that was you ,did you see my new shifter boot

 

Carl, I tried a few years back, to calculate my Cd.
Did a bunch of coast down tests, and recorded acceleration data points (deceleration data I guess), with my old Vericom VC-2000.
It was hard to get consistent data (on the street) but here is one of the old plots.
Red line was theoretical RWHP with .34 CD, blue line in a Polynomial trendline from my data points.
If it's at all real, you would have to conclude my CD was worse than stock.

 

Didnt catch it, I was in reverse at the time. .

 

interesting findings.

Have you though about running with just the groud effects?

Callaway has some claims for thier body kit as well. I think it was add 7 mph to top speed. with a nose that has so many holes I find that hard to believe.

can you do whatever you want with this car out there (rules)?
If so I would just build my own stuff for it.

something to block the air from getting under the car. A smooth bottom. a smooth rear exit, and a set of side rails for ground effects to keep the air under the car, the only air under the car.

something I noticed on the sledgehammer, it had a piece of plexi wver the recesed tail lights. to keep the rear of the car smooth.

did you tape the car up over every seem?

 

well 2 things - #1 - wrong top down dude!
and #2 - dual factory airbags? man thats some crash protection!

 

looks about right - I think stock Cd is about .31

 

omg i lmao, im still lmao lolololololo

 

Claims? I guess a body kit that enables a car to do 254 mph just isn't stable in the aerodynamic dept. That is probably the only body kit made that spent some time in the wind tunnel.

 

lololololololo ,omg you guys are killing me ,he was in reverse lolololololololololololo

 

And if I may finish your sentance, doesn't look like azz

 

So 145mph means you were putting out around 180RWHP....

RWHP requirement does go up quickly.....320 RWHP to reach 180mph and 440RWHP to reach 200mph!!!!

 

I am sure many kits saw wind tunnel action, at about 1/24th scale. Most preliminary aerodynamic testing is done using dimensionally accurate scale models in small ,image 2 feet by 2 feet or smaller cross section of test area, windtunnels.

 

I litterly just spit food out on the the screen from laughing.. thanks!

 

I was not questioning the stability.
it claimed a gain of 7 mph top speed.

how can a nose full of holes add speed?

the sledge? A whole different beast in air managment. Also had some duct tape on the nose holes to close them down. also vented air out the hood through ducts

some things I have read about it getting to that speed, I dont think it ever seen a wind tunnel. they were making aero changes at the track because of how water was comming back out of the nose. a wind tunnel would of picked that up right? maybe they were going too fast?
how fast are wind tunnels anyhow?

I bet it would of gone faster if they taped up the whole nose.

 

They taped the nose b/c it was said air did funny things at that speed. Dirt marks on the bumper indicated that the air had started flowing out instead of in. The motor was being starved for air.

 

air cooling?
or turbo intake air?

 

intake air.

 

For people that also like sportbikes, some years ago Honda launched the CBR900 a very fast and nervous bike.
One thing that caught your eye was the fact that the fairing had a lot of holes in it. There was some questioning on why they did it and finally Honda gave the response.

The little holes act the same way as the little holes in a golf ball, this enables the wind to produce very little separation from the surface, and less drag, and that helped achieve more terminal speed but more important more stability.

I have never rode in one of those bikes and do not know if this can be felt, but I understand that a golf ball can travel very fast and aerodynamics have to do with this.

By the way , how much HP does a C4 need to have to get to 200MPH at sea level?
How much would it need to achive that same speed at about 2200 meters above sea level?

 

More downforce does not necessarily mean more drag. If a body kit can prevent air from going under the car, it will be more aerodynamic, and generate less lift.


Anyone using coastdown data to determine Cd has to factor in rolling resistance, (tire and drivetrain friction). And the curve must be forced through the 0,0 point or it won't make any sense.


Added weight will not effect top speed.

 

Yup - thats about right - remember at El Mirage we only have 1.3 miles - we were still gaining speed when we had to shut it down. At Bonneville we are confident we would get over 150 - probably close to 160 in the 3 mile run. remember this is a stock 88 engine with 102K miles on it!

Before next Month we will put a stealth ram on it - and do some panning around the rear bottom of the car - we want to hit 150 at El Mirage - and 165 at Bonneville wiuth that setup. After that - comes the bigblock!

As for CC's comment about the Calloway Kit allowing a vette to go 254 - maybe so - but it is not nessisary . A stock bodied C-4 has gone 268 out at Bonneville. The only change allowed is an airbox on the hood - everything else has to be stock (you can take off the mirrors!)

so I don't think the Calloway kit had a whole lot to do with the 254 - I suspect a good engine may have had alot to do with that speed! I'm not saying it didn't help - I don't know that - but cars go that fast and faster without the aid of a Calloway kit!

CC - I'm not sure about your more downforce does not nessisarily mean more drag - i guess you are assuming that the downforce will lower the car to reduce frontal area - and "underflow". If you look at it that way - I guess I can buy it - but putting more downforce on a car does nessisarily increase drag - the question is does the downforce have a physical effect on the car enough to reduce drag in other ways! In other words does the changes in attitude result in enough reduction of drag to cancel out the increased drag from the increased downforce!

Carl