After C&C we went and had breakfast with the SCCA Solo peeps Brad and Jen Maxcy, with me and Amy plus Brandon and Sofi from Vorshlag. Best breakfast ever = the Chicken and Waffles at Whiskey Cake Cafe. Bacon is infused into the waffle...!! And After four mimosas it was nap time for Terry, and Amy drove us home. Then we switched cars and went to some Irish Festival all afternoon, where I had plenty of Irish beer and ale. And that was my first day off in about 4 weeks, which was epic.
I drove the Mustang to the shop the next morning, with a healthy hangover, after the temperature dropped by more than 60 degrees. It began raining then sleeting on my drive in, of course. Oh well, the defrost and wipers worked just fine, and the DOT Hoosiers had enough grip on the slick roads to where I didn't even notice the slick conditions (left the traction control on, just this one time). Worked about 7 hours while it continued to sleet and I drove another vehicle home, towing an empty trailer in much worse road conditions... passing inexperienced winter drivers on the highway. Good grief, Texas drivers on ice are terrible.
Dyno Retune Finds Some Lost Power?
Yesterday the tuning gurus at True Street Motorsports in McKinney, TX made time for us in their busy schedule and we got them the 2011 Mustang for a re-tune and dyno check-up. We have changed the exhaust (added the lighter Magnaflow mufflers and dumps) and needed a re-tune and
NASA Time Trial Dyno Certification Form for this season. We don't plan to make any more changes that would affect power.
Dyno pulls from 3/5/2014. Left is STD correction factor, right is SAE correction factor (which NASA uses)
So in the past ~8 months we had been making from 419 whp to 421 whp and around 402 wtq, right before Nationals and again in a late December dyno test. That's the number we used to get to that 3770 pound TT3 race weight, which we used to ballast up about 45-85 pounds to meet (depending on fuel load and driver). Well this new dyno pull kind of threw a kink in those numbers.
Left: New TT3 classing sheet, page 1. Center: New TT3 classing sheet, page 2. Right: Dyno Certification Form
The 442 whp and 429 wtq STD corrected numbers were a little shocking, until I realized that the SAE numbers were only 432 whp and 419 wtq - SAE numbers are what NASA uses to get to the correct power-to-weight for our TT class. I've included the updated TT1/2/3 classing sheets as well as the dyno certification form. I did the calcs and it looks like the bump in power was only a modest bump up in minimum weight, going from 3770 to 3802 pounds with the new power boost. This was helped by the fact that at 3801+ pounds we get the highest bonus possible from weight, +0.6. The non-OEM aero penalty is -0.4, taking the 9.0:1 base TT3 ratio to 8.8:1. Then if you do the math... 432 whp x 8.8 = 3801.6 pounds, rounded up to 3802. While it might seem backwards how we came up with these numbers (and it is opposite of how the TT sheets have you calculate it), this is
exactly how the NASA TT National Director (Greg G) showed us how to do it at the 2013 NASA Nationals.
I asked Olof to modify the existing weight box bracket to make it a bit more robust ballast, to hold additional weight. I never liked the old one (it was the black 1x2" tubing that bolted in at 2 points/4 bolts), and the new design is a "T" shape with two more mounting bolts + an all new thicker/stronger M14 bolt to secure the weights with. Please don't over-analyze this brace - you can lift the back of the car from that bolt and brace.
We figured the new flares and especially the much wider (and taller rear) tires would add some weight, and boy it did. With nearly a full tank of fuel and me sitting in it (210 pounds, been eatin' good!) with my helmet and the new weight box bracket we're at 3822 pounds sans ballast, so that is overweight now by a solid 20 pounds. And that was
after removing the rear seats today (33 pounds) because it was
way over minimum an hour earlier. Granted it has about 80 pounds of fuel in it, and it can probably go down to 1/2 tank on this course safely, but dang this car is heavy. Those new tires added some
pounds, but a lot of added width - should sill be quicker, I hope? We will see soon enough.
Olof and Kyle did a ride height change in the rear - Shiloh had it "tucking some tire", which looked cool for pictures but it bottomed out on the street a bit much. Then they did a corner balance adjustment to get the cross weights even.
Getting a quick corner balance done on the car after some changes. It was at 48.2/51.8% cross but we got it to 49.9/50.1%
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