mr henderson
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| posted on 9/10/08 at 08:16 PM |
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Twin engined car?
Supposing it was possible to install a transverse engine'gearbox in both the front and the mid engined positions, how would one best deal with
keeping the roadwheels turning at same speed?
In a reliable and practical manner. Also how could it be set up to alow one engine to be turned off when not needed?
Interested in anecdotes, opinions etc
John
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zilspeed
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| posted on 9/10/08 at 08:20 PM |
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With the exception of the transverse bit, the Tiger Z100 WR is essentially like this.
Front engine drives front wheels.
Rear engine drives rear wheels.
This car really on whel sensors and several grand worth of motec ECU to control and modulate the respcetvie power plants.
On a more humble note, try looking up Durocco which is a twin engien scirocco.
This seems to work very well.
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Mark G
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| posted on 9/10/08 at 08:40 PM |
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You don't need the engines to run at the same speed as they'd do it them selves. The engines just don't have to work as hard to
drive the wheels so they'll run faster and easier.
Think of it this way. Just because the rear wheels on a hatchback aren't driven doesn't mean that the fronts always spin...
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adam1985
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| posted on 9/10/08 at 08:41 PM |
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i thought i read somewhere that the z100 had both engines feeding some kind of transfer box which then powered the rear wheels i am proberbly wrong
though normaly am
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LBMEFM
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| posted on 9/10/08 at 08:45 PM |
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I agree with Adam, I think they were linked together and both drove the rear wheels.
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chrisg
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| posted on 9/10/08 at 08:47 PM |
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twin engined golf
Cheers
Chris 
Note to all: I really don't know when to leave well alone. I tried to get clever with the mods, then when they gave me a lifeline to see the
error of my ways, I tried to incite more trouble via u2u. So now I'm banned, never to return again. They should have done it years ago!
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zilspeed
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| posted on 9/10/08 at 09:08 PM |
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quote:
Originally posted by LBMEFM
I agree with Adam, I think they were linked together and both drove the rear wheels.
First car did.
The second car, the WR for world record had the front engine drivng the front wheels.
This pic gives it away.
The other car has both engines pointing to the back - hence both exhaust going out the nearside.
In the case of a mega powerfull twin engined car with light weight and non interconnected powertrains, balancing the power delivered to each road
wheel is far from trivial. This is a sub 600kg with 380bhp remember.
[Edited on 9/10/08 by zilspeed]
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MikeRJ
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| posted on 9/10/08 at 09:21 PM |
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Synchronisation is often made out to be a major problem with twin engined cars for some odd reason. The road and the tyres will ensure they turn at
the same speed. If you don't get the throttles balanced, you will simply change the front/rear torque distribution.
If Russ can manage with each rear wheel being driven by a separate engine in the Furore, front and rear axles being driven by separate engines
shouldn't pose much of a challenge!
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zilspeed
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| posted on 9/10/08 at 09:27 PM |
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Ok, what happens when you're on the absolute bleeding edge of adhesion. The type of use a competitive seven type car will be put to in a
competitive environment.
You're right on the limit, it simply isn't possible to corner any quicker when one of your engines goes out of whack with the other
one.
Twin engined rear wheel drive I can deal with, indpendent engines and transmissions though...
I have the greatest of respect for Russ, but he is a much much braver man than me.
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Mark G
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| posted on 9/10/08 at 09:50 PM |
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they'll have a power curve that they stick to, You could have a busa engine powering the back and a blade powering the front if you wanted to.
No problem. Remember most 4wd cars are approx 60/40 split anyway.
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Maradona
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| posted on 9/10/08 at 09:52 PM |
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Here in argentina one crazy guy do a car with 2 engines, one in front and one back, he used 2 Fiat 128 engines, and the car run like hell, I will try
to find some pics.
cheers
Diego,
The locost builder from Argentina
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Daimo_45
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| posted on 9/10/08 at 10:09 PM |
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z cars transfer box...job sorted
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stevebubs
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| posted on 9/10/08 at 10:22 PM |
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quote:
Originally posted by zilspeed
quote:
Originally posted by LBMEFM
I agree with Adam, I think they were linked together and both drove the rear wheels.
First car did.
The second car, the WR for world record had the front engine drivng the front wheels.
This pic gives it away.
The other car has both engines pointing to the back - hence both exhaust going out the nearside.
In the case of a mega powerfull twin engined car with light weight and non interconnected powertrains, balancing the power delivered to each road
wheel is far from trivial. This is a sub 600kg with 380bhp remember.
[Edited on 9/10/08 by zilspeed]
Nearly right...there were actually a few of the original z100s (RWD) produced.
Don't know of any more than the 1 Z100WR, though.
In theory Z-Cars' 1000bhp Ultima should have blown it out the water (twin turbo busas) but nothing was ever heard of this car other than
"we're building it"
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stevebubs
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| posted on 9/10/08 at 10:24 PM |
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There have been a *number* of VWs with this sort of configuration, though...
Vaguely remember hearing of a Vauxhall Nova in this configuration also....
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stevebubs
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| posted on 9/10/08 at 10:25 PM |
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quote:
Originally posted by mr henderson
In a reliable and practical manner. Also how could it be set up to alow one engine to be turned off when not needed?
Stick the one turned off in neutral...
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MikeR
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| posted on 9/10/08 at 11:10 PM |
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Daft question, bearing in mind the idea of running a more powerful engine on one end, why not take two identical engine and gearbox combinations (you
need the boxes so that they turn at the same rate and therefore you change up at the same time) and then tune the more powerful engine - that way its
always the 'lead' engine - you'd have to make sure at all places the torque and hp are greater all the way through.
Perhaps you could do it so you take a 1800 and 2l zetec engine (not sure if you've got similar options with bike engines).
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gator
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| posted on 9/10/08 at 11:10 PM |
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Twin Engined Car
Introducing an oldie but a goodie...Warren Creagh and the Twinnie! Has been around local hills for yonks.
Regards
Alan
http://www.hillclimbnsw.com/r5.html
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MikeR
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| posted on 9/10/08 at 11:16 PM |
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Oh, John Cooper did ok with a 2.5l 16v mini - thats two 1275 engines in a mini. BL scrapped the idea when a track rod end gave way and he crashed in
a big way on a local road whilst 'testing' it
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mad4x4
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| posted on 10/10/08 at 06:26 AM |
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New a guy who used to do autocross using an "alpha -Sud" it was twin engined. don;t know much more
Scot's do it better in Kilts.
MK INDY's Don't Self Centre Regardless of MK Setting !
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mr henderson
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| posted on 10/10/08 at 07:19 AM |
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quote:
Originally posted by stevebubs
quote:
Originally posted by mr henderson
In a reliable and practical manner. Also how could it be set up to alow one engine to be turned off when not needed?
Stick the one turned off in neutral...
Sounds simple, I suppose the question should have been expanded to be clearer, for instance,
"how can the gearboxes be controlled in such a way as to ensure that the gear changing can be synchronised when the engines are both required,
but allow one to be set in neutral while still controlling the other?"
It sounds like quite a complicated set up, bearing in mind that although most modern transverse power units have cable changes, the cable lengths and
therefore the lost motion is going to be different. perhaps some kind of electronics controlling solenoids might be the best way?
It's unfortunate that most of the info on the 'net that I have found so far tends to be very vague on this particular issue
John
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Moorron
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| posted on 10/10/08 at 07:57 AM |
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I remember the twin engined renault 5 turbo and the guy who built it. It was mental but was very nice.
All thou it had an MOT and was used on the road i was informed that you cant have a car with indipendant powered axles legally on the uk roads???
You can have 2 engines and 4x4 but not two engines not conected to the same drive train.
Sorry about my spelling, im an engineer and only work in numbers.
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MikeCapon
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| posted on 10/10/08 at 08:37 AM |
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Hi John,
This may be similar to what you are looking for. Done over here in 1954
Sahara
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nick205
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| posted on 10/10/08 at 08:50 AM |
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Check out Ian Birch aka Dubsport. He's built a few VWs with twin engine set-ups. IIRC there was a MKI Golf with VR6 motors front and rear.
IMHO the most complex part will be getting all te throttle, clutch and gear change linkages to work in a usable and harmonious fashion, not the the
actual synchronisation of power to the wheels.
A modern 4wd set-up with ATB/LSD, stability and traction control will be varying the power to each wheel when driven hard any way.
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Stott
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| posted on 10/10/08 at 10:06 AM |
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As above - Dubsport
And to reinforce the point that power sync is of little importance, in the mk3 twin VR6 he did, the front engine was the 2.8 and the rear the 2.9
unit
Don't bother looking at the website, or rather, do, because it's been a spoof page for about 3 years now, probably done by the web
designer they didn't pay,
http://dubsport.net/home.htm
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PeterW
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| posted on 10/10/08 at 12:35 PM |
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quote:
Originally posted by mr henderson
quote:
Originally posted by stevebubs
quote:
Originally posted by mr henderson
In a reliable and practical manner. Also how could it be set up to alow one engine to be turned off when not needed?
Stick the one turned off in neutral...
Sounds simple, I suppose the question should have been expanded to be clearer, for instance,
"how can the gearboxes be controlled in such a way as to ensure that the gear changing can be synchronised when the engines are both required,
but allow one to be set in neutral while still controlling the other?"
It sounds like quite a complicated set up, bearing in mind that although most modern transverse power units have cable changes, the cable lengths and
therefore the lost motion is going to be different. perhaps some kind of electronics controlling solenoids might be the best way?
It's unfortunate that most of the info on the 'net that I have found so far tends to be very vague on this particular issue
John
Tiger did this with 2 '7' shaped handles side by side - they clipped together at the top to drive both boxes on a single change.
It all went wrong when Tiff Needell unclipped them by accident, and upshifted one engine without the other.... Front engine hit 15k revs and blew a
rod...!
Peter
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