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The mkiv Supra Owners Club

Decats for my n/a


trebor69

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Whifbitzs sell a package of 1st/2nd decats, as said it will be loud and you will need some gaskets too which can be picked up cheap on ebay. If the car is quite loud Whifbitzs also do some twin box cat-backs which keeps it nicely in check.

 

The decats will be 2.5 inch too.

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Thanks for the heads ups guys ;)

 

- - - Updated - - -

 

Hi mate

From what I can remember the imports both use the same second de cat. Just make sure the pipe size isn't to big. Can't help with a first decat. But put up a wanted as someoneay have one to sell.

 

Hi Ian, do you still have your first cat on or have you taken both off ?

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Hi rob

Mine is fully de catted, but my first cat is a full stainless steel tubular manifold and not just a cat pipe.

If I was you I would replace them one at a time, as it can make the car really loud with them both done. I had to fit a bung in the tail pipe to reduce the noise a bit.

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Hi rob

Mine is fully de catted, but my first cat is a full stainless steel tubular manifold and not just a cat pipe.

If I was you I would replace them one at a time, as it can make the car really loud with them both done. I had to fit a bung in the tail pipe to reduce the noise a bit.

 

Yeah I reckon that would be the sensible thing to do ..........I guess I'll have to think on it for a while, maybe look out for one that doesn't have any on so I can gauge just how extreme it would become ....thanks Ian ;)

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Don't do it ;), mine is completely decatted with an OBX manifold and the noise of it gets on my t*ts big time :(

 

Is it really that bad ? My girlfriend wouldn't get in my Celica as I'd decatted that and she complained about the constant droning in her head ....I thought it sounded good :D .....I guess it would be a fair bit louder than that yes ?

The thing is , I would like to improve the power without messing with the engine and just removing one will prob not improve it that much ????

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Don't do it ;), mine is completely decatted with an OBX manifold and the noise of it gets on my t*ts big time :(

 

:iagree:

 

I only removed my 2nd cat then after a week I put it back on, it's insane especially if you have cat back exhaust fitted :blink:

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Like I said whifbitz twin box sorts out the noise, mine is getting a bit louder now as I have out a few miles through it which is a good thing as it was almost too quiet at first even with a manifold/1st decat and a 2nd decat too.

 

Is the twin box in place of the cats or would I have to buy the twin box set up on top of the decats ....Thing is, I already have a fairly new stainless cat back exhaust .....what to do ??? :rolleyes:

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No the decats replace the cat converters but the twin box is indeed a catback exhaust. It all depends what exhaust you have already, you could go the silencer route or you could do it and sell yours if it is too loud. I would imagine there is more to gain by replacing the first cat over the second if you decide to only change one of them to keep the noise down a bit.

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No the decats replace the cat converters but the twin box is indeed a catback exhaust. It all depends what exhaust you have already, you could go the silencer route or you could do it and sell yours if it is too loud. I would imagine there is more to gain by replacing the first cat over the second if you decide to only change one of them to keep the noise down a bit.

 

Hmmm, interesting, I initially thought there would be more gains by removing the second one .....my line of thought is that there is more force ramming the gasses through the first than the second thus the second would stifle more .....?????

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Hmmm, interesting, I initially thought there would be more gains by removing the second one .....my line of thought is that there is more force ramming the gasses through the first than the second thus the second would stifle more .....?????

 

More the reason to get them both changed then ;)

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Is it really that bad ? My girlfriend wouldn't get in my Celica as I'd decatted that and she complained about the constant droning in her head ....I thought it sounded good :D .....I guess it would be a fair bit louder than that yes ?

 

The droning is what gets on my nerves.

I've got a fibre glass bonnet too so no sound proofing which makes it worse I think.

My neighbours get the hump with it as well especially as I go out to work at 0300hrs every day ;)

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I am also thinking of getting a whifbitz 1st decat fitted to my na. Currently have a veilside cat to back exhaust system which splits after where 2nd decat goes then exhaust rejoins behind backbox before tail pipe. She sounds lovely now and do hope when get 1st decat she sounds even better.

Have been looking at decats for while and think thw whifbitz one is the best i seen so far.

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Well I've purchased the Whifbitz 2nd decat so we'll soon see what difference it makes .....although I'm pretty sure that I'll also be buying the 1st decat soon afterwards no matter how loud it goes :p .....I figure ..........What the hell !!

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interesting. let me know what you think noise wise, might fit mine too but i'm restricted exhaust noise wise :(

 

do people with decats think it makes the actual exhaust louder, or is it just resonance / rasp within the cabin? I could cope with the latter.

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interesting. let me know what you think noise wise, might fit mine too but i'm restricted exhaust noise wise :(

 

do people with decats think it makes the actual exhaust louder, or is it just resonance / rasp within the cabin? I could cope with the latter.

 

Yes the Exhaust is louder, much louder. The noise mine made on the motorway (with 2nd de-cat) was rediculous, my work collegues knew I was on my way long before I reached the car park!

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Yes the Exhaust is louder, much louder. The noise mine made on the motorway (with 2nd de-cat) was rediculous, my work collegues knew I was on my way long before I reached the car park!

 

Erk!!! ha ha thanks for the reply mate, i think i'll have to leave them for now- no way i'd pass a noise test then :(

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Erk!!! ha ha thanks for the reply mate, i think i'll have to leave them for now- no way i'd pass a noise test then :(

 

I'm not sure what the current restrictions are on noise come MOT time, my exhaust was still very loud with both cats in place, so I've recently fitted a baffle to quieten it down, it’s now much nicer to drive, and only a little bit louder than stock.

 

All being well I'm taking my car in tomorrow of an MOT re-test, while I'm there I'll ask the guy about noise restrictions.

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