TWIN BIKE ENGINED MINI COOPER | eBay UK
Cheers
David
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...
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
See link below, Tiger Racing did this years ago, mental to drive.
http://www.tigerracing.com/z100.php
Twined Tiger famously blew up it transmission on Top Gear.
Whole thing is a can of worms.
Russ Bost built a twin engined Furore (2 x ZX10) one driving each rear wheel
Sva'd and on the road.
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]
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]
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.
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
so we posted at the same time......
Cheers
Fred W B
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.
What about linking through some sort of differential used in reverse. Then different speed and even different gears are less of an issue?
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
^ thats what twin engines karts do
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.
quote:
Originally posted by britishtrident
Twined Tiger famously blew up it transmission on Top Gear.
Whole thing is a can of worms.
ah, 5th gear! thats why i never saw it then
quote:
Originally posted by blakep82
ah, 5th gear! thats why i never saw it then
Here is one, who is brave/rich enough
TWIN BIKE ENGINED MINI COOPER | eBay UK
Cheers
David
quote:
Originally posted by britishtrident
Twined Tiger famously blew up it transmission on Top Gear.
Whole thing is a can of worms.
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
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!
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
quote:
Originally posted by coyoteboy
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!
Secondly they are are in plentiful supply and they are cheap cos they pretty much never
break. I worked in a building we shared with a huge bike breakers over here for a few years and was always fascinated by the engine stock. There were
one or two GSXRs, ZXRs, and YZFs but there were dozens and dozens of VFRs on the shelf. If ever they sold it was for peanuts compared with the rest of
the big Jap motors. This would not be a problem on tarmac though. There have been a couple of notable twin engined tintops, one being a Nova (Corsa A) built in germany for Regal (shudder). It had 2 Calibra Turbo
(C20LETs) with about 300hp each. It lead to a 2.8 sec 0-60 and a 11sec 1/4 mile IIRC.
http://video.google.co.uk/videoplay?docid=-8933077605569731631&q=nova#
The other was a Golf (mk3 IIRC) that had 2 VR6 engines and had some equally impressive stats.
http://video.google.co.uk/videoplay?docid=-3582964599649062492&q=twin+engined+golf#
The hardest thing ive heard is sorting the gear change linkages to ensure both engines engage the same gear at the same time.
I'd not be going to a jack shaft, I'd be running two separate outputs for simplicity.
quote:
Originally posted by Fred W B
I don't see a problem with two engines driving a common output/jackshaft.......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]
quote:
As for your gear selection question beware if you're playing around with motors that are not running. Bike boxes rely on the rotation of the gearshafts to line up the dogs when shifting. If you are trying this out with dead engines the boxes will be very reluctant to shift. Once rolling they slip into gear much more easily.
I'm thinking a hydraulic shift mechanism might be used to provide the shifting required. Providing enough time is allowed with ignition cut, hydraulic cyls on each shifter would provide equal pressure and maintain force until electronic confirmation of engagement (full lever travel), allowing ignition cut to both engines should a mis-shift occur on either. If the mis shift feels like a normal shift (i.e. full travel) , this still leaves a problem. If it doesn't, the electronics could control a downshift on the missed engine, or repeat the shift as required on one engine, just with a big stutter!
This made me curious today, does anyone know of (or know of a reason not to make) a vehicle that has an engine driving each wheel. It would make for the ultimate traction control that's for sure.