GT750 Powered Race Car (D-Sports Racer)

[sav0r (CL MotoTech)]

It was really nice meeting you! Make sure to come and hang out next year!

It has a Pertonix based ignition. Heat may have been a factor, but who knows? In a month once we feel willing to look at it all again we will assess.

[pidjones]

You might consider reset-able circuit breakers that you can reach in the cockpit. Burning a wire isn't too bad. You don't want it to burn down the while car!

[sav0r (CL MotoTech)]

We had that discussion after the race. Either auto reset breakers or a second ignition circuit with a second ignition switch. The latter being common in stock car racing. We have a while to think about it.

My guess is that we will chase the wires, fix the chaffing or whatever, thereby correcting root cause. Hopefully then we will never have the issue again. As Clem says, there isn't much there to look at.

Typically in race cars you let the wires burn and if there is fire you pop the bottle and hope for the best. This is very common race cars, the only race car that I have ever driven that had fuses is this one. Keep in mind there is literally one of these cars. So my father has been a bit more cautious with it. Of the many professionally built race cars I have driven, where you get many spares should you need them, there isn't a fuse on the thing. But they also have wiring looms designed and braided by professionals.

Anyways, I think after a week or so we will feel a little less deflated. We were truly close this year with most things going our way and yet another gremlin emerged. The game of whack a mole continues.

[Clem710]

Complete 2nd set of ignition system is also common in aviation and it really shouldnt add much weight.  I could put you in touch with a guy in E. Liverpool that builds his own frequently if it will help.  Also, I think its been tested that dual plugs make more power. 

Really shouldnt be necessary though, I'm thinkin you'll find something simple and obvious once you see it.

Good luck, more fun to drive em but good fun working on them as well:)

[sav0r (CL MotoTech)]

We pulled the head yesterday just to do some analysis of the engine condition. That lost needle circlip did just about as much damage as a circlip can do. Certainly not terminal but the head took a nice mashing. The ports look clean on initial inspection. We were planning on a new head anyways, so we aren't gutted about it. The piston seemed to survive without much damage at all. I guess that is one benefit of that soft Suzuki aluminum.

[irk_miller]

I shattered the rings on an SBC in a race once.  It's amazing how metal can imbed itself into things while simultaneously bouncing around like shot peen.

[automan]

I shattered many HEMI pistons.
No foreign debris, just bad iggy timing and/or hot exhaust valves(bad seats)

OTOH, I lost a few parts in the intake and did zero damage.

Funny luck.

[sav0r (CL MotoTech)]

Well boys, the band is back together. And by that I mean, Mom's bout with cancer is over and my divorce is finalized. So my father and I are free to ignore the real world and indulge ourselves with 2 stroke powered race cars.

We have slowly been working on the car in the background, but with life getting in the way, things were slow. Probably the the biggest update was the rear brake.

To save you from digging through the thread, failing brakes on the street course was a common theme for us. We think we narrowed it down to pad knock back on the rear caliper. The single rear rotor had a lot of run out, this knocked the pads back, meaning a long pedal. To prevent the inconsistent pedal I would touch the brake pedal well before the brake zone to return the pads to the rotor and get the pedal feel I desire. This generated excess heat at single rear caliper, boiled the brake fluid, and meant that it was difficult to achieve proper braking pressure at the front due to the balance bar. If you are familiar with how a balance bar works you probably understand.

Beyond that, we made yet another head. I, like a fool, didn't get a picture of it. It has a nice toroidal combustion chamber. We went slightly large on volume, squish came in at .032" with a .035" gasket. It should be a cool runner. I'll check squish again after a heat cycle and retorque.



We have better tires lined up. I am working on licensing. The plan is to get a test in mid June, a month away. Then off to PVGP in mid July.

[RDnuTZ]

very cool Chris  Getting that kind of weight off your shoulders makes life a million times more enjoyable and easier to think about fun in your future