CCC, July 1996 – SBD Westfield

Blimey! All of a sudden everything’s gone a bit tunnel vision, a bit fuzzy round the edges. This thing really is seriously ballistic, the straight is fast disappearing, the engine howling at 9000 rpm. Time for the brakes and a blip down into third for the Chobham banking. Grip, serious grip. The momentum pushes you up the shallow bank as the car keeps on accelerating. Out of the corner, floor it. Engine pick-up is instant and the revs whip round to 8500 rpm. Back into fourth, flat out at 120 mph thanks to sprint gearing. 

 

Crikey! Steve Broughton’s Vauxhall propelled Westfield-come-rocket-ship has changed a bit since I drove it last year. For a start it’s no longer a road car. Free of the restraints of the highway, Steve has binned things like lights and windscreens, heater and road tyres. This is a fully fledged racer, and a winning one too. In case you didn’t know, Steve Broughton is the SB behind Vauxhall tuning specialists SB Developments. Steve knows a bit about tuning Vauxhall 16-valve engines, and the Westfield is a bit of a rolling advert for his undoubted talents. The 270 bhp engine fitted is one of Steve’s ultimate spec engines. But it’s not just the engine that’s impressive. It’s quite obvious that Steve is just as adept with suspension geometry and general car set-up, not to mention aerodynamics and even ground effects. 

 

 

Steve runs in the CCC Speed Championship and has designed his Westfield to run in the Sports Libre class. That means he’s up against some very quick Mallocks which have serious downforce dynamics, if not the ultimate grunt of this Westfield. This is only Steve’s second season, but he’s not experiencing much of a learning curve given that in his first season he won the overall Southern Championship And that was despite swapping between the road-going kit car and sports libre classes. 

 

This year’s car is all new and features a whole load of trick bits, and improvements over last year’s car. For a start the chassis is both lighter and more rigid. The standard Westfield chassis is designed to take a variety of engines and for that reason the front is comparatively open. There is plenty of opportunity to stiffen it up with extra tubes, and the factory agreed to modify a lightweight racing chassis to Steve’s specification. He has also taken the opportunity to have some extra tubes added to the rear. The result is a complete lack of flexing and an incredibly stable ride. The latter is also helped by Westfield’s new wide track front suspension set-up. 

 

Naturally the suspension is fully rose-jointed. Steve favours Avo dampers and has had some specially valved to his own specification. He claims that he has still to properly sort out the geometry, but I couldn’t feel much wrong with it! The sticky 14in Avon slicks give incredible grip but progressively so. You can really push into a corner and feel the car start to give. It is confidence inspiring more than anything, knowing that its not suddenly going to come round and bite you on the bum! 

 

But more impressive, of course, is the sheer oomph that Steve’s engine building skills provide. Steve wasn’t actually planning to build a 270 bhp motor, it just kind of happened. This sort of power, lest we forget, is the kind of grunt that 2-litre Touring Car engines used to produce a few years back. When utilised to power a mere 480kg’s of Westfield, it’s downright explosive. 

 

 

The secret is some lightweight internals that allow the engine to really rev, coupled with Steve’s tapered throttle body injection set-up and a heavy breathing cylinder head. A mere brush on the throttle is enough to send the rev counter blipping to the red zone, the engine is seriously responsive. In fact, Steve advises not to change down a gear mid-corner, as the resulting engine de-acceleration will spin the car round. 

 

Steve had a steel crank specially designed and manufactured by Doug Kiddey, who also makes the cranks for the Mercedes/Ilmor F1 engine. This is a massive 25% lighter than previous efforts. This turns ultra light Arrow con rods and specially made Omega race pistons. As this is being written, Steve is out of stock of all these goodies since the TWR Formula 3 team scooped up everything he had, and since doing so have started to win some races! 

 

Surprisingly, despite such power from just four cylinders and two litres, the engine is amazingly tractable and can be teased off line with just a few revs (should you want to). Ah, the wonders of engine management.  

 

Typically, the car bristles with innovative touches. Under the nose a front, F1 style, splitter cuts through the airflow. Does it work? Well Steve’s F1 mates tell him that it will make some difference. Likewise the rear ground effects undertray, properly moulded from fibreglass (aluminium lash-ups tend to distort when the air starts rushing around them), should in theory help keep the car glued down. If you’re interested, Steve can offer both these items to fellow Westfield racers or, indeed, road racers.

 

Having driven a few Westfields in my time, and being the owner of a race Westfield, I can say this is probably the best handling and dynamically impressive one I have ever driven. Above all, despite its rampant power delivery, it is easy to drive. And when you can concentrate on the driving rather than wrestling with the car as it tries to catch you out, then that is half the battle. 

 

 

Wind back to the March’96 issue of CCC, and you will recall that we were getting pretty excited about the tuning potential of the new Vauxhall 1600, 16-valve Ecotec engine. Just by fitting his tapered throttle body fuel injection system, Steve has seen a solid 164 bhp from an otherwise stock engine. That’s seriously impressive. What’s so good about the 1600 Ecotec? Well lets recap briefly. Unlike the 1800 and 2-litre Ecotec 16-valvers, the 1600 engine features a power friendly cylinder head. In fact, according to Steve, it is quite obvious that the 1600 Ecotec was designed to be the smaller power producing brother to the legendary 150 bhp 2-litre Vauxhall unit. The head is reputed to have been designed by Cosworth, and doesn’t feature the emissions trickery of the other engines. It is thought that the 1600 Ecotec was designed with power in mind. In fact the only thing that Vauxhall has done to keep the power down is fit very mild cams. The evidence is plain to see. Take the valve sizes: 31mm inlet valves and 27.4mm exhaust valves compared to the original Vauxhall engine of 33mm and 29mm respectively. Doing some quick calculations, this means the 1600 has 88% of the 2-litre’s inlet valve area from just 80% of its capacity. This effectively means that the1600 runs larger valves than the excellent power-producing 2-litre engine. And it gets better. The 1600 valves have a 6mm stem while the 2-litre runs 7mm, so the effective area is better on the smaller engine. Things are just as good on the exhaust front. The 1600 engine has 89% of the 2-litre’s valve area – even better than the inlets. As a percentage of inlet-to-exhaust ratio – another good sign for tuning potential. The two engines also use identical cam followers. Given that the standard engine gives such excellent power, Steve reckoned that 175-180 bhp would be a mere formality with some tweaky cams. And that was the next phase of the project that we were expecting to cover. However, this has been put on ice (Steve has developed a 180 bhp spec, but we’re concentrating on bigger and better things here) since Steve was given the opportunity to fully develop the engine with a serious cash injection from, of all places, Russia? Starting from scratch, Steve had just eight weeks to develop an ultimate spec 1600 Ecotec engine. Given the engine’s similarities to the 2-litre unit, Steve decided to go for a scaled-down version of the 270 bhp engine that resides in his Westfield, bar a few changes. Down at the bottom end only the standard crank remains, since a Doug Kiddey crank couldn’t be manufactured in time. This turns Arrow rods and lightweight Omega Race pistons. At the top end the head is virtually standard aside from basic stuff like matching up the ports and wasted valves. An all new SBD cam profile has been adopted for the 1600 engine. Steve describes this as a bit of a concept cam in that is was a bit hit and miss as to whether it was going to work. But work it most certainly does. Fuelling is naturally by Steve’s highly successful tapered throttle body injection set up with engine management via an MBE black box. Power? Well you’re dying to know are you not? Well given that this is the beginning of the development programme, 202 bhp is pretty stunning we’re sure you will agree. A good 220 bhp must surely be on the agenda with a steel crank, bigger valves and peakier cams. A Corsa with 200+bhp would be a pretty potent device but what about a Westfield or a Caterham? As soon as someone starts running one of these engines in, say, an up to 1700cc class in sprints and hillclimbs, whether it be in 164, 180 or 202 bhp form, then it’s bye bye Crossflow, Zetec or even K-Series. Even an all steel Crossflow would be struggling against any of these specs and the Zetec and K-Series don’t really have the cylinder head potential to produce this sort of power, not from 1600cc’s anyway. And there are plenty of these engines around too. A mere £400/£500 should get you a good low mileage donor engine