Supercharged Aprilia RSV 1000 R at the Texas Mile
Supercharged Aprilia RSV 1000 R at the Texas Mile
Steve and I drooled over the then brand-new red 1983 Suzuki GS1100 sitting in the Rock Store parking lot one Saturday morning. The Suzuki owner was more than happy to tell us all about how much horsepower his new bike made, its quarter-mile drag strip times, and its cost. It was the hottest thing on two wheels.
He asked what we were riding, and we pointed to our well-worn mid-70s Kawasaki and Honda mounts. He nodded politely, but was a bit distracted, his attention focused on himself. After a few minutes we said it was time to go on a canyon ride. He asked if we would mind if he tagged along. Sure thing, buddy.
We waited for him at the end of the canyon road, sitting in the shade with our helmets off. He eventually rolled up and stammered some lame excuses why it took him so long to reach the destination. We nodded in sympathy and simply observed that he had been “Punished.” He gave a puzzled look. We felt no need to explain.
Most of us in our early riding years did not have the financial means to enjoy the ownership and riding experience of the latest two-wheeled equipment; our bikes generally consisted of last generation performance machines. Out of nothing more than envy, we dedicated our efforts to building, testing, and riding our bikes in a manner that demonstrated to those more fortunate individuals that they could not simply buy their way to status and speed.
“Those who take the easy road to motorcycle performance shall be Punished.” That guiding principle has been applied to each successive model of last generation bikes I have owned. They have all been simply called The Punisher.
Fast forward to 2008. Twenty-five years later, my current bike was good, but not the latest and greatest. My 2003 Aprilia Tuono Racing performed well, yet was rapidly being eclipsed by the latest generation of powerful and expensive Ducatis by as much as 40 horsepower. The seemingly endless parade of shiny new red machines clogging up the Starbucks parking lots slowly awakened those old feelings of class warfare, and could no longer be ignored. Punishment must be served, but how?
I knew the answer as soon as I saw the Spoon Valley Racing supercharger kit for the Aprilia RSV motor. It was compact, powerful, and fit entirely beneath the stock bodywork. The plan to build a stealthy supercharged Punisher streetbike was hatched, and a leftover 2007 Aprilia RSV 1000 R Factory was purchased. I could hardly contain myself at the thought of ambushing unsuspecting Ducs, turning their smug smiles into slack-jawed disbelief with a simple twist of the throttle.
The kit contained the basic mounting brackets, pulleys, and a fabricated intake bonnet, though not the 200-horsepower rated Rotrex C15-60 centrifugal supercharger. There were still lots of ancillary parts to purchase, some machining, fitting, and fabrication work, as well.
An extension shaft taken off the engine counterbalancer drives the supercharger, and that required some delicate machining to the engine cases and balancer shaft to accomplish. Overall, it took about eight months from the time I received the kit to having a running bike. And it did run – for about two minutes before an oil leak developed from the shaft seal. Three months and three prototype shaft and seal designs later, the oil leak problem was permanently resolved.
Early dyno tuning sessions identified an inadequate fuel pump and undersized fuel injectors. Once sorted, the bike showed great promise by making over 170 rear wheel horsepower (ed. note: all horsepower numbers in the story are rear wheel), with mostly OEM engine parts. The question of longevity was still unanswered.
“We should run this bike at the Texas Mile,” suggest my horsepower freak friend Micah Shoemaker. Micah is one of the owners, and chief tuner at AF1 Racing in New Braunfels, Texas, who opined, “I think we can do a little more tuning and make enough horsepower to go 200 mph.” Did he just say “200 mph?”
My eyes glazed over and my mind raced. I had always dreamed of breaking that magical speed barrier. Was this possible with an Aprilia? From that casual remark, we launched a three-year project to be the fastest twin in Texas Mile land speed racing.
Another friend, Dave Malmberg of Leucadia, Calif., was to become the third member of Team Punisher. Dave is a design engineer at Scripps Institute of Oceanography, as well as a championship motorcycle racer/builder with a full race shop. He had already been advising me on the project from time to time, so it seemed prudent to drag him into the black hole of race bike development.
Our first Texas Mile event in March of 2010 showed potential, and made clear how much farther we had to go. During that initial outing, we only managed a total of five passes and 175.4 mph before a melted stock piston with fractured rings forced us to quit. At least that had given us plenty of time to study how the big boys were getting it done.
We figured that we could develop another 20 horsepower by increasing displacement and overdriving the supercharger, but that would still not be nearly enough. There was no room for a higher flow rated supercharger and, even if there were, it would require completely redesigning and fabricating all of the hardware.
The answer was in a bottle – a nitrous oxide bottle. The addition of a Nitrous Express wet system provided a wide range of options for how much power could be added. Power increases in the 60 horsepower range seemed safe, but we designed it for as much as 100 horses. Reliability was ensured with the addition of forged CP pistons, Carrillo rods, and a Falicon Supercrank.
Something had to be done to the chassis to match the increased power. McIntosh Machine and Fabrication added a six-inch extension to the stock swingarm. To reduce wind resistance, we went to the aerodynamics experts at Airtech, in Vista, Calif. Kent Riches fixed us up with a Harley Sportster LSR1 fairing, a slippery design that required a lot of custom fitting and bracket fabrication, and we used the matching Airtech LSR2 tail section.
The fairing fitting was not without incident. An abrasive cutting wheel that was being used to split the freshly molded fairing down the middle disintegrated at 30,000 rpm. A major fragment from that cutting wheel struck me in the chin, requiring a trip to the emergency room. Well, at least now I have a really cool renommierschmiss (dueling scar) and can say without fear of contradiction that “I’ve got skin in the game.”
We settled into a routine in the six months between races. Three months of planning, processing, and purchasing, plus three months of preparation, assembly, and tuning. This time all was going according to plan, with the bike assembled a full week prior to departure.
The March 2011 Texas Mile event was essentially a shakedown for all of our latest systems. We started with low power settings, and all seemed well. The chassis was supremely stable at speed, indeed so much so that Dave declared that he could “eat a sandwich going through the lights.” The electronics were working as designed, so we turned up the nitrous to a 50-percent setting.
So far, so good, although we had some concerns about the clutch’s ability to hold the power. Those concerns were immediately justified, as the first pass with the stiffer nitrous load smoked the clutch. Back in the pits, we slammed in a new Barnett clutch pack, shimmed the springs to maximum preload with some custom-made washers, turned up the nitrous, and I laid down our first 190+ mph pass. We turned up the nitrous to a 60-percent setting and Dave ripped off a 192.8 mph run. Now we were getting somewhere!
With only enough time for one more pass, we put Micah on the bike and turned the nitrous up to 70-percent. Unrelated to the nitrous load, a stock intake valve in the front cylinder fractured at the lowest of three valve keeper grooves, dropping the valve into the front cylinder. In the seconds that it took to pull in the clutch and kill the engine, the front head and piston were completely destroyed.
Unbelievably, the valve stem had flown back up the front cylinder intake port, past the throttle plate, bounced off the plenum, dropped down through the rear intake port, and destroyed the rear cylinder as well. It was a million to one shot to take out two cylinders with one broken valve, and now the entire top end was a total loss. We were elated with our performance, but crushed by the mechanical failure.
The lengthy drive back to California seemed extra-long this time. We had gotten closer than ever before, but still no cigar. There was lots of time to review the results and make a new plan. What did we learn? We learned that the mountain was still very tall, and that we needed the equivalent of 35 more horses to get from 192.8 mph to 200 mph.
David and I immediately pulled the engine, disassembled the top end, and diagnosed the problem – manufacturing had inaccurately positioned a rivet on the multi-layer head gasket. We removed the same problem rivet from a brand new head gasket, reassembled the engine, stuffed it into the frame and hooked everything up. I stabbed the starter button, and it lighted on the first try. Total elapsed time: 25 hours.
With the bike fixed, we loaded it into the van, stacking all the containers of spare parts, tools, and riding gear around it. Off I went once more on the 1400-mile drive back to AF1 Racing in Texas for final assembly and tuning. I arrived in New Braunfels in the early evening, and immediately headed for the hotel for a night’s rest. The next morning, I showed up at AF1 and unloaded the bike and gear.
Micah and I took The Punisher and a chase scooter out for a 45-minute break-in ride. Upon our return we went straight to the dyno room. Low-power testing (no nitrous) was handled in a single afternoon session.
The auto-tune feature of the PNP-Interface Megasquirt ECU made the tuning job simple. Plug in a target air-fuel ratio and let the system adjust itself under load. We manually verified max power and optimum CO exhaust gas levels using the AF1 Factory MD dyno, and made adjustments where required.
Superchargers (and turbochargers) cause a lot of heat to be added to the intake charge. Intake temperatures at 13.5 psi boost can exceed 200 degrees. Our water/methanol injection systems did a great job of cooling the intake charge down to around 120 degrees at full load.
The result was an impressive 191 rear wheel horsepower at 11,000 rpm. We were already exceeding the rpm design limits of the Rotrex supercharger and Rotax engine, so we just left it at that. We didn’t need more horsepower from the basic engine/supercharger package – we still had nitrous.
Because we were using a progressive nitrous controller, we could dial-in a percentage of power for a given set of jet sizes. We tightened down the bike straps to the point where the footpegs were starting to bend. Repeating the above procedure yielded a very respectable 216 horsepower at 116 ft/lbs of torque.
We were within a few horsepower of what our low power testing projections indicated we would make. Screaming rpm, open pipes, supercharger boost, nitrous, water/methanol – it was a visceral experience. Micah said the sound wave pressure in the dyno room was enough to beat his heart in his chest. Things were looking good.
We loaded the motorhome, trailer, and van with all our bikes, gear and supplies, and headed for the new Texas Mile venue in Beeville, Texas. As the primary builder and test rider, I was determined to put the bike in good working order for Dave’s afternoon qualifying pass. After experiencing some crosswind-induced front-end lift and headshake at 175 mph, the decision was made to remove the aero tail and a prototype panel on the front of the bike.
Riding a previously proven aerodynamic configuration, Dave stepped up and qualified easily at 188 mph, using only a 50-percent nitrous load in order to save the motor. It was obvious that wind was going to be a problem all weekend. The only chance to break 200 mph would happen during the calm wind conditions of the first hour of running, with all of our aerodynamic modifications installed. Belts, plugs, and fluids were all okay.
The engine-logging module self-destructed due to vibration, and was removed from service. The water/methanol injection computer was replaced as no fluid was consumed on that qualifying run, indicating a fault. We parked a scooter in the staging area overnight, reserving our turn in the next morning’s calm conditions.
Saturday morning, Dave lined up and fired off a 197.8 mph shot down the one-mile course. Not 200 mph, but it was the best we had done to date by 5 mph, which is hard to come by at those speeds. Apparently, our engine, chassis, and aerodynamic development project was paying off.
I made a 182 mph run early Saturday afternoon, but with the wind gusting upwards of 30 mph, we decided to park it for the rest of the day and get ready for our probable last chance at 200 mph on Sunday morning. We followed the same routine as the previous day, checking all systems, but servicing some critical items.
Mike Wood and the Nitrous Express race team were pitted right next to us, and they gave their expert tuning advice. Aerodynamic drag calculators on the RB Racing-RSR website confirm that a 3 mph increase in speed at close to 200 mph should require 10 horsepower. We estimated the nitrous jetting changes to be worth about five horsepower. It may not be not quite enough of a change to gain 3 mph over our previous best, but we didn’t want to break the motor.
Whether we achieved our goal of 200 mph or not was all coming down to one final run on Sunday morning. Our hopes were tied to perfect conditions, perfect tuning, and perfect rider execution as we were already operating at power levels never before seen in a Rotax V-twin. We held a team meeting and decided that Dave would be the rider, while Micah and I would take care of all the bike preparation. We ordered Dave back to the motorhome at 10 p.m., instructing him to rest. Micah and I worked in the trailer until 2 a.m., making sure everything was perfect.
We had again parked a scooter in the staging lane the night before, and looked to be about the tenth vehicle up. The pre-dawn silence was broken by the harsh crackle of the supercharged engine, as Dave fired up the beast and drove it from our pits to the staging lane.
I double-checked that all switches for power, ignition, fuel pump, nitrous arming, water/methanol injection, and the nitrous bottle heater were in race mode. The engine was warmed up to operating temperature, and then shut down to prevent overheating.
Tire pressure had been raised to reduce rolling resistance. Nitrous bottle pressure was raised from 975 to 1050 psi to lean the mixture a bit for more power, and to make certain we maintained bottle pressure all the way down the track.
When 7 a.m. arrived, track operations got underway. I fastened the dead man kill switch lanyard to Dave’s glove, as required. The line started moving, and I accompanied Dave to the hold-short track position, making a final check of all systems, and giving him a thumbs-up signal. With visor down and earplugs in, he was already in the zone and hardly aware that I was there. In moments, it would all be up to him. No pressure, Dave.
Mike Wood and I watched from behind as the bike pulled up to the line. Dave rapped the throttle, and waited for the starter’s signal. With the rising sun behind him, the distorted plumes of hot exhaust gasses ejected from the open exhausts made The Punisher look like a Top Fuel dragster.
Dave executed a hard launch, the front wheel skimming the ground through first and second gear. The engine sound took on a decidedly angrier tone when he shifted into third gear and thumbed the nitrous button.
The thunderous roar of the supercharged/nitrous injected engine filled the morning air as The Punisher rocketed farther and faster down the track with each successive gearshift. The pureness of that sound and the grace of the bike at speed were very satisfying, having worked on every piece of that engine and chassis.
We could see that the bike had already passed through the timing lights, but the sound continued at full song for another eight seconds. Then there was silence, and this frozen moment in time shifted back to reality.
We looked to the large digital speed display, but no numbers appeared. Every vehicle’s speed is announced over the public address system, but we heard nothing. What happened?
Mike and I dashed for the AF1 scooter and raced two-up back to the pits, where we would get the results first-hand. When Dave pulled into the pits pumping his fist, we knew that we had done it. A quick look at the timing ticket showed 200.8 mph. Wow! High fives and cheers for everybody!
We set this record under very challenging conditions. Dealing with high crosswinds, chassis setup, power adders, and advanced electronics put tremendous pressure on the team to make the final run count. I am very proud of the way our team performed, and what we have accomplished. Team Punisher did it.
Story from an issue of Ultimate MotorCycling magazine. To read the latest issue in digital format free of charge, click here.