Is this a worth while mod??
What sort of power increases are achieved??
Is there any downsides to this mod??

 

From what I can astablish the pre 98 or 98 cars had a cat in the up-pipe which makes it worth changing but after the 97 I do not think it is worth it.

This is no way set in stone, I really have no definate idea just bits I remember from previous threads.

Try a search for up pipes there is bound to be a few somewhere.

Neil.

 

No Impreza had a cat in the uppipe prior to the New Age cars ie. MY01.

I think the current philosophy is that it is only worth doing it on pre-MY01 cars if:

1. Headers are ported/changed thus increasing/modifying gas flow characteristics which may be hindered by the OEM uppipe (although this can be ported also).

2. Increased boost is being used where the sliding joint in the OEM pipe has been known to split.

Andrew...

[Edited by AndrewC - 11/21/2002 9:23:52 AM]

 

Just picked my MY02 up from scoobysport with new up-pipe and ported headers.
Upsides? It takes off soooo much better in 5th gear at motorway speeds, spools up earlier, pulls better off boost, faster on boost, revs cleaner to higher. No noisier at lower RPMs (with my APS system which is fairly quiet), snarls more and sounds nicer and a little louder at 3.5k+.
Downsides? It's a difficult job, didn't fancy the DIY, and fitting costs/gaskets etc cost about as much as the cost of the bits themselves. That's about it though.

 

Hades,
how much did that job cost you overall??

ScoobyDoo69

 

Scoobydo - YHM