More specifically, motorcycle engines. There's a twin engine GSXR750 autograss sprint car built by RVEngineering across the pond, very very cool.
https://www.youtube.com/watch?feature=player_embedded&v=IztNFtaZZb4
https://www.youtube.com/watch?feature=player_embedded&v=pgrgCOFqRII
Turns out it's not much more power than a Busa engine, and heavier to boot. For coolness factor, I started thinking about the possibilities of joining two different engines together, say an I4 1000 (R1, ZX10, etc) and a V-Twin (SV1000, TL1000, RC51, etc). I'd have to take a closer look at the gear ratios, but optimally I envision both connected to a common jackshaft, and geared according to their RPM range (i.e, V-twin at ~9000 RPM and I4 at ~15,000 will be spinning the jackshaft at the same speed). Throttles and clutches would have to be synced as close as possible, but the idea is that both are contributing to work done. If you hook two different sized trucks to the same log with different chains, they will both contribute to pulling the log.
I would imagine the major roadblocks would be internal gear ratios, packaging both engines on the same chassis. I'm sure there's more...
I submit that it's totally impractical and nonsensical...but is it possible?
Sure. Same theory as a duel engine car, but instead of the road connecting the two engines it's a shaft or chain. The hardest part would be synchronizing then so they are working together as closely as possible.
There are a lot of tractor pull...tractors with heterogeneous multi-engine setups like this.
My understanding was that the tractor pull setups were joined at the crank, whereas these engines would be joined using their output shafts, past their gearboxes.
^That concept is pretty much the same as a dual-powertrain car, where the engines are joined even later - by the ground.
I dunno what the effect of the different 'power' pulses would be, but it might break shafts like crazy. If you used two engines that were the SAME, I'd think you should be able to sync them via making the spark events happen at the same time and then hopefully the power pulses would be similar.
Or just give both engines a huge flywheel?
ORRR, use a small (like miata 1.6) open diff and run a chain or shaft drive into each 'output' flange. The diff would then combine the two into one real output. (after thinking about this a little, it actually might cause a non-linear output shaft speed as each engine speeds up and applies torque differently.)
rcutclif wrote:
I dunno what the effect of the different 'power' pulses would be, but it might break shafts like crazy.
I remember seeing an image of a pair of SBCs joined by meshing two flywheels together. One engine had the flywheel (flexplate maybe?) attached to the front damper. Apparently it worked well enough for drag racin'.
I wouldn't want to change the plugs on the center eight cylinders, though!
Knurled wrote:
rcutclif wrote:
I dunno what the effect of the different 'power' pulses would be, but it might break shafts like crazy.
I remember seeing an image of a pair of SBCs joined by meshing two flywheels together. One engine had the flywheel (flexplate maybe?) attached to the front damper. Apparently it worked well enough for drag racin'.
I wouldn't want to change the plugs on the center eight cylinders, though!
http://www.tractorpulling.freeserve.co.uk/howit1.htm
TL:DR - Clutches, lots of clutches.
that was a very helpful link, thank you!
OSULemon wrote:
Knurled wrote:
rcutclif wrote:
I dunno what the effect of the different 'power' pulses would be, but it might break shafts like crazy.
I remember seeing an image of a pair of SBCs joined by meshing two flywheels together. One engine had the flywheel (flexplate maybe?) attached to the front damper. Apparently it worked well enough for drag racin'.
I wouldn't want to change the plugs on the center eight cylinders, though!
http://www.tractorpulling.freeserve.co.uk/howit1.htm
TL:DR - Clutches, lots of clutches.
From that link I read the following tidbit about "Desperate Dan"...
Engines
For the 3.5 tonne modified class we use 4 , 540 cubic inch (8.8 Litres) , V8 Big Block Chevrolet engines . These are supercharged using 8-71 Littlefield Hi-Helix retro fit blowers and run on methanol fuel . Each engine produces approximately 1600 horsepower. For the 4.5 tonne class , the rules allow us to add a 5th engine , which is a 572 cubic inch (9.4 litre) V8 , Arias Chevy Block , supercharged with a 14-71 SCS blower , again using methanol fuel , producing in the region of 2000 horsepower .
So, if my math is ok that is a 9200 horsepower tractor.
rcutclif wrote:
bearmtnmartin wrote:
So, if my math is ok that is a 9200 horsepower tractor.
'Merica
It is a British team competing in Europe on this link, but they do reference getting ideas and parts from 'Merica. 
I think the toughest issue you would have would be the integral gear boxes in the motors you listed. You could have each motor output to a common shaft that would then drive a diff and then wheels. Each type of motor would want different shift points even if you got the overall gearing close for redlines.
If you fitted a slipper clutch, you could eliminate the issue of one motor over revving the other and only have them adding power.
Fitting upshift/ downshift quick shifter to each you could run a single throttle for both and not have to worry about throttle inputs for shifting. A single shifter and compromised power band or a dual shifter and better power band controls might be more efficient, but actual concentration to work might make you slower.
In other news, their idea of autocross is different from what I thought.
https://www.youtube.com/watch?v=tR05Nil-lpQ
former520 wrote:
rcutclif wrote:
bearmtnmartin wrote:
So, if my math is ok that is a 9200 horsepower tractor.
'Merica
It is a British team competing in Europe on this link, but they do reference getting ideas and parts from 'Merica.
I think the toughest issue you would have would be the integral gear boxes in the motors you listed. You could have each motor output to a common shaft that would then drive a diff and then wheels. Each type of motor would want different shift points even if you got the overall gearing close for redlines.
If you fitted a slipper clutch, you could eliminate the issue of one motor over revving the other and only have them adding power.
Fitting upshift/ downshift quick shifter to each you could run a single throttle for both and not have to worry about throttle inputs for shifting. A single shifter and compromised power band or a dual shifter and better power band controls might be more efficient, but actual concentration to work might make you slower.
After some playing with a gearing calculator, a Busa and TL1000S seemed to match up OK by gearing down the Busa motor just slightly:
I tried a few other engine combos, like an R6 + TL, ZX10 + SV1000, etc, and they didn't always match up on every gear. For those I would have to find a compromise, like keeping the twin in the meat of the powerband for lower speeds, and letting the I4 eat in the higher. Would need some overrev protection.
Not motorcycle engines, but still awesome. Mostly a grassroots type solution. This was in HotRod in 2009. He used something like a guibo to link them.
link
In reply to pushrod36:
I remember that car. I think that I would have gone for 4wd with the front engine attached to some sort of transaxle driving the front wheels and the rear running through a standard automatic transmission (4l60e or whatever).
ncjay
Dork
3/5/15 12:19 p.m.
Many moons ago someone welded up two Chevy 350s together to make a V16 engine. With enough time, money, talent, and engineering almost anything can be accomplished.
http://www.museumofamericanspeed.com/Sweet-16-Chevrolet-700-CID-V-16,15339.html
moparman76_69 wrote:
In other news, their idea of autocross is different from what I thought.
https://www.youtube.com/watch?v=tR05Nil-lpQ
Kinda what I envisioned autocross when I first heard the term. Motocross with autos instead of motorcycles.
Gymkhana I heard of before I saw one. Knew people that spent time in Europe.
