By, Rick McDowell & Trevor Hedge
It takes either complete insanity, absolute bravery or a high level of commitment at least to hang to the handlebars of a motorcycle producing 1200 plus Hp as it hurtles down the quarter mile at 200mph on route to a six-second pass.
Jay Upton would probably say that it takes all three of those ingredients and he ought to know.
In conjunction with Sprintex Australia and Powerhouse Performance, Jay and a team of dedicated supporters have been developing the most radical motorcycle ever seen on the Australian drag racing circuit – with the ultimate goal being to break the current drag racing World record of 6.06 seconds.
It’s no pipe dream either. Jay already runs times in the six second bracket at close to 200mph. There is still quite a gap to the world record but Jay has set his focus and is chasing that dream. Reducing times by even tenths of a second at this level of competition requires much in the way of development let alone luck, yet the technology involved in Jay’s machine is unique to say the least.
As can be seen in the photos, the bodywork on the Sprintex Top Fuel Triumph makes the bike look like something from a Star Wars movie, yet the kevlar / carbon fibre composite shell is really where this project began for Jay.
“There’s a phenomenon that happens when you reach 290kmh … basically your body gets lifted off the bike and you crash …” Jay’s good friend Elmer Trett set the still standing World record of 6.06 @ 235.34 mph even if he was ‘sucked off’ his Kawasaki and thrown to his death. “I decided to do this project in honour of Elmer,” stated Jay, “and began collecting parts within days of attending his funeral.”
Interestingly, Danny Williams, the founder of Powerhouse Performance in Perth and the head man of Sprintex Australia, was in America for that fateful drag race meeting. “It didn’t take long for Danny and I to realise that we both had some common goals,” recalled Jay. “As it’s turned out, I’m now the Chief Technical Officer for Powerhouse and involved with numerous projects never mind the Triumph !”
Combating the rider lift problem at high speed was a job given to Aeronautical Engineers Australia P/L in Perth. More particularly, Steve Corboy played a key role, while Charlie Urwin from Universal Plastics performed the actual manufacturing. Curiously, a wind tunnel wasn’t used, but the bodywork has been moulded to Jay’s body shape. Oh, and it must be said too, that jay’s son Luke came up with the original design concept.
To date, the bodywork has worked exceptionally well, although the rear wings had to be re-designed recently due to one of them bending at high speed and acting like a boat rudder. “I hit the wall at the 800 foot mark at Ravenswood Raceway,” said Jay. “We had a real bad handling problem for a while where the bike just pulled hard to the left and it took us quite a few months to figure out what was going on.”
Now for the moment you’ve all been waiting for – what’s underneath that high tech’ bodywork. The heart of the matter is a 1409cc four-cylinder engine which, although based on a Triumph 1200cc motor, is anything but.
In fact, the crankcase, barrels and head were made by English high performance specialists, Puma, with each of those items having some rather special characteristics. “The aluminium crankcase is similar in design to a Donovan top fuel dragster in that it’s a girdle style, which essentially makes it a four-bolt bottom end,” explained Jay.
The crank which lives inside the cases is a Doug Kiddy item from the UK and it’s made from a very rare metal indeed. “It’s made from English EN 40B military grade steel that Australian steel makers haven’t even heard of,” stated Jay. Trick metal aside, it’s the fact that the crank on this bike runs its cam drive up the outside of the motor which sets the Sprintex Top Fuel Triumph apart from any other drag bike on the Australian scene.
Just in case you’re not familiar with motorcycle engines, the favoured method of running a cam chain is up the middle of the motor and the Japanese have been doing it like that for years. (we’ll leave Ducati’s desmodromic system or Moto Guzzi pushrods for another time !)
The problem with the Japanese design however, is that the camshaft drive area in the middle of the crank has to be small in order to allow both clearance for the cam chain and to provide the necessary 2:1 drive ratio (which is a design fundamental for the average internal combustion engine).
Yet the small diameter area in the middle of the crank is a potential weak point and while there are motorcycle engines with cam drives up the outside of the motor, they in turn pose another problem. As Jay explained, “The new ZX-12 Kawasaki engine, for example, has the cam drive up the side, but the stud pattern is too small and so re-boring to a decent capacity is going to pose all sorts of problems.”
It needs to be understood too, that even though Top Fuel bikes run aftermarket engines based on production motors, the rules for the class are exceptionally stringent and require that the cam drive position and numerous basic measurements of the original production engine be retained. In other words, simply going all out to build a totally one-off engine with no engineering relationship to anything in production is illegal. It’s a complicated and intricate balancing act, which for Jay had only one solution. “As far as I can see, the late model 1200cc Triumph motor is the only one offering outside cam drive and a large enough stud pattern.”
Mechanical satisfaction aside, the Triumph engine also has a personal connection for Jay. “I’m originally from England and began racing on Triumph Bonnevilles back in the 70s – so it’s kinda’ nice to come around full circle again.” Incidentally, motorcycle engines with side cam drive mechanisms tend to be narrower then their centre driven counterparts and the Puma motor in this weapon is a full 2” narrower than even any of the leading bikes in the USA. And the advantage ? “It gives us about a 10% reduction in frontal area.”
In all fairness to the excellence of Japanese engineering, the inherent weakness with centre driven cam chains only makes its presence known when power levels are raised excessively. Consequently, most of the Japanese based bikes on the Australian drag scene are reliable, yet as Jay succinctly put it, “If they had anywhere near the power output of our bike they’d be snapping cranks all the time.”
The 1200Hp being produced by the Sprintex Trumpie’ had to be calculated from air flow and fuel consumption data, as a dyno capable of both accommodating the bike and recording the horsepower couldn’t be found !
As you might imagine, power figures like that require some very special internal reciprocating components. “The Bert Hopkins rods are made from aluminium, but at 610 grams each they’re actually heavier than a steel rod for a small block Chev”, Jay explained. “As for the pistons, well, yes, they start out as Cosworths, but we do some modifications here in Australia which I’m not going to discuss.”
Now to that 6061 alloy head which sports 30mm thick aluminium / bronze combustion chamber inserts to prevent it from burning up. Said Jay, “The head is very Cosworth in design, so the camshafts are quiet close together.” “Having the cams this compact has allowed virtually straight intake and exhaust ports and you can actually see the top of the piston looking down the intake ports.”
Incidentally, the head is held in place by ten 1/2” bolts, but even these and the girdle style crankcase can’t keep everything perfectly in place. “There’s so much pressure in the engine that the gudgeon pins are squeezing the small ends down the con-rod and extruding material out the sides….” Much of the pressure is generated by the 50psi being pumped into the engine by that one-off Sprintex screw-type supercharger. And no, that wasn’t a misprint – the blower is pushing a maximum of 50psi into the combustion chambers !! No specific details would be given on the Sprintex supercharger, except to say that is a true screw compressor and part of an on going ultra high-power development programme.
Not surprisingly, air flow is critical. Said Jay, “This cylinder head is without a doubt the highest flowing motorcycle head around …. we’ve had to do some fairly elaborate air directional work to avoid blower bypass and having enough plenum to match the supercharger size is critical too.” Ian Jenkins in Perth played a key role in this area too, designing and manufacturing the inlet manifold to match the blower. As it turned out, Jenkins became involved in many other areas of the bike, including the electrical side of the equation.
And then of course there are the cams, “The cams are bigger than the best of the US 4-valve pro-stock engines…. 500 thou’ lift with maximum duration of 286 degrees at 50 thou. We’re talking massive air flow capacity.” Perhaps ironically, in light of the high tech’ metallurgy and basic engine mechanics, electronic fuel injection is not allowed and so the fuel has to be delivered mechanically. The rules also prevent the use of any closed loop fuel system and mass air flow meters (for matching fuel delivery) are also ‘illegal’.
The fuel – 90% nitro methane, or for all the chemists out there, CH3 NO2 – is stored in a 33 litre tank underneath the bike and pumped at a rate of 30 gallons / minute. To put some perspective on those figures, Jay said that he just about always runs out of fuel in the braking area ! The fuel pump and a mechanical throttle valve help control the delivery of fuel to no less than eighteen (18) nozzles. “There’s eight that fire directly into the intake ports, another eight spray directly onto the back of the intake valve and two are plumbed into the inlet of the supercharger next to the Jenkins Performance inlet manifold.”
Keeping an engine like this in perfect harmony, even for a couple of minutes to warm up, go through staging and then run a pass, is no small achievement. The ignition system is essentially a twin magneto arrangement with twin coils and twin spark plugs per cylinder. Yet there is so much more to keeping this motor turning efficiently and in tune. As can be seen in the photos, the right hand side of the engine resembles the inside of a Swiss watch, thanks to a combination of 5 belts and 13 pulleys / cogs. “The reason it’s so complicated is that we have two magnetos and one fuel pump to drive, plus a three stage dry sump oil pump. Bear in mind too, that because the camshafts are so close together, we can’t get a sufficient diameter sprocket on the cam to get that magic 2:1 ratio from the crank, so we had to step it through an idler.”
There’s no denying that this is one complicated piece of machinery and the full inventory of parts involved in the show seems endless. One really interesting little component is the set of ordinary automotive points attached to the throttle on the right hand handlebar. “The points simply work the clutch and fuel timers on full throttle … we tried using micro switches, but they kept burning out and as a result the engine would blow up !” The points were just one of those wild ideas, but it works a treat.”
The clutch meanwhile is another of these key items which gives the bike its unique identity. Unlike all other drag bikes in Australia (and overseas to an extent too), this Triumph doesn’t have a gearbox and drives the rear wheel directly through a massive drum clutch of Jay’s own design. The primary drive from the engine to the clutch is a 4” belt custom made by US specialists, Gates. Yet it is the clutch which is so special, “every drag racing vehicle has a centrifugal clutch … this is not centrifugal, but air operated and my own design.
“The actual mechanics of it work extremely well, but trying to calculate the best tune up for it is quite difficult !” Internally, the clutch features off the shelf plates from the USA, comprising three friction and four steel plates that are 8” in diameters and 5/16” thick.
The two flywheels with a pneumatic actuator in one of them is Jay’s part, with air feeding in through the primary drive shaft and then internally through ports in the flywheel. A variable pressure regulator is then used to control the clutch, thus increasing the ‘bite’ in stages as the bike travels down the strip. As indicated above, there are in fact seven stages of harder bite, but seven stages of fuel delivery also exist. All things considered, this is one timing nightmare and every area has to be linked and timed in perfect harmony.
It would be easier if more modern, total electronic control could be used, but those rules insist on more mechanical methods and the clutch isn’t even allowed to be directly linked to the throttle. Data logging is allowed, but it’s probably more accurate to call the system data collecting, as it isn’t allowed to ‘tune’ the bike in flight. In other words, data collected from 20 sensors at up to 125 times / second must be downloaded and then used to pre set mechanical or electro mechanical devices on the bike prior to the next run. Air for the clutch is actually nitrogen and is stored in the 4130 chrome moly chassis built by John Clift in the UK.
In addition to turning the chassis into an air tank, Jay also added a few more tubes for additional strength.
The forks hanging from the front end are 41mm GSX-R Suzuki items and the front brakes are from the same source. Out back again and that massive 14” wide by 31” diameter Goodyear Eagle slick is driven by an EK chain that can handle 18,000 lbs / square inch of tensile strength. Oh, and get this – the chain uses 126 links at $4.50 / link. Ultimately, the Sprintex Top Fuel triumph will be used as a test bed for radical high boost supercharger applications being developed by Sprintex. If you think the 20-odd psi you’re pumping into that WRX motor is scary, consider that Sprintex want to develop their own twin-screw compressors capable of forcing in up to 100psi !! As Danny Williams put it, “Jay will have to trial these for us… so all I can say is Good Luck !”
TECHNICAL SPECIFICATIONS – SPRINTEX AUSTRALIA TRIUMPH DRAG BIKE
Class For Racing: Australian Top Fuel
Engine basics: 1490cc, four-cylinder, DOHC, 16-valve by Puma in England, based on Triumph 1200 design
Crankcase: Aluminium girdle style , four-bolt mains
Crankshaft: Doug Kiddy EN 40B military grade steel
Con-rods: By Bert Hopkins
Pistons: Cosworth blanks custom machined
Camshafts: Custom offering 500 thou’ lift with maximum duration of 286 degrees at 50 thou’.
Heads: 6061 alloy
Induction: Sprintex twin-screw supercharger providing maximum of 50psi boost & mechanical fuel injection system
Fuel system: 90% nitro methane (CH3 NO2) stored in a 33 litre custom tank and pumped at a rate of 30 gallons / minute. Single fuel pump and mechanical throttle valve control fuel delivery to 18 nozzles.
Ignition: Twin magnetos with twin coils and twin spark plugs per cylinder.
Exhaust: Fully custom
Data logging: 20 sensors providing information up to 125 times / second
Clutch: Fully custom, seven stage ‘air operated’ with three friction and four steel plates that are 8” in diameters and 5/16” thick. Two flywheels with a pneumatic actuator and a variable pressure regulator.
Gearbox: No gearbox – primary drive only by 4” Gates clutch
Chassis: 4130 chrome moly chassis built by John Clift in the UK.
Front forks: Suzuki GSX-R 41mm
Rear tyre: 14” X 31” Goodyear Eagle
Bodywork: Fully custom