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A set of donor fenders (Thanks to 928 International) were chopped up to harvest just the section I needed for front fender skirts. Each is chamfered on their leading and trailing edges. Then I moved them down from their original mounting location to skirt as much of the opening as I can. Our front tires are only 23" tall...
These are my engine and power steering coolers. They are going to take a beating with the front tire throwing salt at them! So I fashioned a louvered cover to protect them both.
I'm still looking for extra hands at the race! I pay for your pit pass, and I buy lunch. If you cannot come for the whole of Speed Week (not many can) just come for a day! I figure to be there August 10th to the 12th, and possibly longer if the weather does not cooperate.
It's a blast, and Bonneville is like no place you have ever been. The cars are amazing. And we could use the help on any day you can make it. You don't need to be a mechanic, just a willing gopher.
Its just 9.5 hours from LA, 7.5 hours from Sacramento, 9 hours from Denver.
Will do. I did pick up a crewman just in the last hour, but Its always good to have a 928'r drop by. All are welcome! Come and visit, help, or just watch!
Good luck Carl ! i hope you get your goal … amazing preparation ...chapeau !
PS don't forget the triple plate Tilton clutch is really a on-off system... i used it on my rally BMW and it ( compete new ! ) hold for 2 rallies… you may not play with it as with a common clutch. I know storys of one playing with it to drive his car on a trailer was enough to destroy it …. Here they say , the more violent you use it , the longer it last ….ON or OFF as quick as you can ….
So far, so good. I've driven it only a little, on to the dyno and off... down the street a bit... haven't found it hard to modulate so far, even in reverse. We'll see.
Air dam work. The shape of the 928 "Shark" nose is great for creating a high pressure area right in front of the radiator, and works well. Unfortunately, it also generates too much front lift and drag for me at this event. In the wind tunnel in 2012 we experimented with different nose treatments to lower our Cd, and wouldn't you know it, the complete air dam ala NASCAR provided far-and-away the best numbers. Those NASCAR boys do it for a reason!
We make ours out of polypropylene, the stuff they use to make yogurt cups. Tough, cheap, inert, and very stable. Handles heat well too. Here are some pics of the process.
The shape of the shark's nose can create lift and drag at very high speeds. Its great for driving air into the radiator at lower speeds, though. We learned at the wind tunnel that a NASCAR-style front air dam was the very best at reducing drag Even with a hole cut in it, I continued to function better than anything else. Test-fitting the air dam It must conform to the profile of the car very carefully for maximum effectiveness Then just for fun, we gave Meg her teeth.
Last edited by Carl Fausett; 08-02-2019 at 11:35 AM.
Yes, we are emulating a P-40, but then again, the 928 is "the shark" and we are emulating that, too.
Does that leave enough air for cooling?
Karl - with all my access to fine engineering minds - you'd be surprised how difficult that question is to answer. Apparently air flow through a 1/8" barrier at 200 MPH is a tough one because it is not a tube. Harder yet is: how much heat does 1,100 HP generate? How efficient is the radiator? How much air flow do you need for that radiator? How much air flow do you need for the intercooler? How much air flow do you need for the ENGINE to make HP? In 2012, I did a run with three 3" holes in the air dam and it was not enough. I carried a 3" hole saw with me, and back in the pits I added a fourth 3" hole in the air dam. No difference. This time I am starting with three commingled 4.5" holes - and if my temps are too high, I am carrying a 4" hole saw with me and we will punch more in.
Every hole adds drag, but then, I don't want to overheat and harm this terrific motor either.
Here is a picture from 2013 and 2014 - we never got to run those years because of rain and flooding. But we were there. In those two years I was ready to run radiator-less. I had 40 gallons of water on board under 20 psi of pressure not including what was in the motor, and we hoped that it'd be enough for 90 seconds of full throttle before the system became heat-soaked. For the intercooler, we packed it in ice in a cooler. The only air that we needed, then, was for the air intake of the motor. Put a turbo bellmouth in place for that. This is what it looked like below. Again, this iteration never got to race.
Big day - the car is finished, she's as ready as she can be. So happy to load it into the trailer! Now we are packing, and we leave tomorrow for Bonneville.
With the belly pans 1.5 inches off the ground, we install OEM tires and wheels on the front to get the nose up a bit, and I raise the rear suspension as much as I can too. Even with that, it takes careful planking to get the Meg loaded into the trailer.
07-29-2019, 01:23 PM
