Gennady7

Hey all,
I recently installed a Greddy Evo 1 exhaust and I am loving it. During the install, my mechanic who is also my friend told me that my cat is no good and it could be a big reason for the not so good mpg rate. He recommended getting a new one. But I figured I wanted to get a high-flow cat.

Heres my question, I do not want to go with a straight pipe since it is really harmful for the enviornment. Are there any high-flow cat convertors that do the same job as the OEM but allowing more emissions to flow. The OEM ones are way too over priced, dealer wants 4 hundred something.

Thanks, looking foward to the replies.

NmexMAX

iTrader: (22)

A failed cat could mean problems elsewhere.

How many miles? Are you sure you believe him?

Maximaum Driver

From Redline Max:
http://redlinemax.com/catalog/produc...58e45a55709cc2

Random Technology:
http://www.randomtechnology.com/nissan.html

Of the 2, I think only Random says it's a High Flow catalytic.

Overall I'm not a big believer of the environmental angle on the emissions systems. Call me a heretic. But when I have relieved a car of the catalytic systems and see a marked power/mileage difference, I'd say they are terribly inefficient and cause you to use more fuel. Using fuel would cause me to pollute more, etc etc etc.

DOOD! It's just The Man trying to control you!!!! Run Logan!!! We must head for Sanctuary!!

NmexMAX

iTrader: (22)

A cat is a cat, it wont provide no more than 1hp no matter how high flow it is.

RT has a bad reputaion in the early days of the org.

Gennady7

Yeah I do because it does stink like gas coming from the exhaust. Plus the car has 100k now.

Gennady7

Thanks for the replies guys, do you think I should just find an OEM one form a junk yard or something like that?

NmexMAX

iTrader: (22)

Strong fuel smell from the exhaust, like unburned fuel? It's not your cat then ...

Your cat might be dead as a result of another problem, as I stated before.

Gennady7

Yeah I think my car runs very rich.
As a result the cat broke.

Im looking into buying a S-AFC II just so I can control the air fuel ratio. But that will be as soon as I can save up to get it.

My ECM is acting weird and wouldent update when I was at the dealers.

NmexMAX

iTrader: (22)

Your car wont run that rich as to kill your cat, you probably have a mis-fire/dead coil .. something along the lines of that.

Gennady7

Coils were changed like 10k miles ago. Spark plugs are NGK Irodium and were changed 15k ago. Engine runs rich and has almost 100k. Time to change cat 100% but since it runs rich its like 150% lol.

Thanks for the help though

BewstAdd1ct

how did he diagnose the cats being bad? are they plugged/clogged or losing efficiency or what?

you make it seem like he was installing the exhaust and said 'oh, your cats are bad'...

and fix the problem rather than trying to put a band-aid on it (ie, the SAFC)

NismoMaxm

My cat has a piece of the honeycomb rattling aroudn inside...time for a new one?? hahahaha im stuck as to which brand to buy.

NmexMAX

iTrader: (22)

What's your a/f?

Gennady7

im not sure what he did but I do know that when Nissan did a dignostic to my car back when my check engine light came on in august, they wrote that the Cat needed to be replaced.

Puppetmaster

iTrader: (48)

If your cat really is bad, just get whatever ya please... OEM isn't that restrictive anyways, so you're not really gonna get crazy gains on a NA car with a high-flow.

Gennady7

Only thing I am worried about is passing inspection with the high flow cats. The OEM are way too overpriced

Puppetmaster

iTrader: (48)

Maybe try a junkyard or the .Org Classifieds?

NmexMAX

iTrader: (22)

OEM is high flow ...

Gennady7

What kind of gas difference did u get? A lot more mpg?

NmexMAX

iTrader: (22)

A cat wont change MPG

Your posts are killing me

Gennady7

Thats cause I do not live on the forums like somebody...

However a clogged cat can cause a lower MPG rate. Its been proven

NmexMAX

iTrader: (22)

True, yes, but you asked the question in the context that a high flow cat would give gains over a functioning OEM cat in terms of MPG, and that's not the case.

Gennady7

incorrect, he was stating he has no cat, since he does not believe in them.

NmexMAX

iTrader: (22)

I don't either, and still, my statement stands.

remembermorriso

Just punch your cat out until you buy a new one thats what I did.
Stock cats are as high flow as you can get them. As some .orgers know when they experimented with their cats and gained nothing.

GBAUER

iTrader: (2)

This post has good timing. Recently I've noticed that when my car gets nice and warm, the outside temp is near a 100, and I drive the car hard, it seems to want to not go. Keep in mind this has only been happening for about 3,000 miles (3 or 4 weeks due to my job). I have a relativly new tranny in my car. My MAF seems fine because there's no SES and it'll still rev fine in neutral. My air filter was cleaned last weekend. Basically, it feels like I get on it, the engine blows a little smog (I also burn a lot of oil), the cat clogs and the car runs like a$$. Also, the intake gets REALLY loud even at 3k rpms at mid throttle. After about 200 miles of gentle driving, it seems to run OK until I give it gas again and I start the cycle over. I have 124k on it (not mistyped). Is there a way to test the cat? Any other place to look?


I know, looks like a noob question, but I've never had a cat fail in the past.

remembermorriso

I know their is a way to test the cat but Im no mechanic just a Naval engineer. With that many miles make sure you change fuel filter tranny fliud and spark plugs. You probally know this or have done it but It really helps. Im no maxima genius but I wonder driving it hard in heat would cause the engine temp to rise. What oil are you running? Make sure its synthetic and the proper grade. The intake geting loud I have never heard of. Maximas amaze me with the engine computers O2 sensors etc. So their might be some feature that inhibits the cars performance to help control the heat. Also makesure you do a radiator flush with that many miles.
BTW my cat failed at 66k.

GBAUER

iTrader: (2)

Just had the engine / tranny / radiator all flushed 3k miles ago. Changed the plugs 24k ago (at 100k). Never really thought about the fuel filter, but the smoke coming out the back is black which tells me it's probably running rich (blue=oil, white=antifreeze, black=rich fuel mixture). The intake thing has me scratching my head. I have an Injen, but I've had it for 50k so I know what it sounds like. I almost think the cat's clogged causing the rear o2 to ready funny and making the engine run lean to compensate. Just a thought. Anyone else have any ideas? I'm up for anything!

BewstAdd1ct

you can test the cat with a vacuum gauge, for restriction anyway. efficiency will be tested by the ECM...

Maximhuh

OK- No smoke from tailpipes - codes p0430 p0420 - mechanic sais CATs bad. Ordered cat and Y pipe from Warpspeed. Warpspeed sais Y - Pipe eliminates ONE of the 2 front Pre - Cats - Can I eliminate the other ? or better yet find an aftermarket replacement for it? 650$ sais the dealership >.< Could bad plugs cause Cats to go bad? Checking on the ECM update tommorow - will the outdated ECM program cause Cats to fail? 150 thousand miles - ya one hundred fifty thous. yr 2000 Cali-Spec according to the hood / O2 sensors. 5sp.

Will the Cats fail again or do you think it was just the end of their life. ?

OH- Car won't idle for more than 1 minute with the AC turned off. AC on, it stays on ( most of the time ) also - When I rev the engine in neutral and let the RPMs drop - they fall and it stalls - sometimes with AC but always without AC on - I assume the ECU compensates for extra load from AC and thats why it doesnt die as easily with it on - That indicate something or just a bad Cat?

also i'd like to complete the exaust - which 'B' pipe to go with? is there an affordable CAT-back ( including muffler ? ) thats out there..

thanks alot you guys!

GBAUER

iTrader: (2)

I just got the cat from RedlineMax.com (actually, truth be told, I went to Redmax's house and stole it out of his living room...). At 126k, a fried cat didn't surpise me. Since I installed the new one, my gas milage is back up to 26-27 mpg, my accelleration is completely smooth again, and my finely-tuned butt dyno says that I got my power back. The quality of the cat is far superior to any aftermarket or stock I've seen so far. Plus, it fit perfectly. No leaks at all.

Edit: I just looked at the link to Redline max: that's NOT the one I got. Call Redmax (Cory) at 301-218-7336 and tell him you want the one I bought off him. He will have to order it, but its worth the extra chash and time.