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Escargot Flambי
The life and times of a 2CV turbo
By Steve Cropley
Copyright CAR Magazine, reprinted with permission.
Appeared in CAR May 1988
At the height of its career, my turbocharged Citroen 2CV produced 60 percent
more power
than standard – 46.4 bhp on the rolling road instead of 29bhp off the
showing floor.
It clocked an honest 87mph on the motorway, and might have gone faster still
if we’d had the
courage and cloth ears to rev its engine higher. But so agonised was its
shriek at 7000rpm,
and so vivid were our mind-pictures of liquorice pushrods and a spaghetti
crankshaft, that we
always backed off when the needle on the Hejira kart tachometer came around
to the seven.
As it turned out, 87mph was plenty of speed, accompanied as it was by a
14sec reduction in
the car’s 0-60mph time – from 34sec to just over 20. Speaking
practically, it made a big
difference to A-road journey times and to the general ease of driving a Deux
Chevaux, now
that it could hold on to 70mph, up the hills as well as down them. True, the
boost didn’t really
hit it’s stride until 3800rpm and never did span completely the gaps
between gear ratios, but it
still made a power of difference.
So much for good sense: there is invariably a hooligan side to supertuning.
The 2CV was
magnificent for its element of surprise. Sixty percent more power made the
car, outwardly a
standard red B-registration Special (apart from the doubled diameter of its
exhaust and the
load hornet’s buzz that came out), into something of a scourge on
A-roads and motorways.
Even Volvo estate people with Show Dogs In Transit noticed that its maximum
cruise
corresponded to to 93-95mph on their speedos, error included. Dudes in
205GTIs, used to
looking straight through slow-lane impediments like Citroen twins, were
peeved at having to
do a ton-plus to put ours firmly in the mirror. Other Dyane and 2CV
travellers, struggling up
inclines at the standard 55mph, must have been astounded as our red car
swept by at 80.
In
five or siz thousand miles of driving, Struggler (as we came to call it)
shocked a lot of people
and made a few of them very angry indeed.
The whole mad plan came from Richard Wilsher, Then development engineer at
Turbo
Technics, the Northampton tuning firm, now its agent in Highbridge,
Somerset. He reckoned
the 2CV did not cope nearly as well with road conditions in this country as
it did with those of
France, and it was the fault of those who designed so-called rolling English
roads. Constant
curves and hills prevent the unmodified tin snail from getting into its
stride.
After a few years
in the Arrows formula one team, and a few more developing impressive
aerodynamics and
extremely powerful engine of the Tickford Capri, Wilsher was widely
experienced with
turbocharging, and one of it’s keenest supporters. What was more
logical, he argued, than
equipping a 2CV with exhaust driven puffer?
Paul Buckett at Citroen mentioned the idea to me. Wilsher had been on at
himabout finding a
suitable car to work on. After a couple of years of happy Deux Chevaux
ownership, I’d
contacted Buckett about
Getting hold of French tuning advice, and experimenting with an anti-roll
bar kit they offer over
there.
Already well known as expediter, Buckett saw how everyone’s
onterests could be
served. He gave me the Wilsher phone number and I rang it. It wasn’t
a clear-cut decision for
me. I’d often disliked turbocharged engines in test cars for their lag
and non-progressive
power delivery – and I’d been annoyed by the priorities of
turbo-tuning firms who seemd to
modify engines that were merely receptive, like the Ford V6s, rather than
those that needed
more power. The Ford was powerful already; why didn’t somebody
turbocharge a Mini? From
there it was a small step: come to think of it, why didn’t somebody
turbocharge a Citroen
2CV?
Everyone I talked to reacted with howls of laughter. But from the first,
lots of people
maintained a special interest in the car – expressly because they
could visualise it beating up
Rover V8s on the M4. If it worked we’d have had some fun and produced
a little bit of history;
if it didn’t we’d still have had the fun. And the cost was only
money. At the other end of the
phone I found Wilsher a cheerful, straight-talking bloke with all the
technical answers and
more enthusiasm than seemed decent in an accomplished engineer of 42. I
commited my car
into his custody one snowy day outside Milton Kaynes railway station.
The 2CV is a tough subject for turbocharging from just about every angle.
Its tiny engine
produces hot exhaust gasses – needed to propel a compressor wheel
– in very small
amounts. Its opposed cylinder layout means that the sources of the little
exhaust puffs are
widely separated, not centralised as they are in a decent, God fearing
in-line engine. The flat
twin also breaths through very long induction tracts, no help in the problem
of minimising
throttle lag, and the whole plot is cooled by air, a system which promises
trouble with ‘hot
spots’. None of this could inhibit the Wilsher energy. With
after-hours help from those at TT,
and propelled by laughter, he had the first version built in a couple of
weeks.
The Garrett T2 turbocharger was mounted centrally in the engine bay,
directly above the inlet
manifold to suck through the standard carburettor. Exhaust gases were fed up
to it from either
side of the engine bay, siamised together in a neat piece of piperwork just
before they
reached the turbo unit itself, then exhausted through a 1.75in pipe
equipped with a smallish
central silencer. The ignition system was fitted with an electronic timing
retard module,
designed to react to rising induction system pressure and inhibit
pre-ignition, a common petrol
turbo problem under full noise.
But it didn’t work. The turbo housing, the smallest generally
available, was still too large to
squeeze the 2CV’s little exhaust puffs tightly and mobilise the
compressor. But Garrett had
built one experimental T2 with a smaller housing, and after a couple of
weeks it generously
supplied it. The improvement was immediate. The exhaust flow now generated
boost, but no
sooner did it appear, than the electronic retard-box detected it, knocked
back the timing, and
the extra urge fell away. Limited extra power was delivered in a most
unsatisfactory kind of
wave motion that had nothing to do with good throttle response – and
it was accompanied by
an exhaust racket that left cracks in the workshop ceiling.
Wilsher rapidly dispensed with the electronic retard and installed a Bosch
breakerless ignition
capsule, re-engineering the advance-retard to work on conventional vacuum
advance
principles. That gave conventional ignition advance for off-boost cruising
and gentle
acceleration, and smooth retardation to limit pinking as the boost began to
increase. In went a
pair of platinum-tipped NGK B7HV spark plugs (they have a wide heat range
and resist oiling)
and the silencer was doubled in capacity. To iron out flat spots, the
carburettor was re-jetted,
but that didn’t work either, so it was swapped with single-throat
downdraught Weber. The
compression was lowered from the standard 8.5 to one to about 7.5 to one, by
filament of
very tough, thicker head gaskets. I imagine that this was simply to reduce
preignition; Wilsher
explained that its real benefit was to increase the capacity of the
combustion chambers. The
bigger the chamber, the more gas you could pack in under pressure.
After all this was done, the car really began to percolate. On his third
run, Wilsher caught an
XR2 napping, and it took the driver five miles to get past again. Early
experience soon
showed that the 2CV’s sure handling, and mighty front disc brakes were
well up to coping
with more power, even if the body roll did get a bit copious at times. The
car would now get
close to 90mph if your ears could stand it, and the acceleration was
downright dramatic (for
602cc) if you used full revs. Beyond 3500rpm the top gear performance was
almost elastic.
The problem of the engine falling off boost between second and third
remained. A solution to
that would have cut acceleration times even further, but it was clear that
only an even smaller
turbocharger – in effect a Garrett T1 – could solve it.
There were some startling development problems. Once, as he was bounding
down the A5
checking the ignition settings, Wilsher heard an awful rattle from the
engine, the oil light came
on and a large cloud of smoke filled the cabin. But it was not the expected
comprehensive
blow-up. Instead, half of the sump’s oil had been dumped into the air
filter. It seems that the
standard 2CV has a breather valve in the neck of its oil filler pipe to
relieve the high crankcase
pressures generated by its opposed pistons. The heat and load of the turbo
engine had
destroyed the standard valve and the pumping of the flat-twin’s
pistons had forced oil into
unwelcome places. Wilsher designed a more robust system, and used the oil
returns from his
new breather to flood – and - cool the exhaust valves.
After about 3000 development miles I took the car away for shakedown driving
in London, but
had some problems with carburretor icing. The exhaust system also threatened
to fall apart.
Worst of all was the failure of the new ignition system – it stuck
fast with the timing at full
retard. It had worked well at providing the right timing range, and at
taming any pinking, but
road grime had made it jam. Wilsher redesigned it, giving it a better
mounting, and protection
against grit. What none of us could trace was a sort of ‘hot’
smell that occurred when the
engine was worked hard.
With the cooperation of Keith Spenser at Turbo Technics South, Aldershot,
the Struggler went
off to the rolling road, where it showed 46.38bhp at 6500rpm after an hour
or two’s carburettor
and ignition tweaks. It might have given 50bhp had it been measured for full
power at
7000rpm, but so awesome was the mechanical noise, Wilsher says, that he
cried enough at
6500. At that stage, he says, the curve was still climbing steeply.
For all its hard times, the Struggler seemed to run ever more smoothly. The
tickover was that
of a Swiss watch, and the pulses of the power delivery were smoothed by the
turbo system.
Most times, the engine seemed as sweet as a good four – sweeter,
perhaps, because it did
not suffer the in-line’s four’s typical 4000rpm tingle. The
exhaust, within legal limit, had a rasp
and boom to it when on boost to it that would have done justice to a big BMW
bike.
Wilsher fitted the engine sump with Shell’s Gemini oil (claimed to
‘stay in grade’ at extremes
of heat and hard use) and the gearbox with Amsoil gear oil, the
last-a-lifetime stuff they put in
grand pix cars. Then, after an outlay of something like 1400 Pounds, it came
back to me for a
life in London traffic.
There was nothing fair about this. Though the bones of the car, and the
outlay were mine, the
idea and the inspiration, the thought and the sweat, were Wilsher’s.
It had been no ordinary
job. I could see that in his eyes as I drove away.
Apart from my enjoyment of the finished car, this should have been the end
of the story. The
Struggler worked well. It burst into life hot or cold, it beat it’s
share of 1100cc hatchbacks at
traffic lights but behaved as docilely as an ordinary Deux Chevaux. Its
turbocharger managed
to avoid abuse because Wilsher had incorporated a little red warning light
in the dash that
winked at you when the turbo housing was too cold to call up the boost, plus
the little Hejira
tachometer, down near the driver’s right knee. The Struggler was
always popular with friends.
A lot of miles were accumulated in demonstrations of its prowess.
The chicken shed-on-wheels felt faster than a greased Ferrari. For one
thing, whenever your
right foot was properly nailed to the floorboards, there was no reliable
indication of speed. The
needle of the matchbox-sized dial tended to wind so far beyond the highest
graduation
(70mph) that its only use was a belly-button indicator.
In the absence of a speed guide, your imagination tended to run away with
you. It was easy to
project yourself beyond the magical 90mph – the sound barrier as far
as twin-cylinder
Citroens are concerned. What brought you back to Earth were a variety of
aural and visual
speed indicators. At 75mph, the tops of the front doors were sucked outward
by the
slipstream. By 80mph, the din of the wind, road, and engine made
communication between
occupants, even by shouting, impossible. We learned to signal
would-you-like-to-stop-at-the-
next-Happy-Eater? by hand. Above 82-83mph you would suddenly recall,
whatever your train
of thought, conversations with other Citroenistes about the strength of 2CV
bottom ends.
By
85mph you’d be praying that it was as true as this day as ever.
We always intended to write about the Struggler. Too many people had shown
interest to for
us to sweep it away uncelebrated. One day in summer, Mr Richard Bremner and
a
photographer set out to capture the car on film and to make some sensitive
studies of
Wilsher, brains and impetus behind the whole thing. They accomplished all
this and were
cruising quietly home along the M1 at 80mph when green-brown smoke began to
billow from
under the dash and bonnet. They pulled rapidly across two lanes of traffic,
but in time it takes
to read a sentence, orange flames were shooting six feet in the air.
Fool that I am, I had never bought a fire extinguisher, but it probably
wouldn’t have helped.
Nobody with a brain opens a the lid of an engine bay when there’s a
fire underneath. And so it
burned. Luckily the car was at the southbound entrance to Scratchwood
services on the M1 –
ironically, right next to a huge sign advising drivers to ‘REDUCE
SPEED NOW’. Fire fighters
arrived quickly. Bremner told me as much on the line to Germany where I was
that day. He
and the photog where unscathed, and a good few thousand pounds’ worth
of photographic
gear was saved too, but the car burned out completely ahead of the
windscreen. The Weber
carburettor melted away quietly, as did the alloy brake clippers, and the
master cylinder. The
engine appeared OK, but its oil seals and the pushrod tubes had been well
cooked. The
plastic dash and trim hung down inside the car, like carefully arranged
spaghetti. The trim,
once fawn, was black.
Nobody knows what caused the fire, but the likelihood is that the two pieces
of ventilation
trunking across the top of 2CV’s engine bay got so hot that they
ignited, even though they
have been carefully heat-shielded. They were probably the source of the
‘hot smell’. Made of
kind of glorified cardboard, these tubes are widely thought to have caused
fires in many a
standard Citroen twin, too.
Wilsher, having heard of the news on the phone from me, went out and got
drunk. He said it
wasn’t the first time months of his work had been wasted in an
accident, but it was a profound
blow, just the same. I contemplated a hefty financial loss because I have
been to stupid to tell
my insurers that the engine had been modified. There was no question of
making a claim.
I
nearly sold the ruins to a bloke in the pub for 500 pounds.
In the end we made the only sensible decision – to build a Turbo 2. It
was exciting the
enthusiasm grew all over again. The fire had been a sort of a friendship
test I suppose; the
fact that we could contemplate doing it all over again told us things we
liked. Peter Jackson of
Brampton Garage, an enthusiastic Citroen dealer, was an immediate help in
rescuing the car
from Scratchwood, and offering to find parts for the rebuild from his
extensive second-hand
cache. He also helped in relocating the car to Wilsher’s new
headquarters at Highbridge,
Somerset.
Wilsher, after a short period of mourning, went to work on the ruin. His
wife, Leslie, stripped
the fabric upholstery out of the car and washed it repeatedly until the
color scheme came
back. We made various attempts to get a newish 2CV write-off to strip for
parts, but affordable
examples were rare. In the end, Wilsher settled for an old but healthy Dyane
to provide the
needed electrics, instruments, brakes, driveshafts, tie-rods and an engine
(it had a label
which read: ‘Next service 97,000miles’). A local panel man
rejuvenated the burnt and rusted
skin to a better-than-new state, and a lighter, non-standard grille was
fabricated to plug the
ugly hole that remained in the nose.
Just for the heck of it, Wilsher gave the car a facia of his own design, (to
go around the Dyane
instrument pack) and, bless my soul, a flour change using a lever
‘won’ from an old DS.
A big, white-faced boost gauge was given pride of place in the middle of the
dash. The ‘black
armband’ was my idea; we painted a single black stripe horizontally
across the offside wing to
commemorate the Scratchwood Inferno.
There had been talk of building an intercooled turbo engine with water
injection this time. But
it made little sense on an engine of this age – and the budget
couldn’t stand it, anyway. Our
official reason was that the charge-cooling benefits wouldn’t be best
utilised by an air-cooled
engine. Still, the new suck-through system, really a third generation
design, used previous
experience in relocating the turbo unit to give a shorter travel for gases
between exhaust
ports and turbo. The heater was redesigned, the ‘cardboard’
trunking replaced with modern,
fireproof ducting, and the whole engine bay was smothered with shiny
fireproof material.
The
turbo was overhauled by Turbo Technics and fed this time by a 1.5in SU
carburettor on a
modified TT adaptor. Wilsher reckoned the SU’s constant vacuum
characteristics would give
better flexibility down low.
And so it has proved. Today the engine lacks a little of the bite of the old
Weberised version
(particularly since Wilsher is loathe to allow it quite the boost pressure
of the younger engine).
It runs about 5.0psi now; in the old days it had various boost guises up to
about 8.psi, while
the driver watched like a hawk for pre-ignition on hot days.
The Struggler Turbo 2 lived with me until late last year, putting in a
trouble-free 4000miles.
The ‘new’ old engine uses oil, and it needs watching, but the
car will still do 80mph plus on
the motorway. And its extra torque really tells on long hills and on
give-and-take roads. It will
rumble along at a steady 70 where other Citroen twins are hard-pressed to
average more
than 50-55. You can drive without any of the brain-curdling concentration on
saving
momentum which quick progress in standard 2CV demands. The performance is of
the order
of a 950 Fiesta’s – useful and flexible.
I can’t remember any previous hot-up project interesting people as
much as this one. It broke
a general rule: it provided performance for a car which previously
didn’t have any, instead of
starting with something that was good anyway. How good it could have been if
there had
been a small and cheap turbocharger truly suitable for small engines
(Garrett marketeers,
answer please).
We’ve learned lessons out of this, Wilsher and I. His is that doing
one-off projects for people
never makes your fortune; mine that true engineering skill will probably
have a good result on
the most unlikely project. I’ve also learned to carry a fire
extinguisher and to tell my insurance
company. I’ve made a good friend too.
Nowadays, the Struggler lives at Wilsher’s place, which is where it
belongs. The engine has
lately turned 119,000 miles and will need to be replaced one of these days.
The gearbox
groans a bit and the ancient dynamo has a struggle keeping the halogen
headlights alight.
But the turbo installation continues to be reliable. And in the cabin
there’s not even a funny
smell.
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