Dual Engines

How is it possible to mount a second engine to the rear end of a car? And
how does the driver control two transmissions with one shifter? Does the
advantage outweigh having a single, high-power engine?

 

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Yours is one of the strangest questions ever posted her. Here's an even
stranger answer:

http://www.mrsharkey.com/pusher.htm

'Curly'

 

For the original poster, since you're contemplating something pretty
strange, why not try the following instead:
Get two cars, cut them in half (front and back) and weld both fronts
together. Two engines, four wheel drive, four way steering.

We expect to see pictures when you're done.
Remco

 

Absolutely.

Chevrolet made a one-off Chevette back in the '80s that had two engines.
Car and Driver reported on it in an article entitled "How to Scare Your
Mother".

Citroen made those out of their 2CV years ago (it was sold in Africa and I
think was called the "Sahara"). Renault made them out of their R5 (Le Car)
as a rally homologation special.

If I can find my copies of Practical Classics that have these, I'll scan
the articles and post them.

Transmission control with a single shifter is easy enough. Many, many
vehicles have been made with rear linkages. I'd assume the shifter would be
somewhat heavier to move, though.

The advantage is simple: Engine makes 100 hp. Car weighs 2,500 lbs. Each hp
has to move 25 pounds. Now put in two engines. Car now has 200 hp, but only
weighs 3,000 lbs. Each hp only has to move 15 lbs. That's a 40% increase in
motive power.

The disadvantages are complexity, expense, and thirst.

 

of course you can. how much do you want to spend doing it? advantage
of the weight of two engines, two transmissions, and the control
elements? not much. better to go for a single power unit, single
transmission and keep it as simple as possible.

 

i remmeber seeing a 'car challenge' program that had that as a
challenge. 3 teams were given a thousand pounds (about $1800) to buy
two cars and anything special, then they had 2 days to make the car
you described, ready for a race with offroad, high speed, and handling
areas, including those where 4wheel steering would be required to
crab. Each car still had 2 drivers in it.

The winner used the front oend of a rover 800 vitesse (with a 200hp 2l
turbo unit) and a fiat panda front end for the 'back'.Was a very
interesting episode, 2 of the cars made it, one broke down before the
end, but not far before 9it was smoething like a 8 mile course)

 

Someone did that to a Volkswagen Golf a number of years back. The car
competed in the Pikes Peak run, and I believe it won its class. Can't
find any references to it on the web, though.

 

Chrysler's done it. Check out the Jeep Hurricane concept vehicle.

"...Hurricane is not just HEMI®-equipped, but HEMI squared. There are
two 5.7-liter HEMI engines in the vehicle: one in the front and one in
the back. Both engines deliver 335 horsepower and 370 lb-ft of torque -
a total of 670 hp and 740 lb-ft of torque."

http://www.jeep.com/autoshow/news/hurricane.html

 

Yeah, it also did a run on top gear, i think. Well, either top gear,
or one of clarkson's videos.

Then there was also the dual engined Mercedies A-class cars that were
given to Hakkenin and coulthard around 97-98 time.

 

Very cool! I'd love to see that one.
There's a show here in the US where they do similar things called "Monster
Garage" -- they can only cram so much in a 1 hour episode so it tends to be
more drama than technique, but some of the thing they make are very
interesting.

 

Why stop at two?

 

Yeah, its not really the same kind of show, since therse only one team
in MG, theres 3 in the other one, and the start vehicle is chosen by
the production company, and the parts buying is rigged. The british
one is a hard limit (because UK tv companies are cheap) and the money
you got it is. No new engines and high end parts for them. Its
junkyard cars, and parts from the lcassified ads. makes for a more
interesting show

Some friends and aquaintencies ahve been on Mgand at least one said
that the end vehicle is heavily 'steered' towards. You don't really
get much say in what the design will be. That was when he was on the
delorian hovercraft ep (i think)

 

Dual drive systems are used quite a bit in industry. It is best to use
servo controls with high resolution encoders for feedback for these types of
systems.

 

absolutely! especially on larger equipment where transmission over
distance is problematic. but on something like a racing car?
especially a mid-engined one, you're just increasing weight & decreasing
reliability. but then again, the "cool" factor gets the fans excited,
so it's great for publicity.

 

4 - 4000 RPM direct drive servo's on a car frame, each with 200 lbs/ft or
more of torque. Brushless with all digital drives, co-ordinated within 2 or
3 encoder pulses (5K pulses per rev min digital encoders) . No need for
breaks, the drives are regenerative!

I'd pay to see that.

What the hell, half of the specs are right there. With a little money and a
little time.... OK, maybe a LOT of money and time....

 

Some friendly people over at rec.autos.makers.vw.watercooled suggested
http://www.dubsport.com/ (currently down) and
http://www.wellcheap.com/gallery/Homers-Gallery as references.

 

The Car and Driver dual engine CRX is still alive and kicking. Great,
simple project car that worked out much better than anyone anticipated.

 

anyone got any pix?