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Unread 01-16-2015, 11:55 AM
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Join Date: Jul 2004
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Default Re: Vorshlag Budget TT Build: Project DANGER ZONE

continued from above

The factory seat mounts are reinforced with extra steel from the factory, but we added more. 1/8" thick steel plate wraps around the stock stuff and was stitch welded to the floor as well as wrapped around up into the tunnel and frame on the sides, where it is bolted or welded for more support. The harness anchors for the lap and anti-sub belts are from G-force. These eyelets allow the clip-in ends from a Cobra/Schroth 6-point Profi-2 harness to attach. These are my favorite harnesses and made by Schorth in Germany to FIA specs. This set has 2" upper shoulder straps to better work with he NecksGen HANS device I will be wearing this weekend.

As usual, any "pretty" pictures you see here were shot by shop manager Brad with his Canon gear. The rest of the pics are from my "potato-cam" Galaxy S4 camera phone or my Nikon D90, which I can't seem to use worth a damn. The shoulder harnesses were wrapped around the harness bar tube with the proper wrap technique as specified in the diagram on page 42 of the NASA CCR.

Last but not least, a 2.5 pound fire extinguisher was added. This is a small "Halotron" (Halon replacement) hand held fire bottle that can be used to put out small electrical, oil or grass fires and doesn't leave a big mess of dry chemical or foam residue behind. We add these things to every track build possible, even when they have a full fire "system" with multiple nozzles. No need to blow a big bottle when all you have is a little grass fire under the car after pulling off track into dry grass. We used the Drake quick release mount here, which we have used a half dozen times. CNC aluminum, roll bar or floor mounting with the same kit, and one pin can be pulled for fast bottle removal but it stays tight and rattle free when racing. Good stuff.

Weight Check!

Now you've seen how crazy I am about dropping weight and weighing everything in this and other build threads. Weight is the enemy! Lowering weight helps all acceleration vectors, be it braking, forward acceleration or lateral acceleration (cornering). We do a LOT to lower the weight on any race car build, and this car has gone from about 3300 pounds stock (we never weighed this car with the interior but that's what my 1994 Corvette weighed) down to about 2720 pounds. This weight drop was from lighter wheels, no interior, no passenger seat no side or rear glass, and no HVAC bits. The air conditioning compressor has been removed as have the headlights. The lighter wheels and tires help, too.

Left: 2841 pounds with fuel but no driver or ballast. Right: 3200 with driver, fuel and ballast

We have added about 60 pounds in the roll bar and about 120 pounds of fuel (its nearly full) and the heavier J55 brakes and it was sitting at 2841 pounds. That's a solid 700 pounds lighter than our TT3 Mustang was without ballast or driver! Sadly we have to weigh 3203 pounds with driver (or else we have to burn points to run lighter), so ballast went back in in the above right picture to get us there. The plexiglass hatch should help remove about 30-35 pounds out of the 46 pound OEM glass, but it might not arrive in time, so we will save that 3rd 45 pound plate for then.

Classing Sheets, Dyno Test and Custom Tune

So we haven't built "letter" class car for NASA TT or PT before, but have helped a number of people class their cars. The base classing + mod points thing is nothing new to us. Just like TT# (numbered) classes, the TTx (letter) classes have an adjusted power to weight ratio. In TT3 the class has a 9:1 ratio but we were able to get ours to 8.8:1 with the adjustments. Likewise, TTC's base 12:0 pounds per horsepower limit has some adjustments as well, namely with a smaller tire...

Using the 245mm tire has had so many benefits and this is just one more - we get a 0.8 ratio bump for this small tire. That might not seem like a lot, but when you are at 3203 pounds it is nearly 20 extra horsepower allowed...
  • 3203 pounds / 12 = 266.9 whp (267 rounded up, in favor of the driver)
  • 3203/11.2 = 285.98 whp (286 rounded up, in favor of the driver)

Which is a good thing, as it was going to be hard to only make 267 whp even with a dead stock engine, manifolds, cats and muffler. We had the car over at True Street Motorsports yesterday and they were able to coax 284 whp and 331 wtq out of this 24 year old, bone stock iron block LT1, through the stock cats, manifolds and exhaust. Not too shabby. It even sounds better after the tune.

Above: Video of the stock LT1 motor at idle and revving, after the dyno test.

We have our dyno plot and classing sheet attached below. As you can see we've started with TTC + 7 penalty points, which left us with 12 points to play with. We got one back for running 245mm tires (-10mm below base class tire) for 13 points total. We burned 10 on the Hoosier R7 and still have 3 points to play with. We will be very stingy how we spend those this season, so stay tuned to see what we invest these points in to make Danger Zone faster.

Left: The SAE corrected dyno plot making 284 whp. Right: TTC classing sheet with points

Last Minute Tweaks and Fluids

The Moroso oil pan for this motor is huge and the motor now holds 8.5 quarts of Mobil 1 synthetic oil (15W50 is my preferred weight for track cars), with a fresh Wix oil filter. Olof went over the car and filled out a NASA tech form but we still need to get a Logbook issued for the car at the event, so the plan is to leave Dallas early and make the 4.5 hour trek to south Houston on Firday and get there before dark. Then I can set-up the trailer, unhook, unload the C4, get the logbook tech and weighing, and make sure we have our ballast set correctly.

I couldn't leave the massive openings in the hood where the pop-up headlights used to be so I asked Olof to make some aluminum brackets to bolt to the inner hood structure and to the existing holes in the headlight covers. Those went on and now forms a fairly seamless clamshell hood surface. The front turn signal and corner light assemblies were also reinstalled to fill holes. We will go back and make flush mounted aluminum covers later, when we have the time.

Brad jumped into the Danger Zone this week as well and did a lot of wiring and some light fab work to the Corvette. He used to race a C4 himself and knows the car all too well. The wired AMB transponder from our TT3 car was moved to the C4 and Brad made some brackets for that, wired it up to a lighted switch (sometimes its handy to turn off the transponder - if we want to make another entry in the same car with the 2nd battery powered transponder we have). He also got the rear brake lights to work, after repairing some cut wires.

He made an aluminum panel to mount the switch in the center dash area as well as the 3-port "power panel" shown above. This was a cheap purchase which arrived in only a few days for $31 shipped. This panel has waterproof covers over a 12 Volt cigarette lighter port, a volt meter and a stack with dual 5 Volt USB ports (one a high amp and the other a low amp draw - see detail image above). Very slick little package that should prove handy when it powers my onboard vidcam and AiM SOLO timer. I will report back with how well this worked, or not.

The formed, lightweight, plexiglass rear hatch we ordered a week and a half ago arrived this morning so there's no time to fit it, so we reinstalled the OEM back glass. Order Desk Manager Jon wrapped the "ugly" mis-matched door with white vinyl. He also designed, cut and mounted graphics for our logos, "DANGER ZONE", Hoosier and Bilstein decals, and some class/number decals for all sides of the car.

Its time to load up so I didn't get the final pics... tune in next week for the post race update to see the final look, or look for it on Facebook with this hashtag #DANGERZONE.

What's Next?

The only thing on my RADAR right now, outside of cutting metal next week on our new CNC machines (tooling is FINALLY here!), is the race this weekend at MSR Houston. I will be paddocked with Costas, Matt White and other friends probably near Turns 16-17.

We are running MSR-H in the Clockwise direction this time (they alternate the direction for NASA events every other year), so I haven't run this track layout since 2013. The video above shows the lap record I managed in the TT3 car 2 years ago, on the skinny 315 tires. The lap record for TTC is currently a 1:50 but I think we might be able to manage a 1:46 if everything manages to stay together on the car...

We have a pretty crazy class lined up: Our 92 Corvette, a 2003 Mini Cooper S (fully race prepped) and a 2005 Mazda RX8 (fully race prepped). Talk about an odd mix... and we will once again be the heaviest yet most powerful car in class, just like we were in TT3. I will post up more details after this weekends race. Until then...

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