Project Update for Sept 17, 2013: Lots to cover in this update - the final pre-Nationals aero prep, paint, new wheels, coverage of NASA Nationals, the trip up and back, and plans for 2014. So much to cover that I'm going to break it up over several days. Otherwise it will be a mega update, then the eyes on the Short Attention Span kids will just glaze over and they will skip ahead just to see the pretty pictures. And believe me, there will be a lot of pretty pictures. Brandon went with us to Miller and shot hundreds of pics of dozens of cars, and Ryan worked on the car and helped me find 6 seconds of improvement over the 4 days we were racing at Miller.
Don't forget that virtually every picture in my forum posts can be clicked for a
larger resolution image. Some of these pics are from my camera phone (GS4), but the ones Brandon took with his high end SLR gear are obvious and worth the effort to see the higher rez versions.
Pre-Nationals Prep
After our ECR test session we had one more week to do work on the car, and that included painting the entire front of the car. As you can imagine it was a nearly round-the-clock thrash to get the car finished, pretty, and loaded into the trailer. Most of this thrash was done by Ryan, Jason, me and Olof, with some help from Ed (who blew out his knee, yet still stopped by to pitch in).
So over the past three years of owning, racing and developing this 2011 Mustang GT we have learned one thing that has held true on every wheel and tire iteration: BIGGER IS BETTER. This big, heavy car has a lot of power and a lot of mass, and each time we went to a wider tire the car got faster, without exception. We have not found any limit to this rule yet, and even 345/35/18 Hoosier A6 tires were still easy to spin at autocross speeds, as seen below.
And while it looks like those 345mm tires fit the Mustang under stock fenders, they DON'T. They rubbed everywhere inboard, like mad, and wouldn't even bolt on the car without major changes to the rear swaybar (Whiteline style), a Watts Link, and more. It would still take a large amount of chassis fab work to make these fit - cutting the fenders and adding big flares would do it. Unfortunately Amy never allowed this, and even in the final months of ownership (more on this below) she is sticking to this limitation. Without flares the widest we can fit under the stock S197 fenders at the front or back is 315mm - anything wider rubs inboard or sticks past the fenders (and rubs under cornering if you run the ride height low enough). 315mm tires are not very big when you are talking about a 3500+ pound car making close to 500 hp. I looked at a lot of ST1/ST2/SIX cars at the recent NASA Nationals and all too many were on 345mm rears.
In my
Sept 20th, 2012 thread update I mentioned that that we were working on solving this tire width limitation by making some bolt-on flares, inspired partly by the AIX Mustang shown above (the flares shown above are not for sale). We had planed on doing this to our 2013 GT, which I bought with the intent of cutting up and building a dedicated ESP classed autocross car. After the SCCA rules SNAFU we changed our plans, so we didn't get to do the chassis cutting needed to develop the S197 rear flares. There aren't any
proper flares out there for this chassis (and yes, we know all about the RTR and Shelby versions, and all the rest); by proper I mean flares that can fit REALLY big tires, with a decent aero signature, and that don't cost $6000+. When we bought some extra front fenders, Amy gave us the green light to cut and flare the front. Which we did a week before Nationals...
What we had in mind was something a bit more modern and sleeker than the "cover the top of the tire" flares shown on the black AIX Mustang. Leaving the leading edge of a spinning tire in the airstream creates lots of drag; for lower drag and better evacuation from the fenderwell/undercar areas you want the back side of the flare OPEN, and even curve the trailing edge of the fender opening in if you can. We took some aero cues from several existing race cars and melded that with a little styling from the hard parking ("rough") crowd's flares and made these.
Now I will be the first to admit that these flares are far from perfect; these are very functional prototypes, with which we learned many lessons. I'd say they are a 6 out of 10 cosmetically, but we will make prettier versions. We have learned a lot and have more yet to learn with thermal formed plastic flares - making the bucks/molds, tweaking our heater, improving our vacuum table, and experimenting with more materials. We made all of our own vacuum forming equipment (which I'm not showing on purpose - sorry) and this is about version 1.2 of the flares. We still have several more iterations and technique improvements in store before we make something worth selling. And honestly, most people will want the "more looks/less aero" version with a little more styling (something more akin to
this), which we plan to do. And we will make the rear flares, just not going to cut on this car's chassis due to Amy's restrictions on her car. Someone will bring us an S197 we can cut on a little, and we will make the rears around a 345mm wide tire at that time. The fronts clear 335mm wide tires.
The honking oil catch can system
The oil catch can and hoses were upgraded from the old JLT kit we had added (then heavily modified). I talked about this before the ECR test, but in short the new system has a larger catch can (from Moroso) and mounts to the firewall. We
thought we routed it the same way as the Boss 302-S race cars, but not quite. Instead of the JLT system that was pulling from just one cylinder head, we pulled air from both, with the lines T-'d together on the right side of the catch can. On the left of the can is a line that pulls from a vacuum source in the intake manifold. So theoretically the engine vacuum from the intake manifold pulls through the catch can, and grabs oil/vapor/air from the top of the motor from both valve covers, and the oil separates out into droplets inside the metal mesh filter inside the can. Once it falls out of suspension it pools in the bottom of the catch can, which can be drained between race weekends. In theory only
air goes back into the intake manifold, not "oily air". Burning oil can cause detonation, of course.
So we showed a version of this system before the ECR test and the heater hose we used there was collapsing badly under deceleration/high vacuum - so much so that it made this loud "honking" noise that sounded like a dying goose (see video linked above), even at idle. Pinching off the vacuum source made the noise go away. So we replaced the heater hoses used at the ECR test with suction rated hoses. And it still collapsed on one side. Bruce from Ford Racing looked at the routing and immediately saw the issue - we sill have the
PCV valve in the passenger side valve cover. Duh. So that valve closes under load, which puts that hose under extreme vacuum on that side. The fix is to get a driver's side valve for both sides - which deletes the PCV valve, suitable for a race car. We will try this before the next event (NASA @ TWS) and see how it does.
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