Probably a stupid question, where are the cats located on the exhaust system? I have looked at it and can see there are 3 parts to it, down pipe, mid and rear. Which section has the cat?

It's a 3-way cat system I think.

They are at the end of the downpipe. Look under your car and where the exhausts come very close there are heat shields around the exhaust which looks like a metal plate with holes in. They are side the downpipe where the heat shields are.

 

Stuart

Thanks, I think I can see them now. Is it a 3 way cat system?

Originally posted by Nelson MainFella

It's a 3-way cat system I think.

 

LMAO!!! :D

 

the 3 way cat refers to the conversion process of the gasses, not how many parts it comes in!!

 

the cats are in the front section, after the downpipes. if its a later one you may also have pre cat(s)

Originally posted by Paul C

if its a later one you may also have pre cat(s)

 

...or kittens.

Thanks all, now I can see them I will get rid of them. I've heard that it can give a 10% increase in power!

Originally posted by Homebrew

Thanks all, now I can see them I will get rid of them. I've heard that it can give a 10% increase in power!

 

LOL, don't know about that but it does 'feel' better, and you get a deeper exhaust note. Possibly the turbos's spool up quicker

 

James

Heya homebrew,

 

What are you gonna replace them with (I know they'll be straight thru or 'test' pipes), where ya getting them from and how much is it gonna cost?

 

 

TIA

 

Nibbler

Homebrew i am in the middle of getting rid of the cats ssh:D

ther are 3 in total if you have a series 2 z ........a precat just off of the n/s turbo will need to get a piupe made to replace this!

Don't know if mine is a series 2, how do I tell if It is 1 or 2?

Series 2 has:

Manual override fan switch instead of ambient temp display on the heating pod.

Suede-look trim on glaovebox/lower door panels intead of 'dogtooth pattern' carpet

A precat on the passenger side downpipe :D

 

Get rid of these pesky moggies, you'll notice a big difference ;)

Dave

Your turbos might also start to smoke if the mileage is quite high.

 

This can be down to some seal wear in the turbos and the effect of reduced back pressure once that cats are away.

 

Not supposed to be legal after 01/08/92 either

How do you get on at MoT time with no cats?

My series 2 (with all 3 cats still in there) was right on the limit of the emissions, hate to think what it would be without em! How the hell would it pass then?

Intrigued

Nick

:cool:

 

Yeah, 1 week after decat, the driver's side exhaust is smoking more than Duff after a can of Stella :rolleyes:

 

Dave

i believe emission levels are dependent on date of manufacture, so levels must be lower on a series two...

Originally posted by DaveW

 

Yeah, 1 week after decat, the driver's side exhaust is smoking more than Duff after a can of Stella :rolleyes:

 

Dave

 

Flamin hell, suprised the fire brigade dont follow you round then Dave!!!!

 

Nick

:cool:

Mine passed easily with no cats at all - remember they have to do a non-cat test for Jap imports ....

 

Make sure your O2 sensors are working correctly, plus you can always rely on the old 'air leak on the plenum trick' to pass the emssions. ;)

 

 

Originally posted by zcar

How do you get on at MoT time with no cats?

My series 2 (with all 3 cats still in there) was right on the limit of the emissions, hate to think what it would be without em! How the hell would it pass then?

Intrigued

Nick

:cool:

Originally posted by AndyP

Mine passed easily with no cats at all - remember they have to do a non-cat test for Jap imports ....

 

Make sure your O2 sensors are working correctly, plus you can always rely on the old 'air leak on the plenum trick' to pass the emssions. ;)

 

its a non-cat test on ANY zed before 8/95 ;)

What happens to the lamda sensor when you decat!

Originally posted by yewcheck

What happens to the lamda sensor when you decat!

 

Absolutely nothing.

Originally posted by DaveW

 

 

Dave

 

So why does it start to smoke when decat? Why does less back pressure cause this?

Originally posted by Homebrew

So why does it start to smoke when decat? Why does less back pressure cause this?

 

because the rear oil seal in the turbo is a dynamic seal that relies on a certain amount of back pressure to keep the oil from flowing straight past & down the exhaust.

Originally posted by Paul C

its a non-cat test on ANY zed before 8/95 ;)

 

Knowing your knowledgable background Paul, how come? I know we had to look in an addendum or some other section from the main test but we still did a cat test and mines a 93 UK car.

Should I be telling them not to test the cats? If so why and whats the justification?

Intrigued!!

Nick

:cool:

Originally posted by zcar

Knowing your knowledgable background Paul, how come? I know we had to look in an addendum or some other section from the main test but we still did a cat test and mines a 93 UK car.

Should I be telling them not to test the cats? If so why and whats the justification?

Intrigued!!

Nick

:cool:

 

what vehicle have they tested it as on the printout?? the Zed is NOT in the emissions database, & is therefore tested as a non cat vehicle. after 95 a default cat test is done

 

unless its recently been added. ill check & repost! ;)

Ok, from 92 on the cat test was introduced

 

from 1/8/92 -> 1/8/95, an EXACT match must be found in the emissions database to do a cat test. if no match is found a non-cat test is performed. (3.5% co 1200 ppm HC)

 

after 1/8/95 a default cat test is done regardless of make & model

 

got the latest emission book in front of me now,

 

100NX is in it

200SX is in it

350Z is in it

R33 & R34 skylines are in it

 

300ZX Z32.................................

 

 

 

 

 

 

 

 

wait for it.................................

 

 

 

 

 

 

 

 

 

NOT IN IT!!!!!!!!!!!!!!

 

so..................... under the new tests, a BET test is done, if it fails that then an EXACT MATCH must be found, or it is tested as a non-cat vehicle.