To cat or not to cat - on an L Series

[Fang]

Recently I got some exhaust work done on my L Series. Apparently it was suffering from a major catalytic converter failure and I ended up forking out handsomely to replace the thing. Old Mate was impressed that it was nearly 20 years old and still going

I know is the law to have these things - but do L Series (carby model) work happily without them?

[someguy]

Recently I got some exhaust work done on my L Series. Apparently it was suffering from a major catalytic converter failure and I ended up forking out handsomely to replace the thing. Old Mate was impressed that it was nearly 20 years old and still going

I know is the law to have these things - but do L Series (carby model) work happily without them?

Depends what state you live in.

My L series has a 3" straight pipe all the way to the muffler and I got a noticeable amount of power increase from doing that. (any extra HP on an EA82 is essential :P)

Your L Series will thank you for it

Unfortunately if you live in Vic/NSW and you get caught without a cat the fine is $2000 per cylinder. (not too sure about QLD but I don't think they are too strict)

If however you are in SA/WA the police don't seem to care too much. Both my brother and I don't have cats and we have never been defected when pulled over. (would have to put a cat on to go over the pits though, but that very rarely happens in SA)

[twilightprotege]

i wouldnt run without a cat. you can get good cats that flow really well and cost very little. certainly saves the big fines if you get caught, mind you i've never been pulled over for a smog test. BUT, they pull over the older cars because those are the ones that put out the smog...

[spike]

was reading a hot 4s magazine, and they reacon there not that bad.
skyline godzilla with or without, had a 2 hp increase, and they have the best cat around so if you can find a low milage one around throw it on.

[AndrewT]

I have heard it's a good idea to hold onto the old ones. Apparently scrap metal merchants pay handsomely for them....they contain some kind of rare metals.

[someguy]

I have heard it's a good idea to hold onto the old ones. Apparently scrap metal merchants pay handsomely for them....they contain some kind of rare metals.

Yeah, I have heard that too.

U-Pull-It in SA (Wreckers) will pay $20+ for cats in any condition

[twilightprotege]

d@mn! should have held on to my old ones.

and that 2hp difference between cat and no-cat could easily be put down to many other factors, such as air temp, engine temp, heat soak in the intake manifold, heat soak in the intercooler etc etc etc

[Alex]

if youre worried about fines get a sturdy peice of wire and just poke out the internals of the cat. Its made up of like a honeycomb material. Did this to my l-series when it was carby, made f/a difference, but did make it abit poppy haha.

alex

[TOONGA]

that is correct CAT surfaces are coated with palladium, platinum or rhodium of the noble metals = big$$$$$$ in large amounts

Most modern cars are equipped with three-way catalytic converters. This refers to the three regulated emissions it helps to reduce.

*The reduction catalyst is the first stage of the catalytic converter. It uses platinum and rhodium to help reduce the NOx emissions. When an NO or NO2 molecule contacts the catalyst, the catalyst rips the nitrogen atom out of the molecule and holds on to it, freeing the oxygen in the form of O2. The nitrogen atoms bond with other nitrogen atoms that are also stuck to the catalyst, forming N2. For example:

2NO => N2 + O2 or 2NO2 => N2 + 2O2

honeycomb catalyst

Ceramic honeycomb catalyst structure.

The oxidation catalyst is the second stage of the catalytic converter. It reduces the unburned hydrocarbons and carbon monoxide by burning (oxidizing) them over a platinum and palladium catalyst. This catalyst aids the reaction of the CO and hydrocarbons with the remaining oxygen in the exhaust gas. For example:

2CO + O2 => 2CO2

There are two main types of structures used in catalytic converters -- honeycomb and ceramic beads. Most cars today use a honeycomb structure.

full text here

http://www.howstuffworks.com/catalytic- ... /printable

and people are starting to steal them for the scrap value


TOONGA

[spike]

my point of view
dont bother.

[Fang]

Thanks for the replies guys. I have heard of the hacking the guts out of the cat. The case of mine was split and apparently it was blocked so I ended up replacing it. The car seems to have a bit more torque. I am hoping the hideous fuel consumption will improve now.

[someguy]

Thanks for the replies guys. I have heard of the hacking the guts out of the cat. The case of mine was split and apparently it was blocked so I ended up replacing it. The car seems to have a bit more torque. I am hoping the hideous fuel consumption will improve now.

What do you consider hideous fuel consumption as I am getting around 400-450km out of a tank (normal 55l L series tank) and think I could do better.

EDIT: I noticed you have a weber....thats probably where all your fuel is going. might just need a good tune up

[Fang]

What do you consider hideous fuel consumption as I am getting around 400-450km out of a tank (normal 55l L series tank) and think I could do better.

EDIT: I noticed you have a weber....thats probably where all your fuel is going. might just need a good tune up

Hideous is around 400km out of a tank.. on a good day. Yes I have a Weber - but a Weber in theory should give better fuel economy if driven properly. Mine is definately tuned properly. It was like this before I put the Weber years ago.

[sven '2']

my point of view
dont bother.

In SA if a workshop fits a exhaust with no cat to an ULP vehicle the EPA can fine up to $10k. Cannot remember the fine for the owner. And yes, have been checked with an roadside emissions check at Pt Wakefield some years back.

My NA L ran 15% better with a decent cat + 2 inch exhaust. Quiet too.

I recall reading somewhere cats have a life of ~ 10 years. Less for city cars.

Decent cat + engine in good tune = win

Sven

[El_Freddo]

What do you consider hideous fuel consumption as I am getting around 400-450km out of a tank (normal 55l L series tank) and think I could do better.

L's have a 60 litre tank I've managed to put 62 into mine :/

Hideous is around 400km out of a tank.. on a good day. Yes I have a Weber - but a Weber in theory should give better fuel economy if driven properly. Mine is definately tuned properly. It was like this before I put the Weber years ago.

How many litres to that 400km? With the old EA82 carbie I was getting about 400km to 53 litres - it was in bad shape and jerry rigged with the wiring to the carbie as I had the MPFI wiring in there. With the EJ I got about the same fuel use - while towing a cub 3 camper trailer in a head wind at 100/110km/h

In SA if a workshop fits a exhaust with no cat to an ULP vehicle the EPA can fine up to $10k. Cannot remember the fine for the owner. And yes, have been checked with an roadside emissions check at Pt Wakefield some years back.

Decent cat + engine in good tune = win

Is this the time to tangent onto the arguement that cat's ease the smog problem (thats why they exist on our cars) but some scientists reckon their emissions cause more problems higher up in the atmosphere? I can't remember the source or the paper someone got it from but it was an interesting read - that was discussed probabily 3 or 4 years ago now!

In regards to a new cat, I've heard of people using a larger cat on their exhaust for better flow. Basically they'll take your regular dime a dozen commondore cat for a 6 or an 8 and drop that into their exhaust setup. I dunno if that'd help with the breathing issue or have problems with the cat getting up to temp though as I've not done it myself - just heard about it.

Cheers

Bennie

Cheers

Bennie

[sven '2']

In regards to a new cat, I've heard of people using a larger cat on their exhaust for better flow. Basically they'll take your regular dime a dozen commondore cat for a 6 or an 8 and drop that into their exhaust setup. I dunno if that'd help with the breathing issue or have problems with the cat getting up to temp though as I've not done it myself - just heard about it.

Yep, you are right - larger cats are sometimes sold as 'sports' or 'high flow' cats to 4 cyl buyers.

I used a 6 cyl cat and was very happy with the overall performance / combination

Sven

[Prunes]

For the sake of not getting fines just use a high flow cat.

Hollowing out a cat serves no benefit over a good cat because a hollowed out cat can still be picked up by the transport guys by checking the temperature of it, and a hollowed cat can cause exhaust pulses thus creating a performance decrease.

From what people seem to say go a cat one size up from your exhaust piping and use a high flow one.

Not to mention its better for everyones health.

[Jludcke86]

The easiest way to think of it, is any car or engine released after the first of the first 1987 should have a cat.