4 replies to this topic

[Shooter63]

I collate information, at the moment it's a spreadsheet of maximum torque values for all the engines fitted to minis in there various guises and states of tune from the factory plus a few known tuning companies. At the moment I have an enigma, the 1070 Cooper S, all the online articles list max torque at 4500 rpm, this seems high for the general engine spec especially as a 970 S has max torque at a lower rpm reading, when an identical engine spec is used but capacity varies you would normally expect the max torque value to be reached at a lower rpm as the capacity increases. So to the question, has anybody on here got a copy of the factory dyno read outs for both the 970 and 1070 S ?

Shooter

[timmy850]

There were probably a few things at play, the 970 is listed as a 9.75:1 compression ratio and the 1071 only 9:1

 

The 970 also had the airbox and alloy elbows, generally the longer the length pre-carb the better the low down torque will be

 

They were also given significantly different amounts of timing, nearly 10 degrees more on the 970 which would have increased low down performance

 

 

The other thing is it could have been a typo and carried through in all the brochures. You'll notice it also lists the ignition system as having "vacuum control" which it clearly didn't have

Edited by timmy850, 17 May 2025 - 10:28 AM.

[Ethel]

The S engines vary in stroke, not bore. The same cylinder pressure on the same piston area will give the same force, but a longer crank will create more torque from it. The flip side is the piston acceleration & maximum velocity also increases with the stroke

The compression ratios were likely for different grades of fuel. As we know, all the S's were built for race homologation & are a rebore away from a class engine capacity limit.

[Spider]

If you go to this thread, post #25;-

https://www.theminif...-rubbish/page-2

 

You'll get the numbers from the horse's mouth

[Shooter63]

If you go to this thread, post #25;-

https://www.theminif...-rubbish/page-2
 
You'll get the numbers from the horse's mouth

Cheers mate.

Shooter