catalytic converter..

[809king]

is there any gain in hp if you remove the catalytic converter??


i was just wondering because my uncle is a bitch and he was argueing with me that a car without the catalytic converter is faster then a boosted stock car.. if that makes any sense

[ExplodingCake]

It won't give you noticeable gains. However , out factory cats are mildly restrictive , so taking it out will give better engine response and ,ehhh some power you don't even notice.

[HondaGuy1212]

Get a high flow cat. You'll stay emissions legal, gain a little HP, and best of all, you won't be choking mother nature.

[darkfusion42]

But definitely not faster than a boosted stock car. Lol

[stretch JDM]

yea man taking it out will help on hp gains. not much , every little bit helps .809king did you ever score on a muffler ?

[Cobalt]

Back in 03/04 a magazine did a test with a ~450 hp Supra(those were huge numbers back in those days). They had two identical DP's one with a cat, one without. The Supra gained a whopping 10 hp from the catless DP. That is a 2% gain. Our F's have what 120 or so in well maintained, non rebuilt, 20 yr old form? Is it really worth that extra 2.4 hp?

[4CYLPOWER92]

I think we might be talking about 1hp here, possibly 3 at the most. Not worth polluting the environment over....

[bcjammerx]

1/10 of a HP

Seriously though...you would get more by vacuuming your car, or only filling your gas tank 1/2 instead of full...or by cleaning out the trunk...or by changing your oil...or changing your air filter...etc etc...or by going on a diet.

Will it gain...sure...but that is only said because scientifically it does...is it significant? No.

"not notice" that means it is such an insignificant amount that the gain is not worth the time it takes to remove the cat...or think about doing so. More importantly, it is not worth the money you spend replacing the piping. That money is better spent on intake mods.

and none of those would harm the air my lungs ingest.

[dano28]

Everybody is looking at this question wrong. Look at it like the K&N Air Filters or SplitFire spark plugs people do.

Removing a clogged catalytic converter can give up to a 100% horsepower increase !!!!!


Just to clarify...hi-flow cats do not "flow" any better because of any internal design superiority. They flow better because the inlet and outlet pipes are larger to better match the plumbing of high performance header and cat-back systems. So, you would have a difficult time installing a hi-flow cat into an otherwise stock system.

[deevergote]

High flow cats don't really offer much of a gain. No cat at all offers very little... maybe 1hp, as said above. The tradeoff is a terrible exhaust tone, an awful smell, and lots of toxic fumes being released into the air. People that run around without a catalytic converter are the people that are responsible for the ever-increasing emissions legislation that is making it harder and harder to pursue our hobby.

If the cat is clogged, yes, there will be a gain... but you'd be stupid to remove it.


Now, I assume your uncle is an oldschool car guy, right? A catalytic converter installed on a mid-70s or early-80s V8 that was producing 160hp... yeah, those are choked by pretty restrictive emissions components. Our cars are quite different.

[wed3k]

a stock cb7 is probably faster than my "boosted" Volkswagon is that makes you happy.

[tm123]

Back in 03/04 a magazine did a test with a ~450 hp Supra(those were huge numbers back in those days). They had two identical DP's one with a cat, one without. The Supra gained a whopping 10 hp from the catless DP. That is a 2% gain. Our F's have what 120 or so in well maintained, non rebuilt, 20 yr old form? Is it really worth that extra 2.4 hp?

yes.
when you got other multiple things that equal 2-3 hp
little things add up and especially with a NA
when you delete unnecessary components such as AC, EGR, PS, balance shaft......
although just doing ONE of these alone will not gain noticable difference, drive your car then delete them all at once and see the difference if that makes sense

[acefighter028]

jjust gut it. thats what i did and i passed inspection

[wed3k]

yes.
when you got other multiple things that equal 2-3 hp
little things add up and especially with a NA
when you delete unnecessary components such as AC, EGR, PS, balance shaft......
although just doing ONE of these alone will not gain noticable difference, drive your car then delete them all at once and see the difference if that makes sense

thats one thing i love about NA is that the correct combination can make or break an engine setup.

[bcjammerx]

yes.
when you got other multiple things that equal 2-3 hp
little things add up and especially with a NA
when you delete unnecessary components such as AC, EGR, PS, balance shaft......
although just doing ONE of these alone will not gain noticable difference, drive your car then delete them all at once and see the difference if that makes sense

You are comparing a TURBO SUPRA...to an n/a engine? one making over 450hp...and the other making barely 120? You will NOT gain 2hp...I would like to see the data on their setups, they make cats for boost that do not restrict flow...maybe we should use updated data?

...we are only going to say this 5 times...gutting/removing a healthy converter will not yield sufficient hp, no where near enough to be worth it in any way shape or form.

I get what you are trying to say about modifications adding up but this is not one of "those" mods. "those" mods do not gain only 1 hp (which is a generous est. imo for a gutted cat) but 5-10 at least. Why? Because 1hp is gained or lost with the wind blowing, the oil being old, the car not being warmed up/cold, it is nothing.

DO the OTHER mods...which are dyno proven to work...and then think of this...1hp

...if I tried to sell you a product guaranteed to give you a 1hp gain, I could never prove it. Would you buy it? I would hope not. And...your car does not make xxx hp each time you punch it...it actually varies each time...by more than 1hp too. This mod is not just a waste of time/effort...it is just plain not worth it period.

I have gutted my cat...when I knew NOTHING about cars that is. Then I learned. I know folks look for cheap "tricks" to gain some power, but this is not one of them...it is along the same lines as removing the vacuum line on the FPR and thinking it will give you extra powa.

Allow me to be Frank...
Frank is a mean sumbitch that has no tact

"No one respect folks that gut/remove their cat expecting "performance" gains on modern cars...it is a pointless thing to do."

Ok...easy Frank...keep it cool man