30 replies to this topic

[Oscar1985]

just thought about exhausts, as there will be an engine up front and 1 in the back then would the pipe on the back engine need to be made the same length as the front in a curved type of way to match the back pressure of the front?

[Calman]

No because you could make the one for the rear however, and then make the front exhaust smaller diameter for example to restrict the back pressure making them run in sync if you get me?

[Oscar1985]

No because you could make the one for the rear however, and then make the front exhaust smaller diameter for example to restrict the back pressure making them run in sync if you get me?

yeah, I understand, right, I need another Mini. Anyone fancy a trip to Margate to help build this, lol, theres as much Stella and Dorito's as you can dare cram in your face's

[alexcrosse]

If you just knock one engine into neutral and switch it off, then drive with the other, surely you will destroy the gearbox? Itll still spin one shaft and a few gears at very high RPM with no oil feed?

[Oscar1985]

if thts the case alex mabee i'll only use 1 engine for MoT time, lol. But thanks for that little insight, i wasn't aware that that would happen, since i now do i can try and get around this somehow.

[R1mini]

Just my worthless opinion, but you will go faster round a circuit with a single high power engine in a lightweight well sorted mid engined mini

Cheers
David

[al_reidy]

If you just knock one engine into neutral and switch it off, then drive with the other, surely you will destroy the gearbox? Itll still spin one shaft and a few gears at very high RPM with no oil feed?

see i thought the gears in the gearbox sat in oil, so the only thing spinning would be in oil naturally circulated around the box due to the spinning motion.
i dont know much about bike engines but i cant see it being a problem.

[alexcrosse]

nope, as far as i can remember the gearbox is above the oil in the sump on the r1...?! the gearbox is actually at piston height, but to be honest i cant remember what the oil feed situation is to the gearbox.

*edit*



Here you can see where the gearbox is in relation to the oil site glass

Edited by alexcrosse, 09 November 2009 - 02:55 PM.

[R1minimagic]

I agree with David, a single engine with more power would be quicker.

Regarding the gears, they sit in oil in a mini gearbox because it has the gearbox and sump combined into one but most bike engines have the gearbox higher up than the sump so they would not be sat in oil, whether that means there would be a problem when running in neutral i dont know...

[alexcrosse]

i cant see an awful lot keeping the oil in another reservoir when cornering etc, because eventually it would spil back into the sump, im guessing this little reservoir is what makes all the difference when you look at the oil sight glass with and without the engine running?

[De Blerende Beetle]

Just my worthless opinion, but you will go faster round a circuit with a single high power engine in a lightweight well sorted mid engined mini

Cheers
David

I must agree. Same power, less weight/better distribution.

[Zcars Richard]

Twin engine can be done but a good turbo hayabusa will eat anything 4wd for breakfast. We have done twin engined 2wd, 4wd lots of times but to get the 4wd to work properly you need alot of experience and the right equipment which for electrics alone is over £20k. The extra weight isnt really overcome by power . would be ok for drag car but a nightmare on a track.

[Zcars Richard]

Just my worthless opinion, but you will go faster round a circuit with a single high power engine in a lightweight well sorted mid engined mini

Cheers
David

Very true

[Zcars Richard]

we can sell a drive box so both engines are running the same driveshafts but this would be 2 wd only. You will struggle to do a twin engine 4wd mini but it isnt impossible will just cost a fortune to make it any good. see my later post .

The idea of using an engine to power each set ofwheels would surly mean doing away with any trick boxes. Using 1 engine/gearbox to drive the front and one to drive the rear! Therefore creating RWD-4WD-FWD all on the move.
Thats the part i like the idea of, then surly to disengage 1 of the engines you just knock it into neutral?

that does sound sweet, the trick would be to get each to change gear at the same point but still allowing one engine if you wanted to be left alone.
easier with the sequential bike engines as you could link both sticks as one and unbuckle them to drive on the road.

having different final drives might cause other problems. getting top power out of one engine will cause the other to overrev? equally down shifting could over rev one. how about just down tuning or restricting one engine so that its power curve matched the other engine but just less power. that way it would have predictable smoother power ?

That sounds like the way to go Reidy, As I said a 'T' shaped shifter split down the middle 1 side of the T on 1 gearbox and the other side of the T on the other, ok guys we need an engineer of some kind to make this work, i think i know just the man. Would you suggest using Z cars front/rear subframes and kits and bolting to an existing shell, or going for a space frame?

[mika]

just run two engines have the gear change linked to solonods and have then wire to ignition switch have to switch so each engine can be started weperate now as i see it if both engines are running solinods would fire at same times so same gears no stick both in nutral turn off any engine that would kill solinode to that engine and you can run one engine and only one will change gear simples now anyone like to buy my spaceframe project lol tc