Ok, I intend to start a thread here where people argue back and forth the pro's and con's of aftermarket high-flow catalytic converters... I am trying to decide whether they're worth $70+install to complete my header-back exhaust system. I have heard many people swear by them and others say they're no better than stock... What I want is some opinions and hopefully a few fact-based arguments to go with it to decide... for or against... Thanks for all constructive comments in advance.
when i did my header i did a high flow maganflow obd2 cat
other than it being more on the loud side than i like , i know i need a resonator added to it
being that im supercharged , i wanted the whole exhaust 1 size
frankly just eliminate it if your draging only off road use more flow is more power but if i had to leave it on due to gov regulations by passing emissions free flowing cat all the way but keep in mind you can only put out whats coming in through the intake side and the best id size for exhaust that i have tested header 3in down pipe to free flow cat then 2.1/4 cat back if turbo'd 3in all the way baby
check my ride out from scratch to present and vote for me !!!
http://www.cardomain.com/id/ztwentyfo
That doesn't sound like a bad deal...
www.kronosperformance.com / 732-742-8837
well, Fury, I would agree except my cat has only 11,000 miles on it... so it's not exactly "old"... I wish it was, that way I wouldn't have a problem replacing it... as such, however, it's brand new.
The Header is 2 1/2 inches then it necks down to the 2 inch factory cat and then back up to the cat backs size you had Tony put on. So the whole exhaust system may as well be 2 inch because it can not flow any more air then its smallest diameter part.
Think of it this way. First start off at a fire hydrant and your running regular fir hose.
then have that hose neck down to the size of a garden hose and then back up to the fire hose size. Now how well do you think that the water will flow from the hydrant to the end
where the fire needs to be put out ? You'll be lucky if the water trickles out but the hydrant will still have tons of pressure. Well your engine is the hydrant and the end where the fire is is your tailpipe tip.
Any questions?
Semper Fi SAINT. May you rest in peace.
Jackalope wrote:The Header is 2 1/2 inches then it necks down to the 2 inch factory cat and then back up to the cat backs size you had Tony put on. So the whole exhaust system may as well be 2 inch because it can not flow any more air then its smallest diameter part.
Think of it this way. First start off at a fire hydrant and your running regular fir hose.
then have that hose neck down to the size of a garden hose and then back up to the fire hose size. Now how well do you think that the water will flow from the hydrant to the end
where the fire needs to be put out ? You'll be lucky if the water trickles out but the hydrant will still have tons of pressure. Well your engine is the hydrant and the end where the fire is is your tailpipe tip. Any questions?
lol those analogies are getting more and more complicated.
but yeah, changing your exhaust but leaving the stock cat is a waste of money. You won,t get half the power you would get if you replaced it one that is the same diameter as your exhaust.
15.574 @ 89 mph stock
Ok, so it's not so much that the way the cat is designed actually "flows" better, just that the inlet and outlet are bigger... correct? If I had a 4-1 header and 2.25" cat-back exhaust, would it be very beneficial for me to get the high-flow? Worth the $70?
exactly. and I will throw your statement the other way. It is not worth the hundreds of dollars you spend on an exhaust if you don't spend the measly 70 $ to change the cat.
15.574 @ 89 mph stock
The stock cat has 8 years of warranty so it should be good for at least 8 years.
Gilles
2.3 Ho
As the others already stated, your exhaust can only flow as much air as your smallest diameter opening. A header and cat-back are practically a waste of money because you're stil restricted by your cat's inlet/outlet diameter. Yes, our cats flow pretty well but its their size that has the most restriction on the exhaust.
Blown.
Ok, so far the common consensus is that it's more than worth the $70 for one of those cats ESPECIALLY to complement a full exhaust? You guys reccomend the 94035?
stock cat and high flow cat < no cat
- 93 mph in the 1/8 mile
Member of J-Body Of Michigan.
Skilz10179 wrote:stock cat and high flow cat < no cat
for boost, yes. for anything not boosted, no.
I was a retard, and now I'm permanently banned.
Tim wrote:Ok, so far the common consensus is that it's more than worth the $70 for one of those cats ESPECIALLY to complement a full exhaust? You guys reccomend the 94035?
I installed a 91035 on my car last weekend, and haven't had any issues.
I'd do an eBay search on both and see if you can get better pricing.
Desert Tuners
“When you come across a big kettle of crazy, it’s best not to stir it.”
Tim wrote:Ok, so far the common consensus is that it's more than worth the $70 for one of those cats ESPECIALLY to complement a full exhaust? You guys reccomend the 94035?
I've read some people have had some codes thrown because of the new cat and some have had no problems. I have the 94035 hi flow cat from Magnaflow (2.25" in/out) but I have yet to install it (I'll do this as soon as I get my header). In my personal opinion, I would look into a cat (94035 if you're looking for 2.25"). There's too much ambiguity about 'codes being thrown' and its a waste of exhaust if you don't.
Blown.
Spotabee Racing (The Fake Z24) wrote:Skilz10179 wrote:stock cat and high flow cat < no cat
for boost, yes. for anything not boosted, no.
Not this ish again.
Yes catalytic convertors are restrictive.
No catalytic convertors don't just fail.
They go bad when heated up excessivly. Like misfiring or running rich. Or burning coolant or oil.
Yes "cats" go bad when they hit things. like rocks and small animals.
If you have the money to replace the stock cat, go for it.
If you're saving some money then the "high flow" cat is not needed.
IMO, you're not going to gain much by changing the pipe size. The muffler is the restrictive part.
Maybe after the cat as the exhaust gas temperature rises after exiting the cat.
anyone used a metal core cat...like this one...
they look like they flow damn good
Spotabee Racing (The Fake Z24) wrote:Skilz10179 wrote:stock cat and high flow cat < no cat
for boost, yes. for anything not boosted, no.
I have seen many n/a dyno comparisons in Sport Compact car magazine comparing a test pipe to a cat. Test pipe always makes more power. Plus a test pipe is much cheaper than a aftermarket cat. I personally killed 2 Catco hi-flow cats within 20,000 miles of each other, i don't recommend them.
- 93 mph in the 1/8 mile
Member of J-Body Of Michigan.
^^^^^ mesra, I just bought that cat, getting it all put on next friday. I'll let you know how it goes.
Tim wrote:Ok, I intend to start a thread here where people argue back and forth the pro's and con's of aftermarket high-flow catalytic converters... I am trying to decide whether they're worth $70+install to complete my header-back exhaust system. I have heard many people swear by them and others say they're no better than stock... What I want is some opinions and hopefully a few fact-based arguments to go with it to decide... for or against... Thanks for all constructive comments in advance.
whats to argue on it?
if you increase pipe size, you need a cat with similar pipe size.
pretty much all cats these days are high flow, however tthe pipe size will restrict flow if you use a stock cat on a 2 inch plus system. hence the reason to upgrade.
Quote:
I have seen many n/a dyno comparisons in Sport Compact car magazine comparing a test pipe to a cat.
between SS, sport compact car, and HCI for that matter, i;ve seen more cars and exhaust articles on reg street cars and NON RACE ENGINED cars where cats included gave the higher power margin. also to note alot of times, HP was similar, but torque was significantly higher.
Quote:
getting it all put on next friday. I'll let you know how it goes
please do...ive looked at one of those in person and they look like they flow soooo much better than the magnaflow one i have on right now...it seems hard to find any of them though
