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Project Miatabusa – Part 3
by Dave Coleman
Page 2
Tow Hooks – 6 lbs
Miatas were built in Japan and had to come here on ships, so you can forgive Mazda for installing tie-down hooks on the car. But why so HUGE? Does a 2300-pound car really need to be tied down THAT hard?
Since I don’t plan to ship the car anywhere, I can’t imagine why I would need these hooks. When I dyno test, I can strap to the rear subframe and the front wheels. When the car gets towed (on a flatbed), they can use tire straps. The only thing I need a tow hook for is getting dragged into the pits when I screw up on track and for getting dragged onto that flatbed. I’ve got a better solution for that.
A seat belt holding a 250-pound driver in a 9-g impact has to withstand 2250 pounds. That’s more than the Miatabusa will weigh, so this piece of seat belt should be strong enough to pick up the car, and more than enough to tow it.
Wrapping the belt so it won’t pull out is tricky. This wrap is occasionally recommended when wrapping harnesses around roll cages. This was bolted in place with a thick washer to keep from pinching the belt.
Wiring – 6 lbs and counting
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| The Hayabusa ECU and harness are much smaller than the Miata’s. After being cut down by Peter D Motorsports, the whole thing weighs just under 4 pounds. (We haven’t added this weight to our total yet.) |
Since we’ll be running the Hayabusa’s wiring harness and ECU, there’s no need to keep the Miata’s ECU in place. The same goes for the tangle of wires connecting that ECU to the engine. To be totally fair, some of this wiring weight will go back in when we install the Hayabusa harness and ECU, but they are significantly lighter. Since Hayabusa harnesses have strange shift interlocks, kickstand switches and motorcycle-specific junk like that, we farmed out the Hayabusa harness work to the experienced hands of Peter D Motorsports, a dwarf car shop that specializes in making bike engines power little race cars. For about $150, he sends back a simplified harness with the various kill switches removed and shorted appropriately, and labels indicating the external hookups (power and ignition swtich, for example) that you still need to connect. We’ll take a closer look at this, and all the wiring adventures a bit later when we’ve actually finished the job.
One of the many sources of bloat between 1989 and 1996 was the relocation of the ECU. Early cars had the ECU under the dash, which provided the shortest wiring possible at the time (now they could just put the ECU on the engine, like it is on the upcoming Mazda2). With the introduction of a passenger’s side airbag, though, the space under the dash had to be rearranged and the ECU got forced out. its new location, behind the passenger’s seat, required about a pound and a half of extra wiring harness.
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We’re about 2/3 of the way through the job of removing all the engine-related wires from the car. So far the tally is just over 6 pounds of ECU and wiring.
Spare Tire – 18 lbs
Cell phones and liquid latex have fundamentally changed my feelings about spare tires. Do you really need a 22-pound wheel and tire taking up a third of your trunk when modern roadside patching technology lets you just pump liquid condoms into your tire to patch it from the inside? Having witnessed firsthand the lack of problems caused by NC Miatas and RX-8s selling with no spare tires and no runflat tires, I’m finally inclined to say no. As long as you don’t puncture the sidewall, most flats can be fixed well enough to get to a tire store with a simple kit.
This kit, found in the trunk of a new Camaro, weighs 4 pounds and not only saves you space and 18 pounds of trunk weight, it also gives you a pump that’s handy for juggling tire pressures at the track. The liquidy latex goo it pumps into the tire is harmless to wheels (unlike some of the aerosol patches) and is reasonably effective at stopping or at least dramatically slowing leaks from punctures in the tread. Since we don’t have a Camaro, we’ll be looking for something similar for our trunk.
Now, to be honest, I have, more than once, been victim of a flat that neither a goo pump nor a cell phone could fix. If you like attacking mountain roads like I do, you too could find yourself out of cell range with a split sidewall from running over a surprise rock. Do that with this patch kit and you’re stuck. I’ll be keeping the spare tire in the garage for just those excursions.
