On Jan 15, 1:19*pm, Tim Streater wrote:
In my Dizzle C4 (50mpg):
1500 / 50 * 4.55 = 126.5 litres x 1.3 = £164.31 fuel cost for me
Saving of £427, not bad eh?

Diesel with DPF?

Your saving of £427 would not go far if a DPF failure occurs.
DPF clogs... injector leaks... diesel leaks past injector diluting
oil... oil level starts to rise... incorrect oil used... oil pickup
clogs... turbo fails... intercooler suffers cracking...

DPF require regeneration when soot has built up to a certain level.
DPF soot buildup is highly dependent on fuel, driving style & engine
condition. For example if you do lots of short trips there will be
more buildup, likewise if there are any unattended engine faults which
cause an increase in sooting, blowby etc.
DPF regeneration requires quite some time at high-RPM, essentially a
long motorway trip rather than around town driving. If the car does
not see much long distance driving then regeneration is either
inefficient or incomplete by turning the engine off whilst it is
underway at journey end. Inefficient regeneration due to increased
fuel injected for regeneration to occur can result in faster soot
buildup rather than its removal, and fuel dilution of oil causing oil
pickup problems.

Failures of DPF equipped cars range from turbo failures right through
to DPF replacement and even engine failure. Some systems are better
than others and driving style is likely to be very important - lots of
short cold start trips may actually be very disadvantageous to engine
longevity and bills. So the economics of "high MPG" may be met by
"insanely high repair bills or short vehicle life". Not surprising the
green attack on vehicles is leaving a lot of R&D to be borne by end
users with marque walking away.