Top speed vs Coefficient of drag

[carbonBLUE]

Ok in my celica gts i have a few bolt ons and im putting down about 175-185 whp and about 120 wtq ive gotten up to about 150 mph and im pretty close to sea level.

I was wondering, if my celica can do 150 with a coefficient of drag of .32, what top speed do you think the ft 86 could achieve with a coefficient of drag of .27 and more hp and more torque???

sorry if this is a post in the wrong section :/ move me if needed

[Sea1monkey2]

my guess, with no research done, no references looked up, and only going by basic ratios and a couple of other (probably wrong) car speed ratios says it should top about 163mph

[carbonBLUE]

believable especially with a long enough stretch and bolt ons.... just curious i want to hit the texas mile on this thing and see how fast itll go in a mile it may be a suitable drag car with a turbo considering how well it slips through the air at higher speeds

[old greg]

Originally Posted by carbonBLUE

I was wondering, if my celica can do 150 with a coefficient of drag of .32, what top speed do you think the ft 86 could achieve with a coefficient of drag of .27 and more hp and more torque???

Since both have approximately the same frontal area, if we assmue that sixth gear isn't ludicrously short/tall, I'd estimate the top speed at..

150*((.32/.27)*(~170/~180))^(1/3) = 156 mph

The FRS will have a little less power stock than you Celica has now. At the same power level, you might expect 158.

[fatoni]

that information is not really even close enough to make an estimate on the subject. my ls430 has a lot more power and a lower drag coeffecient but i doubt it will go much faster than 130 mph

[Ryuu0u]

Originally Posted by carbonBLUE

believable especially with a long enough stretch and bolt ons.... just curious i want to hit the texas mile on this thing and see how fast itll go in a mile it may be a suitable drag car with a turbo considering how well it slips through the air at higher speeds

Lol I hate seeing miatas and s2ks just set up for drag racing. Just my opinion but i think the strip is out of their element. I guess the mile would be fun just to stretch the cars legs. Probably would hit up one of the road courses in houston when i get used to the car.

[old greg]

Originally Posted by fatoni

that information is not really even close enough to make an estimate on the subject. my ls430 has a lot more power and a lower drag coeffecient but i doubt it will go much faster than 130 mph

Of course it wouldn't, it's electronically limited to 131.

[fatoni]

Originally Posted by old greg

Of course it wouldn't, it's electronically limited to 131.

well that was a pretty lucky guess on my part. the point is that i think more important factors are being left out of this scenario partially because of the newfound hype over the cd. i dont think that number is really important and when you hear companies bragging about things that arent really that important it makes me wonder if the car has substance. i hope they have a wonderful car and are just looking for things to combat the communities desire for more hp and stuff.

its just funny to see people getting excited about a cars sportiness based on this number since on one end of the spectrum you h ave f1 cars with cds that get up above 1 and on the other end you have the frs chasing the insight and prius

[serialk11r]

If you take the wings off an F1 car the frontal area is TINY. The wings have crazy AoAs and are huge, so they contribute basically all the aerodynamic drag. Can't compare a car with no body to a street car...

Not to mention they have like 700hp to use.

[fatoni]

Originally Posted by serialk11r

If you take the wings off an F1 car the frontal area is TINY. The wings have crazy AoAs and are huge, so they contribute basically all the aerodynamic drag. Can't compare a car with no body to a street car...

Not to mention they have like 700hp to use.

why cant i? they both have to obey the laws of physics. horsepower and size dont affect the cd and while i understand that open wheels and huge wings dont help it has to make you question the importance of the number, thats all

[carbonBLUE]

Originally Posted by serialk11r

If you take the wings off an F1 car the frontal area is TINY. The wings have crazy AoAs and are huge, so they contribute basically all the aerodynamic drag. Can't compare a car with no body to a street car...

Not to mention they have like 700hp to use.

which also brings up another question, with a .27 drag ratio i wonder what the down force numbers look like, at the track this would be useful info considering high speed cornering...

[Sully]

Downforce is also drag. You can get lots of downforce(F1), or a low C/D. Not both.

[old greg]

Originally Posted by serialk11r

The wings have crazy AoAs and are huge

Nah, they're adorable little things.


I give you A-mod. 240hp and a drag limited top speed of ~70 mph

Originally Posted by Sully

Downforce is also drag. You can get lots of downforce(F1), or a low C/D. Not both.

Ahem.

[serialk11r]

Even without fans creating a vacuum under the car you can do pretty well. The sides of the car should be completely sealed off (is almost possible with nylon brushes lol), splitter in the front as close to the ground as possible, underbody of the car slowly sloping up towards the top edge of the car, which meets the bottom of the car at as close to parallel to the ground as possible. Putting channels into the bottom of the car like Lotus is a way to mimic this although it's best to have no air escaping in through the sides. Basically have the car shaped like an enormous upside down wing.

Sealing off the bottom completely with nylon brushes and then using fans is something I want to try someday