removing cat convertors when using LPG

subie_1st_timer · Post by **subie_1st_timer** » Fri Mar 14, 2008 10:42 am

cause my brumby is on duel fuel, id like to get it tuned properly to run straight LPG, cause right now it feels really dead and dont wanna rev... think its cause its tuned for both fuels

in doing so, id like to find out if i can remove the stock cat and help open up the stock exhaust a little better. only other thing im gunna do to the stock exhaust for now is remove the back muffler and replace it with a little $1 stainless cannon muffler i got off ebay for a bit louder note.

but am i allowed to remove the cat when running LPG?

steptoe · Post by **steptoe** » Fri Mar 14, 2008 12:37 pm

give nsw rta technical enquiries a buzz on 1300 137 302 re the removal of the cat. The dual fuel set up may be your rev restriction. What set up do you have ? I run an Impco 125 mixer that then feeds my twin hitachi carbies [that are only there as a throttle body] through a custom made box and piping. I also rejgged the dizzy to no more than 28 deg total advance with initial being about 14. First motor was shaved heads and sports cam. Current motor is standard as far as I know and have even been too slack to change dizzies. I believe if you totally remove the petrol functions it can be a no cat set up.

Was just thinking last night if the factory dedicated gas cars ie Falcon has a cat?

Too Many Rubes · Post by **Too Many Rubes** » Fri Mar 14, 2008 12:38 pm

Leave the cat.
Advance the ignition timing and make sure the plugs/leads/etc are good.
If you don't already have one, fit an electronic dissy.
Make sure the cooling sytem is perfect, maybe a slightly colder thermostat.
Run a nice cold air intake if you don't already have one.
Make sure guy who tuned the system knows what he's doing.
Hope this helps

You should still have a cat on gas - the gas system should be an electronic closed loop system.