sprouts-car
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| posted on 25/5/11 at 09:39 AM |
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Twin engined car
I've been wondering about cars with more than one engine.
For instance the z-car ultima with two hayabusa engines.
In that car i believe one engine powers the front and one the back with some very clever electronics to control them.
What would the problem be of just connecting two engines up to the same diff.
I'm thinking two bike engines, so two gearboxes. Then two chains down to the same diff.
Would the engines be "fighting" each other?
OR
What if you had each engine output going into each side of a differential. Then if the engines aren't going at the same speed its less of an
issue.
This isn't a plan just a crazy line of thinking.
All thoughts welcome...
Build blog
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JeffHs
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| posted on 25/5/11 at 09:46 AM |
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Many many years ago I saw a twin engined grass track car called I think a Buffy Mowog. It had mini engines front and back and no clever control
systems. He stalled one engine on the start line and the rest of the field, all 2wd, leapt ahead until he manged to bump start the 2nd engine when it
shot through the pack and left them for dead. Most impressive but must have been a nightmare to drive
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JacksAvon
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| posted on 25/5/11 at 09:54 AM |
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See link below, Tiger Racing did this years ago, mental to drive.
http://www.tigerracing.com/z100.php
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britishtrident
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| posted on 25/5/11 at 10:03 AM |
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Twined Tiger famously blew up it transmission on Top Gear.
Whole thing is a can of worms.
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gavin174
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| posted on 25/5/11 at 10:18 AM |
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Russ Bost built a twin engined Furore (2 x ZX10) one driving each rear wheel
Sva'd and on the road.
http://www.essexkitcarclub.com
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40inches
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| posted on 25/5/11 at 10:55 AM |
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Tiger Z100
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Oliver Jetson
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| posted on 25/5/11 at 11:10 AM |
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Westfield Twin Bike Engined
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Fred W B
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| posted on 25/5/11 at 11:12 AM |
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I don't see a problem with two engines driving a common output/jackshaft. They will be constrained to run at the same RPM (unless a dual chain
drive has slightly different ratios for each engine - maybe an idea to broaden the power peak) and even if they make different power they will both
contribute to the force moving the car along.
Biggest issue from what little I've read is controlling the chain slack/tension, if chain drive.
Cheers
Fred W B
[Edited on 25/5/11 by Fred W B]
You can do it quickly. You can do it cheap. You can do it right. – Pick any two.
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adithorp
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| posted on 25/5/11 at 01:17 PM |
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quote:
Originally posted by Fred W B
I don't see a problem with two engines driving a common output/jackshaft. They will be constrained to run at the same RPM (unless a dual chain
drive has slightly different ratios for each engine - maybe an idea to broaden the power peak) and even if they make different power they will both
contribute to the force moving the car along.
Biggest issue from what little I've read is controlling the chain slack/tension, if chain drive.
Cheers
Fred W B
[Edited on 25/5/11 by Fred W B]
One problem is that if one engine misses a gear change the rev limiter can't save it as the second engine drives the revs up.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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sprouts-car
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| posted on 25/5/11 at 01:30 PM |
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quote:
Originally posted by adithorp
quote:
Originally posted by Fred W B
I don't see a problem with two engines driving a common output/jackshaft. They will be constrained to run at the same RPM (unless a dual chain
drive has slightly different ratios for each engine - maybe an idea to broaden the power peak) and even if they make different power they will both
contribute to the force moving the car along.
Biggest issue from what little I've read is controlling the chain slack/tension, if chain drive.
Cheers
Fred W B
[Edited on 25/5/11 by Fred W B]
One problem is that if one engine misses a gear change the rev limiter can't save it as the second engine drives the revs up.
Unless the rev limiter could cut both engines.
Build blog
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Fred W B
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| posted on 25/5/11 at 01:31 PM |
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Fair enough, but you could maybe have the rev limiters/engine mangement/s configured to cut both engines if just one is over-revving?
Cheers
Fred W B
You can do it quickly. You can do it cheap. You can do it right. – Pick any two.
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Fred W B
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| posted on 25/5/11 at 01:32 PM |
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so we posted at the same time......
Cheers
Fred W B
You can do it quickly. You can do it cheap. You can do it right. – Pick any two.
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matt_gsxr
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| posted on 25/5/11 at 01:37 PM |
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quote:
Originally posted by adithorp
quote:
Originally posted by Fred W B
I don't see a problem with two engines driving a common output/jackshaft. They will be constrained to run at the same RPM (unless a dual chain
drive has slightly different ratios for each engine - maybe an idea to broaden the power peak) and even if they make different power they will both
contribute to the force moving the car along.
Biggest issue from what little I've read is controlling the chain slack/tension, if chain drive.
Cheers
Fred W B
[Edited on 25/5/11 by Fred W B]
One problem is that if one engine misses a gear change the rev limiter can't save it as the second engine drives the revs up.
If you can be bothered to put 2 engines in a car, then it wouldn't be difficult to provide some control circuitry to prevent this happening!
Thousands of ways of doing it. What about:
having the ECU from one engine driving the fueling on the other engine and vice versa. This wouldn't work for sparks (as the engines
won't be in phase) but fueling is more forgiving.
or
have circuit that requires the two engines to be in the same gear, or cuts power
or
have an external rev limiter for each engine that cuts both engines
or
having a gear shift that forces both engines to be in the same gear
To build a car of this complexity and fail to implement a basic interlock would be foolish. The downshift problem is still present, but we all have
that to deal with to some degree.
Matt
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sprouts-car
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| posted on 25/5/11 at 02:02 PM |
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What about linking through some sort of differential used in reverse. Then different speed and even different gears are less of an issue?
Build blog
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Liam
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| posted on 25/5/11 at 04:01 PM |
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quote:
Originally posted by Fred W B
unless a dual chain drive has slightly different ratios for each engine - maybe an idea to broaden the power peak
[Dr Evil look]
Iiiiiiiiiiiiinteresting
[/Dr Evil look]
Forget compound turbocharging - I propose compound twin-engine-ing! A diesel for the low-end grunt driving a common shaft with a bike engine
(appropriately geared) providing the top-end! Mu ha ha ha haaaa - motorsport domination is miiiiiiiiiiiiiiiiiiiine.
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blakep82
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| posted on 25/5/11 at 04:07 PM |
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^ thats what twin engines karts do
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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JoelP
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| posted on 25/5/11 at 05:14 PM |
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as said above, it cant be too hard to make a revlimiter that cuts both engines when either hits max rpm. Also, though missed gears are quite common on
bike engines, i would imagine that a pair of flatshifters would have a much lower failure rate. Then just have an additional button to only change
gear on one engine, in case they do end up out of sync.
In fact, if flatshifters can be linked to the ecu, i bet you could make it automatically correct a missed gear.
Beware! Bourettes is binfectious.
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Paul TigerB6
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| posted on 25/5/11 at 06:30 PM |
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quote:
Originally posted by britishtrident
Twined Tiger famously blew up it transmission on Top Gear.
Whole thing is a can of worms.
And clearly you know why it blew up given the can of worms comment then BT???
Just so you know - Tiff thought he knew better than Chris Allanson and missed a gear change on one of the engines after being given specific
instructions on how to change!! Driver error / stupidity rather than can of worms!!
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blakep82
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| posted on 25/5/11 at 06:37 PM |
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ah, 5th gear! thats why i never saw it then
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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Paul TigerB6
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| posted on 25/5/11 at 09:49 PM |
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quote:
Originally posted by blakep82
ah, 5th gear! thats why i never saw it then
Just for you Blake 
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Minicooper
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| posted on 26/5/11 at 02:28 PM |
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Here is one, who is brave/rich enough
TWIN BIKE ENGINED MINI COOPER | eBay UK
Cheers
David
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Mark Allanson
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| posted on 26/5/11 at 09:11 PM |
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quote:
Originally posted by britishtrident
Twined Tiger famously blew up it transmission on Top Gear.
Whole thing is a can of worms.
More like clumsy "Tiffany Dell" broke Chris Allansons dream car!
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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froggy
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| posted on 30/5/11 at 05:58 PM |
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done this with a pair of tl 1000 v twins and although interesting its not a good idea as there are many synchronisation issues and however well put
together you cant drive it 100% as missed gearchanges are always in the back of your mind .
plenty of easier ways to make more power
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
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coyoteboy
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| posted on 5/7/11 at 11:27 PM |
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I keep coming back to this as, while playing around with a few bike engines, I can't seem to get them to mis-shift in a way that would allow one
to shift and one not - if it doesn't shift it jams the shift lever on the engines I've been faffing on. If they're both linked
rigidly and one jams, what's the chances of the other going in? Genuinely quite curious to hear more from those who've done it like you
froggy. A pair of vfr 750s would knock out 200hp and weigh around 120kg (engines only) which is pretty competitive. Never get something for nothing
though I suppose!
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froggy
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| posted on 6/7/11 at 12:20 AM |
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Mine made 220 whp on open exhausts but failed noise miserably on track days . Peak torque was 160 lb/ft so losses were pretty low , the chain
maintenance got very old having 2 chains onto the jackshaft then another to the final drive which stretched twice as much .
Makes sense for a grass track car but not for Tarmac or road use imo
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
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