SwoleDaddy

What's up HT,

I'm got a lot of suggestions/recommendations to swap out the stock cat and install a hi-flow cat along with the installation of my Toda header (2.5"). However, i don't have too much knowledge on hi-flow cat's at all. Can someone steer me the right direction on which one to buy or a specific one to buy? I know there are direct fits/universals but i have no clue what the difference is.

Thanks!

grumblemarc

iTrader: (4)

Are you talking about REAL high-flow units or the cheap Ebay test pipes that call themselves "high-flow"? If the latter it doesn't matter. If the former, Magnalow come to mind.

X E Ryder

I have the Magnaflow; price is reasonable and cat is short, yet wide, straight through type. Would be hard to run one less restrictive without removing it altogether.

nealnanoHX

Just do a test pipe. If you must do a cat then Magnaflow.

mikekh10a

iTrader: (2)

i also stand by magnaflow

canadaek

the difference is direct fit comes with the flanges and 02 sensor hole and the universal just has a couple of inch's of pipe on each end.

dirty19

iTrader: (1)

I dont see any benefit from a high flow cat.
If you do get one make sure it has its CARB number or off to the Smog Ref you'll go when you get pulled over.
Not like you are going to see any noticeable hp gains.
Louder yes, HP you might pic up one or two.
Power to money ratio....not worth it.

Marvin1985

iTrader: (5)

Dropping the cat will give you a few extra hp. All depends on setup. Stock with bolt ons max ~5. Turbo setups I've seen ~30 hp difference on dyno

slomofo

iTrader: (1)

I've seen more than 30 with a turbo, but this guy has a Toda header, I doubt he'll see more than a 2hp increase. He might even lose a pound of torque in the process.

dirty19

iTrader: (1)

These 30hp gains are with a turbo not a cat... Im almost certain the OP isnt looking to turbo his car.
He lives in California.
SOoooooooooooooooooooo that being said and there are no carb legal high flow cats..
he has no choice but to be illegal or stay stock.
If the OP lives in So Cal he has a good chance of being pulled over for a mobile roadside smog check.
Seen many a import pulled over by the CHP only to get that famous smog referee pass for illegal parts on the car.

dirty19

iTrader: (1)

This is very true.
Only with copious amounts of money falling out of ones pocket can you achieve substantial hp gains.
Not all go fast parts equate to HP gains. Some negate others.
Buying a box load of parts doesnt always mean you will have more hp.

nealnanoHX

Magnaflow makes Cali emissions legal high flow cats. Most aftermarket replacements cats are made to meet Cali emissions. As for a universal cat not having a O2 sensor fitting that is only for OBD1 and older style cats, pretty much all OBD2 universal cats will have a O2 sensor fitting.

slomofo

iTrader: (1)

There's no such thing as an OBDII specific cat, furthermore not all OBDII cars have an O2 sensor in the cat. Lastly, some OBDI cars have an O2 sensor in the cat.

2LEM1

iTrader: (1)

??

Yeah there is. Well, there's a difference in OEM cat's between OBD1 and 2, and aftermarket ones as well. And there's CA specific cats as well.

2LEM1

iTrader: (1)

OP - your header creates your exhaust scavenging, everything after that is just a bottle neck. If you're looking for power lose the cat and go with a 3" exhaust.

https://honda-tech.com/forums/all-motor-naturally-aspirated-44/3-exhaust-vs-2-5-b18c-any-dynos-2860054/

jbpnoman

2LEM1, that's the all motor forum, where they do **** like high comp pistons and long duration cams, and need stupid amounts of airflow to actually make power. Since OP A) lives in CA, B) hasn't said anything other than TODA header, and C) Lives in the **** state of CA, he should neither lose the cat, nor go 3".

...I don't even think the TODA header is CARB cert...

2LEM1

iTrader: (1)

Toda is not Carb cert, nor is any 'high flo' cat I know of legal in CA anyway.

Read the threads. Backpressure is a myth. Bigger is better. Always. Even on a B16.

jbpnoman

For power, maybe. That's not a conversation for the general tech section.

I can't believe I just spent 10 minutes finding this for OP.

MagnaFlow 47256. CARB legal, 2.5", high flow. Yes, it does exist, yes, it is legal. Have fun paying out the nose for it.

slomofo

iTrader: (1)

Negative, Ghostwriter, there's vehicle specific and universal, no OBD specific. I never said anything about CA, you're tossing that in yourself.

X E Ryder

Yea it would help if OP told us what he's working on, though right now seems only we are worried about it - no reply from OP!

Magnaflow claims only difference in 49 state to CA cats is the stamped writing in the casing bottom, and the huge sum of cash they had to pay Cali for the right to make them...

http://www.magnaflow.com/02catalytic...irectfit=36636

SwoleDaddy

Sorry for the late reply guys I was out of town

I have a 2000 EM1. My biggest concern right now is swapping out my current stock exhaust manifold because it has a crack on it. I have a Toda Header in my garage waiting to be installed but I just want to know what hi-flow cat I will need.

I live in CA so there's no way I'm going to run without a cat. Thanks for all the info though y'all!

SwoleDaddy

This is a universal cat yes? Would you recommend a direct fit?

There's so much different models for my 2000 Si.

Magnaflow 51093
Magnaflow 22630
Magnaflow 446630

Not sure what the difference is besides it's price tags.

crazyhouse2011

Why does california have to be such a dick about cars? i've always wondered that. hell, my car basically has NO exhaust. a 3 inch stainless piping with ONE resonator all the way out to a 6 inch chrome muffler and a 4.5 inch tip. Thing is louder than any flowmaster mustang or hillbilly camaro in these parts. believe me, it's unbelievably, break-your-ear-drums loud. it took me 6 months to finally get pulled over for my exhaust being too loud. 6 MONTHS. and i tend to lay hard on the throttle. My car is ridiculously loud for a 1.6. i got a written warning.
my suggestion to you is buy an oem cat. not only wil you be paying a **** load of cash for the part, but you will be hemmoraging cash when the berries pull you over and send you to the smog ref. just get the oem and be happy you have RESTORED lost power. game over.

X E Ryder

Hehe Now that I can relate to - Why is right! Well said man.

49 State cats are the Same Product as the CA cats, but they don't have to pay to certify them and they don't have the stupid stamped lettering "This is a Stupid CA Cat" on it.

Damn the torpedoes and run what you want if you don't mind crawling under there to set it right if you get popped. I live in a smog exempt cty of CA so I don't have to deal anymore (Thank you God) but I would be right with you otherwise.

ZenkaiRacer

Is the Toda header's flange in the same spot as the stock manifold? If not, you may have to get the universal and get flanges welded on.

I know with my Tri-Y it doesn't leave much room for a cat. I'm going to have to get a pretty short cat for it to work.