HT: Specifically, how will you cool the engine--minus the radiator--using the water tank?
JR: In the photos, you see the car in its early stages when it had a radiator. You have a small block-off plate on what would be the grille, but the whole undergrille is still open. So there's a tremendous amount of air flowing through that motor.
The way the car looks now, there is a lower air dam from what would be the bumper molding all the way to the ground. There is no airflow in the front of that car anymore. It's all going around it or over. Nothing under, nothing through. We went out in October and it didn't take long at all to see that there is no cooling airflow. We can negate that a bit with holes and trying to duct air through, but that really hurts the aero drag.
What most Bonneville cars do is run a full tank system, where they have a 20-gallon water tank and just pump the water through the tank, using the thermal mass of the tank to keep the engine cool. You can't run it forever and you can't do this on a dyno; on a dyno they usually have hose setups where they can pump in cold water, kind of like working on a boat [engine] outside.
We know that we only need about 13 gallons. That would give us a 50-degree F rise over the course of a run. So we're going to do a 15-gallon tank. At Bonneville, it's virtually impossible to get back-to-back runs. If everything were perfect, you [still] couldn't run for another hour and a half.
HT: Where do you mount the tank?
JR: Passenger seat. There is no passenger seat [in our car]. Right now there are all the fire bottles there, but in the footwell where the fire bottles would go we're doing a custom tank. It'll also be pressurized and there's an electric water pump right there, so you can let the engine heat up fast, then turn the flow up once you get going. And it's all automatically controlled by [AEM's] EMS.
HT: Tell us about the coil-on-plug setup you've adapted from Honda's motorcycles.
JR: I couldn't be less of a fan of distributors. I like the concept that if you're going to run an ignition system, you want to have individual coil-on-plug. And there are a couple of reasons for that. One, you want the plug to fire its own time. At high rpm, you've got to remember that if you're running a distributor, you've got one coil. It's running four times faster than any one cylinder. For a CDI, it's not a big issue, but for an induction system it is. You need charge time to bring the thing up. These coils can really handle high voltage without breaking down. The factory Honda coils can't. And the factory Honda distributor cap has a problem where if you put 55,000 volts at it, it has a tendency to jump from spot to spot if you're running very large advance numbers. If your timing is varying by 30 or 40 degrees over the course of the rpm, it can never be perfectly on. And when you've got an ignition system that can jump almost half a foot, then you've got to be careful how you handle it. You have mating cylinders that don't have any pressure in the combustion chamber, and you've got the one you're firing at a very high pressure, so you'll have a much lower impedance going through one of the dead cylinders than the one you're firing on.
Little things like when you're running really high rpm tend to give you misfires that you never can seem to track down and there's no need to mess around with it. We've got the technology to do it, we've got the EMS that can do four-channel coils. It was very easy to put the coils on the motor and wire it in.
HT: What bike are those from?
JR: Those specific coils are from Honda's 929. I think they're also on the 600F4i. They're very common coils made from Nippon Denso. The only difference is the length of the rubber bootie. You can get the same coils off a Suzuki, a Yamaha R1, a Hayabusa--they're all the same. They just have different rubber booties depending on how tall the actual head is. Those from the 929 happen to work great on a B series.
It's not a popular application because you can't use it with the factory computer. It's only got one ignition output. You gotta have something that's completely programmable.