17 replies to this topic

[Minigman]

Will a car stop accelerating once max bhp has been achieved?

[Steve220]

No, max BHP is just that, it's maximum. As long as you have the torque to overcome friction (both mechanical and wind drag), the car will continue to accelerate until it comes to its vmax where power is equal to drag.

[Minigman]

I wonder how VMax is calculated on a mini. Probably well beyond my A-level maths of yesteryear.

I know the project 64 car made low 300bhp to achieve 146mph. How much bhp would be required to make 120mph?

[DeadSquare]

I wonder how VMax is calculated on a mini. Probably well beyond my A-level maths of yesteryear.

I know the project 64 car made low 300bhp to achieve 146mph. How much bhp would be required to make 120mph?

 

That depends on the gradient and wind direction.

[Steve220]

I wonder how VMax is calculated on a mini. Probably well beyond my A-level maths of yesteryear.

I know the project 64 car made low 300bhp to achieve 146mph. How much bhp would be required to make 120mph?

There are so many factors! Torque, BHP, wheel size, rolling resistance coefficient, weight, chassis drag coefficient, gear ratios, final drive ratio, mechanical drag factors.

[smurfomatic]

Using a formula found online here: https://metinmediama...bugatti-veyron/ (this site has examples of a Mercedes C180 and Bugatti Veyron)

 

Power (in Watts) = 1/2 * coefficient of drag * air density * frontal area (m^2) * velocity (metres per second)^3

 

Air density is 1.25 at sea level, and according to this thread http://www.theminifo...icient-of-drag/ coefficient of drag is 0.48 to 0.53, frontal area is 1.533 m^2. 120mph = 53.65 m/s.

 

Therefore, power = 1/2 * 0.5 * 1.25 * 1.533 * 53.65^3 = 73.98kW = 99.2HP.

 

Would a 100BHP Mini make 120mph?

[nicklouse]

your gear ratios will also effect things mine will only just go over 100mph with current set up.

[Minigman]

1293 Miglias with 140bhp do 125mph on a 3.9fd at 8000rpm.

Just wondering how much faster they’d go on 2.76.

‘Some’ say they’d go much faster but I’m not convinced.

I think you need a lot more power to get above that.

Edited by Minigman, 04 September 2018 - 07:46 PM.

[nicklouse]

1293 Miglias with 140bhp do 125mph on a 3.9fd at 8000rpm.

Just wondering how much faster they’d go on 2.76.

‘Some’ say they’d go much faster but I’m not convinced.

I think you need a lot more power to get above that.

they dont go that fast at 8k 3.9 more like 115mph

[Turbo Phil]

Nor do they have 140hp.

 

Phil.

[Minigman]

I wonder why mini7 publish this info?

[dotmatrix]

Would a 100BHP Mini make 120mph?

my k-series metro with 106bhp did 120mhp so providing the various drags is comparable the answer is yes almost.

[dotmatrix]

Nor do they have 140hp.
 
Phil.

from the same dyno I use with my cars I have seen outputs from other cars of 135 and 137 bhp on a 1293 5-port swiftune engine, so close to 140bhp at the crank is achievable. although I dont know how their appendix k setup compares to the miglia setup.

[A-Cell]

Would a 100BHP Mini make 120mph?

my k-series metro with 106bhp did 120mhp so providing the various drags is comparable the answer is yes almost.

The Metro drag coefficient was 0.4 versus round nose mini 0.51 and clubman 0.53.
Airflow over body shape has a big effect on the drag.
The HLE Metro (marketed as the economy version) had no rear mud flaps fitted to achieve the best economy as well as rear strakes and a higher final drive.
The external seams on the mini have large adverse affect as would wheel arch extensions...

[DeadSquare]

 

 

Would a 100BHP Mini make 120mph?

my k-series metro with 106bhp did 120mhp so providing the various drags is comparable the answer is yes almost.

The Metro drag coefficient was 0.4 versus round nose mini 0.51 and clubman 0.53.
Airflow over body shape has a big effect on the drag.

 

 

The external seams on the mini have large adverse affect as would wheel arch extensions...

 

People used to go to a lot of trouble to "De-seam" a Mini.

 

I used to flatten the seam backwards with a hammer.