is reowned as one of the UK's top Vauxhall tuners.
and lusty torque from a 1.6 Ecotec sounds tops to us.
Broughton's SB Developments concern down in deepest Surrey will be familiar to may CCC readers,
buts it's been a while since we've checked out what he's up to, so the
offer to try out his latest Vauxhall-engined Westfields was not to be
missed. Since we last chatted to Steve he's moved from Chessington,
to nearby Surbiton (still a piece of cake to get to off the M25), to
what Steve describes as "better organised premises".
perhaps best known for its conversions on and components for the trusty
Vauxhall 2.0 litre XE and Ecotec units, and have have written previously
about the success they and their customers have achieved with Westfield
and the SBD-powered Jade sports racer in hillclimbs and sprints, using
the power plants. The Jade has also been successful on the circuits,
and back in the hands of constructor Tony Sinclair it won the 2000 Winter
GT series at Brands outright, and class B in the 2001 Castle Combe GT
Steve reckoned that many of his customer were using Westfields and the
like on road and track, so it made business sense to go full circle
again, and develop engines for those cars. Steve figured the 1.6 litre
16 valve Vauxhall unit was the perfect partner, and as he had been gradually
developing this motor to ever greater performance levels, it was the
logical option for the latest manifestation of Broughton brilliance.
well-proven, but ever developing ideas about all aspects of performance,
including chassis construction, suspension design and aerodynamics,
to name but three. So he isn't likely to just drop an uprated engine
into a standard car. His more holistic approach ensures that all areas
of the car knit together to create a nicely poised, but seriously quick
machine. Of course if you want to drop one of his engines into your
standard car he'll be happy to help, but hopefully by the end of this
feature you'll agree that the SBD method is very effective.
SBD decided to build their new Westfield, Steve's mate Martin
Bailey also decided he wanted one for fast road (and perhaps track)
use too. So they built a competition version and another for Martin.
"The only major difference between them really is the engine
spec" related Steve' "although Martin's road car has
to have the necessary bits to comply with the SVA regs, including
lights and stuff".
chassis are substantially similar, the suspension is pretty near
identical and is to Steve's specification, both run Quaife transmissions
and Wilwood brakes, and both are based on the neat 1600 Vauxhall
motor. But there are differences, the most obvious being the aerodynamic
treatment on Steve and co-driver, and SBD stalwart Dick Hulbert's
yellow and carbon competition version.
with his earlier Westfield, Steve has built his latest competition
one to comply with hillclimb and sprint sports libre regulations.
This is an unusual approach, most people with Westfields etc,
are sticking to the less extreme modified production regulations
rather that pitting themselves against purposed-built sports racers.
But Steve explained his logic, "I wanted to show the engine
to my customers but I didn't necessarily want to put them off
by running in a class they may well be planning to run in, like
the modified production class"
chassis are both lightweight Westfield racing spaceframes, 'SEi
Wides' to be precise, and the sprint chassis has had a few superfluous
tubes removed from behind the rear axle to save some weight. The
road car retains these tubes for safety reasons because they offer
some rear impact protection. The roll hoops are different, the
road car's bestowing security to the expected brace of occupants
whereas the sprinter has a single, smaller hoop, braced diagonally
fore and aft as well as laterally.
design is an aspect that Steve is particularly interested in, and he
uses computer-based geometry analysis software to help refine his designs.
The front geometry has evolved from its use on his first Westfield and
the Jade sports racer, and the latest evolution now resides on these
two machines. Steve's approach is two-fold - to attain the best possible
wheel camber control in roll to maintain the biggest possible tyre footprint
at all times in cornering; and simultaneously to minimise roll-centre
movement in roll, to provide a consistent and predictable feel. "Interestingly,"
says Steve , "as you run through different layouts doing reiterations
with the software, as one aspect comes right so does the other.
all the analysis worthwhile, the suspension and the Avo dampers utilise
rose-joints or spherical-bearing (with the exception of the front, lower,
outboard joint on the road car). Steve found that swapping the dampers
from flexible bushes to solid spherical bearings made a huge difference
to handling, basically allowing the dampers to do their job. Nigel Kimberley
at Avo is currently putting some double-adjustable aluminium dampers
together to run on the sprinter next year in an effort to gain traction
track is normally wider on this model Westfield, which Steve and Dick
found annoying when competing with their earlier car because precise
positioning of the front wheel next to a kerb would mean the rear wheel
would run over it. So the front track has been widened on both the cars
to make them a bit 'squarer'. Another detail on the front suspension
of the sprinter is that alternative pick-ups can be fitted to allow
different wishbone inclinations, which enables different roll centres
and camber curves to be dabbled with.
comes courtesy of an SBD-specified Titan rack and pinion, mounted in
a position to provide the correct steering arm length and angle to eradicate
bump steer. Rear suspension is the standard Westfield multi-link independent
system. Both cars sport anti-roll bars front and rear for fine chassis
tuning, and both sit on Image three-piece alloy rims with Avon tyres
(slicks/wets on the racer and cut slicks).
mentioned earlier, braking is by Wilwood calipers, four-pot at
the front on both cars, two-pot on the rear of the sprinter. The
standard Westfield (Ford Sierra) rear calipers are retained on
the road car because of the obligatory hand-brake. Discs are also
standard Westfield (Ford origin) items front and rear, but skimmed
and cross-drilled to lighten them on both cars. The road car uses
polymatrix pads whilst carbon metallic pads are used on the sprinter
- "absolutely brilliant, and they work from stone cold,"
gearboxes on both cars are made by Quaife in Kent. The road car
'box is Quaife's 'Professional' four-speed synchro unit, encased
in light alloy. This connects to the tubular steel prop shaft,
fitted with heavy duty UJs, otherwise the regular Westfield/Ford
parts are retained. The final drive is a 4.1:1 Sierra unit coupled
to a Ford Escort Cosworth limited slip diff. The sprinter's 'box
is a four-speed dog engagement unit, also in light alloy casing,
and the same type propshaft connects to a 4.4:1 final drive from
the Sierra again. Because of the higher rev range of the race
motor Steve is attempting to source lower ratio final drives of
4.7 and 5.1:1 ratios. The diff is currently also a Ford viscous
cars utilise a compact clutch and flywheel arrangement, enabling
the engines to be located low and well back in the chassis. This
keeps the weight low and central, improving grip and handling.
AP Racing's 5.5-inch (140mm) twin plate sintered clutch has been
used, bolted to a 233mm steel flywheel weighing a mere 2.1kg.
engines have exactly the same basis - the 1600cc XE - and both are solidly
mounted in their respective chassis, but they have been very differently
prepared to suit their different applications.
road car engine. The technical aims here were to produce rubber-burning
power while retained tractability for tootling in traffic. The budgetary
aim was to keep the modification kit affordable. Bearing in mind the
level of performance achieved, a surprising proportion of completely
standard components has been retained. The head has only minor machining
to the valve spring pocket diameters to allow the use of larger diameter
valve springs, and to the casting to clear the increased height of the
cam lobes. Compression ratio is therefore quite close to standard at
about 11:1. Steve got Kent Cams to grind some 'relatively mild' SBD-designed
profiles for him which give 284 degrees duration and 11.4mm of lift
on the inlet side, and 278 degrees and 11mm lift on the exhaust side.
Standard valves sizes are retained although titanium caps are used,
which increase the fitted length of the uprated valve springs. Vernier
pulleys allow the cam timing to be optimised.
key to matching performance with tractability is the engine management,
an SBD forte, incorporating a four-injector fuel system and an MBE Systems
ECU. With long carbon (optional) inlet trumpets and SBD throttle bodies
this really is the business and offers features like adjustable launch
control (or lunch control as the label on the button says!). Dry sump
lubrication, a stainless four-into-one exhaust with SBD carbon silencer
can and a custom-made Pace lightweight alloy radiator complete the package.
Dyno-tested output is 191bhp at 8000rpm, and Steve reckons there's possibly
more power to come beyond that, while peak torque is around 138lb.ft
at 6000rpm. You can see from the dyno plots that torque curve is pretty
flat from 5000 to 8000rpm and power is actually still rising at 8000rpm.
On 'standard' 90mm non-carbon ram pipes peak power is still 185bhp and
that this engine is designed to be a 'plug and play' kit, easy for the
novice engine builder to assemble and the kit starts at £2275+VAT,
depending on what accessories you choose, with dry sump systems starting
engine in the sprinter shares few common features with its road-destined
cousin - as Steve puts it, "everything is very much state-of-the-art
in the competition engine." But then the aims are different
- traffic is not something you encounter on sprints, and outright
performance was the aim! So there's rarely a standard component
lightened, balanced steel race crank mates to steel rods and skirtless
slipper pistons, making for a stronger, lighter and more responsive
reciprocating kit. Much work has been carried out on the head
and Steve takes up the tale: "Quite a large amount of port
work is carried out which includes welding and several machining
operations to remove the emissions parts from the head. There
are bronze valve guides, and we fit standard size stainless valves
on the inlet and exhaust. The inlets have a waisted stem and reduced
valve seat contact area. We also modify the valve platforms and
head casting for cam lobe clearance. We used chill-cast cam blanks
, and currently the inlet cam is 308 degrees duration, the exhaust
300 degrees, both with 12mm of lift. We run double valve springs
with solid followers, titanium valve caps and new valve platforms.
We are experimenting with compression ratio but the engine has
been running between 12 and 13:1" The head gas flowed as you
might expect, but Steve reckons this aspect is not fully optimised
as yet, figuring there's more top end performance to come....
stainless, ceramic-coated four-into-one exhaust is fed from the other
side of the head by SBD's masterpiece, an eight-injector induction system
controlled by a more advance MBE Systems ECU (featured launch and traction
control if required). Sparks are dispensed by direct coils. Dry sump
lubrication with high-performance Risbridger oil filtration, and lightweight
Pace radiator top off this engine's spec. Peak power is currently 242bhp
at 9000rpm, though Steve expects this to increase, and at higher rpm,
with more development. Maximum torque is a healthy 156lb.ft at 7500rpm,
with a pretty flat curve from 5750 upwards. This conversion does not
yet have a finished kit price, but obviously it'll be quite a bit more
that the 190bhp kit. There also intermediate steps between the two,
so call Steve to discuss the best kit for you.
road car & Steve's sprinter
Body: GRP GRP and carbon
Chassis: 'SEi Wide' spec spaceframe , honeycomb floorpan 'SEi
Wide' spec spaceframe with SBD mods, honeycomb floorpan
Engine: SBD Vauxhall 1.6 XE, 191bhp at 8000rpm 133lb.ft at 7000rpm SBD
Vauxhall 1.6 XE 242bhp at 9000rpm, 156lb.ft at 7500rpm
Transmission: Quaife four speed 'Professional' synchro 'box, LSD. Quaife
four-speed dog 'box, LSD
Suspension: SBD-designed double wishbones front, multi-link Westfield rear,
anti-roll bars, Avo dampers. SBD-designed
double wishbones front, multi-link Westfield rear, anti-roll bars,
Brakes: Wilwood four-piston calipers front, Sierra two-pistons calipers
rear, Ford discs. Wilwood four-piston calipers
front and two-pistons calipers read, Ford discs
& Tyres: Image three-piece alloy rims, Avon cust slicks,
8.2/20.0-13 fronts, 10.0/20.0-13 rears Image
three-piece alloy rims, Avon slicks or wets 8.2/20.0-13 fronts,
Weight: N/A, but heavier than sprinter. 417kg
road car, whose maiden voyage was coming to our test! The spartan interior
is fitted with moulded composite seats with integral cod piece which
means you stay in exactly the right seating position! The carbon dash
was made by Martin, and incorporates a Stack display as well as bunch
of switches to do all those essential road car things, like turn the
lights on and sound the horn.
the four point Willans harness, fire it up effortlessly, snick it silently
into gear and away. Squirting up through the ratios the engine did exactly
what it said on the label, displaying tractability and endless get-up-and-go.
In fact you could feel extra urge coming in at the top end, an indication
of the potential beyond the red line. The ratios were nicely spaced,
but such was the engine's flexibility that you could toot around in
a leisurely manner should the mood take you. The suspension was taught
and controlled the chassis well, but the car felt a little squirmy,
which, as Steve Broughton said , was probably down to the lack of time
for a proper suspension set-up. The brakes have yet to be sorted too-
they almost absent! But with those two points easily remedied, Martin's
going to have some fun.
is equipped with a single, lightweight version of the over-familiar
seat and the carbon-lined cockpit is even more minimalist. The dash
incorporates a sophisticated Motec display so powerful it predicts next
week's lottery numbers- well it does just about everything else anyway.
sounded predictably more purposeful as it fired up, and would rev responsively
with a sniff of throttle. The dog box engaged easily, though with more
of a clonk and off I went. First impression - was this supposed to be
less tractable? Because it was a pussycat at low rpm too. Then pressing
the loud pedal harder releases some serious performance. The pulling
power is very impressive, the urge to climb to max rpm inescapable
as the 240-plus bhp propel the 417kg Westfield to silly speeds very
felt grippy even on the test track's soggy leaves, and the chassis soaked
up the cornering force as I explored its potential. The brakes were
fantastic, the carbon metallic pads pulling you up rapidly with light
Steve and Dick have recorded class wins already with this car. Their
campaign in the CCC BARC Hillclimb and Sprint Championship next year
will be well worth following.
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