hacker-pschorr

In other news, Ford F-250 set a record at Bonneville = 182mph:

http://autos.yahoo.com/news/built-fo...s-182-mph.html

I've always supported racing the tow vehicle while you are there

Carl Fausett

I should clarify... on the 7 mile (long course) at Bonny, the first laser is tripped at 3 miles and then again at 4 miles where it takes your reading, then from 4 miles to 5 miles, then again from 5 miles to 6 miles.

Between 6 miles and 7 you are supposed to get out of it and pull the chute.

Pulling the chute at speeds above 200 MPH can generate up to 8 G's on your straps during decel....

Carl Fausett

I always wanted to see "tow vehicle races" at the road race course during the Saturday lunch break....
the problem comes with how to tow the broken tow vehicle home if you fudge it up.

hacker-pschorr

- So true...

If folklore is to believed, that is how the truck category started in the One Lap Of America. One of the teams broke the "race car" and asked if they could finish the event using their support vehicle (a full sized pick-up IIRC).

Carl Fausett

I think I will miss the black stripe down the site line at Bonny. That single black stripe on the white salt is part of my memory as a kid, and I'm sad to see they dont use it anymore.

It was made by pouring waste oil on the salt in a straight line.... the environmentalists got after that eventually, and it is said there were some racers who objected to the oil on the track (go figure).

Still, I don't know how easy it will be to maintain "straight" without some reference. I can look at the mountain in the distance, but I dont excpect that to be the same. We'll see.

mark kibort

and we sometimes go 145 going into turn 1 at thunderhill! (with a tallwind)

mark kibort

its good that you have got some rake in the car downwards. but remember, the benoulli effect will not do much up front, as that air under the car is mostly ambient pressure. the air toward the rear might be a slightly higher pressure, but all that does is lift up the rear. what you want is to divert the air rearward at an angle to reduce turbulence as it exits . that is a complicated discussion, so lets just say you are fine with what you have done so far. The point is, just because you are low up front, doesnt mean you are getting a lower pressure under the car. generally, its ambient. we are dealing in differential pressures. what you need to look at is what is happening on the hood and the top of the car. we are lucky to have the charts to tell us exactly what is happeing with our 928 shape. the GREAT thing about aerodynamics, is that it scales. so you take models and see what is going to happen, or extrapolate to figure out what will happen. (till near supersonic )
when the speedvision corvette in GT went to the canada wind tunnel. they had splitters, wings, etc. (just like a normal race car) they started with 100lbs of lift in front! why?? because of what im talking about. you cant use intuition here. they also had 200lbs of downforce in the rear due to the huge wing. they left with near 400lbs of downforce in the rear and 100lb of downforce in the front. Now I dont know the speed, but i imagine it was near 100mph based on what ive tested and the size wing they were using.

obviosly, you have the right idea . keep the car real clean. take any wings off and just let the weight of the car do its thing, but also if you can keep the air under the car channeled, as well as divert more air over and to the sides of the car , than under it, it will pay dividends in less lift (or downforce if you want to call it).

have fun, be safe and we are all counting on you!!

as far as the mazda , its pretty obvious he had some wheel spin and wasnt able to correct. im sure its a kind of feel of driving at that speed on that surface. the good news things are happening slow on the acceleration side, so you dont have to hurry to get to speed I would imagine. if you do, its like driving on snow up a hill at 80mph on bald tires and too much of anything will be bad.

Carl Fausett

Photos from today.

The chin splitter and air dam is finished.

In one photo you can also see the ice water spray bar mounted in front of the inter-cooler with fogging nozzles. We are only allowed to use water spray. Nothing else.

IcemanG17

Damm Carl that is VERY nice.....after working all day on my "not so nice" racer....I really appreciate the HOURS and HOURS of work it takes to make something like that!!!

Carl Fausett

Yesterday was a bit of a bear - converting used wheel weights into clean lead and pouring it into the molds. Here are a few pics. The finished belly pan weighs about 750 pounds (right side) and the left side will be about 600 pounds.

Why a difference of only 150 pounds? The driver weighs 200, and scaling the car with driver we know that 150 pounds of that loads on to the left tires, and 50 pounds of that load on to the right-side tires. A delta of 150 pounds.

928mac

I am not sure I understand the need for more weight?

Is there not down force that increases on the car with speed?

Doesn't the splitter by stopping air from getting under the car cause a vacuum.
Think formula 1 where there is enough down force to drive the car upside down.

I don't know Carl, I thought the way your design looked that it was perfect?

I'm sorry if I missed this in a prev post, Can you please explain.
Its good that he has a mask on.

Ispeed

You are going to need some really good attachment for those lead pans.

Iwanna928

Keep up the amazing work!

dprantl

https://rennlist.com/forums/8818403-post212.html

Dan
'91 928GT S/C 475hp/460lb.ft

James Bailey

Going forward many cars are O K but get sideways and the game changes dramaticaly. Was reading a blog by a guy whose family had set 12 or so records had 7 in the very exclusive 200 mph club. He lost a son when the car flew at 230 or so rolled and fiberglass
went everywhere then the exposed cage dug into the salt......this is real serious stuff.
And it is very, very hard to do well on your first attempt. As I recall Carl spun out twice on his best run up Pikes Peak, spin here and the game can be over...
To qualify for the long course one MUST hit 175 MPH at 2 1/4 miles into the short course which is a HUGE task ! Have to give you credit for trying to do it, very few have done so.