Bubba po

Wait for the poll!

Brun

ALi-B

iTrader: (1)

Although there is evidence to suggest some emissions control system - whilst reducing one type of pollutant, create another even more deadly pollutant in the process.

And also the improvement in fuel econmy could lend its way towards burning less fossil fuels.

Then there's the load of badly serviced cars, driven by people who can't detect missfires or anything wrong until the grinning MOT inspector hands them their failure sheet reading 10 times over the CO limit. In which case, emissions control or not - it still would do **** all difference as the cat would have overheated, melted and shattered to smitherens and become useless anyway.

So, what do I do?

Well I drive pre1992 cars which kill the planet, knowing that they have little emission control and can fly through MOT's quite legally. Do I care? Not really.

Then I think, what more harm can one more car on the road chugging more crap into the air will do? Whilst we have airplanes, trains and buses chuck billions time more crap out, not to mention 3rd world countries that still use lead in their fuel.

I never liked cats anyway...ask ajm

Bubba po

There's always some contrary evidence quoted... but of no weight compared to the overwhelming amount of evidence that shows that CCs do reduce pollution.
Do you have a child that suffers from asthma?

When you see a smashed bathroom suite fly-tipped in a country lane do you think "Ah, well... they probably couldn't afford to pay the grossly unfair charges that this government levies against people who just want to make a decent living without too much interference, or just can't exist if they have to get bathed or have a **** in something that's avocado-coloured, "?

WRX_Rich

iTrader: (5)

sports cat over here

Bubba po

And everything that Ali-B said is bollox. Divide a bus's pollution by 50, a train's pollution by 200 and an airplane's pollution by 500 and it's easy to see the fallacy in his argument. If he personally doesn't care about the pollution he causes that's up to him.

WRX_Rich

iTrader: (5)

agree but in Worcester most bus's have about 3 people on unless its rush hour


reason which i went for sports cat is insurance which is a different matter

ALi-B

iTrader: (1)

I suffer myself

Consider this: It is possible to produce an engine that can pass post MOT limits set out by VOSA for cat equipped cars WITHOUT a cat fitted. I know so as I used to own such a vehicle. Then there's the huge number of vehicle I see Fail the MOT on emission with a cat fitted - in many cases they don't work as well as they should as they rely on certain conditions to operate effectively. Coincidentally these operating conditions for low emssions without cats are also the same.

So evidence that cats reduce polution is flawed in that the "real" key to low emissions is <deep breath>: high compression, advanced ignition timing with high output ignition, high octane fuel, "swirl", "may" or "pent roof" combustion chamber design, Lean burning, Closed loop engine control and seqential fuel injection......All of which popped up in mass production the same time as cats were fitted

Although most items on the list are emissions related, most don't detract performance (in some cases increases it) and improve fuel economy. Except for the ruddy cat.

Subarus are a bit of a different animal to the norm, they run mega rich fueling, run open-loop control when the turbo is working and run low compression which make the thing as efficient as a car from 60's when driven off-boost. They are only "clean" when the cats are working 100% which is not as often as you like to think.

So really, we should make scoobs illegal

Bubba po

Firstly, I'm sorry to hear that, Ali... -secondly, I bow to your superior technical knowledge about engines and their emissions; we've met often enough in threads for me to trust you about the things you say. Thirdly: why do subarus have to run that way off-boost?

Paul_M

I don't know the figures, but I've been previously led to believe that the pollution produced per mile by a 500 passenger aeroplane is far, far more than 500 times that of a car.

Can anyone confirm or deny?

ALi-B

iTrader: (1)

No need to be sorry. My knowledge is not superior....I can guarantee somobody who apprarently knows more will post up with something equally bewildering to prove everything I typed is tosh

Generally concerning the off-boost inefficiency, (trying keep it short and in laymens here ) Scoobs (or most largish Turbo cars) run 8.0:1 compression ratio, this is your squish before your bang - an important key to burning all the fuel without wasting it through the exhaust. An average modern n/a car should run close to 9.5:1 (in an ideal world we'd have 10:1+) Now on-boost it great, as the lower compression is made up by ramming a load of air into the combustion chamber. Off-boost however, you don't have this, so it's more of a struggle to get a big bang. Also this is less than favourable for "lean burn" ideals, so essentially you need more fuel to keep the engine running without it misfiring.

Bottom line is it isn't efficient, the average Mpg of a car from the 60's with a 2.0litre engine was around 20ish mpg...not that different is it? Things like the closed loop control, Efi, better ignition and better fuel have improved things vastly but there is only so much it can do. I would be very intesrested to see how a scooby turbo engine, performs in terms of MPG, performace and emissions if the turbo was removed and ECU setup accordingly, I'd guess the figures achieveable would not differ that much from comparable cars from 25 years back (with cat removed - of course ).

edit: I should mention why a turbo engine doesn't run a high compression ratio. Basically, on-boost it would detonate and melt the pistons. To combat this you would have to massively retard the ignition timing (which reduces performance and efficency) or lower boost pressures (thus lowering performance). Or run higher octane fuel (thus the optimax debate). Normal hum-drum cars from yester-year ran low compression ratios and retarded ignition because of potential crap fuel. With the exceptance of cars that ran on 5-star fuel

AJbaseBloke

I voted in the "green" column, but mine came with more ponies than mentioned std. Now the beastie has more, and with upgraded metal sports cat is cleaner than when it was std even though there is lots more shove (yep, at cruise the thing sips very gently now).

I give lotsa cred to the tuner, and the exhaust (made by the tuner ) for making things better all round.

Having said which, a Prius style hybrid with some handling mods is getting more appealing as my green genes start to nag at my conscience...

Bubba po

That's a very good point, if it's true... it's all grist to the mill, and I don't mind the debate being widened. The poll is only a light-hearted troll in some respects, but I am interested in the choices people make, and what their justifications are......

Molds

I run de-cat but only drive 2500 miles per yr in the scoob. I cycle to work regulalry and walk to town etc., try not to use taxis and never use the bus etc. etc.

May be running decat is not environmentally friendly with my low mileage and holier than thou attitude (how many ppl are too lazy to go anywhere without the car?) I don't lose any sleep over it!

Cheers

Molds

julian N/W wrx my93

thats to do with everyone having gas fires in there house these days!

as well as my polluting scooby, i also have a fossil fuel(coal) fire, and burn most things on it.......................

the amount of fresh air that thing uses........................

lightning101

I think a child that suffers from asthma will release more pollutants than a de-cat.


And how does it compare to working kids down the mines / jute factories / chimneys ?


We seem to be going backwards

Pavlo

where is the option in the poll "I spent £££ to retain performance and emission control"?

bigsinky

exactamudo paul. i didnt spend XX,000 quid on my street racer to have some tree hugger tell me it is a global killer. my car may be high powered, but it still passes emmissions at MOT time, and there is no tw@ting about removing exhausts to put a cat back in.

cheers

sinky

NotoriousREV

My car manages to meet emmissions standards without a cat and because it doesn't have a cat it produces less sulphur and NOx emmissions.

Farting cows produce far more greenhouse gasses than cars do globally. Motor vehicles are only responsible for 0.1% of CO2 emmissions as well.

Chinese and American industry is more of an ecological threat than a few enthusiasts removing an ineffective-under-most-conditions stopgap cludge from their exhaust, if you really care about the environment then you should direct your energies at them.

chris's scooby

I'm doing my bit then. We had roast beef for dinner last night. One less cow to worry about!

Vipa

I think that this is one comparison which is irrelevant!

Dividing the emissions of trains, buses, taxis etc. by the number of occupants is a valid comparison (especially as most cars only carry 1 passenger.... the driver.... guilty as charged M'Lud!)

These are all modes of transport which, if we chose, we could utilise instead of using our cars (in the majority of cases.) and even with buses and trains not filled to capacity they are still, on average, more eco friendly than cars.

When it come to planes however we are then comparing apples with oranges. (Apart from domestic flights which make up the minority.) Your average 747 carrying 3-400 passengers may well produce more pollution per mile than 3-400 cars (even Scoobies) BUT the journeys undertaken in most aircraft could not be undertaken in a car i.e. Transatlantic or sheer distance and time (it doesn't help of course that we live on an island cut off from the rest of the world!) So therefore a comparison is irrelevant.

As for the Poll.. I voted green... 220BHP should be more than enough for me........................................... well.... OK....I'll let you know next week when I get my car

Paul

theotherphil

Most buses are LPG anyway so are way more eco friendly than are being given credit for.

hugo

There's a taller tree to bark up than the one with the few decat enthusiasts in it. Most lung problems are caused by particulates. The king of particulate production is the ever popular diesel motor. They produce huge quantities as a primary product of combustion (as we all see when driving behind one) and finer secondary particulates from the various chemical reactions in volving nitrogen oxides). I would reckon that there are a lot more wheezy kids out there climbing into diesel 4x4's and being driven to Tesco's by their Mum (who's filling the car with secondary *** smoke) than there are with a Dad with a decat. Have a look at this text borrowed from the American Lung Association:

WHY IS DIESEL EXHAUST AN AIR POLLUTION PROBLEM?

Diesel exhaust is a mixture containing over 450 different components, including vapors and fine particles. Over 40 chemicals in diesel exhaust are considered toxic air contaminants by the State of California. Exposure to this mixture may result in cancer, exacerbation of asthma, and other health problems.

For the same load and engine conditions, diesel engines spew out 100 times more sooty particles than gasoline engines. As a result, diesel engines account for an estimated 26 percent of the total hazardous particulate pollution (PM10) from fuel combustion sources in our air, and 66 percent of the particulate pollution from on-road sources. Diesel engines also produce nearly 20 percent of the total nitrogen oxides (NOx) in outdoor air and 26 percent of the total NOx from on-road sources. Nitrogen oxides are a major contributor to ozone production and smog.

WHAT ARE THE HEALTH EFFECTS?

Diesel exhaust has been linked in numerous scientific studies to cancer, the exacerbation of asthma and other respiratory diseases. A draft report released by the US EPA in February 1998 indicated that exposure to even low levels of diesel exhaust is likely to pose a risk of lung cancer and respiratory impairment. And in August 1998, the State of California decided that there was enough evidence to list the particulate matter in diesel exhaust as a toxic air contaminant - a probable carcinogen requiring action to reduce public exposure and risk.

Dozens of studies link airborne fine particle, such as those in diesel exhaust, to increased hospital admissions for respiratory diseases, chronic obstructive lung disease, pneumonia, heart disease and up to 60,000 premature deaths annually in the US.

The health risk from diesel exposure is greatest for children, the elderly, people who have respiratory problems or who smoke, people who regularly strenuously exercise in diesel-polluted areas, and people who work or live near diesel exhaust sources. Studies have shown that the proximity of a child's residence to major roads is linked to hospital admissions for asthma, and there is a positive relationship between school proximity to freeways and asthma occurrence. Truck and traffic intensity and exhaust measured in schools were significantly associated with chronic respiratory symptoms.

TaviaRS

I voted option B in your poll Geoff And being a modded diesel it puts out particulates by the skip load, but hey, at least I have a cat

ALi-B

iTrader: (1)

....And partly belive it or not. The concern and control of diesel emissions have actually forced makers to develop newer better engines...

15years ago a diesel with a cross-flow cylinder head, or 4 valves per cylinder was unheard of. Now most new ones have it. Along with fully electronically controlled fuel injection (thus the common rail or PDi ). The result is better emissions combined with better performance.
Just like before 1992 - almost all humdrum petrol cars had carberettors, no fancy cylinder head design, bog standard ignition control etc etc.

One thing you can thank the tree huggers for...is forcing manufacturers to develop newer better engines. Without them Rover would still be using the "A-series" engine (apologies to mini fans) and Ford would still use their Anglia/X-flow/Kent/HCS/Endura engines (sorry bad example as they only recently stoppped making it...but all they kept doing was plonk on a new cylinder head ).

So thanks to the green lot for making manufacturers dump the dinosaur engine designs

Bubba po

Loads of interesting replies folks! And a good, level-headed discussion.

johnfelstead

The Prius is less fuel efficient than a Turbo Diesel, this technology is not up to spec yet.

The train is now less energy eficienet and more poluting than the average car. http://www.guardian.co.uk/waste/stor...148613,00.html

Vipa

There's a point..... LPG

I went through a phase of owning and running petrol 4x4s and the way forward was to have an LPG conversion done. cost of fuel approximately halved with no discernable loss in performance and emissions reduced significantly.

Apart from the space issues with an LPG tank is there any reason why a Scooby can't be LPG modified?

Paul

Andy916

iTrader: (8)

I've just done my first thousand miles in my '94 WRX. Love it, but in amongst the fun motoring I have to do some steady m'way cruising too and 25mpg isn't too good (am used to VR6 Corrado which did 30+mpg at 90mph). Ok the Scoob's natural territory is fun A/B-roads, and staggeringly capable it is too, but most of us have to do the distance thing too eh?

I've been corresponding with an LPG convertor/researcher who reckons conversion should be possible with the Scoob. Please don't say I'm missing the point of the car, I'm not, I just want it to be more versatile. The basic facts are these: lpg has around 110 octane, so detonation should be avoidable with correct mapping. It has lower calorific value hence 10-20% poorer mpg, but the price difference compared to petrol pays for the conversion costs over 1-3 years (depends on your mileage). The tank goes in the spare wheel well (smaller than ideal on the Scoob, with it being a space-saver). The modern systems can handle up to around 45bhp per injector (one per cylinder) but can be programmed to switch to petrol beyond that (seamlessly, I'm told...). The nearest thing my correspondant has done so far is a 360bhp V6 Maserati bi-turbo, and it took a day of map-tweaking from the passenger seat to get spot-on with lpg all the way up (that's 60bhp per cylinder, ie. nearly into WRX territory). Some convertors won't attempt turbo engines due to backfiring, but it seems that attention to detail (careful mapping) can overcome the potential problems. Hmmm.

Now then, has anyone else tried this (can't see anything in the archives...)? And is anyone else interested in 40mpg (effectively) as well as staggering performance?

cheers,
Andy

Andy916

iTrader: (8)

Whoops, I now see there's quite a bit in the archives. Plenty of "don't even think about it" opinions, but a bit difficult to establish fact from fear. Yes the Scoob engine is tuned near-to-the-edge and rebuild/replacement of the engine isn't uncommon. Detonation is the main worry isn't it? Shouldn't be a problem with careful mapping on 110RON lpg. Other potential problems? ... not sure if there are any ...

BTW, I ran racebikes for a few years, hairy 2-strokes, and a 4-stroke that was tuned too-close-to-the-edge, so I'm aware there may be significant problems in messing around with the Scoob engine. With so few converted to lpg (due mostly to fear rather than fact, and the time it takes to recoup the cost, I would guess) it'll be tricky establishing how real the potential problems are.

Andy