Hi,

 

Sorry if this upsets anyone who is fed up answering the same old questions,

but what are the pros and cons of de-catting a T/T ???????

 

Followed up on loads of old threads, and people seem split on whether it is a good thing or a bad thing.

 

Damaging the Turbo seals seems to be the most common cause for concern.

 

Is any power gain noticeable ??

 

Does it make the exhaust system too loud ??

 

Obviously it would depend on the condition your Turbos were in, what exhaust system you had, etc etc.

 

Any proof, or evidence to support either claims ??

 

Year of manufacture is also an issue for the mot.

 

Just trying to see what the most popular thoughts are.

 

Cheers in advance for any input.

 

Alan.........

go for it, some say the seals will go, but i think that gives you an excuse to change to bigger tubs, there was a huge difference in power when i had mine done (then the clutch started to slip

 

i dont think that there is a need for a cat in any 300 under a 95 (prob wrong though lol)

 

my engine is running at 340FWHP and 261RWHP and all i have done is a blitz air filter lightenend and balanced flywheel and a scorpion exhaust to match the decatts, it only has backboxes on mine and it sounds awesome

 

HTH

Allan

I decatted and removed the washer type restricters (jap import) about 3 months ago, it was a bit louder, and seemed much more responsive IMO. The only prob i had was drilling out and replacing the studs i sheared off (mostly caused by a bad temper!). I think you should be ok MOT wise unless its 95 on, but i will stand corrected!

Cheers Steve

:bow: got mine decatted but mini silencers in the down pipes keep the back pressure there mated to single exit HKS Superdragger sounds awesome :bow: much to the neighbours disgust :rant:

I want to know how to keep appropriate pressure (to keep my new 360 bearing tubs sweet) and stay legal. I am going to get a custom made system that looks stock-ish as I hate the JDM sewage pipe look. I was going to opt for the free-flowing cats as I had heard from 2006 on it will be almost impossible to pass an MOT whatever the cars age (based on new emission regs) without a cat even though they say you do not need cats on cars older than 95. It was described to me as the back door way of getting older cars off the road. I hope I'm wrong :x:

I want to know how to keep appropriate pressure (to keep my new 360 bearing tubs sweet) and stay legal. I am going to get a custom made system that looks stock-ish as I hate the JDM sewage pipe look. I was going to opt for the free-flowing cats as I had heard from 2006 on it will be almost impossible to pass an MOT whatever the cars age (based on new emission regs) without a cat even though they say you do not need cats on cars older than 95. It was described to me as the back door way of getting older cars off the road. I hope I'm wrong :x:

 

 

depends who you know in the trade mate always a way round things :D

like 1 of my mates I used to work with just happens to own his own MOT testing station :nelson:

fitting my decats tomorrow hopefully

MMmmmm !!

 

Quite surprised at the results so far ! ;)

 

Any one got any examples of power increase ??

 

Or on the flip side, any one got any hard facts that removal caused Turbo failure ??

 

Thanks,

 

Alan....

Removed mine Al!-no probs! :rofl: :D

Will be doing the shorty tho'-If they go ,they go :o but can't see it to be honest, more likely suspect for tubby failure is lack of oil changes IMHO! ;)

Aint no room for Cats underneath all that !! ;)

 

Alan........

So far;

19 to remove against 2 to keep.

 

Alan....

I'm going to replace cats and retain cat back section, as its still in good condition, stock back section might keep a bit of back pressure for me :confused:

Bye bye cats!

i would say in terms of a serious mod, decatting is a no brainer, but anyone with an eye on the financial aspect of changing turbos would, i'm sure, rather enjoy what power the car has and not decatt...due to the myth of rear turbo seals.. but this whole topic will always go on and on.....

 

Mark

i would say in terms of a serious mod, decatting is a no brainer, but anyone with an eye on the financial aspect of changing turbos would, i'm sure, rather enjoy what power the car has and not decatt...due to the myth of rear turbo seals.. but this whole topic will always go on and on.....

 

Mark

 

As you say "myth" ?

 

Fact or fiction ? Interested if anybody has evidence that it will really cause turbo seal failure.

 

And again, if there is any power gain to be made, how much ?

 

Cheers,

Alan.

This has been running all weekend and voting seems all in favour of removal.

 

Just need a couple of examples of improved performance, or it caused turbo failure and its make me mind up time !!

 

Alan..........

the main reason i de-catted was cost nissan wanted 900 to replace both cats only 230 for de-cat pipes

It all depends on whether you have the spare money to replace the turbos if they go. I put up the same poll when I was thinking of doing mine and everyone said de-cat so I did. A few weeks after doing it one side starting smoking and my turbos were replaced in 2002! I noticed a healthy power difference but could of done without the expense of a turbo seal going.

Thats why i went with the ones with the mini silencers in from the Z-Centre been on 2 yrs no probs with my tubs yet :x:

doing mines soon.

Many thanks guys too all who voted, or left an opinion.

 

No hard evidence that removing the Cats directly caused a turbo seal to fail.

 

No precise power gain figures either.

 

We are all in agreement that there is a power gain, but in dis-agreement about the turbo seals ! :confused:

 

I am working under the premise that if you have a turbo seal on its way out, any slight oil that does pass will get caught in the cat and be hardly noticeable. Removing the cats would only highlight a problem you already have. Need to fit a new gasket from turbo to downpipe anyways, as mine is blowing, so seeing as its off, will de-cat.

 

Might be looking for turbos shortly, we will wait and see ?! :rolleyes:

 

Thanks again,

 

Alan.

Mine decatted.summer just gone left hand bank turbo seal leaking. now engine out standed garrett 25 off. stage three tubs on,

I decatted and removed the washer type restricters (jap import) about 3 months ago, it was a bit louder, and seemed much more responsive IMO. The only prob i had was drilling out and replacing the studs i sheared off (mostly caused by a bad temper!). I think you should be ok MOT wise unless its 95 on, but i will stand corrected!

Cheers Steve

 

I was told 1992 & under by Danny when I got my Mongoose. my car is 93 so did not to the cats..... :cry:

i believe i have read somewhere that you gain 9 ft/lbs torque + 14 bhp

I had my Cats removed and had the split dumps fitted. I haven't noticed much of a power improvement but the Turbo's do spin up about 500-750rpm sooner. One thing that has changed is the noise levels. But to be fair i think that it is more the fact that the rear section of my 5Ziggens exhaust doesn't actually do much in the way of silencing. I'll be getting some extra silencers cut into the de-cats soon as it is far too loud for me.

 

Mark

I was told that if you de cat a N/A they are a lot louder than a TT for some reason

I was told that if you de cat a N/A they are a lot louder than a TT for some reason

 

yep they will do turbo,s soak up quite abit of the exhaust noise.