Standard Exhaust for RX-Turbo ?

[discopotato03]

Hi all , does anyone know if anyone makes a standard first joint back replacement exhaust for RX Turbos ? Mine looks like a std read small non turbo Leone sedan exhaust and I'm curious to know whats available off the shelf . Don't need a drainpipe exhaust either so a 2.5" and up is out .

Cheers Adrian .

[timmo]

The zorst shop told me that there was no off the shelf alternatives to the standard pissy thing so he bent up a 2 1/4" pipe for me. Pretty cheap and sounds heaps better, especially without whiney clutch fan.

[discopotato03]

Fair enough , RX's have a reasonably simple exhaust (back half) so not hard I suppose . I was also thinking along the lines of 2.25" max with reasonable mufflers and low restriction cat .

Possible long term plan is a better than std header , twin up pipe and if lucky one of those nice IHI twin scroll ball bearing turbos .

Needs engine freshen up first .

Cheers A .

[Suby Wan Kenobi]

Go 2.5in with the turbo and use a normal turbo muffler not a cannon you get a quiet system that has a nice bark when angry

[brumbyrunner]

2.5" is a good size for the RX.
Use a 3" dump pipe if you want to improve things further.

[discopotato03]

Yeah well I have my own ideas on exhaust size and turbo engines .
Where the EA82 Turbo engine is a bit unique is is single exhaust port per bank (head) . I'd say Subaru used reasonably heathly sized header pipe diametre because EA82 MPFI engines have two cylinders exhausting through each one . The fact that the offside head vents into the header pipe at 90 degrees means that performance will be affected because its exhaust pulses have to make a sharp right hand turn and will interfere with pulses from the other head . The result is greater turbine inlet pressure at the exhaust housing which means enhanced reversion dramas . For best results they really need to be equal length and merge as close to the turbo as possible . This way with a propper twin scroll turbo you can divide the exhaust pulses and have them timed to not overlap in the wrong places .
Tiz a great pitty that they don't have an exhaust port per cylinder because with propper manifolding they would work better in a performance app .

Its all fine and well to use huge exhaust pipes south of the turbo but if the restrictions are north of it then there comes a time when going larger down stream has little or no benefit - personally I can live without avoidable noise because I don't use my cars to project myself .
Lots of issues with drainpipe sized exhausts .

1) Noise and efforts/expense/antics to shut them up .
2) Weight/packaging .
3) The larger they grow the more rigid they become and they end up acting
like an engine steady with lots of mechanical noise/vibration resonating
along the pipework . Soft points like flex joints can be used to help avoid
this but more cost/weight/complexity for zip if it was not needed to start
with .
You can only reliably use modest boost/revs with EA82's so for not the most modern 1800cc four big pipes are not necessary in my book .

My opinions only cheers A .

[julian]

For best results they really need to be equal length and merge as close to the turbo as possible .

Don't forget that the reason soobs have that lovely and distinct engine note is that the headers are unequal length.