Circuit Driver Magazine - "Stormbringer"

January 2005

Radical SR8 first drive - Radical's all-new V8 is the most significant race engine since the DFV

Last month Circuit Driver witnessed the first rolling road run for Radical's new V8 engine. This month we bring you the first drive as Mark Hales gets behind the wheel. It's everything we'd hoped for.

To the casual observer, it has always seemed so obvious. Take the top halves from two modern multi-cylindered motorcycle engines, complete with all the trimmings necessary for stratospheric revs, bolt them to a common crankcase and there you have it. A V8 of two litres or more, revving to 10,000 plus and churning out about 300bhp - or double the amount one bike engine gave in the first place. You don't have to make all the clever bits like the cylinder heads and valvegear and the result will be destined for a gap in the market which the likes of highly modified k-series are still struggling to fill. Easy isn't it....

Well, yes , but ....no. As anyone who has ever tried to adapt anything modern and mechanical will know, every last part will have been developed to suit a unique purpose at the least cost , so it is never quite that simple. The two companies which are currently making bike-based V8s will know that only too well, but meanwhile the prospect of eight cylinders and 10,000-plus revs remains as massively exciting as ever. Small lightweight V8s just don't exist and yet I've never encountered anyone who didn't come over all wistful at their experience of Cosworth DFV power.

Sadly , it will remain a thrill available only to those with about £60,000 to spend but a modern bike-derived V8 might just be affordable, and that makes it more tantalising still.

The first of those on offer,. the Yamaha -based RST 2-litre, has endured a very lengthy gestation - the prototype was first mooted in the early 90s - and since then, progress has depended on funding which has not always been swift in coming. We tried it in September last year, mounted in a Caterham, and with some allowance for minor development glitches in details, like mapping of the engine management, it was very promising, and exciting. If it really does cost a similar amount, you would never swop the V8 for a K-series, no matter what is state of tune.

The second is a 2.6-litre by Radical Motorsport's engine partner Powertec and is based on the 1300cc Suzuki Hayabusa which powers the company's Prosport race car. Radical is a much bigger organisation and their V8 has been much swifter in reaching fruition; it was just two years ago that the plastic mock up was displayed at the NEC show. In addition, Radical's customary dedication to the cause had already ensured it had its own test bed in he shape of a modified SR3 Turbo. Radical will sell you an engine if that's what you want,,but they can also sell you a fully-developed SR8 sports-racer to go with it, complete with bespoke six-speed sequential transmission and their after sales service even includes opportunities to compete with your new acquisition. Radical has been smart enough to realise that a place to race was an essential ingredient in the sales message and that the current club infrastructure was unlikely to provide anything which suited their purpose.

I caught up with the Radicals at a damp and windy Bruntingthorpe where company principals Phil Abbott and Mick Hyde explained the details. The Powertec 72º V8 is mounted in-line rather than across the engine bay, a detail which Hyde will admit immediately changes the complexion of the car. Radical have spent a huge amount of money and effort developing the 1300cc four cylinder Hayabusa engine and the transmission solutions which replace the bike's chain final drive,but there were still those put off by its origins. That said, Radical's original intention had been to use the bike's transmission for the V8 and the turbo version which now looks like something of a blind alley was intended to research the possibility. Hyde insists the Suzuki 'box was man enough and could have worked but the decision was nevertheless made to put the engine North-South and to work jointly with transmission specialists Quaife to make a six-speed in-line transmission featuring an extra pair of drop gears to reduce the engine's 10,00 revs. A conventional AP twin-plate clutch transmits the drive.

A special bellhousing mates the 'box to the engine, forming a brace to tie the cylinder heads together as well as incorporating heads together as well as incorporating the swirl pot and the dry sump oil tank which is fed directly from the crankcase. The brace damps out resonance which is potential source of stress and like much of the oil scavenge system is a detail inspired by the likes of Audi's RS Le Mans engines; the rest was the work of former Lotus, TWR and Jaguar designer Steve Prentice and Powertec's David 'Ted' Hurrell.

The crankshaft is flat rather than offset which guarantees a DFV wail rather than a Chevrolet rattle and to the offset is a shaft driven by a gear on one end which spins a separate scavenge pump for each of the engine's pair of cylinders; recovery of oil is a notorious problem in racing vee engines. The shaft also drives a pair of oil pressure pumps and on the back end nearest the gearbox, a rotary vane-type water pump. In the opposite side of the crankcase, a gear on the flywheel end of the crank drives a pair of counter-rotating balance shafts turning at twice engine speed. This leaves only a substantial alternator to be driven by a belt which, like the starter motor, is car rather than bike-drived.

In this 'basic' 2.6-litre version, the cylinder blocks, heads, pistons, rods , valves and cams are all standard Suzuki. Hyde says it made sense to use as many original parts as possible, because not only would it be cheaper than making them specially but they weren't 'reinventing the difficult parts'.

By that he means the top of the engine in which the Japanese engineers have so cleverly installed longevity at 10,000rpm. The desire to retain such qualities is why one block is tuned 180º from the other in order that each one's original chain cam drive can be retained - plus of course, the exhausts then exit on the outside.

The engine is extremely neat although not perhaps as small as you might have expected, but it is light. Abbott says it weighs in around 92 kilos which is 48 less than a DFV (140 kilos) and when Powertec develop a 3-litre version based on the company's 1500cc Hayabusa conversion which is already a favourite with SR3 buyers, then it should give similar power. The claim for the 1500 is 250bhp so for a V8 version Hyde reckons a conservative estimate is an 'easy 450bhp' - or about what the first DFV's gave in 1967. The 2.6 is extremely conservative as you would expect for a first effort (compression ratio is just 11:1 rather than the 13.:1 of the 1.5-litre) but despite that is still pushed out 383bhp at 10,000rpm. Odd how that sounds so impressive whereas 140bhp from the latest 1300 might sound merely ordinary. As I said, it's niche which is awaiting to be filled.....

There is also the all important purchase and running costs which Dr Abbott and Mr Hyde are able to predict, based on their extensive experience with the fours. They reckon between 30 and 50 hours of running - depending on state of tune - before an overhaul is necessary, something which they hope should cost no more than £3000. As Hyde says, there's no reason they can think of why it should be any more than double the four cylinder price.

A 'dressed' 2.6 (with pumps, generator and starter) Hyde says will be about £17,000, with another £3000 for the ignition and ancillaries while the transaxle complete with limited slip will be about £6000, all figures plus VAT. Comparisons with historic Grand Prix engines like the DFV are not strictly fair - to my mind they serve more to illustrate what an exceptional thing that 35 year old power unit was - and neither is any contrast with the 4-litre Judd V10 which is more powerful. You nevertheless have to note that after 10 hours a DFV has to be overhauled at a cost of £12,000 and a Judd is nearly double that. In a market where there is almost no competition - where else can you buy 380bhp from 95 kilos - the Powertec V8 almost can't help but look like a bargain.

Then there's the car - the SR8, which without an SR3 on hand looks almost identical to a relative Radical novice like me. Not so, says Hyde who then takes me on tour to prove it. The front end is different, both to accommodate the front-mounted radiators which exhaust via venturis on the flanks and lovures on top of the wheelaches, and to mount the new undertray. This, together with dive planes on the corners of the front wings, new rear underbody venturis fed by tuning vanes in the sidepods plus a new biplane rear wing all combine to develop a staggering 2.5 times more downforce than previously. The cynic in me was prompted to ask whether preceding efforts had been lacking or whether there was now sufficient power to make an extra drag worthwhile, but my question was politely ignored. Phil Abbott later mentioned that the rear undertray had torn off its mountings during the previous test - and the front would follow suit when I tried to better 160mph for the umpteenth time - so we'll give them the benefit of the doubt. Lets just say it obviously works....

Rear body work is different too because the engine's vee drops the plenum down lower and a smaller hump can cover it, and the tail end is different where the exhausts exit.

Brakes now feature floating discs and the driveshafts are bigger and tougher. So, yes, almost everything is different and you can have a race model for £55,000 + VAT or a trackday version for £50,000. Radical say they have more forward orders for the SR8 than any car in the company's history and that deliveries will begin in April.

And so to the drive, which if I say was completely uneventful, should read as the best possible compliment. The test engine had already undergone some 100 hours of testing on both dynamometer and rolling road and it had undergone one precautionary strip to check for potential problems but thus far there has been nothing serious whatsoever to report, and apart from the car suckling itself apart, there has been nothing nasty during the track work either.

Clambering into the SR8 reveals standard Radical - that's to say comfortable with everything to hand and in its proper place with a quick shuffle of a long lever to check for neutral, you leave the accelerator alone and churn the starter. A second or two later and with a guttural bark, the V8 fires up.

Phil Abbott had already said the clutch was monstrously heavy and that the gearshift had become rather snicky during the latter half of the test programme and that these were items on the to-do list but clearly he doesn't drive historic cars very often. I'd have said either was perfectly acceptable when compared with the majority of Hewland FT or MK9. Clonk it gently into first, ride the clutch against a stack of revs and away you go. Seems perfectly natural as well, but Phil says this is another thing that will be fixed. Mapping at the bottom end is still not finite and they had recently taken some fuel out to reduce the two foot long gobs of flame exiting the exhausts on each downshift. This had introduced some kangaroo factor at pit exit speed. Radical are perfectionists, no doubt about that, because if this had been a BD, FVC or almost any car engine with the potential for 380bhp, you'd have said it was fine. Then comes the exciting bit.

The SR8 attacks the track in a style that only a light car with a powerful engine can affect. The flat out twitch and slither in fourth which tugs your head in all directions as you sear onto the puddle-strewn main straight is the stuff of a proper prototype and yet once above tickover the engine is as refined as any in the best road cars. Unlike the DFV which tickles every part of your anatomy, the SR8 feels utterly, completely smooth at all times. In addition to the balancer shafts inside, the engine is rubber rather than solid mounted like its four cylinder brethren and it's quiet too; the silencer had by then blown out most of its stuffing but the V8 howl was still sufficiently muted that the Bruntingnoise police felt no need to intervene. Not that you need to wind it past 10 in every gear unless you want to, because the spread of power is wide. The engine pulls smoothly form as little as 2000rpm, then grows ever stronger all the way through the range to 10. Which, without wanting to damn with faint praise, is exactly what the standard Hayabusa does, and exactly what Radical is trying to harness in double measures.

Which they have, and more to the point made it usable and reliable. And make no mistake, 380bhp in a 550kilo sports racer is mighty quick in anybody's terms. The track was damp, the tyres were worn out, the SR8's ride height had been raised by a large chunk to cope with passengers and the track's surface (Bumpingthorpe) and the rear undertray was missing.

Despite that, I managed a lap time of less than a second shy of the best Radical test driver, and all round superfast Dutch chap Michael Vergers ever did in the turbo version on a dry road. And no, that ain't because I am a hero. It was cold and the road was wet and with its hobbled setup, the SR8 was understeering far too much through the slow and medium speed corners, and was picking up an inside rear and snapping into oversteer on the exists.

The time came simply from the acceleration of the new engine which produced a genuine 160mph before the right turn off the straight on Gruntingthorpe's short circuit. It was a terminal velocity that finally brought a rattle and shake from the front that sounded and felt for all the world like two shredded tyres. The front undertray - which Abbott says had previously proved capable of supporting his entire body weight - torn through its mountings and was flapping in the breeze .

By that time, I had already done a fair few laps, and so had Phil, and the engine had displayed no serious temperament of any kind. Radical will now do what they are good at and refine the last few details to make sure the trackday market faces a few challenges as possible, but there is no doubt in my mind that the engine will have a similar effect on the amateur race world - not to mention the low-volume car market - as did the K-series, or the Ford Kent, or perhaps more relevant, the overrated bulky old donkey that was the Rover V8. Radical have ambitious plans for the future that include the international sports car categories and even Le Mans, a race which he reckons you might soon be able to tackle with an LMP 'costing less than £100,000'.

Can't wait to try the 3-litre version, not least because I know Mick Hyde or Phil Abbot will say what they always say, which is to go out and do as many laps as I like. At £10 per mile, DFV owners just never say that....