Anyone w/ Highflow Cats?

[RCA1186]

My catalytic converter is making a horrible horrible rattling and it has been for a LONG time (I know its not the heat shield or anything else but something inside the cat). Anywho, I was wondering if anyone on here has installed a high-flow cat (magnaflow) I was planning on replacing mine, and I figured might as well throw a performance one on there, they're even cheaper than stock.

I want to know if the highflow cat will trip the MIL or cause me to fail emissions, if so I'll have to go stock. Anyone?

[wireless]

I can't say for the Aurora... but on an older truck I had, I had the catalyst inside of the converter rattling around (VERY ANNOYING) and I bought a cheap $90 converter and it didn't trip any codes or anything. It was OBDII also..

[lanceslambos]

ya part of the honeycomb inside has broke off. worst case scenario it could block the exit and your car could burn to the ground. though it's unlikely. performance cats are regulated and must pass a sniffer so i wouldn't worry about it. if one fails i would just keep all receipts and make the manufacturer take care of it.

[XJSman89]

Solution:

Step 1: Get emissions tested now and get a sticker that's good for a couple years
Step 2: Buy the hi-flow cat because you know you want to
Step 3: In a couple years when you need a new inspection, go to the junk yard and get a stock cat for $1.50 and bolt er' on there
Step 4: ;D

I rest my case.

[auroradude]

I just had a Magnaflow high-flow cat installed on my '95. It was only $60 for the cat so I figured what the heck, cant hurt to replace one that is 17 years old. It made no difference in performance or sound that I can tell though. Maybe a slight difference in growl from the exhaust..

[RCA1186]

Thanks for the responses guys. Collins, I'm almost certain our testing is once a year haha, as long as it doesn't trip the MIL (and from what you guys said and what I've read I don't think it should) then I should be alright for the test, they just plug in the OBDII port.

Lance, thats exactly what I think happended, I also think it maybe holding my car back and possibly messing with idle, it used to only rattle when it was warm but now it does it all the time and the other issues just appeared as well.

[XJSman89]

I think you should be fine... the high-flow cats shouldn't set off any kind of sensor. The ones in production are probably made to still pass emissions. I think you'll be alright.

Buuuuuut I'm INFINITELY glad that we don't have inspections or front plates in Kansas. All that you need to do to own a sidearm is to have a background check saying you're not a psyco and it's yours, too. We love guns down here. God bless America. ;D ;D ;D

[RCA1186]

LUCKY haha, I'd kill not to have to take emissions, I probably would'nt even have a cat lol But yeah I'm almost certain that the magnaflow should be ok. In fact I think there is a shop nearby that actually installs them for you.

[Deleted]

Oct 13, 2011 9:48:13 GMT -6 RCA1186 said:

LUCKY haha, I'd kill not to have to take emissions, I probably would'nt even have a cat lol But yeah I'm almost certain that the magnaflow should be ok. In fact I think there is a shop nearby that actually installs them for you.

Hold on....we have to take emissions when we live in chicago land? In central IL I know for a fact that we aren't required emissions testing.... 13 title registrations in springfield and I never once had to pass a sniffer test.

[RCA1186]

Well I'm in Cook county that could be it, the closer to a major city the more strict the testing, and don't get me started on California, HOLY H-E-L-L.

But to register your vehicle here you have to pass emissions testing, you could also lose your license if you were to fail testing and never get it fixed.

[RCA1186]

Well I have the high-flow cat on its way, what do you guys think I should expect to pay for a muffler shop to weld it in?

They would have to cut off the old one, weld this one in and weld in a bung for the post-cat o2 sensor.

Also on that note, how will they do that? Just weld in a bung a little downstream of the cat?

[Randy T.]

I don't like most auto shops, I had a cat installed and resonator removed, cost about $300 and they did a hack job, also installed a smaller cat. Eventually, I had to scrap that whole exhaust system.

Do you have a link to the cat you bought so we could get a better idea of what we are working with? I would tell them you want your old cat, too. Those are valuable and will help you pay for the work you are getting done. Even if it's just the stuff broken from inside the cat, it is still worth money.

A lot of people on here just hallow them out, but then, we don't have emission testing either. Another thought, kinda like Collins said, a spare exhaust system, it takes about 45 minutes to swap the whole thing, lol. And I think it's the '06 DTS, it's exhaust will pretty much bolt on with a little tail pipe mod, and it's a 1/4 inch bigger.

Oh and Collins, cats are so valuable that that is one of the first things they cut off when a car goes to the scrapyard. Stock @ ones are the larger GM type, so they are more valuable, I have got a bill for a scrap one. Just the stuff from hallowing them out get you 20-40 buck depending on the price that day.

[RCA1186]

Randy its magnaflow 99006HM the one they recommend for the Aurora on their website.

I know how valuable they are haha, around here at the Metra train stations, people get their cars robbed of them while they are parked in the lot during the work day. Thats right, they go under the car and hack off your catalytic converter and sell it.

As far as the bolt on exhaust swap, one I think I would be too lazy for that haha, but also, the connection point where the cat bolts up to the rest of the system is so rusted that the bolts don't even resemble bolts anymore, they are for sure going to have to cut off the cat to get it off.

[Randy T.]

That was going on at the airport parking by my old house, too. I was surprised that when everything got stolen out of my van at my house that they didn't cut the cat off.


www.summitracing.com/search/Year/1997/Make/OLDSMOBILE/Model/AURORA/Department/Exhaust/?Ns=Rank%7cAsc

Here are a couple other types, a couple are an easier bolt on version. Those bolts are a pain when they rust off, they break off and you have to drill them out.

I also don't see where it says yours is a "high flow" cat, except that it's a magnaflow, it appears to be a universal design. Correct me if I am wrong.

Are most Aurora cats considered high flow because of the size of them? Am I correct in thinking this? Or is there a way a high flow cat is made differently?

To cut it on both sides, weld it in and weld the bung in, I would guess you are looking at $100-$200 depending on where you go. It could even vary higher or lower than that.

[RCA1186]

Not 100% sure that one is a highflow, it doesn't even matter much to me either way, was just looking for a cheap replacement, and at $74 not bad haha.

[RCA1186]

Got the cat installed today! Rattle is gone (FINALLY!) And the exhaust even sounds deeper/more throaty, I am well pleased!

[lastrights]

Just wonder is it 3 in 3 out ? Is the 02 hole on cat or our side ? Getting ready to do mine

[RCA1186]

The o2 sensor is actually just past the cat so it doesn't need to be altered the inlet and outlet its 2.5 inch I believe

[lastrights]

cool ! thats easy replacement , i was just gnna swap to the 2.5 size cat then a 2.5 flowmaster then 2.5 all the way back and remove the big 2 muffller

i didn this with my ram and it was awesome , i just wanna do this onece with the car and be done lol