dawrenn

I was wondering if a gutted OEM catalytic converter would add any HP,Would it make the exhaust any louder? He says it will make the CEL come on, He told me that I could piggy back the sensor or get a high flow sensor. Which would be better to do? Or should I just ignore the light?

fasthatchb18c1

Gutting your cat most likely wont give you HP from all the turbulence that will be created in wide open area. If you get a strait pipe and put it were your cat goes that will give you some more HP, and if you do either your car will definitely be louder. And im hoping your doing this for the track and not for the street

dawrenn

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fasthatchb18c1 &raquo;</TD></TR><TR><TD CLASS="quote">Gutting your cat most likely wont give you HP from all the turbulence that will be created in wide open area. If you get a strait pipe and put it were your cat goes that will give you some more HP, and if you do either your car will definitely be louder. And im hoping your doing this for the track and not for the street</TD></TR></TABLE>

I would have it for the street and switch it over when I need to get emissions done.

Vero

putting on a test pipe shows gains of 1-2 hp.

it will make your exhaust loud and pungent.

You are a tool if you think it is worth those gains to spend an hour switching it out every time you get pulled over/emissions.

eg6_rick

i have a custom fabricated test pipe on my exhaust right now. it wasn't my idea, but the mechanic at the shop put it in there saying that, " your cat is no longer useful and is holding Hp." Showing me that the honey comb was all blocked. I say big deal and had him put the test pipe in there, now my car is hella loud but it feels alot faster than before and response is better. BTW i have sport headers and my state dont ref. but check your state law and stuff before gutting it. and make sure you have a spare cat in case you go to ref your car.

Galaxy Si

a staright pipe or gutted converter will not give you any hp during daily driving, matter of fact it actually decrease hp, because you need at least 1-2 pounds of back pressure for sufficent exhaust flow. if your racing, then in that case it does add a few horses.

BadRelge45

on my old gsr integ. i made the mistake of listening to my friends and gutting my cat. it didn't set any engine codes but it sounds absoluteld HORRIBLE. It makes it louder but the worst **** is when you let off the gas and you get that horrible gurrgling noise. Sounded like a caviler with a rusted out muffler

fasthatchb18c1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C1 Del Sol soon &raquo;</TD></TR><TR><TD CLASS="quote">a staright pipe or gutted converter will not give you any hp during daily driving, matter of fact it actually decrease hp, because you need at least 1-2 pounds of back pressure for sufficent exhaust flow. if your racing, then in that case it does add a few horses.</TD></TR></TABLE>

you never need backpressure

Galaxy Si

if your not racing and not reving your car to high rpm's, then no you dont need back pressure, but for daily driving and cruising you do. with no back pressure at low rpm's, the exhaust actually starts to recirculate over and over through the gutted cat. this in return cause blockage from gases trying to excape. the reason why this doesn't happen when your racing is becuase the exhaust is being pushed through at such a high rate, no wind tunnel is being created

Bond

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C1 Del Sol soon &raquo;</TD></TR><TR><TD CLASS="quote">if your not racing and not reving your car to high rpm's, then no you dont need back pressure, but for daily driving and cruising you do. with no back pressure at low rpm's, the exhaust actually starts to recirculate over and over through the gutted cat. this in return cause blockage from gases trying to excape. the reason why this doesn't happen when your racing is becuase the exhaust is being pushed through at such a high rate, no wind tunnel is being created</TD></TR></TABLE>

This is untrue if you are running a test pipe. There is no way any gases could recirculate with a straight pipe. With a gutted cat then yes because you give the exhuast somewhere else to go other then straight out. Gutting a cat is stupid. Why not just run a test pipe instead of wrecking a good cat. As for the guy that had that "gurguling" noise, that is what happens when you gut a cat. You are allowing gases to move in other directions (side to side) other than just one with the added room. It screws up the flow pressure and back pressure.

hatch34

dont gut the cat just get a test pipe if you have to do it. guttin your cat will mak eyour car sound like total **** i did it and hated it.

stripes777

dont gut a stock cat, those babies are expensive

Honduh Tooner

i fabbed up a test pipe for my 99 si. welded a O2 bunge in for the sensor. the light came on till i put my chipped P30 in. it gets a lot louder but as for the sounding light **** part, it depends on ur exhaust too. i have a apexi N1 and my buddy has hayame and ours is fine, i heard it done on a car wit a no name muffler wit no resonator, and yea, its sounded like a swarm of bees were coming

jbscivichb92

flowmaster high flow cat. inexpensive and unrestrictive.

Galaxy Si

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bond &raquo;</TD></TR><TR><TD CLASS="quote">

This is untrue if you are running a test pipe. There is no way any gases could recirculate with a straight pipe. With a gutted cat then yes because you give the exhuast somewhere else to go other then straight out. Gutting a cat is stupid. Why not just run a test pipe instead of wrecking a good cat. As for the guy that had that "gurguling" noise, that is what happens when you gut a cat. You are allowing gases to move in other directions (side to side) other than just one with the added room. It screws up the flow pressure and back pressure. </TD></TR></TABLE>

well if you read the original post you will see that is exactly what were talking about, a gutted cat not a test pipe

fasthatchb18c1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C1 Del Sol soon &raquo;</TD></TR><TR><TD CLASS="quote">a staright pipe or gutted converter will not give you any hp during daily driving, matter of fact it actually decrease hp, because you need at least 1-2 pounds of back pressure for sufficent exhaust flow. if your racing, then in that case it does add a few horses.</TD></TR></TABLE>
well then why did you type this

_gurusan_

Bleh this guy posted on superhonda about this too....

Gutted Cats are still the stock 1.75'' piping.....why would you ruin an expensive cat for a straight through tiny pipe that smells and rattles.

I got a carsound cat on ebay for 55 shipped......I'm not a super green earth-concious guy, but I don't want to put out a whole ton of emissions either.

High flow cat
Test Pipe
Gutted cat

Bond

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C1 Del Sol soon &raquo;</TD></TR><TR><TD CLASS="quote">a staright pipe or gutted converter will not give you any hp during daily driving, matter of fact it actually decrease hp, because you need at least 1-2 pounds of back pressure for sufficent exhaust flow. if your racing, then in that case it does add a few horses.</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fasthatchb18c1 &raquo;</TD></TR><TR><TD CLASS="quote">
well then why did you type this</TD></TR></TABLE>

That's my point exactly. Atleast someone else reads all the posts. Thanks for having my back on this one .

xEnderx

Ok, so has anyone dyno'd a test pipe? Lets say.....Omni pipe? Seems to be the standard pipe from what I've seen. HONEST whp gains and powerband adjustments?

Galaxy Si

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C1 Del Sol soon &raquo;</TD></TR><TR><TD CLASS="quote">if your not racing and not reving your car to high rpm's, then no you dont need back pressure, but for daily driving and cruising you do. with no back pressure at low rpm's, the exhaust actually starts to recirculate over and over through the gutted cat. this in return cause blockage from gases trying to excape. the reason why this doesn't happen when your racing is becuase the exhaust is being pushed through at such a high rate, no wind tunnel is being created</TD></TR></TABLE>

then why do you think i typed this, notice how i said GUTTED CAT

_gurusan_

Need backpressure?

?? You mean velocity.........

2.25'' test pipe with a mildly modded engine isn't going to lose much low end torque...in fact you'll probably gain some.

Bond

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by _gurusan_ &raquo;</TD></TR><TR><TD CLASS="quote">Need backpressure?

?? You mean velocity.........

2.25'' test pipe with a mildly modded engine isn't going to lose much low end torque...in fact you'll probably gain some.
</TD></TR></TABLE>

And that's the truth .

mildly.interesting

my test pipe got me 17 hp, but that was on a turbo car too.