2004 Legacy GT Exhaust

[Gowest]

Hey guys in need of some help here. Am looking at getting a new exhaust for my 2004 GT Wagon with a bit of power gain in mind. Any sugestions? Is there any advantage of having a straight single pipe instead of the 1 into 2 like factory. Rest of the engine is standard with just and aftermarket air filter. Cheers

[syphe]

Best thing to do is the downpipe, it\'s the most restrictive part of the exhaust, and Subtech in Auckland make a catless piece which gives very good gains.

In terms of power that\'s the only thing that\'s going to change dramatically, you may get a bit more out of replacing the Y pipe, but I think it\'s minor compared to the DP.

I\'ve currently got this setup on my 2003 wagon, it\'s definitely helped, just make sure you get a tune as mine was running very rich as soon as I installed it so needed a tune to get the AFR\'s back to normal.

I\'m currently looking into some mufflers to get a bit more noise out of this setup, just the downpipe makes the exhaust note very raspy, so i had a resonator installed which helped quiet it down but I still wanted a bit more of a growl so going to get some Ultrex mufflers to finish it all off.

X-Force also do a catback which you can get from Redline Performance (have a look on trademe), so along with a downpipe this should finish it off nicely.

[Gowest]

Yeah cool. I really need the cat back at least right now as it got ripped off from the cat back and lost forever. Dont ask how lol. am i better going with a full exhaust system no cat and single exhaust unlike standard double? Does the lack of back pressure matter at all? And if I was to get one made up what diameter? Cheers

[Marky]

Twin is just for looks, dont lose sleep over it

Turbo engine means less back pressure is better

[funkytown]

 Marky said:

Twin is just for looks, dont lose sleep over it

Turbo engine means less back pressure is better

he said before turbos were overspooling and factory boost control wasnt doing its job

[syphe]

if you go for single exit I\'d be keen to see your results

I\'ve read from the American guys that the twin pipes just helps resonate a bit more so technically you\'d be fine getting it converted to a single, might just be noisier.

[Gowest]

 funkytown']

[quote name='Marky said:

Twin is just for looks, dont lose sleep over it

Turbo engine means less back pressure is better

/quote]

he said before turbos were overspooling and factory boost control wasnt doing its job

Thats exactly the kinda thing Im trying to find out.

[Marky]

That is what the reflash is for

Not like an old evo where you have to port out wastegates etc, it\'s just a matter of adjusting to suit the new condition

[Gowest]

 Marky said:

That is what the reflash is for

Not like an old evo where you have to port out wastegates etc, it\'s just a matter of adjusting to suit the new condition

Reflash??

[Rosssub]

Reflash/Retune so it\'s not running rich after changing the downpipe.

[Gowest]

Ok so Ive heard good things about the subtech downpipes. If Im getting a new exhaust made up for me would I be better of getting one made from the turbo back or get the subtech downpipe and get custom from downpipe back?

[GorGasmSpecB]

subtech + custom.

[Gowest]

Has anyone on here gone for the single exhaust way on the single turbo Legacys and with standard turbo and not have any overspooling issues like funkyton said in earlier post?

[Marky]

A twin exhaust will not change the amount of flow - it is twin purely for looks and as said it may play a small part in the tone of the sound it puts out

It\'s not generally a problem most subarus have, and worst case if it did there\'s a dozen guys on here who could re-tune to suit it for you in an evening with their laptop

[syphe]

I did have overspooling issues on mine when I went with the downpipe, but that was down to a split wastegate actuator vac hose causing the wastegate to not open properly, if you did get overspooling that\'s probably a good place to look first.

[Gowest]

Alright I did a bit of research on my engine as when I had the cam belts redone the mechanic told me it was a rare car cos of the engine, he said that engine didnt come into the NZ Legacys until 2010. Just looked it up on carjam its got the EJ207 which is the WRX Sti 1999 and up. Would that be right? It is a JDM car imported from singapore.

In saying that then it would be safe to say that I wont have any problems with the new exhaust overspooling the turbo etc? Thanks heaps for the help guys

[syphe]

2004 should be an EJ20X or EJ20Y depending on transmission, I wasn\'t aware of any BP/BL\'s which had the EJ207, but I may be wrong.

[lunchie]

A remapped ecu will get you more power than doing just the exhaust, if you do both together you should gain a good 20-30kw atw and have a smoother acceleration and better fuel econ