#62 Mazda-Kudzu DLM 3-rotor
#63 Mazda-Kudzu DLM4 4-rotor
Text & images copyright Michael J. Fuller
I have never come back from a test session so weary! Let us hope the race is nothing like this!
To quickly brief everyone. Downing/Atlanta has entered two cars for the Daytona 24 Hour race. The tried and trusted Mazda-Kudzu DLM 3-rotor and the new and more powerful Mazda-Kudzu DLM-4 4-rotor. The 3-rotor DLM is being driven by a gaggle of "rent-a-drivers"; John Mirro, Doug Campbell, Ralph Thomas, and Dennis Spencer. The final driver lineup for the 4-rotor has not been established, but more than likely will consist of some combination of the following: Jim Downing, Howard Katz, Yojiro Terada, Franck Freon , and John O'Steen.
Friday: Our first day out should have given us some indications of the trouble in store. The 3-rotor ran flawlessly, the rent-a-drivers taking their time to learn the track and the car, being careful not to bang anything up or crunch any gears. The troubles were just starting for the 4-rotor. The first time out we wound up with a fried connector to one of the fuel pumps. No big deal, diagnose the problem, replace the wiring. We lost track time, but the car was fixed. The final session of the day had the 3-rotor running fine as usual. The drivers were beginning to feel more comfortable, getting the times down into the upper 1:50s. The 4-rotor on the other hand just stopped in the middle of the session, Howard brought the car in, and it would not re-fire. Diagnosis found a loose bolt zinging around in the bell housing. Well, a couple of engine sensors reside there too and didn't like being wacked around by this flying bolt. So more lost track time (had to take the rear end off to get to the bell housing). Testing day one saw 3 good, solid hours of track time for the 3-rotor, and about 40 minutes for the 4-rotor. Fast time on the day for the 3-rotor was 1:56.072, for the 4-rotor, 1:59.570.
Saturday: Morning session, about 25 minutes into the session. Jim is coming down the front straight in the 4-rotor, passing the pits, the car is showing more speed. As he passes our pits, at maximum speed (about 180+), the rear wing tears off the rear end and the car snaps into a 360. Getting backwards, all the body work sheds off, raining debris and body pieces all over the front straight as he careens out of our view. Fortunately Jim is OK. Had the spin gone into the wall instead of away the consequences would have been very different.
Damage to the car is substantial. All the body work is trashed. Close inspection reveals that the rear wing mounting plate failed. The wing reached a certain vibration frequency (which is normal) but the mounting plate couldn't cope with the oscillations and it had to give. The result was that the wing mounting plates bent at such a lurid angle that the wing sheared right off (this version of the mounting plate was designed without a critical diagonal cross brace--and such this is what happens when you go against engineering convention). The resulting loss of downforce at the rear of the car snapped it into a spin. Jim was just a passenger.
There was no chassis damage, neither the suspension or the tub were damaged. But when the body work departed, it yanked out all the latching mechanisms, not to mention the damage that occurred when the pieces initially took flight, and then landed. The nose box was snapped off when the car spun down the transition area from the banking to the apron. With a quick inventory of spares and salvagables the repair commenced.
So by the time of the night session the car was ready to go out. By the way, let me stick in here a thank you to the Rohr Racing composite guy. He did all the major composite repairs to our bodywork. Thanks! Any how, so the car was readied utilizing repaired pieces and mix-matched spares (Le Mans low downforce nose and splitter) and finally got back out on the track......only to coast to a stop at the bus-stop chicane. Now what?? Well remember that engine sensor that broke the first day? Well....the magnetic device that sets off that sensor had broken this time. You know how it goes...proverbial five dollar part on a $100,000 motor...
Sunday: We put the 4-rotor back together and went out for the morning session. Jim ran his laps, there were no problems, and he came in. None of the other drivers had had seat time, so Jim stepped aside and let John O’steen take a spin. Well....John’s second lap by, into turn 2 he apparently locked the brakes up and ended up putting it into the Armco. I was on the radio with the 3-rotor, Doug said that it didn’t look bad, that it appeared that the 4-rotor was just off course. Well...it was all right...the front right was crunched (fortunately no suspension or tub damage!). The Le Mans splitter and nose were out of commission. The right rear had also tweaked the barrier damaging the wheel, and on closer inspection, bending the upper A-arm. You would have thought we’d have packed it all up and headed home! Nope. Most of the damage was to body work and we had basically run out of body work. But we were able to utilize the nose and splitter damaged in the Saturday accident and amazingly enough we got out in time for the final session of the test. Franck was finally given some seat time and he ended up setting the fastest time for the 4-rotor the whole weekend. The 3-rotor ran fine, getting into the 1:55s. Franck set fast time in the 4-rotor at 1:49.287.
Where does that leave us for the race? Well....lets just say prepping a lot of spare pieces....The test was a wash for the 4-rotor. Very little set up information was learned. Most of the time was spent chasing flying bodywork or gremlin engine sensors.