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differentials
liam.mccaffrey - 12/6/04 at 05:28 PM

Would it be possible to use a differential to couple 2 engines together? What i mean is to use 2 engines, say bike engines, to drive the half shaft flanges and use the driveshaft flange as the output.. As i understand diffs, this arrangement would average the input speeds of the engines but would sum their torques. I have thought about this and whether it would have the same adverse tooth loading effect as "flipping the diff" say for a wrong way turning honda engine. At the moment i don't think it would. I have a problem visualising differentials so am open to be proven wrong. Assuming all problems like synchronous ignition and getting both the engines to turn the same way (i.e. just bolting the engines to the diff flanges would cause them to rotate in opposite directions) were addressed, would this be mechanically possible?

I am not proposing to do this, it is just a though experiment.

[Edited on 12/6/04 by liam.mccaffrey]


JoelP - 12/6/04 at 05:41 PM

having an LSD would be a good start i think, to encourage the engines to go at the same speed.

it is hard to think of a drivetrain setup in which this would be beneficial though, as the engines would be transverse. t'would end up very wide. with bike engines i was thinking of chain-driving the diff flange, from two engines side by side. Then they have to go at the same revs.


liam.mccaffrey - 12/6/04 at 05:54 PM

as i said it was just a thought experiment
i have thought about a way in which it s possible to do, you could run 1 engine straight to diff and the other could be above the diff but pointing the same way but running the other side of the diff by chain. But yes the configuration whilt it is possible is by no means practicle.

LSD would be a good start though.

whilst writing this i have had an idea which would let the engines be mounted longitudenly side by side, using bevel gears to run the diff flanges!!


JoelP - 12/6/04 at 06:07 PM

thats what im going to do, to make a middy with 2 zx9r engines! i got a catalogue from HPC gears, they make all sorts of gears and chains, custom too i think. Plus by including a chain drive, you can choose the final drive ratio more specifically!

ps on the o/s engine you would need a short extension driveshaft to clear the gubbins.

[Edited on 12/6/04 by JoelP]


liam.mccaffrey - 12/6/04 at 06:45 PM

you could do whatever you wanted methinks!

were you going to do this anyway or did my post prompt you?

I think i will do this too it'd be a bit cheaper than those 2 in 1 bike engine v8's


JoelP - 12/6/04 at 06:56 PM

yeah, i've been planning it for a few months now. seems like a good plan! I have the first engine, gonna get it running before i get the second...


Alan B - 12/6/04 at 07:23 PM

quote:
Originally posted by liam.mccaffrey
.......as i said it was just a thought experiment........



Being surrounded by a bunch of naked women usually figures in my thought experiments........


liam.mccaffrey - 12/6/04 at 09:12 PM

this particular thought experiment involved many naked women assemling the twin engined diff coupled drivetrain, all greasy with oil and stuff


Alan B - 12/6/04 at 09:40 PM

There ya go...great minds think alike...


Peteff - 13/6/04 at 12:23 AM

It would have to be a locked diff for it to work, wouldn't it? The engines would have to be well synchronised also or you will have some strange characteristics.


liam.mccaffrey - 13/6/04 at 09:52 AM

i dont think it would be too hard to synchronise ignition if you had an aftermarket ecu like emerald or something, would it?

I thought that having a LSD would minimise any torque differences between the 2 engines if they had a locked diff coupling them wouldn't they work against each other somtimes? What i mean is that the engines will have slightly different characteristics and running them backwards through an LSD would make for a much smoother drivetrain.