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Twini Mini? Options For Rear-Engine, Rwd...


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#1 Tremelune

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Posted 05 October 2019 - 01:05 AM

I'm converting my Mini to electric, and I have half a mind to try and put the motor in the back. The up side would be more flexibility of weight distribution (for example, 47% front to 53% rear), zero torque steer, and the characteristics of RWD (which I rather like). The down side would be cutting the chassis, packaging complexity, brake bias, and sorting the suspension without very few comparable examples to compare to...

 

In any event, I figured I'd ruminate about it...Someone pointed me to a wild twin-engine Mini, and I'm wondering if there are more details? How do the axles attach to the wheels?

 

https://sites.google.../the-twini-mini

 

Cooper_s_Twini_Mini.jpg


Edited by Tremelune, 05 October 2019 - 01:13 AM.


#2 Spider

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Posted 05 October 2019 - 07:19 AM

A Modified Front Subframe was used in the very heavily modified rear of the Mini.

 

Usually, no steering rack is fitted to the backend, but additional linkages are fitted to take the place of the steering rack and keep the Hubs pointing straight ahead.

 

 

As an aside, I'd just like to mention that one thing that keeps the Mini so stable on the road is that most of the weight is so far forward and IMO, with such a short wheel base, if the weigh was closer to 50/50, if the back were to 'come out. it swaps very fast.



#3 Algordo1100

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Posted 05 October 2019 - 07:54 AM

Anyone remember the GTM Coupe? Or Rossa?
They had two front subframes, one front, one back, engine out back and steering locked off on the rear.

Also the original NCF blitz buggy. That had a mini engine out back within a mini front subframe I believe.

I wonder with the GTM kit cars though. With no engine up front in a lightweight fiberglass shell, the suspension would be very stiff indeed?
Unless you converted over to coil overs to set it up for the weight properly.

#4 mini13

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Posted 05 October 2019 - 08:31 AM

You might want th check the legality of driving the rear wheels, apparently in the UK "twinis" are not allowed to be used in that configuration on the road as failure of one engine could upset the balance and cause an accident, might be different with a secondary electric propulsion though.

#5 nicklouse

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Posted 05 October 2019 - 09:45 AM

Z cars are looking at an electric kit. The battery pack becomes the floor.

Mini engines in the rear have been going on since the Mini was born. Many many mini based kits have rear engines. And this was taken on to the Terapin race car.

#6 mab01uk

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Posted 05 October 2019 - 09:48 AM

mini_twini_zps99108b16.jpg

 

"Who came up with the mad idea of sticking a second engine in the back of a Mini – doubling the power and the driven wheels – isn’t clear, but there’s a good case for maverick engineer Paul Emery. The man who ran front-wheel-drive F3 cars in the early ’50s, and fitted the first disc brake on a racing car in Europe, was always non-conformist. By the ’60s, this ingenious specials builder had moved away from racing and focused on Minis. As well as the Dart, he designed a ‘Twini’ but gear-linkage problems handicapped its progress and Emery’s Fulham workshop switched to tuning Hillman Imps. “Good traction, but that’s about all,” was how Emery dismissed the failure, yet his concept soon set others off on the same track. First, Alec Issigonis developed the ultimate Mini Moke, whose four-wheel drive and doubled torque proved highly impressive on winter snow trails in 1962."

 

"During a visit to the Longbridge factory, John Cooper got a chance to drive the Twini Moke. The BMC design team relished any opportunity to demonstrate its four-wheel-drive toy and the motor sport legend was hugely impressed by its power and dramatic traction. The test sowed a seed, and he tore back to his Surbiton factory with the idea of building a Mini road car with a similar layout. While his single-seaters struggled to deliver, Cooper became obsessed with the Mini project and talked of nothing else. Mini parts were scattered over the workshop floor, and within six weeks a running prototype had been built up from a bare shell and was soon scaring motorists around the Hollyfield Road works......"

Mini Twini: twin-engined, four-wheel-drive concept tested in full:

http://www.classican...-tested-in-full

 

mini_twini_rear_engine_zps48b65b71.jpg

 



#7 DomCr250

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Posted 05 October 2019 - 10:25 AM

Anyone remember the GTM Coupe? Or Rossa?
They had two front subframes, one front, one back, engine out back and steering locked off on the rear.

Also the original NCF blitz buggy. That had a mini engine out back within a mini front subframe I believe.

I wonder with the GTM kit cars though. With no engine up front in a lightweight fiberglass shell, the suspension would be very stiff indeed?
Unless you converted over to coil overs to set it up for the weight properly.

With all the mini based kits because of the weight reduction you 'tuned' the rubber donuts. On my old Mini Marcos the rear units had been spun in a lathe and were a sort of slightly curved rocket shape.  The other method was to drill loads of holes in them with a half inch drill.



#8 Ethel

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Posted 05 October 2019 - 12:31 PM

You wouldn't necessarily eliminate torque steer, depending on how literally you define it. The front end will lift more if it's lighter with more suspension articulation of the steering angles - potentially at both ends if you use a front subby on the back.



#9 no66

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Posted 05 October 2019 - 10:10 PM

Back in about 71, ST built a 1293 8port and used the Austin Ant 4wd drivetrain. 
https://en.wikipedia...wiki/Austin_Ant

The Ant used an A-series engine with a special gearbox with an output shaft. A small diff at the rear. 
It had a special rear subframe with vertical rubber donuts to clear the rear drivshafts. 
There are some photos on Facevook, but can't remember the the group.

Bet if such a kit existed today, it would sell well 

 



#10 no66

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Posted 05 October 2019 - 10:13 PM

https://tentenths.co...ad.php?t=143380



#11 gazza82

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Posted 05 October 2019 - 10:34 PM

They had an electric Mini on Fifthgear Thursday. Only £80k!

Edited by gazza82, 05 October 2019 - 10:34 PM.


#12 Tremelune

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Posted 06 October 2019 - 03:52 AM

These cars are wild.



#13 jaybeeonline

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Posted 06 October 2019 - 08:05 AM

Anyone remember the GTM Coupe? Or Rossa?
They had two front subframes, one front, one back, engine out back and steering locked off on the rear.

Also the original NCF blitz buggy. That had a mini engine out back within a mini front subframe I believe.

I wonder with the GTM kit cars though. With no engine up front in a lightweight fiberglass shell, the suspension would be very stiff indeed?
Unless you converted over to coil overs to set it up for the weight properly.


The GTM used a custom steering lock kit, that is still available from a company called Rossabitz.

http://www.gtmdriver...bf9b813933563f7

On my Rossa, the suspension is stiff, but no worse than my last Mini due to the Rossa being slightly heavier overall and having a longer wheelbase too.



J.

Edited by jaybeeonline, 06 October 2019 - 08:11 AM.


#14 nicklouse

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Posted 06 October 2019 - 10:20 AM

 

Anyone remember the GTM Coupe? Or Rossa?
They had two front subframes, one front, one back, engine out back and steering locked off on the rear.

Also the original NCF blitz buggy. That had a mini engine out back within a mini front subframe I believe.

I wonder with the GTM kit cars though. With no engine up front in a lightweight fiberglass shell, the suspension would be very stiff indeed?
Unless you converted over to coil overs to set it up for the weight properly.


The GTM used a custom steering lock kit, that is still available from a company called Rossabitz.

http://www.gtmdriver...bf9b813933563f7

On my Rossa, the suspension is stiff, but no worse than my last Mini due to the Rossa being slightly heavier overall and having a longer wheelbase too.



J.

 

that was never provided by any of the retailers. it is a very good self make part that does the job very well and i wish was available 30 years ago.



#15 jaybeeonline

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Posted 06 October 2019 - 01:16 PM

Anyone remember the GTM Coupe? Or Rossa?
They had two front subframes, one front, one back, engine out back and steering locked off on the rear.

Also the original NCF blitz buggy. That had a mini engine out back within a mini front subframe I believe.

I wonder with the GTM kit cars though. With no engine up front in a lightweight fiberglass shell, the suspension would be very stiff indeed?
Unless you converted over to coil overs to set it up for the weight properly.

The GTM used a custom steering lock kit, that is still available from a company called Rossabitz.

http://www.gtmdriver...bf9b813933563f7

On my Rossa, the suspension is stiff, but no worse than my last Mini due to the Rossa being slightly heavier overall and having a longer wheelbase too.



J.
that was never provided by any of the retailers. it is a very good self make part that does the job very well and i wish was available 30 years ago.


Here is a good couple of threads showing the latest versions

http://www.gtmdriver...e-t3569-15.html

http://www.gtmdriver...a-cz-t3004.html



J.

Edited by jaybeeonline, 06 October 2019 - 01:25 PM.





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