward Scott Exhaust fitted to the car. They are quiet when you want them quiet but do still have the distinctive Scooby Burble when you want it a bit louder.
Also, if you change the exhaust on the car you will need it remaped as it may have an affect on performance.
Lastly a WRX with a STI turbo wont make 330Bhp.. It could make around 280-290Bhp
There are 3, the 1st one in the uppipe, the 2nd in the downpipe and the 3rd final one just before the mid pipe in the exhaust.
If you buy a WRX Prodrive exhaust Turbo Back this will not include the Prodrive sports CAT. The WRX Prodrive pack only replaced the 3rd CAT with a Bypass Pipe..
The main CAT in the downpipe was only replaced on the STI PPP Pack.
Once you know which CAT has Failed i would get a HAyward Scott Exhaust fitted to the car. They are quiet when you want them quiet but do still have the distinctive Scooby Burble when you want it a bit louder.
Also, if you change the exhaust on the car you will need it remaped as it may have an affect on performance.
Lastly a WRX with a STI turbo wont make 330Bhp.. It could make around 280-290Bhp
As said, not too sure of the spec, but from memory he had uprated injectors, fuel pump, internals, plus more (don't know full specs though).
He said he only has the main cat, so think he is going to go to Hayward and Scott.
As a side note, are the ECUs of Imprezas (2003) 'cracked' to enable live mapping? He keeps mentioning he has a licence for the map? Wondering if he as a 'piggy back' style ecu? Keep reading about EcuTeck.
He said he only has the main cat, so think he is going to go to Hayward and Scott.
As a side note, are the ECUs of Imprezas (2003) 'cracked' to enable live mapping? He keeps mentioning he has a licence for the map? Wondering if he as a 'piggy back' style ecu? Keep reading about EcuTeck.
There's no live mapping of newage Denso ECU's. Even Ecutek has to stop and reflash the ECU eachtime you need to make changes to the mapping in any one session. Open Source is the same. It might take me 5 or 6 flashes + before i'm happy with the end result and it may take 1/2 day + to complete a proper remap but if i'm happy i know my customer will be too.
IMHO i would have left the standard Subaru exhaust manifold on and fitted a 2-bolt slip jointed decatted uppipe. That makes absolutely sure you keep a deep and satisfying burble right the way through the rev range and allows your turbo free flowing exhaust gasses for faster and earlier spooling.
I would leave the std main cat on after the turbo and remove the scrubber (final CAT) replacing it with a straight through pipe, and then replace the long middle section and backbox for something stainless steel from a manufacturer like Miltek although there are others and you should shop around. Just keeping the main std cat in place will get you through MOT emissions testing. Don't be tempted to buy a sports catted downpipe because they don't get you through emissions testing.
The standard Subaru exhaust pipe diameter is actually two and five eighths inches so you should stick to that to keep the exhaust note a little bit quieter and maintains a soft and sweet burble plus a little bit of a restriction keeps torque up. With a 3" exhaust system you are going to lose some of your torque and will make more noise. The standard diamter system will get you up to 340-350bhp with a VF35 or TD05 16G and STi pink injectors. You just need a decent high flow flat panel air filter and a Snorkus Delete mod will finish that off.
Use as much of what Subaru provided you with. You don't need to spend big money to make big gains!!
IMHO i would have left the standard Subaru exhaust manifold on and fitted a 2-bolt slip jointed decatted uppipe. That makes absolutely sure you keep a deep and satisfying burble right the way through the rev range and allows your turbo free flowing exhaust gasses for faster and earlier spooling.
I would leave the std main cat on after the turbo and remove the scrubber (final CAT) replacing it with a straight through pipe, and then replace the long middle section and backbox for something stainless steel from a manufacturer like Miltek although there are others and you should shop around. Just keeping the main std cat in place will get you through MOT emissions testing. Don't be tempted to buy a sports catted downpipe because they don't get you through emissions testing.
The standard Subaru exhaust pipe diameter is actually two and five eighths inches so you should stick to that to keep the exhaust note a little bit quieter and maintains a soft and sweet burble plus a little bit of a restriction keeps torque up. With a 3" exhaust system you are going to lose some of your torque and will make more noise. The standard diamter system will get you up to 340-350bhp with a VF35 or TD05 16G and STi pink injectors. You just need a decent high flow flat panel air filter and a Snorkus Delete mod will finish that off.
Use as much of what Subaru provided you with. You don't need to spend big money to make big gains!!
If you wanted a one stop solution stew at www.tfsracing.co.uk could sort the exhaust and mot and bring it to me for mapping as required.
Isxit possible that there is no cat fitted ? If they changed the exhaust it maybe decatted.
Quiet exhausts like revolution, miltek etc work well
As mentioned the sti turbo should do 300 to 330bhp
Simon
Isxit possible that there is no cat fitted ? If they changed the exhaust it maybe decatted.
Quiet exhausts like revolution, miltek etc work well
As mentioned the sti turbo should do 300 to 330bhp
Simon
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