He may be right. I do know in S.A. if the car is gas only (no fuel tank) there are no emission controls required eg. carbon canister ect. this is based on older carby cars. The converter is for unleaded fuel. Have you ever seen a deisel with a cat? My car had no cat for 24 hours and sounded, went better with the new cat on. Check your local laws, you may have to have no petrol system fitted to the car (no tank) instead of only not connected.

yeah the convertor is for unleaded fuel....lpg doesnt have any lead in it so it is an unleaded fuel...

lpg is predominatly butane/propane
petrol is mostly octane

ie theyre both hydrocarbons that produce identical products when combusted - c02 + h20

but yeah i have no idea on the actual LAW

In Victoria its a $2k fine for individuals & $10k for a business. My car had a hollow cat for a bit & didn't go any harder or sound any different..

chances are this magical power you have unlocked is cos your old cat was simply clogged up.


someone had his cat smashed out by a few of the e series guys and it did sound different, however its now fixed. there was very little performance gains. if you are willing to risk a $2k fine or whatever it is why not just get a high flow, the flow rate is pretty similar, but the harmful gasses are still removed.

What are the pollution control equipment requirements for LPG
vehicles?
Usually, no re-testing of engine exhaust emissions is required for LPG conversions if a vehicle is
intended to operate primarily on LPG. However, catalytic converters and associated emission and
engine control systems of any vehicle originally operating on unleaded petrol must remain operational.
In the case of vehicles which are capable of using either petrol or LPG, all emission control systems,
fuel emission systems and devices and engine control and management systems, including catalytic
converters and oxygen sensors, if originally fitted, must remain operational. Allowances are made for
minor air cleaner and carburetion/injection modifications required to fit the conversion. The heated air
intake system and original air cleaner can be removed and replaced by a new unit if it is compatible
and recommended by the system manufacturer.
From January 1994, new LPG installations on vehicles originally designed to operate with a closed
loop engine management system, that is, one which monitors the exhaust emissions and adjusts the
amount of fuel being delivered to the engine, must also be installed with a closed loop engine
management system for the LPG fuel system that results in exhaust emission levels for LPG operation
that are not inferior to the levels produced by the original vehicle.


this i got from the rta,,it is australia wide,,i think it is adr 37

Last edited by naughtyfalcon on Mon Jun 11, 2007 10:53 pm, edited 1 time in total.

Modified exhaust systems
Modified exhaust systems may be fitted to passenger vehicles provided the following conditions are met :


The system is efficient.

The exhaust system does not pass closer than 25mm to fuel tanks or the body floor.

The system does not foul the body work or limit axle travel.

No part of the system projects below the rim lower edge

The system terminates behind the last body panel.

Systems on the left hand side of the vehicle do not deflect gases directly to the left.

The noise level of the modified system must not exceed the noise level of the manufacturer’s original system by a noticeable amount.

Side exhaust systems (sometimes called lake pipes) are not permitted.

The system must be effectively supported and must be free from cracks and leaks.

Where the vehicle is subject to ADR 27A - Emission Control. Extractors may be fitted, but the features of the original manifold must be maintained (i.e.. hot air transfer tube, manifold to air connection). Vehicles subject to unleaded fuel control emissions (ADR 37) must remain as specified by vehicle manufacturer..

Noise level will be the most important factor in assessing any exhaust system. Close attention will be given to this factor during examinations and in the on-road situation.

If LPG cars don't need a cat ... how come my AUII EGAS dedicated LPG ute came out from factory with one installed?????

Must be there for a good reason me thinks.

well as the adr states,,if it came out with a cat then the cat must be retained regardless of the fuel used or exhaust system fitted.

Hmmm interesting.....

Exactly. I had this discussion with EPA and NSW RTA several years ago.

mechanik, i would say that its probably cheaper to put the same mass-produced exhaust system on every car regardless of LPG or not than to change the whole system for a handful of cars

not that it matters, if you get found without one you will get bent over by authorities, and then when you plea innocense saying it was the mechanics fault he (should) get doubly pentetrated by fines

Is a high flow cat worth installing when you go for an aftermarket exhaust. Would ya notice the gain over the stock cat?

Well........If your running gas only.... and get pulled up for an Emisions test without a cat..on gas your FINE.

i mean yeah 10,0000,00000000 fine...

The whole fine thing is pretty interesting.
My dad got an exhaust fitted on his unleded v6 narvara. It doesn't have cats the exhaust shop claims its legal as it's a commercial vehicle or something.
ben