Toyspeed.org.nz Message Board

by **cat007** » Wed Mar 27, 2013 2:36 pm

Hi all

Just wondering what peoples opinions are on removing a catalytic converter and replacing it with a piece of straight pipe.

Pros/Cons?

by **RomanV** » Wed Mar 27, 2013 2:55 pm

depends on car, but mine dynoed zero difference before and after, and sounded worse.

by **FST4RD** » Wed Mar 27, 2013 3:07 pm

Depends, my one on my old Starion was so blocked up I'm surprised the car was still running!
Also metal buyers will give you money for them.

by **cat007** » Wed Mar 27, 2013 3:08 pm

FST4RD wrote:Depends, my one on my old Starion was so blocked up I'm surprised the car was still running!
Also metal buyers will give you money for them.

Yeah good call - I guess it depends if it's blocked or not. And as long as there's no O2 sensors after it as this might do weird things to the computer?

by **jacobrjett** » Wed Mar 27, 2013 3:22 pm

i guess if you had a turbo the loss of restriction(edit - backpressure?) in the exhaust would help the turbo spool up a bit?

and to be honest I dont think ive ever heard a raspy turbo car?

on an NA car it will sound like shit from experience just replace it with a resonator...

by **2jayzgte** » Wed Mar 27, 2013 6:25 pm

In a Supra running that 3' mid-pipe you'll need to upgrade that wastegate for starters I think there 20 mm from stock if my memory serves me correctly.

by **gt4dude** » Wed Mar 27, 2013 7:24 pm

sounds good on a turbo, gives a bit of "engine character" to an otherwise monotonous turbine sound without increasing the total sound volume

by **jacobrjett** » Thu Mar 28, 2013 4:11 pm

FST4RD wrote:Also metal buyers will give you money for them.

yep. they are worth a bit. pretty sure you can get something like 80 bucks a pop of them.

You hear of people stealing copper wires from building sites to sell them off, im surprised ive never heard of anyone climbing under high up 4x4s and stealing the cats.

Anyway, ive heard of garages doing a decat for free, if you let them keep the cat. you go in they cut it out, replace it with a bit of straight pipe and send you home while they keep the cat, and throw it into the metal recycling pile.

by **Sick Puppy** » Sun Apr 07, 2013 10:08 pm

jacobrjett wrote:yep. they are worth a bit. pretty sure you can get something like 80 bucks a pop of them.

You hear of people stealing copper wires from building sites to sell them off, im surprised ive never heard of anyone climbing under high up 4x4s and stealing the cats.

I've read of this happen a few times on the garagejournal forum... anecdotal mind :wink:

by **MAC_HATER** » Sun Apr 07, 2013 10:45 pm

yeah in the states ive heard of a few cases where someone gets into their truck in the morning and its 10x louder for some reason

take it into the shop and they have a giggle cause someone pinched the cat overnight

by **~SlideWays~** » Mon Apr 08, 2013 11:41 am

Definitely make sure you have a resonator either where the Cat was or already there further down the exhaust. Reason I say this is because I made a 3" exhaust for my single turbo 1JZ, it sounded $&#$% terrible with a straight pipe out to a single oval muffler. It sounded awesome revving it but was horrible at cruise speed. Adding just one resonator made it sound great again, if bit too droney still (I have 2 resonator and 2 silencers now :lol:

since its our daily, but it still sounds awesome).

by **Heylin** » Mon Apr 08, 2013 4:01 pm

Ditto here, decatted a 04 legacy GT-B sounded raspy and horrible. 300mm AdrenalinR resonator mounted in the midpipe fixed it up good.

In a turbo, faster spool up, smoother power delivery. In an NA, not much difference

Note: your exhaust will smell very fumey.

Note: Unless your cat has prematurely failed most cats will last the lifespan of the vehichle. By that one can assume 180-200K.

by **cat007** » Mon Apr 08, 2013 4:02 pm

Heylin wrote:
Note: Unless your cat has prematurely failed most cats will last the lifespan of the vehichle. By that one can assume 180-200K.

The car's done 215K....

by **Heylin** » Mon Apr 08, 2013 5:23 pm

cat007 wrote:
Heylin wrote:
Note: Unless your cat has prematurely failed most cats will last the lifespan of the vehichle. By that one can assume 180-200K.

The car's done 215K....

LOL chop it out

by **Mr Revhead** » Mon Apr 08, 2013 7:54 pm

Since when is 200k a "lifetime"

OMG so shiny! · by **Dell'Orto** » Mon Apr 08, 2013 9:01 pm

In countries other than NZ and 'straya, it is easily the car's usable life :lol:

by **cat007** » Mon Apr 08, 2013 9:04 pm

Dell'Orto wrote:In countries other than NZ and 'straya, it is easily the car's usable life

That's because 150k's is the max for a euro....

by **iOnic** » Mon Apr 08, 2013 9:06 pm

Rx8 just ticked over 130kms. Cat is stuffed.

by **cat007** » Mon Apr 08, 2013 9:09 pm

iOnic wrote:Rx8 just ticked over 130kms. Cat is stuffed.

Oil will kill a cat

no grip · by **Akane** » Mon Apr 08, 2013 10:21 pm

cat007 wrote:
iOnic wrote:Rx8 just ticked over 130kms. Cat is stuffed.

Oil will kill a cat

Or an apex seal.............

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Removing cat for straight pipe.

Removing cat for straight pipe.

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