Baffled Vs. Straight Through

Chris and his friends had great luck in just removing the Cat.  That increased the sound, especially during hard acceleration, quite a bit and only increased the cruising sound a bit.  

They just used a straight pipe, flanged on both ends with quick-connect S/S fittings so they could put it back for the yearly inspection.  

You might be able to find a relatively cheap straight pipe to pop in there and see what'cha think.

Yes, you must leave that O2 sensor there for the engine ECU to work.  Otherwise it freaks out.

Seems like just yesterday that Marty was waxing poetic about his new IM being perfect for him and just the way he wanted it.

So far, (in less than two years) new wheels, new tires and now he's fiddling with the exhaust.

Marty, you have fallen prey to the madness in a big way. How soon before you completely change directions, sell the car and have Henry build you an outlaw?

You have my sympathy, can I have your wallet?

It's an addiction.

Merry Christmas to you, Sandy and the family, buddy. Look forward to getting together once the final thaw takes hold!

I have to agree with the earlier post. Simply pulling the cat and replacing it with a stub pipe with flanges is going to be the most cost efficient way to improve the sound and performance of that system. 4 bolts. Maybe $50.00 - 100.00 (TOPS) and you'd be done.

That's a lot of plumbing hanging out back there. Seeing that photo removed any delusions of me growing my own Subi motor install. Looks pretty involved. I bet it hauls ass though!

Ted

Marty:

I assume your car has all the engine management computer junk, as I know Henry installs all that.  Just be careful fiddling with the exhaust, as my Impreza's check engine light comes on if it is not driven hard enough (read: wife drives it sometimes). 

It has a custom exhaust, and I've had to have work done on it to keep the CEL from coming on.  It still does once in a while.  Thankfully, I assume you don't have to go through emissions testing on a two year basis with your car, as I have to with the Subie.

Marty..remember the backfiring I had in Carlisle?  Carey thought it may have been a small leak in one of the welds... but not so.  Only when he added a small cat did the backfiring go away.  Just a thought.

Yeah, there is that possibility that removing the cat will give the O2 sensor the "illusion" that it's running too rich.  Some of the ECU's compensate for that, others don't.

Marty,

All of the suggestions above are easily doable, depending on the results you are looking for, i.e, sound, more HP, ECU tune, etc.  I suggest that you find a reputable Subi tuner in your area, show him what you have, and go from there.  He'll give you options for power, cost, etc. 

Thanks.  I have the OBD-1 which has less brains which is a good thing in this example.  I spoke to the guy who cut and custom reworked the harness and he said that the engine will not know the Cat is missing.  Its only for smog and my car is SEMA registered.  Jim, good idea; one of the best tuners on the planet is one mile from my house. 

http://www.amsperformance.com/

Marty, I'm going with what the guys already said about trying a cat by-pass tube (simple & relatively inexpensive). Worth a try before investing more money unnecessarily. 

I had one for my '78 911SC Targa. R&R was simply removing flange bolts and disconnect o2 sensor. Noticeable difference in performance but not much in sound. Put cat & o2 sensor back in every 2 years for DMV smog certification.

After living in South Carolina with absolutely NO emissions or safety inspections at all (pretty scary, huh?), and then moving back to Massachusetts with a full inspection every year (not to mention that Pearl's inspection month is JANUARY!! ), I almost envy you guys who only get inspected every two years.

Still, it's kinda cute to see the inspection mechanics fight each other over who gets to drive it into the spec bay.  Then they realize that some of those guys just ain't ever gonna fit (especially with the top up).

Sparkplug non-fouler should fix the cel.