| Walker’s
World July 04
Some
months seem to go better than others and we had had more than our
share of winners recently.
Winner
1
Managed
to get some time off on a Saturday and found myself at Snetterton.
We were there to watch the Mid-engined GT race which Matt Cummings
was running in. Matt bought a damaged Lotus Exige and after running
a non-too-quick K Series engine was looking to fit a Honda motor
for this race series. Here at Emerald we talked Matt into an Audi
TT engine and gearbox conversion from Bernard Scouse. First time
out the car had a suspension problem but the potential was there
to do well.
After a race long battle with a very fast K-Series car Matt finally
managed the win – his first. The motor is currently making
just over 300bhp but the potential is there for a lot more. Once
the engine gets some development under its belt I don’t think
the K cars will get a look in.
Winner
2
Phillip
Myatt runs a Caterham Seven but races something rather different
- a Citroen 2CV. The annual 2CV 24-hr race was coming up at Snetterton
and Phillip had himself a new engine build from Pete Sparrow. Pete
is well known in 2CV circles and was the man behind my one (and
only) 2CV circuit appearance.
My task was to check the jetting and set the ignition timing the
day before the race started. Happily the mixture was as good as
a carburettor gets and the timing was set to a known figure before
the first power run. Then I simply adjusted the ignition by hitting
the trigger ring with a hammer and old screwdriver. It wasn’t
exactly high tech but I had a scratch mark on the plate so I could
return to my starting point. The way it works is that you give the
timing a tap and then take a power run. Our new graphing software
then shows the power difference ( if there is one) and you keep
tapping backwards and forwards until you get the best power curve.
I have done a few 2CV engines in the past and the competition is
fierce. Phillip’s engine was a good one and he had a little
tweak (totally legal) for qualifying which put him 1.5 seconds ahead
of the pack. He made it first into the first corner and the car
was never headed in the next 24 hours – winning by an astounding
17 laps!
I can’t pretend it was all down to hitting the base plate
with a screwdriver a few times but it’s a good feeling to
be even a small part of a winning team.
Winner
3
Andy
Silman runs a Westfield in sprints and Hillclimbs fitted with a
2.0 Vauxhall XE engine. He, along with father Dennis, came in for
a power run, just to see where they were before looking at an engine
upgrade. I put the mixture reader in the exhaust, (to log the AFR
as usual) and we took a power curve. I had asked Andy the rev limit
and had to ask twice because I thought I had heard it wrong the
first time: 8700rpm was the shift point (the engine being fitted
with a steel crank, forged rods and steel pistons).
Andy and Dennis were expecting 235 bhp but he is so quick up the
hills that the rumour was he had 250bhp. The graph was showing a
peak of 204bhp. The mixture wasn’t miles out but it was rich
enough to affect throttle response and probably mid-range torque.
It was one of those strange results where bad news is really good
news. If Andy could win with 204 bhp how quick would he go with
235?
We arranged a day for mapping and cam timing swings. Since we only
map our Emerald M3dk ECU Dennis wired up a second plug in parallel
with the original. On the day we took another base run on the original
set up and then plugged in the Emerald ECU. Playing with the cam
timing first we established that the original figures were just
about spot-on with the inlet cam turning out to be just one hole
advanced (too much lift on overlap).
Then I remapped the engine and we put the before and after power
curves together. Peak power was still only 212bhp at 7,000rpm but
the mid-range torque was way up – see the curves elsewhere
in this feature. Andy was still disappointed, especially since the
team had geared the car right down to take advantage of the 8,700rpm
rev limit. There was not much point in pushing past 7,000rpm because
the torque was dropping away.
First time out with the re-mapped engine Andy was ballistic, almost
2.5 seconds faster than his previous best. Learning to use the torque,
rather than the revs, the next two meetings saw even bigger gains
plus class wins by a big margin. At North Weald the Westfield on
List 1A (conventional road) tyres only missed FTD (Fastest Time
of Day) by 0.5 seconds claiming overall second place. The FTD holder
was driving a 2.0litre Ralt single seater with slicks and wings!
We are currently trying to hatch a plan to make better use of the
steel bottom end by moving the torque up the rev range – but
all on a budget: Andy is getting married this year so spare cash
isn’t exactly in abundance at the moment.
Loser
Well
it couldn’t all be great news could it? The Big yellow XJS
that we mapped a couple of times had a terrible day at Snetterton.
When we first watched it circulating in the wet the engine was cutting
on the right hander onto the pit straight. We assumed it was fuel
starvation but then it broke down all together. All in all it broke
down three times in three races; what they call a 100% failure rate.
We had the car back at Emerald and went through the wiring, finding
a few suspect areas but nothing much wrong, it started and ran fine
all week. All we could do was re-wire the injectors and fit the
twin coil distributor arrangement. Jag V12s have a bit of a problem
with cross-firing in the cap, due to having so many HT pick-ups
so close together. This new dizzy had a stepped rotor arm and cap
arrangement with two king leads. Basically it turns the system into
two six cylinder engines. We had to write new software to run the
two coils alternately and it seems to work really well. The added
bonus is that the coil is only worked half as hard as before because
they share the work load between them.
Back at Snetterton for a test day the car ran a dozen laps without
problems – apart from a suspect fuel surge at the same corner
as before. The tank and fuel lines are coming out next to sort that
one and then it should be all systems go for the next race.
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