Posted: Sun Mar 17, 2013 7:42 pm
Adam, The engine braking is at a different rate I guess that is a way to put it. The Clutch / Flywheel Moment of Inertia are a lot less with the 1.6
Kurt, Lets talk about your Trans rebuilds first, what was broken and then fixed. I raced in the SE for years so I'm very familiar with the tracks in that area of the country. Most guys in the SE can get in the range of 40 to 50 events out of a gear box, if you change the fluid regularly and lift a little when you drop a wheel off edge of the asphalt and drive back on. Do you use a OEM type clutch? In the last phew years there has been a couple different series of parts and if missed matched in a gear box, the life is pretty short. Do you think that is what happened to one of your gear boxes? Anyway shock loads or fatigue, heat and contamination are what shortens the life of our gear boxes.
Lets talk about the new Duratec engine, it's very close to the same output of the 1.9 until you reach the upper mid range. Then the modern design of the 1.6 starts to shine. So even though the 1.6 has a greater output it comes at an increasing frequency which lowers the shock loads on the gear teeth. Lower RPM Torque is a little bit harder on gears than higher RPM HP. The next thing that is a gross change is the weight of the clutch and flywheel, which lowers hit on the gear box at each shift.
The minimum weight of the class is also going to be lowered, lessening the load on the drivetrain in general.
Last, at least for now I don't see an increase in tire grip coming anytime soon. So all those things together I don't believe we are going have a big problem, in short running 13 R&D cars we will learn a lot.
If we need too, I can detune the output of the engine a little. I truly believe we will be in a good tune / performance window when GEN 3 is released. Also by tuning the engine on the safe side of optimum output it makes it a little harder for the clever racers to find tuning benefits.
Denny, I was amassed at the overall performance increase of the car, braking stood out to me a lot….I was 1511 lbs or 160 under weight, it felt good to shorten the brake zones a very noticeable amount. I never had the slightest hint of long peddle or brake fade. I'm using ATE fluid.
Franklin, We are way to slow to run with IMSA Lites, even the ESR's or FE with sports racer body were pretty slow to run with a DP02 on a pro weekend. We will still be 10 / 15 plus seconds slower than an FE. If I could have a run session or 2 without all the traffic, after looking though my data I think I could have run in the low 30 or high 29 second bracket @ COTA. I think the FE's were in the 16's
Tom, Not to start a panic, Mazda is happy to make our gears for the foreseeable future, When I start the quoting process for the ring and pinions, I will also get the 3rd / 4th / 5th gear sets quoted as well. If I was to optimize the ratios for the new engine…I think I would go taller on the ring & pinion and shorter on 3rd / 4th and 5th to close up the drops just a bit and make 2ed just a little more usable. Driving the car with the 1.6 and the current ratios was better than I excepted. I don't think everyone understands that ratio drops are a percentage not an absolute. So everything gets a little wider or a larger step with the 1.6, it drove pretty nice really.
Bob, I was using about 2.3 gal a session on the test day, how much was everyone else using?
Everyone, ECU stuff…Closed loop running, Map switch, Pit speed limiter…You guys should look at your sups tracks are starting to impose pit speed limits…I think it was 35 MPH at COTA, Fault code light….all of these things are the cost of a switch or light bulb and socket and a little extra wire…pretty std stuff on even entry level stand alone ECU's these days. I haven't programed it, but I used the STD Speedo drive on the gear box. Pretty sure it will work out just fine. If we have a reduced torque map, it's up to you if you want less power or not. If you have ABS built into your foot and don't need or want it….don't use it. If your feel is not so good, it may help you out and it's really no different the timing plug on your 1.9 EFI harness. Bet you didn't think about that did you….good luck everyone and time will tell.
Mike Davies SCCA Enterprises
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