October 28, 2007

Mr. D&D Talks with Barnett's magazine

A Past Interview with The Pope of Pipe About Bonneville

This is a new column that I hope to continue in the magazine; it will be in the form of an interview with people at the cutting edge of technology in the v-twin field. I have interviews planned with tire and wheel companies and hope to entice the Motor Company into granting interviews with their engineers to show how much science is going into the products that we all enjoy today.

Today’s interview is with Team Boarzilla represented by D&D Exhaust’s Dave Rash, rider and engine tuner John Minonno and engine tuner Bob Dowdy. Last year they set a land speed record of 225 mph in the 100-inch push rod blown fuel class. I will begin with a little background, as I learned so much in my short interview that I realized I would have to explain why salt flat records are so difficult to achieve.

We’ve all heard that the high altitude and salt create difficulties, but there are several factors that have to be balanced in order to achieve record-breaking performances.

First of all, drag racing Harleys running 90% nitro-methane fuel can achieve 600 or 700 horsepower. But in a six or seven second run, their engines only turn over about 600 times! (You can do this one in your head: 6000 revolutions per minute for a tenth of a minute are 600 revolutions). Getting large amounts of horsepower out of a v-twin using nitro generally won’t work on the seven mile run of a Bonneville attempt, much less on the required back up run.

To get a record, a team must balance horsepower, aerodynamics, reliability and traction. The bikes that Team Boarzilla were after were the turbo-charged Suzuki Hayabusas that run at about 250 mph. Trying to do this with a pushrod twin and not an overhead cam multi-cyclinder is what our intrepid team set out to accomplish. And of course, when they started researching, making phone calls and asking around, not only had the required horsepower not been made before (without using 90% nitro in v-twins), many said it couldn’t be done.

Mark Barnett: Why did you decide to use an S&S Sportster-style motor and not a big twin?

Team Boarzilla: That was S&S’ idea. They talked us into it. They said that because of the pushrod angles and the unit construction of the engine and gearbox, the Sportster-style, S&S four cam pro-stock motor was the engine for us.

Mark Barnett: And how about the decision to turbocharge?

Mr. D&D : When we started doing a little research into turbocharging, many people told us we were all a bunch of fools for even considering turbocharging because you couldn’t make it work right. Well, that was kind of like slapping us upside the head with a gauntlet.

Mark Barnett: Were these drag racing people telling you this or salt flat people telling you this?

Mr. D&D : It was Harley-Davidson people in general. You can take a Hayabusa and because of the even firing pulses, you can turbocharge it. But the firing order of the v-twin doesn’t make this easy.

Mark Barnett: But people turbocharge Harleys all the time.

Mr. D&D : But not at 20 to 30 pounds of boost. You can bolt on one at 10 or 12 pounds and not have any trouble. This year what we had at 21 pounds of boost was a consistent 361 horsepower at 6200 rpm. It’s definitely got a considerable amount of power now.

Mark Barnett: How is this bike fueled?

Mr. D&D : What we use is a major management system off a V8 car; it controls the timing and fuel injection. In everything we’ve done to date, there’s been no experience from anyone else we could draw on. It’s just been a trial and error deal. Just see how it works and go from there.

Mark Barnett: What other challenges did turbocharging present at so high of a boost level?

Mr. D&D : Plenum design. We are in the process of right now of designing that all over again. We pulled up all the information we could find and bought a few books. As far as the size of the plenum, we asked enough questions until we got some idea of what the proper size of it should be. Many people acted like they knew everything, but really didn’t know anything. The guy I bought the turbo from told me he didn’t have any idea what size turbo or plenum to use, but that he would work with us if we gave him data from our dyno runs.

Mark Barnett: In what other areas did you search for power?

Mr. D&D : This year we found that kind of like making a good martini; just a touch of nitro in the alcohol made a ton of difference. We used 10% nitro this year. I spoke to a lot of fuel people. Nitro will break down the beads of alcohol into a finer mist so it atomizes better. That’s why we did that.

Mark Barnett: So in the fuel class, you can run anything you want?

Mr. D&D : We can run anything: rocket fuel, nitrous, anything you’ve got. If you’ve got the cajones to put it in the tank, you can run it.

Mark Barnett: When you mentioned to me earlier today that a university was consulted in the planning of this bike. Did they help with the motor or the aerodynamics of the bike?

Mr. D&D : What they worked on for us last year was the chassis and fairing. They had five graduate students who took this on as a project. They did a CFD fluid dynamics program on our bike and gave us their interpretation of what we needed to do to get the bike through the air better.

Mark Barnett: Was that done in a wind tunnel or all in a computer?

Mr. D&D : That was done all in a computer at the University of Texas at Arlington.

Mark Barnett: This is where you got the idea that your air-cooled Harley, with its narrower engine, could compete with the higher horsepower Hayabusas that had to run the wide radiators?

Mr. D&D : yes, and we just had a conference with the the other day, Mark, and what they’re going to work on for us this year is our plenum design. One of the problems that we’ve had is fuel distribution to the cylinders, especially to the front cylinder. I have great faith in their results; they certainly helped us with the fairing. This year we have a five student team working on the plenum. We might go to a single injector if they suggest it. Our plenum was pretty much just garage designed; we had nothing to go by. Our plenum favors the rear cylinder as compared to the front.

We feel very strongly that once that particular problem is resolved we hsould have a very reliable motor makin in excess of 300 horsepower—time and time again. This particular S&S motor is a very robust motor. We’ve had no problems with the bottom end ofthis scooter. It is designed to handle over 600 horsepower. On our 225 mph run last year, we think it was only making about 250 horsepower.

Mark Barnett: So overall, your goal was setting a land speed record, which you did last year right off the trailer. What are you shooting for now?

Mr. D&D : Johnny is 60 years old. The guy racing this motorbike is a 60 year-old man. He’s got more times down the salt than anyone I know. He’s been racing at Bonneville for 30 years. (In the background, “His first bike ran on steam.”) Hell, I’m 59 (Dave) and Bob is 55. This is our swan song, pal. This is something that is very important for all of us. The whole deal here is to take this bike and when we are old farts sitting around talking, we can say that we did it. We have our aspirations; we’re 25 mph off doing 250 mph. Power is not a problem, based on what the guys at the college told us. The biggest problem we had was traction. We did not have enough downforce to plant the bike. Something that is unique about the Harley-style motor is the power pulse. The Japanese bikes (when they finally come up on boost), they spin, they burn the tires off. This old twin just steadily puts the power down. We just need a little more help with the downforce.

Mark Barnett: This will be my first new engineering column; I’m trying to find people who are at the edge of performance and design and let our readers hear from them directly.

Mr. D&D : In other words, you’re looking for some more crazy people to write about. Is that what you’re doing?

Mark Barnett: Well, I guess so.

Mr. D&D : One more thing, wihle I’ve got the opportunity, we’d like to thank you for all the help that you’ve given us, the financing and the support. You were the first person that had any faith in us at all. We’d all like to tell you thank you very much (Barnett Harley-Davidson was one of Boarzilla’s first sponsors).

October 28, 2007 08:08 AM | send page