81 replies to this topic

[Vinay-RS]

A Mk.1 Cooper 'S' 1275 won't do 100 mph on the level in still air and that has 75 bhp. Around 96 mph was the road-test figure when the car was first released in 1964.

A 998 Cooper with 55 bhp will do just about 88 mph. An 850 with 34 bhp will top out at about 73 mph.

To reach 100 mph a Mini needs about 83 bhp.

Of course, the gearing will have an impact and the top speeds assume that the car is geared to be pulling its max speed at the revs at which max power is produced, so a higher geared car may be slower in top than a lower geared one pulling high revs.

 

Cooperman, at what point does the poor C_d of the mini design take over and nullify any addition of horsepower in terms of top speed?

[Ethel]

The Mini isn't that bad. Yes, the CD is a bit higher, it's a 4 seater that's just 10ft long and making a slippier shape is less productive than minimising the frontal area. Compare the top speed of 75hp Min with a modern hatch of the same power.

 

Minis become sluggish as the speed goes up because the performance (acceleration) advantage of low weight (more properly mass) becomes less significant as more of the power is used to overcome drag.

[Vinay-RS]

The citroen c1/toyota aygo/peugeot 107 has a 1l 3 cylinder engine and produces 67hp and has a top speed of 98mph (according to wikipedia, which we all know is always accurate ;) )

[Tommyboy12]

The citroen c1/toyota aygo/peugeot 107 has a 1l 3 cylinder engine and produces 67hp and has a top speed of 98mph (according to wikipedia, which we all know is always accurate ;) )

 

But that platform was developed with a wind tunnel and with drag coefficient in mind. You can make a very low amount of HP do a lot of MPH if you get your drag low enough.

[Ethel]

Having less frontal area to multiply by the drag coefficient is even more effective. Wind tunnels and CAD can reduce the losses, but they're still losses.

 

Like I said, Minis have a sizeable weight advantage. It's not that they're aerodynamic disasters (especially if you remember CD is meaningless without  body dimensions to apply it to), it's more like the lardy, but more powerful, competition the Mini left on the line has caught up.

[Jedi Master]

http://www.wallacera...P For Speed.php
 
not that far fetched really, a stock 1100 (provided it puts out all 55 hp it was claimed to have) will be just shy of doing 100mph.

A Mk.1 Cooper 'S' 1275 won't do 100 mph on the level in still air and that has 75 bhp. Around 96 mph was the road-test figure when the car was first released in 1964.
A 998 Cooper with 55 bhp will do just about 88 mph. An 850 with 34 bhp will top out at about 73 mph.
To reach 100 mph a Mini needs about 83 bhp.
Of course, the gearing will have an impact and the top speeds assume that the car is geared to be pulling its max speed at the revs at which max power is produced, so a higher geared car may be slower in top than a lower geared one pulling high revs.

My 998 (non cooper but mildly modified) has 55 bhp according to the Minisport dyno. It pulls very easily to 70-75, even when running uphill on the motorway. The piper 255 cam adds torque, which is probably why it will do this. It has done 80 but it does then feel close to max. I think it would do 85, but it would be flat out and on the Rev limit I think.

[mikep12]

What everyone is forgetting is that there are two top speeds for a mini,the first is what it will do with your teeth rattling and the over optimistic speedo showing and the second is what this speed becomes down the pub or on the forum.
A true 100 mph in a mini would really be squeeky cheeks time!

[mini_mad69]

What everyone is forgetting is that there are two top speeds for a mini,the first is what it will do with your teeth rattling and the over optimistic speedo showing and the second is what this speed becomes down the pub or on the forum.
A true 100 mph in a mini would really be squeeky cheeks time!

Mine does a touch over 100mph, and i can verify that a mini does not like it!!


My good condition 998 would scream to get to 90mph indicated on the speedo. Which was closer to 85 in reality,
This topic comes up regularly and weirdly its always people with 998s claiming the top speeds.

[BronkoMini]

In my 998 while it was on the road, I could max out the speedo, whilst not hitting the Rev limiter, and it would keep pulling, however I fitted 10s without changing the spedo so it would say it was faster than it was, but from a guess I recon it probably went faster than 90, ;), just to point out it wasn't standard.

[1984mini25]

A true 100 mph in a mini would really be squeeky cheeks time!

 

Forget 100mph being squeaky bum cheeks time, 120mph + and its clean underwear time. I had a go in a front engine R1 powered mini a few years back and it's safe to say anything over 100mph is fast enough for a mini, although how it gets there is more important than flat out top end imo.

 

https://youtu.be/a88QqfM90_Y

[Cooperman]

A classic Mini can be safely revved to 6000 rpm or just over. If the engine produces maximum power at, say, 5800 rpm, those are the revs at which maximum speed should be achieved. Thus it needs to be geared to achieve this.

If geared too high, say a 998 with a 2.9:1 FDR, it may actually be faster flat out in 3rd rather than in top.

Changing from, say, 12" wheels to 10" won't make any significant difference because the rolling radius of the 12" with the lower profile tyres will give approximately the same rolling radius, certainly no more than about 3% difference.#

The higher the revs at which max power is produced, the lower the FDR needs to be.

There are so many variables in this maximum speed business that it is not easy to explain them all, but the key thing is gearing. The 998 Cooper gave its maximum speed from 55 bhp which was produced at around 5800 rpm and with a 3.76:1 FDR that gave about 88 mph at those revs.

The Cooper 'S' 1275 with 75 bhp had a 3.44:1 FDR and gave about 96 mph at the same sort of revs, i.e. 5800. So the additional 20 bhp only gave an additional 8 mph due to the drag increasing as the square of the speed. So double the speed = 4 x the drag. There is no answer to this and those who claim silly maximum speeds don't understand that their cars are governed by the laws of physics.

So to achieve 100 mph requires approximately 90 bhp and as the engine will be modified it will probably give this power at just over 6000 rpm, so it must be geared down to do this.. 

These figures ignores the torque curve which is needed to enable the engine to continue to 'pull' against the drag curve after changing up.

Another thing which improves max speed by way of drag reduction is to remove the huge wing mirrors and just fit a small rectangular A-post mounted mirror on the driver's side only. Removing any wheel-arch extensions and fitting narrower wheels & tyres will add a couple of mph at the top end as well. The huge 'Sportpack' arches do create a lot of additional drag - look at the cross-sectional area they present to the airflow.

As I said, it's complicated  .

[Ethel]

 Some pointers on getting a bit more speed out of your 1 litre Mini

 

 

(doesn't include any advice on  storing glass)

[tom130691]

my 1275 got to 95mph (sat nav) and a speed of half of a tank on the centre speedo. 
 

[dow62]

Top speed ? No one can admire your mini at these claimed top speeds, keep it slow and steady to allow people to be see your pride and joy. If I want speed will take the wifes 1.5 Almera out lol..

[daenesh]

Where are all these private roads where you can get a mini up to these speeds? When I had a 998 it would take a month to get to motorway speeds.

 

 

 

If you think your 998 can do 100mph, you are wrong.

 

i did 100mph GPS confirmed speed on my 998.. was slightly downhill and i was following a 1.3 closely so i was using his wind space.. and well my 998 is stage 1 and some.. so obviously if you're running stock  you ain't going to get anywhere near that..