200 mph club

[laguna30]

this one time on a flight to band camp......

Sorry wrong club

Carry on

[Gustav129]

The "hp required" formula from Wikipedia is Hp = [(speed in mph) cubed times frontal area in square feet/ 150,000 . The latter # is a constant.
Frontal area on an E28 is, I think, 23.31 sq. ft. This # derived from the car's width * height plus area of the tires.
(200)^3 * 23.31 = 8,000,000 * 23.31.=186,480,000. 186,480,000/150,000 = 1243.20.
1243 hp isn't terribly far off from the number Burke's A5 Audi was turning out.
Keep in mind that this equation doesn't take into account the effect of any streamlining, i.e., a Cd of something less than 1.0.
Said streamlining would reduce the power required, but highly doubtful about coming down into the 570-600 hp level.

Having run Lucifer's Hammer in an over-the-road "what will this thing do" exercise, I saw an indicated 164-and-change mph.
This was not for a few seconds, but sustained for nearly 4 minutes.
Per datalogs, I was was holding a steady 6300 rpm. 3.64 diff, .81 5th gear ratio, tires approx 25.09 in. diameter. Using Bob Tunnell's Excel spreadsheet this yields a calculated 159.5 mph. Send me your email addy and I can forward said spreadsheet.
Said spreadsheet looks at diff ratio, drive ratio for a given gear, stated engine rpm and powered tire diameter. Result is road speed for a stated rpm. It doesn't take Cd into account, nor does it address HP requirements. But it is a very useful tool.
The 6300 rpm redline is dictated by the engine's 95 mm stroke, using the formula redline = 6,000,000/stroke in mm. 6,000,000/95 = 6315 rpm.

Using the Wikipedia formula, (160)^3 * 23.31 = 4,096,000 * 23.3 = 95,477,760. 95,477,4760/150,000 = 636.51 hp. Presumably this is wheel hp.
The car was dug in hard during this run. It would seem that a longer diff would give more top end. Why anyone would want it, I dunno.
There are no trick changes to the body configuration: stock rear spoiler, totally stock Euro front valance and air dam, no side skirts, windshield wipers in place. However, above 135 mph, the car becomes extremely sensitive to crosswinds, the front end especially so.

So from my own limited experience, I would think 200 mph in an E28 falls into the category of being foolhardy. Do all the prudent stuff--full cage, complete suspension rework, proper airdam (think NASCAR Talladega configuration), sideskirts, resized rear spoiler, gut the car to reduce weight--you might get there with enough HP.

Keep in mind that power required goes up as the cube of the speed,as does the dollars involved.

Best post about this so far. There was a good article about land speed racing in Grassroots Motorsports. The owner of DIY Autotune is trying to break 200mph with a 240sx and turbo 2JZ Toyota 6cyl. I've known about the correlation between speed/hp for about 10 years now, but didn't really know the formula. I have put the Bonneville dreams on hold for a while, but the article sparked it again.

Couple things to consider
-The current standing record for the engine displacement class is 207mph.
-You have to earn up levels of racing licenses. 130mph, 150mph, etc.
-140 mph on the street does not equal 140mph on salt. The softer salt really puts a drag on the car. Cookie Cutter tires.
-Aerodynamics reduces over all speed
-Weight is not the enemy of speed, it's the enemy of acceleration. Tonya Harding's 55 Bel Aire has hundreds of pounds of lead ballast in the floorboards. The DIY 240SX is built heavy too (4100lbs)


Upon looking for the build sheet for the 240sx, it looks like they broke 200pmh, and broke the record for F/BGC at Ohio at 210mph. Again, asphalt vs salt.
http://www.diyautotune.com/cars/project ... _240sx.htm