15 replies to this topic

[Wiggywithahailo]

Am I correct to think that most people assume that these cars all had twin tanks ? (Me included)
For some reason I have a bell ringing that it may have been an option?

[Spider]

The first of the UK Manufactured Cooper S's were only fitted with a single LH Tank. The RH Tank was offered as an option. I think later in UK production they were fitted as standard.

 

We made Cooper S's here in local production, all Aust made Cooper S's had twin tanks from the factory from the start. This was done for homologation purposes for the (as it was then) Armstrong 500 Race at Bathurst.

[Wiggywithahailo]

Hi
So from what year approximately would this have been standard?

[Spider]

Twin Tanks fitted as standard in all UK made Cooper S's from January 1966.

[Wiggywithahailo]

Thank you 👍🏻

[Cooperman]

On the 1966 Monte Carlo Rally the works Minis were running in Group 1. At that time the twin tanks were only homologated in Group 2, so the 1275 Cooper S's were only allowed a single 5.5 gallon tank. That was a big problem for a car doing only around 12 to 15 mpg.
There were refuelling BMC cars placed at about every 60 miles and before every special stage.
Of course, the Minis won but were then disqualified in the 'lights fiasco'.

[mikal]

Were those cars really only getting 15 mpg?! How on earth was it that bad?! I thought they were quite restricted on what they could do to the engine in those days? I'm sure my car is more highly modified than theirs were but my fuel consumption is nothing like that, maybe 25 mpg on a thrash? I don't really know but certainly not 15 mpg. Having said that, any idea what Hp at the wheels they were putting out? Mine is about 80...

[whistler]

My 60's 997 used to do between 15 to 18mpg on a night rally. When you're using high revs most of the time you can almost see the fuel gauge going down. Had to fit a Morris Oxford tank in the boot just to keep up with the thirst.

[Cooperman]

My 1964 'S' gives about 12 mpg on a special stage or maybe slightly less and 12 to 15 mpg on a night road rally in Wales.

 

I had a standard 'S' which only gave 25 to 30 mpg on normal road driving. I think if you get 25 mpg on a 'thrash', you are not really thrashing it. Thrashing it means using between 5000 and 7000 rpm all the time at full throttle.

 

Those works cars were using a very low final drive ratio as well.

 

Twin tanks give 11 gallons, so then it is fine on a normal night road rally where it is not likely that more than 110 miles will be covered between petrol stops.

 

I used to rally in a 'works' Datsun 240Z with triple Webers. It used to give 5 to 6 mpg on a special stage and about 12 to 15 mpg on the road sections between stages.

[mikal]

Wow, thanks for the insight, I had no idea. You're correct, my "thrash" is not continuous 5000-7000 rpm so not a true thrash!

Any idea on the horsepower output of the mid '60s works cars (1275)?

[Cooperman]

Wow, thanks for the insight, I had no idea. You're correct, my "thrash" is not continuous 5000-7000 rpm so not a true thrash!

Any idea on the horsepower output of the mid '60s works cars (1275)?

 

The Group 1 cars were standard but their engines were 'blueprinted'. I believe they gave around 80 bhp.

 

The Group 2 cars gave around 95 to 100 bhp in rally trim.

[mikal]

80 bhp at the wheels? That's a hefty increase over stock by blueprinting?

[Cooperman]

No, 80 bhp at the flywheel!

[Retroman]

Were those cars really only getting 15 mpg?! How on earth was it that bad?! I thought they were quite restricted on what they could do to the engine in those days? I'm sure my car is more highly modified than theirs were but my fuel consumption is nothing like that, maybe 25 mpg on a thrash? I don't really know but certainly not 15 mpg. Having said that, any idea what Hp at the wheels they were putting out? Mine is about 80...

12 to 15 is what to expect from a properly thrashed Mini....wheels spinning and a lot of high revs

 

I once had a huge shock, at the time you could fill a 5 1/2 gallon tank for about 7 quid....(I wish)

 

A thirsty rally Mini, so I made a big tank....it cost me £23 to fill up....I nearly fell on the floor, equal to nearly 200 quid today.

 

It would be about the same time I turned down a Mk3 S for £300.

 

Its a bit like when Range rovers 1st came out...one guy took the car back, complaining he was only getting 12mpg.....the dealer told

 

him to think himself lucky, most people only get 8....!!

[Cooperman]

When I had my first Cooper 998 in 1964, a gallon of 5-star was around 5/- (that's 25 pence), so to fill the 5.5 gallon tank with, say, 5 gallons was £1-25 Now a gallon is around £5-25, so it is 20 times more expensive, but that is about the inflation rate since 1964.

On a night raly in the 998 I used to get around 20 mpg, with around 35 to 40 possible on the road.

 

To think my BMW 730D with almost 250 bhp and a top speed of c.150 will easily give 35 to 37 mpg in normal driving. That includes cruising at 80 mph at 1800 rpm in 6th.