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Any - Dirty old cars? - unthrottled

The old Renault sailed through its MOT today. Clean pass, one minor advisory.

So how dirty is a 16 year old 2 valver running on Asda smart price?

Fast idle:

HC: 0 (yes, zero) ppm, Max:200ppm

CO: 0.1% max 0.3%

natural idle:

CO: 0.31%, Max:0.5%

So, not very 'dirty' at all.

So what was the rationale behind the scrappage scheme again??

Any - Dirty old cars? - craig-pd130

Good figures, those. What model of Renault is it, please? It has a cat, yes? Is it still the original?

I remember the scare stories from '92 / '93 when cats became standard fitment: £1000 to replace broken catalyst from going over speed bumps, etc

Edited by craig-pd130 on 28/03/2012 at 17:21

Any - Dirty old cars? - jamie745

The rationale for the scrappage scheme was to help flagging British dealership networks flog some cars. The 'green' argument was merely spin and even the Green Party agree with me on that. There's not much that the likes of Greenpeace agree with me on but that is one of them.

Any - Dirty old cars? - unthrottled

'96 Meggie. Engine is K7M-which is still used as the base engine in the Dacia Logan.

A few years back I melted the original cat whilst driving 'spiritedly' up the M1 on a very hot day. I don't know how old the replacement is, it was a secondhand one. Lambda sensor is original though which surprises me. I thought they had a finite life.

Any - Dirty old cars? - Bobbin Threadbare

'Spiritedly'?

Any - Dirty old cars? - craig-pd130

Melted the cat? Did the matrix collapse, or was it the metal canister? I wouldn't have thought that was possible in a closed-loop fuelling system ...

Any - Dirty old cars? - unthrottled

The matrix collapsed. But it really did totally collapse. At the end of the return leg, it wouldn't go over 30. (Yes you're right-melting a ceramic would be a hell of an achievement!)

I wouldn't have thought that was possible in a closed-loop fuelling system ...

I was surprised but not once I thought about it? Don't forget, the hottest flame is a stoichiometric one ie closed loop. Combine short gearing pushing the RPM up to about 4500-5000 at 70 mph +10%+1+X, and only a single exhaust valve and the EGTs were probably over 900C. Turbo petrols run rich to keep temperatures down and often EGTs drop at full throttle.

It might have been frequent lifting off that did it (no overrun fuel cut off). Interestingly, the engine was not distressed, no audible pinging, no overheating, no loss of power indicating heavily retarded spark timing. Compression check was fine-no burned valves. It wasn't a MAF/lambda problem either. Only the cat wa replaced and it's sailed through emissions ever since.

Any - Dirty old cars? - craig-pd130

Good point, interesting!

Any - Dirty old cars? - ChannelZ

Pretty much similar to my Mondeo. Fresh air coming out the exhaust. 7.5 years old, 71k on the clock, original exhaust still rust free, original cat, original sensors. Doesn't use a drop of oil, and only had the factory plugs changed at 55k. Who says you need a diesel for reliability?

Any - Dirty old cars? - balleballe

To be fair - none of that is anything less than i'd expect for a sub 8 year old car.

Petrols have always and will always be more reliable than diesels - especially nowadays

Any - Dirty old cars? - unthrottled

I don't think that's fair. virtually all HD engines are diesels and they last. The gentrification of diesels is the root of the problem. People want them to behave like gassers and they aren't!

Any - Dirty old cars? - jamie745

The sky high cost of fuel has meant millions of people with no knowledge or experience of diesels are now buying them, because the Government told everybody to, because they're better for the Polar bear you know. The fact is plenty of people need the 60mpg from diesel supermini's these days even if they dont do large mileages, so they buy cars they know nothing about.

You know who to blame on that one.

Any - Dirty old cars? - balleballe
Yep - the people buying them
Any - Dirty old cars? - jamie745

No you blame the Government for increasing tax on fuel and encouraging (or forcing) the purchase of diesels. The general motorist never bought diesels when petrol was cheap did they?

Any - Dirty old cars? - MikeTorque

How much soot & particulates is that old Renault generating ? The MOT figures you quoted didn't mention the worse offenders of older diesel engines (i.e. soot & particulates ).

Any - Dirty old cars? - jamie745

How much soot & particulates is that old Renault generating ? The MOT figures you quoted didn't mention the worse offenders of older diesel engines (i.e. soot & particulates ).

Not many I wouldn't have thought, with unthrottled's car being a petrol.

Any - Dirty old cars? - unthrottled

How much soot & particulates is that old Renault generating

Less than a Euro V diesel, Mike. Like all port injected injected petrols, soot and PM will be negligible. CO and HC emissions will be high from a cold start though.

NOx emissions will be lower too.

Any - Dirty old cars? - balleballe

No you blame the Government for increasing tax on fuel and encouraging (or forcing) the purchase of diesels. The general motorist never bought diesels when petrol was cheap did they?

I'm sorry, I disagree - the final choice always lies with the consumer.

If I buy a diesel or any other product for that matter regardless of who suggested it to me; without doing any research as to it's short-comings or downfalls, then I am to blame. Not the person who encouraged me to buy it.

Not a fan of blame mentality - people should own up to their mistakes. We all make them as we are all human

Any - Dirty old cars? - jamie745

As the last few days of panic petrol buying have shown us - people are stupid. This is the general public, an overall IQ of 37 so Governments need to keep that in mind when making policy. Its all well and good promoting personal responsibility but 99% are incapable of it. People act like children so need to be treated as such.

A car is a complicated thing and most people dont understand it. People don't understand about DPF's either and I blame dealers for not explaining it to customers. The fact is if you push people into diesels with high fuel prices then millions will buy cars which don't suit them and suffer problems, thats fact. I'm more interested in fact than 'personal responsibility' rhetoric.

Any - Dirty old cars? - MikeTorque

>> Less than a Euro V diesel, Mike. Like all port injected injected petrols, soot and PM
>> will be negligible. CO and HC emissions will be high from a cold start though.

I forgot you had a petrol motor, must be all that extra benzine blowing in from the local fuel station forecourts at the moment affecting me. As you mention HCs are high when cold but with zero HC when hot that's a good sign.

Which supermarket brand of fuel are you using ?

Any - Dirty old cars? - unthrottled

Asda smart price. There's a Shell garage nearby that (almost) price match their standard 'fuel save' petrol, but after two tanks I couldn't see any improvement. Asda's pumps pump much more quickly than the Shell ones, so that swung it for me!

edit-It's interesting that you bring up the diesel comparison regarding emissions. Even pollution specialists can't agree on the whether petrol or diesel is 'cleaner' in terms of trace pollutants. There's a huge row about PM from diesels. There's a school of thought (which I'm in) that thinks that the regulators got it wrong with soot, and that old diesels might be less damaging to air quality than new ones!

Edited by unthrottled on 30/03/2012 at 13:54

Any - Dirty old cars? - MikeTorque

Yes both petrol & diesel have their disadvantages. Petrol contains Benzine a known carcinergen which humans can breath in whilst filling up or via the exhaust pollution, along with HC when the engine is cold. Diesel engines create soot & PM which is known to cause a variety of health conditions especially lung related. No winners in either camp.

I find the older diesel engines affect me worse, directly impacts my breathing and eyes run, have to close my cars air vents when driving behind smokey vehicles, whereas a Euro V diesel doesn't cause any problems. Cold petrol engines almost make me sick if they pass by whilst I'm walking such is the toxic waste that exits their exhaust.

The only clean engine is one that doesn't run.

Any - Dirty old cars? - unthrottled

You must be more sensitive than me, but then I like the smell of petrol!

It should be borne in mind that looks can be deceptive. The visible smoke from an old diesel is comprised of relatively few big soot particles that fall out of the atmosphere in minutes. But the new diesels emit large numbers of small partciles that linger in the atmosphere for a week or more. that's why I think they got it wrong.