Will a 300zx UK TT still pass the MOT even if you remove the CAT on a 91'....someone just told me they heard cars before 93' can have their cats removed and this is still classed as road legal.

 

This true, anyone know??

 

Thnx,

 

Dan. :cool:

Only cars from 93 onwards are legallly abliged to have the cats on if fitted by manufactors.....

In short yes. Even if it was not strictly legal, if you de-cat a Z and it fails because it too new they re-test it as a non cat vehicle because it does not appear on the database. But with a '91 car de-cat away.

LOL Tack - isnt that a no then? :p

 

Off with your cats!

They don't test it at MOT pre 93 but if you get stopped by the police and fail the emissions test they'll impound the car sometimes!!! Hmmm, 3 litre 13 year old car... odds on passingthe emissions test... errrr.... opps. Depends if you want to take the risk for a few more horses or not.

 

Personally my cats are staying on... I need the mpg to stay as high as poss as it's my daily driver.

 

David

Personally my cats are staying on... I need the mpg to stay as high as poss as it's my daily driver.

The cats reduce the mpg, don't they?

Anything May 1992 can be de-catted

On any car I've ever heard of the cats being off will increase the flow therefore allowing you to burn more fuel/air and go quicker, but lose mpg.

LOL Tack - isnt that a no then? :p

 

Off with your cats!

 

Well done shrimple. You are the only one who passed the test.

I can't see removing the cats bumping up the mpg!!!

http://300zx.co.uk/forums/showthread.php?t=27060 ;)

I can't see removing the cats bumping up the mpg!!!

 

 

Yes it can. Any thing which makes your car more powerful with using no more fuel will increase

They don't test it at MOT pre 93 but if you get stopped by the police and fail the emissions test they'll impound the car sometimes!!! Hmmm, 3 litre 13 year old car... odds on passingthe emissions test... errrr.... opps. Depends if you want to take the risk for a few more horses or not.

 

Personally my cats are staying on... I need the mpg to stay as high as poss as it's my daily driver.

 

David

 

What doesnt make sense to me is if it passes the MOT how can the police do you? Surely thats what the MOT is for?!

What doesnt make sense to me is if it passes the MOT how can the police do you? Surely thats what the MOT is for?!

:nono::nono: anyone can get an MOT with a cat on then take it off when they get home....:D thats how they can do ya mate....:(

Matt

jus take it off... but.. make sure you have cash in the bank for new turbos.. youve been warned!!!!

Yes it can. Any thing which makes your car more powerful with using no more fuel will increase

 

I think there is a balance to be obtained where fuelling under cruising is optimal, I can't see how removing the cats would bump the MPG up that much!

jus take it off... but.. make sure you have cash in the bank for new turbos.. youve been warned!!!!

 

Will it knacker the turbs then? Heard it changes the pressure which can wear them out faster, but will this happen quickly?? Worrying thing is the turbs i got now i have done 120k so kinda puts me off doing it if this is the case :(

there is a fair chance it will do!!!!

Will it knacker the turbs then? Heard it changes the pressure which can wear them out faster, but will this happen quickly?? Worrying thing is the turbs i got now i have done 120k so kinda puts me off doing it if this is the case :(

 

its not so much wear them out.

 

the rear turbo oil seal is more of a "dynamic" seal (cant have rubber seals in the back of a turbo ;)) that rely's on a certain amount of back pressure to stop the oil from seeping past.

 

with stock tubs, after decatting there may not be enough back pressure on already worn turbos to prevent this from happening

its not so much wear them out.

 

the rear turbo oil seal is more of a "dynamic" seal (cant have rubber seals in the back of a turbo ;)) that rely's on a certain amount of back pressure to stop the oil from seeping past.

 

with stock tubs, after decatting there may not be enough back pressure on already worn turbos to prevent this from happening

 

Ahhh i see maybe not then! Any danger of this happening if I replace the centre and backboxes you think?

Mines on 137k on original tubs and straight through cat back twin 3.5" dia pipes to Apexi rear cans - last 30k and so far so good.

 

boost no more than about 10.5psi max with intake kit so otherwise stock

Mines on 137k on original tubs and straight through cat back twin 3.5" dia pipes to Apexi rear cans - last 30k and so far so good.

 

boost no more than about 10.5psi max with intake kit so otherwise stock

 

You've done well mate...ere what are those alloys you have there?

yeah, you'll be fine on a cat back exhaust