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Black Magic

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Black Magic last won the day on November 1 2020

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  1. FWD cars at some tracks create impressive polygon shapes with the rear wheels, if your ABS can stop this it is worth it. Happens from trail braking into a corner as the inside rear lifts. Gets even worst if the track banks away from you, think turn 1 at NJMP lightning. You have to run soo much front brake bias to stop it (or work on stopping before you turn) that it seems like the rears are doing nothing Somewhere between octagon an dodecagon on the inside rear you decide it is time for new tires and new drivers.... I think it depends on if this will create ice mode, or if the car can handle one rear wheel speed going to zero without flipping out.
  2. @Rodger Coan-Burningham I think you really have 3 classes of cars. Fuel rich, "average" and "fuel poor". Using stock weights, like the chart below I think the fuel poor cars are around 200 lbs\gal, average is in the 180 range and fuel rich is above that in terms of 2020 rules. Granted some of these cars can lose alot more weight than others from OEM, so raced weights would be much more accurate. Same for "not swap weights", getting a pulse on the actual raced weights of the cars would help the balancing immensely. In general you could guess that a heavy car and a light car at the same point on my list using OEM weights, the heavy car has a strong advantage in fuel to weight when you factor in the race weight. This chart is recycled from a fuel balancing petition years ago, with the support obviously better from teams towards the bottom of this list. I think the uproar this year occurred because the assumed PWR required to reduce an extra stop shifted due to the updated fuel rule. Now that the light cars in the 180 range are complaining there might be enough market share affected to bring about change, or at least have more people consider it out of empathy vs sympathy.
  3. I think your car was famously above the curve on power creep, and you may have a point that the creep was just much of the field catching up to the few cars that were out there. I remember about 2015 at VIR you and I chatting. You came over to see what we had in the car, something along the lines of "it must be alot because I have alot". I think that was about the middle of the big inflation, I bolted 30-40 more hp in and instantly could keep up. We had roughly kept up before, 3 years before that you could podium with the lower power. The engine mods points deflated quickly and we had room to add the hp. Look at winners from out east you have run against, you think there isn't a strong power difference from the old Ronald's racers car to the front runners today?
  4. The fastest car a decade ago sat at Rd america ran a 2:56, this year sat the fastest non ec car ran a 2:43. I agree the will be solid laptime sensitivity to camber, tire width, etc, but 13 sec a lap is well beyond what you can brake bias yourself towards. You wouldn't be 13 sec off if you removed the rear brakes, ran narrow tires and added 300 lbs to the car at the height of the driver. I think that is the level of speed creep people have issues with, and the largest inflation was a few years ago as vpi dropped, the swap weights got "updates" and the engine mod points dropped. I think we all know the trend will be towards faster laps even with the same spend, just a matter of rate.
  5. Fuel, tires, brakes, power train all have pretty proportional costs to the speed of the cars. This is sort of beyond the obvious, that faster performance cars tend to have higher values as they have utility in the rest of the world. Unavoidable fact, when we were all racing cars prepped to a performance level that excited no one on the street, the purchase price, repair part values and running costs all represented it. You could argue the spec b cars of today are what the series would have encouraged in the beginning. I bet they are faster than the average car was in 2009. That amount of speed creep would be natural. I think what we have trying to keep a false image of a single class has exceeded that several times over.
  6. You would be best off to slot the hole in the chasis, tack a washer on in the position you want and get good clamp load with the bolt to keep it offset.
  7. Not a bad idea, but the easy money would be running the oe brembo package and moving on to another development project for the car. Sounds like a win win, better brakes at a net weigh reduction. Most of your rotor mass is in the section that would still be iron with 2 piece rotors.
  8. He can be hot headed and warm blooded....need to make sure his helmet and seat volume is measured at the right temp.
  9. The brake wear will be highly non linear with temp. Sizing the brakes to get reasonable temps can be huge. I have run St43 pads that lasted 14 hours, and another that lasted 3 race weekends. Both on the same type of car, one of them is an 10 lb rotor the other is nearly 16. The heavier rotor was an inch bigger and also much more flow area in the vanes. Sounds like a reasonable rotor diameter change (weight cooling and size) would help. I would suggests making a reasonable change, 20% or more increase in braking at the same pressure. We can build you a calculator to determine this, simple answer being up size the rotor effective (center of pad) diameter 20%, make the pistons 20% more area, or some combo of those. I would also up the rotor mass to something nearing 16 lbs + if you want to really open up the pad options you can run and keep the rest of the parts happy.
  10. I also think any light petroleum container would work, like oil bottles (qrt sized to fit better). I think any HDPE container would be a decent bet. I want to do a long term dunk test, one of the lemons teams I have helped asked about it.
  11. Someone please get Bill Nye here.....
  12. I can give you some example petitions to file for next year asking for that. Several people have made similar suggestions. That topic is one of the more bludgeoned horses on the forum. Several of the teams complaining now in the past were not in favor of fuel equalization, seemingly of any method. Maybe being on the other side of the fence has changed some of the minds in the series, or maybe another method\voice would help.
  13. Not sure what coolant tank and hood vent you know that will change the performance envelope of the series in a major way.... but it sounds like I need some..... Until you see people taping over the majority of the nose of their car and trying to maximize the airflow that goes thru the duct..... I think the series will be fine. When they are using a single square foot of cooling duct with a $3000 rad, then we will have issues. The flywheel rule most likely has the greatest creep by allowing a car to be lighter, agreed that one would have been nice if it at least forced steel flywheels on people as a gentleman rule. You will be able to lose 5-10 lbs on a car by simply spending, which does sort of stink for the series. The enforcement I think is what made those open, as it would hard to tell what many cars are running. We can do the energy calcs on a flywheel change, but I think you will be very disappointed in the gain given the ramp rates our motors have on track.
  14. I assume much of your issue is late in the braking zone. Stop trail braking. It is hard to break drivers from this, but it an inherit weakness of FWD cars. You have to brake sooner\roll more speed into the corner (if you car will scrub more speed naturally you roll more speed, heavier cars you brake sooner) You can remove more rear brake bias, but this will most likely hurt your straight-line raw braking potential. I am assuming in a straight line you have good brake bias but feel rear lock during combined braking events. Most FWD cars run a little more front brake bias, which does increase the brake work on the front axle. Upsize those brakes and run good pads. The rears you can often leave stock, using the up size front brakes to get a little more front bias. I have run ST43, lasted forever and was good to the last drop...however the feel and release are tough for many drivers to tame. Carbotech has some pads a step down in durability that are much easier to driver, if you brake temps allow. When you make front running power you will want about 12 lbs of front rotor mass per 2,000 lbs of race weight, some people lean towards 14. A 2000 lbs FWD car will have about 11" brakes, assuming a setup with moderate brake temps, wear and heat. For FWD cars bigger brakes allow more cooling, heat storage and most importantly help keep the temp out of those precious wheel bearings and CVs. They have a hard enough life as it is.
  15. I think he is using his reference to IMSA, where they list a specific weight for the fuel that is only accurate at one temp. If you use the weight method and don't account for changes in density with temp, yes temp will mess up your measurement (even though the real volume never changed) because the method was done wrong. Still, a rigid 15 gal container will have a volume of 15 gal regardless of if you fill it with gas, water or mercury. Yes agreed. Technically there is a small amount of expansion of steel with temp that would make the fuel cell box larger. We can do the math on the CTE of steel, but you are talking incredibly small numbers. Depending on the quality of the install of your cell and prep of the fuel cell container, you may have air trapped between the bladder and the container that could vary the actual volume depending on the density of the liquid you put in there. Also if your cell isn't well supported it can flex when filled and create errors when reading (square box becomes more rounded) but these aren't totally specific to temp. Even with 2021 rules if they are able to fill 15.5 gals in your 15 gal cell (cell only, not total system) you would fail tech regardless of outside temp, assume tech does a reasonable procedure to know they put 15.5 gal of some liquid in your cell.
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