Clementine's Garage
Clementine the Cat
 
Image of flower
Yellow R4
 
Réparateur d'automobiles

European emissions standards and R4s

Andy McGhee

Enthusiast
Messages
1,538
Location
Cheltenham
At a recent MOT, the emissions figures for my GTL were as follows: CO 0.207, HC 46.
What I'd like to know is how this compares to modern cars, and where it would place it on the Euro scale.
(Before anyone says that the CO figure is far too low, the car's been fine for the last 26 years!)
Thanks in advance!
 
Euro scale takes into account grams of pollutant per kilometer travelled, not percentage of pollutants in an exhaust gas sample. Therefore it's a function of average fuel consumption and exhaust emissions.
Your GTL's emissions are really low; to have an idea, in our country catalytic converter equipped cars have to emit 0,5% max CO and 100ppm max HC in order to pass the emissions test.
 
I'll be honest I watched my R4 get mot tested but didn't see an exhaust probe go anywhere near the car...
 
I'll be honest I watched my R4 get mot tested but didn't see an exhaust probe go anywhere near the car...
For the UK Mot, it depends on the age of the car: Prior to 1975 (or it might be 1974; I can't remember), it's a visual check only, for excessive smoke emission.
 
At a recent MOT, the emissions figures for my GTL were as follows: CO 0.207, HC 46.
I assume that test was done at idle, (or at a little above idle), where the fuel passes through the adjustable idle mixture jet.
Above idle, the mixture is set by fixed, (replaceable, not adjustable), jets and it will be richer than that, (otherwise it wouldn't be running at all well!).
 
The garage I take my GTL to are very creative with their positioning of the exhaust probe... As they say, the few hundred miles I do per year and the fact that twiddling the idle mixture to allow it to pass makes it run less well, means the pragmatic approach is not to get wound up about emissions - it's only a smidgen out anyway.
 
Your statement about your garage being "very creative with their positioning of the exhaust probe" reminded me of the time I took a friend's Fiesta in for an MOT for her. It failed on emissions and they said it would need a new catalytic converter. The tester was sympathetic when I explained that the owner was an NHS student nurse who had absolutely no money to spend on fixing her car, so he too was "very creative with the positioning of the exhaust probe" and tested the emissions again while the probe was inserted it into the tailpipe of another Fiesta that happened to be in the next service bay. It passed that time.
 
A GTL with an engine of an average health - up to 300.000 kms -, well tuned up and with no vacuum leaks will pass emissions tests with flying colours, no need to get "creative" ;-) .
 
Back
Top