How much extra CO2 does a 5l RV8 produce without a cat ?
Discussion
With all the news about CO2 emissions, i had started to consider putting cats back in the chim. Does anyone know how much extra CO2 a 5l RV8 pumps into the air ( i dunno - as a percent or something ? ), without a cat on? It has neither main nor pre-cats.
In order to keep the noise levels up, i reckon some Offord inserts may be required
In order to keep the noise levels up, i reckon some Offord inserts may be required
Griffter said:
rev-erend said:
and causing a restriction for the engine.
Thus increasing mpg. Correct. Cats are at best a mixed blessing...
Yes - OK TVR cat's are big and cause less of a restriction - they are still not what would be optimum for the engine. So they will decrease the MPG and power. Just removing the cat probably does not increase power - it just acts like a silender housing (bit like a cherry bomb) without any sound absortion material but the point where they are in the header would be better if it were a straight pipe
i.e. the secondary pipe length.
Edited by rev-erend on Tuesday 31st October 16:33
Wow - ok, i dont think i understood what cats do !
So, a cat turns other pollutants into CO2, and removing them actually reduces the CO2 emissions.
So, what is being measured in the MOT emissions test? I had always thought it was the CO2 levels, and those were what would cause a fail in a de-catted car.
So, a cat turns other pollutants into CO2, and removing them actually reduces the CO2 emissions.
So, what is being measured in the MOT emissions test? I had always thought it was the CO2 levels, and those were what would cause a fail in a de-catted car.
chimune said:
Wow - ok, i dont think i understood what cats do !
So, a cat turns other pollutants into CO2, and removing them actually reduces the CO2 emissions.
So, what is being measured in the MOT emissions test? I had always thought it was the CO2 levels, and those were what would cause a fail in a de-catted car.
So, a cat turns other pollutants into CO2, and removing them actually reduces the CO2 emissions.
So, what is being measured in the MOT emissions test? I had always thought it was the CO2 levels, and those were what would cause a fail in a de-catted car.
The MOT test measures CO and HC emissions, not CO2.
The main reason that cats increase CO2 output is that they make the engine less efficient, which means you have to burn slightly more fuel per journey, which means you create slightly more CO2.
But unless you changed the "map" in the ECU when you removed the cats, the car will still "think" it has them so it will still be running slightly rich all the time (which is what cats need in order to work). I doubt you'll see any difference in performance OR CO2 emissions. TVR cats don't cause much (if any) restriction - you could drive a bus down one! I always felt that the de-restriction you got by removing the bricks was pretty much out-weighed by the poor gas flow - the gas just empties into the big void that's left when you take out the cat and slows right down - then it has to speed up again as it leaves the empty cat can. (unless you've got rid of the cans too)!
I agree that your CO2 emissions will go up (fractionally) when you put them back in because they will turn much of the CO back into CO2.
It was a "great" idea all in all. The environmentalists persuaded the politicians that other pollutants (not CO2) were the biggest threat to the planet (anyone remember the acid rain hysteria?) so the politicians mandated emissions limits that pretty much made cats essential. (They ARE good for getting rid of unburned fuel, carbon MONoxide and oxides of nitrogen). The car manufacturers said "but hey, we're working on lean-burn" technology which will mean you don't burn as much fuel in the first place"!
"Tough" said the politicians. We know best. Fit cats.
So we did and everyone abandoned their lean-burn programmes because there wasn't any point any more. Cars ran richer (for the cats to be able to work) and produced MORE CO2...
...oh and then there's the amount of CO2 you create to produce the precious metals to make the cats in the first place. That's quite a lot of rock one needs to crush!
Nice one lads!
I agree that your CO2 emissions will go up (fractionally) when you put them back in because they will turn much of the CO back into CO2.
It was a "great" idea all in all. The environmentalists persuaded the politicians that other pollutants (not CO2) were the biggest threat to the planet (anyone remember the acid rain hysteria?) so the politicians mandated emissions limits that pretty much made cats essential. (They ARE good for getting rid of unburned fuel, carbon MONoxide and oxides of nitrogen). The car manufacturers said "but hey, we're working on lean-burn" technology which will mean you don't burn as much fuel in the first place"!
"Tough" said the politicians. We know best. Fit cats.
So we did and everyone abandoned their lean-burn programmes because there wasn't any point any more. Cars ran richer (for the cats to be able to work) and produced MORE CO2...
...oh and then there's the amount of CO2 you create to produce the precious metals to make the cats in the first place. That's quite a lot of rock one needs to crush!
Nice one lads!
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