The car is a Westfield SEiW, originally built as a road car, but slowly making the transition to a racing machine.  The engine is a Vauxhall Redtop 2.0L 16V.  As we got it, this had Weber carbs and a Weber Alpha ignition system.  Power at this stage ought to have been around 170bhp, but the Alpha ignition never worked properly.  Originally SVAed at a rather portly 630kg, the car has shed somewhere around 125kg and now weighs in at 504kg.

Over the 5 years we've had the car, quite a lot has changed.  The following is just the things I can remember.

Wheels & Tyres

Compomotive CXR ultra light motorsport wheels
Avon ACB10 tyres (8" all round)

Bodyshell

All interior panels replaced with carbon sheet and carpets removed
Boot box removed and replaced with alloy panel.
Rear arches widened to accept 8" tyres
Front side panels flared at rear of engine bay to provide exit for engine bay air.
Windscreen removed and replaced by aeroscreens
Heating and ventilation system removed
Westfield Sports seats removed and replaced with a single glass fibre shell
Original seat supports removed and side mount brackets welded to the chassis
Scuttle and nosecone converted to quick release.
Carbon dashboard
Dashboard mounted on brackets welded to chassis rather than screwed to the scuttle
Original gauges replaced with digital dash and our own gear indicator/shift lights
Rear diffuser
4" headlights
Motorcycle indicators
Lightweight race mirrors
Lightweight scuttle
Lightweight front cycle wings

Chassis

Extra chassis braces added inside the cockpit and around the front suspension and engine bay
Chassis alloy side panels removed
2 gallon alloy fuel tank fabricated and fitted
VW Polo alloy radiator
Alloy swirl pot
Full roll cage
Engine mounting moved 2" back in the chassis

Front suspension

Widened track
Fitted Protech dampers, new springs.
Added antiroll bar.
Alloy front hubs.
Solid Poly bushes.
Modified uprights to give improved Ackerman.

Rear suspension

Rear antiroll bar
Protech dampers.
A mixture of rose joints and solid poly bushes.

Brakes

Front Wilwood alloy 4 pot calipers and lightened disks
Rear lightened disks and alloy calipers
Floor mounted pedal box incorporating remote adjustable balance bar.

Engine

Doug Kiddie narrow journal touring car spec steel crank,
Matching Arrow steel rods
Heavy duty ARP big end and main cap bolts
ARP head studs
Omega intruder HC pistons with deep valve pockets,
Flowed head with +1mm Ivey narrow stem valves,
Dual concentric valve springs and titanium caps
SBD race cams (modified inlet),
Dry sump, remote oil filter
Jenvey taper throttle bodies.
SBD inlet manifold
ITG foam air filter
SBD 4:2:1 exhaust manifold
Repackable Techcraft alloy exhaust can
SBD lightweight alternator
Alloy catch tank
Aeroquipped fuel lines throughout
Good for 265bhp@8500rpm and 190lb.ft@5000rpm

Transmission

Lightweight steel flywheel
7-1/4" Helix paddle clutch (single plate, sprung centre) with coaxial hydraulic slave clylinder
AP master cylinder fitted to modified Westfield pedal box.
Elite IL200 5 speed sequential gearbox
XoomBox based pneumatic shift system.
Ford XR4 differential case and 3.62:1 crown wheel/pinion, TranX limited slip diff

Electronics

Lightweight race battery
Emerald ECU
Innovate LC1 wideband lambda sensor
XoomBox datalogger/traction control/launch control + 7 segment shift light
Datalogging channels := engine speed, 4 wheel speeds, throttle position, lambda, oil pressure, oil and water temperatures, x & y acceleration
Xtra Flat Shift X10der for XoomBox - semi-automatic pneumatic driven clutchless up/down shifts, gear display.
 

Increased power, reduced weight and stickier tyres have had the expected effect on lap times.  A clockwise sprint run at Kames was around 98s the first time it ran there.  By the end of 2007, this was down to 87.5 - and that was before the fancy engine!  The first event in 2008 saw this reduced further to 85.5 and at the second it went under 85.  Mid 2009 saw both drivers dip below 84s, and in October, Stephen recorded out first sub 83s run.

At its first Autotest A standard road going Westfield	David waiting to start an autotest run
David at Kames 04/2006	Stephen at Kames 04/2006
By the end of its first season sprinting Windscreen has gone, sportseats replaced by shell, rear arches extended for fatter rubber, front lights replaced by lightweight items, RAC legal rollover hoop	2009 livery On the way to the start at Golspie.
2011 The roll cage is the biggest externally visible change for 2011. Underneath though, much more changed.