I'm trying to find a high flow cat for my 2000 accord lx coupe. I'm wondering if anyone has found any direct fit (3-bolt flange) cats. Also I was told that oftentimes installing a high flow cat will cause the O2 sensor to trip the check engine light. Has anyone had this problem, and if so does the manufacturer provide a guarantee that allows you to get your money back if you encounter this problem? Thanks

 

I have a Magnaflow high-flow cat, and I've had no problems with CEL's. Mine was a weld-on cat, but they also have direct-fit cats.

I paid $120 for the high-flow cat, plus $50 labor to have a muffler shop weld it on.

The direct-fit high-flow cat would have cost me $220.

 

I would agree with those comments from philadd.
You are going to pay good money for a "real" hi-flow catalytic converter. $200.00 sounds about correct. Anything cheaper, and you're probably looking at a chrome plated or polished "Test Pipe" mascarading as a converter.
Magnaflow
Flowmaster
There are several "real" converters out there

P

 

>>philadd.... Did you feel any difference from a stock catalyctic to the magnaflow you have now??? ...also... how big is it? What are the measures of yours?
I saw a few universal from magnaflow, they were either 12 or 16 inches long i think!
Did it mess up your mileage? More power?..
Let me know!!!
Thanks!!!

 

if you open it all up on a vtec motor you're probably gonna feel it bog down at low rpms. i went 4-2-1 headers to grab what little torque it gives, stock cat, and apex'i worldsport exhaust so i have just a little bit of back pressure that vtec likes on the stock motor. I/H/E won't give you more power, but it might shift your power band, so it's most likely to shift torque more towards HP or vice versa. if it's practically straight through, you'll get higher RPM power. not my cup of tea in a daily city driver, but it's all about taste. if you like it, do it.

 

Well... here's my impressions according to the inaccurate butt-dyno:

On the low-end, I haven't noticed any loss of power, and my gas mileage hasn't changed. On the top-end there was a noticeable improvement (again, according to the butt-dyno).

I don't know the size... The shop that got it for me just told their supplier they needed one for an Accord, and that's what I got. I believe it to be 2" in diameter, but I'd have to double check that to make sure.

The biggest thing I noticed though, was that my car became a LOT louder.

Cliff notes:
Close to stock size, both diameter and length
No CEL
Exhaust is now much louder
No loss in gas mileage
Some improvement in top-end
No noticeable loss in low-end

 

You say your car is now a lot louder.... Did you already have an aftermarket exhaust? I actually have 2 reasons for getting a high flow cat, one is because the catalyst is actually breaking apart on the inside,causing a rattling noise, the other is because i hoped for it to be an alternative to getting a good sound out of my car instead of getting a loud, obnoxious pipe. Don't flame me please, I know all exhausts aren't loud and obnoxious but I just can't afford an apexi or greddy exhaust right now. Thanks for all the help everyone.

 

It's been said before, but to reitterate...

A true high-flow cat MUST have a catalyst inside. These cost around $200. The ones you find on ebay for $50 are just bolt-up resonators and have no catalyst. With one of these true high-flow cats, you WILL NOT have a problem with your 02 sensors or CEL's since they do exactly what the stock cat was meant to do, just with less restriction. I went with a Random Technology converter because of their reputation, and the fact that is was an exact fit bolt-on.

Adding an aftermarket header allows MUCH more of the engine noises to be heard and usually increases that 'loud pipe' sound. If you have the stock exhaust or a good quiet exhaust like you mentioned, including the stock exhaust manifold, adding a high flow cat will hardly make a difference in the loudness of your exhaust.

For money's sake, unless you absolutely need an extremely free flowing exhaust, there's not much reason to puchase a $200+ high flow cat when you can get an OEM replacement for $80-$100. If you needed that much flow, you would already have a header, test-pipe, and exhaust anyway. If anything, our 4cyl engines can really use the back pressure provided by the OEM cat to maintain good low-end torque. This is just what PHREAK was saying. Open up your exhaust, and you'll start losing your low-end, and that SUCKS.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jake15348 &raquo;</TD></TR><TR><TD CLASS="quote">You say your car is now a lot louder.... Did you already have an aftermarket exhaust? I actually have 2 reasons for getting a high flow cat, one is because the catalyst is actually breaking apart on the inside,causing a rattling noise ...</TD></TR></TABLE>

Yes, I already had an aftermarket exhaust. On a stock exhaust, you may or may not notice a difference in sound at all. I couldn't tell you for sure...

I had to replace my cat for the same reason. Catalyst broke apart... Damn screen rattling around which just seemed to get louder and louder...

 

Very true AFAccord,and thanks for your input, but my car is a work in progress, very slow progress, and the high flow cat is part of my plans and I figured I may as well get it now since I need a replacement anyway. Thanks again everyone.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jake15348 &raquo;</TD></TR><TR><TD CLASS="quote">Very true AFAccord,and thanks for your input, but my car is a work in progress, very slow progress, and the high flow cat is part of my plans and I figured I may as well get it now since I need a replacement anyway. Thanks again everyone.</TD></TR></TABLE>

More power to ya.

 

I dono if this is the same thing u guys are talkin bout but here's my problem:
I got a big magnalflow muffler put on by a muffler shop and it sounds awesome on my 97 accord, but about 3 weeks after i got it, it started making this rattling noise everytime i start it. I asked a couple of my friends and they said its prolly just related to heat cause once i rev it a couple times or drive around for about 5 minutes, then i dont get that rattling noise when i punch it from a dead stop unlike before. I have no idea if its heat related or not but i dont like it when i jump in my car and pull outa the school parking lot at a normal speed, my car sounds like the whole exhaust is gonna rattle off!!!

Can someone pllzz help me!!

 

sounds like you have more of a clearance issue... get under the rear of your car, shake the exhaust around with your hand and look for any possible points where it might make contact with the undercarriage. (obviously you'll want to do this while the exhaust is cold.)

otherwise, take it back to the shop and have them look it over.

 

haha . . . yeeeeeaaah

that makes sense since my muffler is wedged into my frame. First day of school i back up into a parking space but underestimated the length of my accord . . . so i stuck it in drive cause i thought i was too far back. It reved to like 3k and then jerked forward. I was like "that was weird", then im like "ooo no". I run behind my car and see the curb . . . . theres a chunk taken outa the granite curb! Then look at my muffler and theres a tiiiiny bit of granite dust on the bottom of my brand new magnaflow muffler, but then i look closer and theres barely a scratch except that the prongs that are on my muffler were hanging onto the frame of my car.
I tried everything to get the prongs off the frame but it wouldn't work. I think i somehow pulled/stretched the whole exhaust back enough so even if i get the prongs to be under the frame . . . they still will be 4 in. too far back.

Dono how to fix it and i dono how much it would cost to fix it at my muffler shop . . . but i hate the noise when i start my car . . . errrr.

 

in that case, i would say you've broken a hanger, and the two pieces are clicking together. I woul put money on it.

 

I bought a magnaflow high flow cat converter from performancepeddler.com for $100 and it was a direct bolt on. No welding needed. Its not shown on there site but they can have it shipped directly from the manufacturer which is what I did. Just give them a call. Well worth the money.

 

from what i understand....a legit cat, the brand name ones, are well over 100 bucks and perfectly legal. the ones on ebay for about 30 bucks are completly free flowing. and this will loose back pressure and decrease low end power. but will give you more top end. correct me if im wrong here.

i havent decided which one i should put on yet. but if i do either, will i have to mess with the o2 sensor? or should i just leave it?

thanks,

nick

 

If you get a "legit" high-flow cat, you will NOT have to worry about the O2 sensor.

If you get the eBay "cat", which is just a resonator, you will immediately have a CEL and thus need an O2 simulator. If you were to go this route, technically your car would no longer be street legal. So if you have to worry about emissions or smog checks, don't go this route.

Personally, I would always choose a high-flow cat over the eBay resonators/test pipes.

 

Anyone ever tried Catco cats? I use to have one on my CRX and it was very good, especially for $50. I ran open header and then ran the cat and it didn't feel too different, but better low end power with it on.

 

I think Catco and Magnaflow are one in the same.

 

can i pick your brain a little and ask you what a CEL is? also, what is this o2 simulator, and how much does it cost?

thanks,

nick

 

Check Engine Light = CEL

O2 simulator is basically a resistor device that simulates the 'loaded' feedback the car's computer is looking for from its O2 sensors. This way the car see's what it's looking for when it's really not even there. A happy car = no CEL. Forget where you can find them, but do believe they range from 70-90 bucks. No reason not to spend that money on a legit cat converter IMO.

 

thanks for your imput. i th ink i should get a legit cat then. which is a good one that is cheap for a 99lude? idk if i want to get a OEM one if i can find a better one for the same price or a little more

 

has anyone ever seen this site? click the 2 links on the left.

http://www.discountconverter.c...x.htm


what is eveyrones opinion on this. if i have a rattle, its most likely broken inside im assuming. but should i check everything like what it says on the site?

 

Thanks a lot for your attention!
I want to be riding with one of those in a few weeks!!
Again, thanks a lot philadd!!!!!!!!