2003: Choice of kit - Engine - Power - Induction - Weight - Performance
I had built a Westfield Megablade back in 2000 and found that the build, after the usual hiccups, was logical and enjoyable. Having sold this car in October 2002 after having a lot of fun with it, I spent the next four months trying to decide what car to build next.
I looked at other manufacturers offerings in the 7'esque kit arena and also 'supercar' kits, but finally I chose to do another Westfield SEiW. Many things prompted this choice, not least of which was re-sale value, quality of the end product, familiarity and backup from the Factory. This is not to say other manufacturers can't satisfy the above points, just that I know Westfield can.
The next problem was "what engine to fit". I discounted a Car Engined Car (CEC) very early on and went again for a Bike Engined Car (BEC). Now what one to fit....I wanted to keep the car as near to an 'official' model as possible. This meant that I didn't what to go down the route of fitting a non-standard power unit such as a Yamaha R1, Kawasaki ZX9 or 12 or a Suzuki GSX1000-R. So:
Suzuki Busa: Powerful (172bhp), lots of torque, 'heavy', needs a dry sump system for your mental health, relatively expensive - total cost around £4000+.
Honda Blade: Reasonable amounts of power (132bhp), torque enough for the job, relatively cheap, lightweight, if pre-1995 the SVA is simpler - total cost around £1000.
So the Blade looks good, but hang on I've just sold one of those so why do another? Well, the Blade engine is very nearly bullet proof, it's small, very light and sounds wonderful when at 11000 rpm. But I want a car with more power than the last:
To increase the power I could install a Nitrous Oxide (N2O) system and a controller that should give me around 50 to 75bhp extra (this has been done before, very successfully in other Blades). However, the system can cost well over £1000 to install, the gas is an expensive consumable and to get the cost down I'd have to 'rent' a big bottle (£250 to £300 per bottle + £50'ish rent per year). Suddenly this didn't look too good if I wanted to do some trackdays. I worked out that a full day a Brands would use at least one big bottle. So adding £250 to £300 to the cost of the day put me off a bit.
Or I could have the engine 'seen to' (160bhp) with a big bore kit, head work, cams and the like which would cost around the £2500 mark to do properly. But to get back to the same power level if the engine went pop, you'd have to spend another £2500 on top of the cost of a replacement engine. It also shoves the maximum torque/power further up the rev range which might make things a little tricky, so bit of a risk I thought.
So what about a turbocharger? Just bolt it on to a standard engine and get an instant 190bhp, sounds good. Also because the bike engine has to rev 'highly' to get anywhere and the turbo is a very small 'blow through' type, lag should not be an issue.
It's not that simple unfortunately, as you need to lower the compression ratio a bit and change the valve timing slightly. Still, if the engine goes pop now, it's just the cost of a head gasket and a fiddle with the cams plus a new engine. This was looking good, so I found a bike turbo company and arranged to visit them in February 2003 to discuss what could be done, how easy was it to do and how much it would cost.
It turns out that for the sum of around £3200 you get a modified hybrid turbo, all it's pipe work, intercooler, airbox, filter, adjustable cam sprockets, pumps/regulators, engine work and setup. The turbo runs at 7psi (half a bar) and the engine should produce in the region of 200bhp, plus or minus. Add the cost of the turbo kit to the cost of the engine and you get £4000'ish for all that BHP, so the cost is about the same as a Busa - but with more power, less weight and less (£££) risk... not bad - 246bhp per Litre - Gaw'd knows how long the engine will last, but it's gonna be fun finding out.
So anyway, a turbo it is then.
The next point to look at was the wet weight of the car, this is full fuel, oil and coolant. My last Megablade weighed in at around 455Kg but the new one just has to come in under this figure.
The biggest single contributor to weight that you can effect is the wheels and tyres. The last car had wheels and tyres that weighed a total of 51Kg, so reducing this figure would help make a big difference. Next is the brake components, followed by the hubs, uprights and suspension components. Fitting carbon fibre bodywork items, paneling and seats would also help by about a 33% saving on 'standard' components. Using alloy nuts and bolts in non critical areas would also contribute to a useful degree. The research I have done has lead me to believe I can get the wet weight down to around the 400'ish Kg figure.
The overall aim is to build a car that has a Power to Weight Ratio of at least 500bhp/Tonne with an engine of specific power output greater than 224bhp/Litre.
(c) 2000 - 2004 J.B.Cobb
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