pimpUall

Maybe I missed it but, does anyone know why? I know sometime they reduce power on lower modles to give the top more of an advantage. Just wondering. thanks

WRX Rush

iTrader: (7)

Maybe subaru figured out that they are killing horsepower and overkilling emissions by oodles?

Someone may have a better answer but I have no clue myself. Good question.

Rush

Wrxneffect

iTrader: (7)

does the STI turbo setup casue the uppipe to get hotter than the Wrx setup? If so I would think that to save money they only have one type of cat that they use, so to elimate possibbilty oft he cat being destroyed and getting sucked into the turbo the STI upipe is catless. Just a guess though. Waiting for the more knowledgeable ppl to hcime in.

Jason

hockeygod

My guess is that with 3 cats the regular WRX can be better suited for more of a family car while pretty much the only people that buy STI's are more enthuists. Its probably the reason the WRX also comes with RE92's.

pimpUall

Why are 3 cats better for a familly car? The WRX is not sold as a family car. It's sold more as a performance car. If any thing they would save money on one less cat and help spool up. As for the STI uppipe getting to hot. Cats need heat to work properly so heat would not be a problem.

pimpUall

does the forester XT and Legacy GT 2.5 turbo have 2 or 3 cats?

04blkWRX

I thought the STi has variable valve timing to help with emissions so it doesn't need the 3rd cat...

meilers

The up-pipe cat is actually for cold-start emissions; once the engine is up and running and the other cats are at full temperature, its effect is negated. Valve timing wouldn't be an issue on cold-start, I don't think, as this is essentially at idle.

My theory is that the uppipe cat was put in to appease California emissions standards, one of the few states (perhaps the only one?) that tests cold-start emissions. As California always seems to be making their emissions standards more and more strict, perhaps the "pre-cat" was installed to head off any future restriction or penalties on importing the WRX.

As for not having one on the STI, perhaps that engine gets hot fast enough or has a great enough exhaust volume to heat the post-turbo cats quickly and prevent cold-start emissions, or perhaps something else along the drivetrain has been altered to make up for this. Are the EGTs of the STI that much greater that it might produce hot enough temps to damage/melt a pre-turbo cat?

rhenry

iTrader: (1)

could it have something to do with the 2.0l vs the 2.5l as far as emissions go, I have heard before that smaller engines have a stricter emissions regulation.

gotwrx

I suspect it has to do with fleet averages. The emissions sticker on the WRX indicates that it is a "low emissions" vehicle (at least it did on the 2002) but the STI is near the top of the range. The WRX is much higher volume seller than the STI.

There was some discussion about Subaru trying to get a Legacy model to qualify as a truck for this reason. Not sure what happened with that

Tim

EsoterikWRX

IIRC the Outbacks are classified as trucks by the EPA or some other gov't agency...