Exhaust technology query
Submitted: Friday, Aug 19, 2005 at 08:29
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25711
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Rick (S.A.)
Why is it that my petrol 4 x 4 (4.5 L Patrol) has a converter in the exhaust line, after the manifold ? Is this a catalytic converter?
What function does it have?
Why is it so hot?
Why do diesels not have this feature?
The reason I ask is because when in off road situations, it is likely that materials (e.g. spinifex) is more likely to ignite in a petrol than in a diesel.
Thanks
Rick (S.A.)
Reply By: Nudenut - Friday, Aug 19, 2005 at 09:00
Friday, Aug 19, 2005 at 09:00
its to remove some of poisonoius gases by running ULP
The exhaust runs hot to help reduce emissions
Deisel dont need it as they dont run ULP...
and yes a fire is more likely.......NP & WLS prefer us H & C shooters to have diesel in certain areas because of higher risk of fire when travelling in high grasses thru the national parks
AnswerID:
125869
Follow Up By: Exploder - Friday, Aug 19, 2005 at 17:42
Friday, Aug 19, 2005 at 17:42
To not so much remove but convert the gas into a less harmful one
They need to run hot to operate, when cold they do not do anything
“The reason I ask is because when in off road situations, it is likely that materials (e.g. spinifex) is more likely to ignite in a petrol” You think you have problems with the one, My system has 2 of them right next to each other and you are right they put out a lot of heat.
You can upgrade to a Hi-flow Cat, I don’t think it run’s much cooler but.
FollowupID:
380643
Reply By: Leroy - Friday, Aug 19, 2005 at 09:24
Friday, Aug 19, 2005 at 09:24
Late model diesel engines also have catalytic converters so don't feel left out!
Leroy
AnswerID:
125874
Reply By: Willem - Friday, Aug 19, 2005 at 09:41
Friday, Aug 19, 2005 at 09:41
Rick
Having an 'older' diesel I don't have that problem.
On our recent trek over to the West I kept on checking underneath the truck and eventually removed the gearbox bash plate as after a short while, an
Eagles Nest of spinifex and other grasses would accumulte around the exhaust and gearbox. Just to be on the safe side. My Nissan has a cover fitted to the exhaust where it comes from the manifold and that dissipates the heat to a great extent.
But diesels have been know to catch fire out bush apparently not from overheated exhausts, though.
When I used to have petrol trucks I used to remove all bash plates and also check regularly under the truck when doing bush tracks and cross country driving so as to prevent being BBQ'd out there.
AnswerID:
125879
Reply By: spondo - Friday, Aug 19, 2005 at 10:21
Friday, Aug 19, 2005 at 10:21
.... and it is illegal to remove said item
AnswerID:
125888
Follow Up By: Member - Jeff M (WA) - Friday, Aug 19, 2005 at 17:11
Friday, Aug 19, 2005 at 17:11
Only if you get caught! LOL
To increase power it's common for the rice burners to replace the cat with that mesh stuff so that it can be easily replaced when they get a roadworthy.
FollowupID:
380642
Follow Up By: Nudenut - Friday, Aug 19, 2005 at 17:59
Friday, Aug 19, 2005 at 17:59
same old story....laws are made only so one breaks them...hahaha
no laws and we'll never get into trouble...right?
exception ....swmbo
FollowupID:
380645
Follow Up By: Chaz - Friday, Aug 19, 2005 at 19:56
Friday, Aug 19, 2005 at 19:56
spondo,
Very true, but they can be by passed without removing them.
Cat converters are ok while they are new, and produce little restriction, but after a few years they can and will block. I had this problem with my old Feroza when it lost power and became very unecenomical. The simple solution was to cut a piece of 50mm pipe and cut teeth at one end like a saw blade. Then proceed to push and cut through the ceramic material in the converter till it came out the other side. Then simply cut the ends off the pipe and refit the converter. This trick was shown to me by an exhaust specialist, but I won't mention who!
It certainly made the car run like new again.
Hey Nudey, I'm a H&C member also.
Cheers
Chaz
FollowupID:
380660
Follow Up By: awill4x4 - Friday, Aug 19, 2005 at 21:09
Friday, Aug 19, 2005 at 21:09
Chaz, I know quite few people used to do this in VIC but as of a couple of years ago it is now a possible $10,000 fine if you're caught.
Regards Andrew.
FollowupID:
380669
Follow Up By: Member - Jeff M (WA) - Friday, Aug 19, 2005 at 22:58
Friday, Aug 19, 2005 at 22:58
There it is again... If you get caught...
Besides after a CAT is over 5 years old it's bloody usless anyway, my diesel produces less toxins than my brother in laws commodore of the same vintage I'm sure.
FollowupID:
380689
Follow Up By: Chaz - Saturday, Aug 20, 2005 at 11:28
Saturday, Aug 20, 2005 at 11:28
Hey Guy's
I'm certainly not suggesting that everyone with a cat converter should do this, but if I was worried about excessive heat build up, it could be an option, especially offroad.
To get caught, the authorities would have to remove the converter (I don't think so), because a exhaust analyzer would show that the converter is not working and would need to be replaced.
Thankfully, in SA we don't have annual vehicle inspections, so one could argue that these laws aren’t worth the paper there written on if no one is policing them.
Chaz
FollowupID:
380715
Follow Up By: robak (QLD) - Monday, Aug 22, 2005 at 10:06
Monday, Aug 22, 2005 at 10:06
Chaz
Last year I was pulled over by the DOT to
test the exhaust emisions. They let me go when they realised that it was a diesel.
R.
FollowupID:
380905