continued from above
After our 4 dismal runs per side Saturday were over, I put the car on jack stands and yanked off the rear wheels and brakes. The pads looked... weird. Discoloration and weird build-up of material in the grove in the pad, especially strange for a
brand new set of pads. The rear pad swap was the one main variable that changed, so I wanted to change back to a more normal street pad out back, hoping it would get the ABS computer out of the Ice Mode tendencies under heavy braking. So I took the pads to a local O'Reily's parts store in town hoping to match up with a set of pads they had in stock. The 2011 was too new for their catalog but they had 2009 Mustang GT listings, and we found a match for pad shape. ThermoQuiet house brand Ceramic/metallic pads, which AJ has used on a dozen cars with no ill-effects, so I gave them a try. I wanted less braking power out back, not more.
I got back to the event site and realized I needed a caliper piston retractor tool and a caliper compression clamp, so back to town I went. By the time I had all of the right tools and the rear pads swapped it was getting dark, so I drove out to a nearby highway and tried to bed the pads in, after many stops. The stopping power was still very diminished, and easily getting into the "ABS freak out mode". WTF? I came back to the site and pulled the pads back off for a look - they weren't bedding in well. Then I took the G-Tech data logger and went out and did some 60-0 mph braking tests, with what looked like poor results (157 feet??). Then I took Paul M's STU-classed and Brembo equipped 2011 GT (stock pads/rotors on 275mm Dunlops), and it was stopping just as poorly. I did some 0-60 mph test in both cars as well, pulling a 4.5 sec time and .65g in 1st gear in my car and 5.3 second run and .58 g in his car. So they were closely matched, even with his car's 3.73 vs my car's 3.31 gearing. By then it was pitch black out, I ate some of the food at the party we sponsored and drank some beer, then we hit the hotel for some shut-eye. Tried to stay awake and watch F1, but my eyes wouldn't have it.
Since I was Impound Chief for the event, on Saturday I managed to get the Mustang on the scales... haven't weighed it in a while. Showed 3479 lbs with 1/8th tank of fuel in the car. Much better than before but still a solid 55% on the front tires.
Sunday's driving was more of the same frustration, even with the new rear pads - no heavy braking possible or it went into Ice Mode. On this day the ambient temps went from sunny and high-70s/low-80s from Friday and Saturday to overcast, mid 40s, with a BRUTAL wind all day. Most racers brought clothes and shorts for Spring weather but were under-dressed for this late winter cold front. A few racers still picked up some time in the last 2 runs per side, but Costas and I only got a tick faster each. Amy was slow in her class as well. At least she and Costas BOTH cut one perfect .500 reaction time each (I was cutting consistent crap lights). Costas and I were 2.6 and 2.9 seconds off the class winners for both sides, ending up in 5-6th out of 11 according to the results on site, but the posted results show a driver ahead of us that DQ'd himself for driving the course during set-up. No matter - the results still stunk, and we were slow.
We couldn't ever get a complete, good run in without hitting Ice Mode or fighting lots of mid-corner understeer. Tire pressures and shock changes were not enough to counter this massive push, and the wheelspin on corner exit was again ridiculous. Did we simply have too much power and weight for a 265mm street tire? Is all hope lost?
Help me Obi-Wan Kenobi!
I think not. We keep seeing bad tendencies in the data and the close-up pictures of the tires. I think we've been in the completely wrong ballpark on tire pressures, the rear spring rates need to drop, and the brakes need more attention. We've probably run into some pad compound cross-contamination issues with the rotors, so we've ordered a whole new set of rotors and another set of autocross pads (Hawk HP+). We'll cut the existing rotors and re-bed them with the DTC-60 track pads and swap between the matched sets of pads and rotors from autocross to track events - these pads have VERY different cold bite characteristics, as well as different coef of friction, dusting & noise parameters.
We're also awaiting our initial stocking order from Energy Suspension bushings, with some much needed polyurethane bushings for the Mustang being made to order. The OEM front LCA bushings are the softest I've ever felt on an OEM suspension, and as big around as your fist. Soft - like a Nerf football soft. That bushing is deflecting under load and losing lots of camber in corner, and the rear control arms and panhard bar are just as soft, causing who-knows-what out back. We've also noted a side-offset of the entire axle, also due to the panhard bar's fixed length and lowering of the back. We need to start developing a Watts Link for the car. We also still have the stock, non-adjustable swaybars, so we're getting a set of Eibach adjustable/tubular front swaybar set coming ASAP (the 2011 has been "in development" for far too long and I'm tired of waiting). AST is also working with us on this new rear shock and the front strut is getting a revalve as well - we'll get this thing to carve cones, by damn!
We've tested several more wheels in the past week, including an 18x10.5" Enkei with a 285/30/18 Hoosier mounted, which is more appropriate for NASA TT use. But the 285/30 is too short, so we're looking at the 275/35/18 and a Pirelli 305 race tire as well. Another set of 18x9" wheels is on order to help test the many 265mm tires needed for STX autocross use back-to-back; so many choices available, and we need to test most of them. And power never hurts on track, so the headers + custom exhaust bends are going to be ordered soon, and the Steeda cold air + SCT Tuner is already en route.
The E30 isn't forgotten, either. We've ordered a 2nd aluminum seat and two I/O port seat back braces for this thing, as well as another 6-point harness. We need to adjust the rear control arm mounts for adjustable toe and camber and get that sorted. The wiring issues are also being addressed now. And of course we need to find a transmission that can last more than 2 events (we've broken 2 transmissions in 3 events). We have some home-brew aero tricks up our sleeves as well, mostly for on-track improvement. And the ride heights and fender openings will again be lowered/trimmed further, until they are right. We also need to design and build a low-buck adjustable rear swaybar - from scrap metal and used parts (ugh).
Somewhere in this crazy month of March our lead tech AJ managed to replace the tie rods on the E36 M3, align it, pull the transmission, install the shifter/spring kits, a new clutch/pressure plate/TOB, reinstall the trans, fix the shifter, and tidy up a number of things in the process. The car drives like a DREAM now, and is ready for sale finally. More on that in its own thread soon.
Meanwhile I'm going to take a weekend off in April - this weekend - well, one day at least. Already burned out and the season has just begun. There's a Lemons race at ECR I'm driving in (hopefully not crashing in! I've been at the gym for 2 months trying to get ready) and a NASA track event plus 2 or 3 autocrosses, and a test day at the track scheduled. We're trying to set-up a mid-week autocross test day with the AST-USA folks as well. Lots to do.
More soon,