Project Update for April 27, 2012 - Part 1: A lot has happened in the past week and a half so this might be a long-ish update. I will break it into two parts - ESP preparation work from a week ago to get the Mustang ready for the ProSolo last weekend. Part 2 will cover the ProSolo results and a list of new issues that cropped up. I posted some of these pictures below on the Vorshlag Facebook page over a week ago - I put previews of upcoming thread/blog posts on FB first, so follow us there!
ESP Rear Spoiler
In my last "quick update" from 4/13/12, I showed a picture of some rear spoiler bracket and element parts we got from a circle track supplier, as well as some machined washers and struts. We didn't use that bracket or the spoiler elements - they were too tall for use on the Mustang trunk. The manufacturer's website didn't have any dimensions so we took a gamble and it didn't pan out. Oh well, the rear support struts and the machined washers were useful. Instead, we made an all new rear spoiler from scratch using some 1/4" thick plexiglass we bought locally and some aluminum sheet we had at the shop. If you haven't been following along, SCCA Street Prepared rules come from pre-historic times and still do not allow a rear wing, only a rear spoiler. It can be as wide as the widest part of the car (excluding side mirrors) and can extend 10" away from the body in any direction.
This spoiler was built to fit a spare red Mustang trunk we located a couple of weeks ago - one we weren't afraid to drill into for the ESP-legal rear spoiler or for the upcoming TTS/AI legal rear wing. The trunk was set up on a bench at the same angle as it sits on the car, so it could be built while it was off the car. Some of the scrap aluminum we had at the time was anodized, which made it a royal b!tch and a half to weld to, so it wasn't the artwork-like welds you typically see coming out of our fab shop. No worries - it was strong, worked great at the ProSolo, and was built to an insane deadline in only a day and a half. It looks pretty good for a prototype made out of scrap, but the next one we make will use some virgin aluminum.
The spoiler bracket bolts to the trunk using four "nutserts" installed into the trunk metal with a special rivet gun. The four points are shown above, where the black lower strut supports are placed. This aluminum spoiler bracket extends past the trunk and covers the width of the rear of the car, to about the edge of the sheetmetal. It could be another 4" wider per side (to extend out to the rear fender lips), but we felt this was wide enough to make plenty of rear downforce to match the Leguna Seca front splitter. The lower sections where it overhangs the rear fenders was later trimmed out so it wouldn't rub the paint and some Xpel paint protection film was added to the fenders "just in case".
Once Ryan had the bracket laid out and tacked up, he and the guys made a cardboard template for the spoiler element itself. It is 10" tall and laid back at about a 65° angle. The next step was transferring the template to the plexiglass sheet and carefully cutting that out. There's a trick to cutting plastic with a saw - too fast and it melts back together behind the blade, too slow and it won't cut cleanly. My cheap "one speed" jigsaw (he had to pulse it on-off-on-off) was a nightmare to work with and it eventually burned up the motor after about 40" of cutting. A trip to Lowe's produced a variable speed Bosch jigsaw that worked like a charm and cut the 1/4" plexiglass sheet like butter. Drilling holes in plastic also takes ... patience. They managed to get everything cut and drilled without cracking the plexiglass. The machined washers are placed on both sides of all bolted joints in the plexi and held up after a weekend of ~30 autocross runs.
The plexiglass spoiler element was simply bolted in place - it was flexible enough that it did not need to be heated and bent to follow the curvature of the trunk or the two "bends" at the edges, where it meets the rear fenders. The struts hold the element well enough, but we might go back and mount two tension rods to the widest points of the spoiler, with the rods attaching at the forward edge of the trunk. A little testing (and video aimed at the spoiler at speed) will tell us if that is needed.
The rear spoiler was finished up minutes before the car was loaded into the trailer Thursday night and it definitely got a lot of looks at the ProSolo. This was the first time we'd made a rear spoiler here at Vorshlag and we learned a lot. The guys were very careful during mock-up and construction (lots of painters tape used!), there were only 4 holes drilled for this part and not a single scratch was added elsewhere in the paint. Good stuff.
more below...