[sm=icon_ladiesman.gif]because neither Magnaflow or Borla have made an exhaust available to the public YET! But they say it's coming soon.

 

I think Mfish meant to just get a flowmaster muffler and have it made to fit the alpha? Any muffler shop can take a universal muffler and weld it into the alpha.

 

I think there are too many restrictions in the stock exhaust system. Replacing just the muffler or actually even installing one of the so called hi-flow systems does not replace the 90 degreebends at the muffler. I would prefer to move the muffler midships and run dual tailpipes straight out the back.

 

I agree...I hate the stock muffler position on all the h3's. I assume the alpha is similiar. I would just go to a muffler shop (if your not a good welder) and have them remove everything from the cat back, weld on a flowmaster 40 series muffler with single in dual out and run dual 1/2" pipes out to the rear bumper. You'll have enough backpressure from the cats that going dual 2 1/2" pipes won't kill your low end torque. It should cost you around $400 to have all this done. And you'll get nice sound from it. Or if you want to go extreme, you can always go header back with a crossover pipe to equalize the exhaust pulses and smooth the tone out, then you'll have a real nice powerful sound. BUt that'll run you a grand or so at a good shop.

 

I had a guy that muffler shop here told me that he could do the dual Flowmaster 40 for about $430. I'm assuming that is what you're talking about. I wish I had about2 grand laying around. Exhaust, hilljobs roof rack, PCMforless, Granetelli MAF. Oh yea, the atlas transfer case too. Guess I should wish for about 4 grand

 

$430 sounds fair, I have had exhaust done by the same guy for my last 12 cars/trucks so he cuts me a break....I could have the h3 done for $300 through him. I just didn't like the sound of a flowmaster 40 on the I5 so I never had it done.

I've had the atlas II sitting in my shop for a year or so now, got it from a junked truck for $350. The junkyard guy had no idea what it was, guess I got lucky. Now I just need a truck to put it in. I'm hoping that sometime in the future I'll have enough money saved up to buy an old 1970's Chevy 1/2 ton pickup with a 454 and rebuilt it, then I'll use the atlas in that....the way things are going I don't see that kind of extra cash for a long long time[:@]

 

My bro-in-law has a 07' I5 so I will look to see if the muffler position is the same as my 08' Alpha.

The Alpha has 4 cats and I'm wondering if removing the one midships and replacing it with a hi-flow muffler would screw up the computer. If not, then I'd like to do just that, a single hi-flow muffler with dualtailpipes straight out the back, all stainless of course.

But then I'd still need a hi-flow intake or air filter tocompliment the exhaust. Nothing available yet!
AIR IN, AIR OUT[sm=happy046.gif]

 

even if it does have 4 cats...which I don't believe it does, but haven't seen it so I'm not sure. But even if it does have 4 cats the rear ones are more than likely not monitored...just won't build up enough heat for an 02 sensor to function properly back there.

I don't understand the 4 muffler thing...I assume there is one in each manifold, does the manifold go into a collector then there is one pipe going back? Or is it true duals going back? I think there is only single pipe back so where are the other two cats? Two in manifolds, one after collector about mid frame then one near the rear axle? IF that is the setup you have then the one by the rear axle is not a cat...it's a resinator...completely different part and not monitored by the PCM.

 

I don't know about the I5's and it's too damned cold and windy out there right now to go look. But looking at the Gibson diagram for thier exhaust it only shows the muffler and pipes from the front CAT back. Seeing as how alot of guys on here have it, I'm asuming it doesn't cause a problem. None of them have said anything about it.

 

the I5 has a manifold cat, an front inline cat and a rear resinator....the gibson exhaust removes the resinator and puts a muffler in it's place, then runs dual pipes to the rear bumper. This is the ideal setup IMO...the resinator does nothing but quiet the exhaust and is not monitored. A lot og guys confuse the two but the resinator is completely different.