Two/ dual engines...
Discussion
Now i have very little technical knowledge, but it has always baffeled and confused me, how on earth any dual engine set up in a car, would have any speed/power benefit; sure a engine to run the rear wheels and a engine to run the front would create more traction (but obviosuly add significant amounts of weight).
And the other option, say two engines paired together which a rating of say 200hp each, surely pairing them would mean no benefit as both engines would simply be making the same power - but simply working side by side - and not doubling the power to 400bhp. (Linked throtles and therefore rpm of both engines - and state of tune etc asumed).
So can anyone explain the benefit of any dual engine set up? As it's something that has puzzled and confused me for years.
Please don't laugh
And thanks in advance.
And the other option, say two engines paired together which a rating of say 200hp each, surely pairing them would mean no benefit as both engines would simply be making the same power - but simply working side by side - and not doubling the power to 400bhp. (Linked throtles and therefore rpm of both engines - and state of tune etc asumed).
So can anyone explain the benefit of any dual engine set up? As it's something that has puzzled and confused me for years.
Please don't laugh
And thanks in advance.
Wow, just wow!
Of course it doubles the power. It works in the same manner as any other 4wd system, in terms of power at least. What matters is AWHP, the amount of power that is transmitted to the tarmac by the driven wheels. Everything being equal a 4wd car with the same amount of power (and power/torque curve not that this is possible) as a rwd car, will reach the same VMAX, and accelerate exactly the same providing there are no traction issues.
What is a problem with dual engines, is the fact that you don't want to transmit power equally between the front and back especially during cornering, and quite simply any setup that requires two engines is going to be inherently heavier than a single engine set up, as well as have greater frictional losses. In other words it's pointless. Apart from packaging perhaps, i.e. on a a superkart or something.
Of course it doubles the power. It works in the same manner as any other 4wd system, in terms of power at least. What matters is AWHP, the amount of power that is transmitted to the tarmac by the driven wheels. Everything being equal a 4wd car with the same amount of power (and power/torque curve not that this is possible) as a rwd car, will reach the same VMAX, and accelerate exactly the same providing there are no traction issues.
What is a problem with dual engines, is the fact that you don't want to transmit power equally between the front and back especially during cornering, and quite simply any setup that requires two engines is going to be inherently heavier than a single engine set up, as well as have greater frictional losses. In other words it's pointless. Apart from packaging perhaps, i.e. on a a superkart or something.
i always wondered this too...
If you have two engines creating 4wd, then you would get twice as much torque surely over the entire car, rather than having just one engine and fwd. SO, i would have thought that acceleration was much quicker, plus the fact you have more traction. The engines would have to be identical though. would you use one ECU and split it? or 2 ECU's set up individually for the 2 seperate engines with the same feed?
SO many questions...
If you have two engines creating 4wd, then you would get twice as much torque surely over the entire car, rather than having just one engine and fwd. SO, i would have thought that acceleration was much quicker, plus the fact you have more traction. The engines would have to be identical though. would you use one ECU and split it? or 2 ECU's set up individually for the 2 seperate engines with the same feed?
SO many questions...
intrepid44 said:
Of course it doubles the power. It works in the same manner as any other 4wd system, in terms of power at least. What matters is AWHP, the amount of power that is transmitted to the tarmac by the driven wheels. Everything being equal a 4wd car with the same amount of power (and power/torque curve not that this is possible) as a rwd car, will reach the same VMAX, and accelerate exactly the same providing there are no traction issues.
Really? 
Is this a fact? Still a little confused surely the max -lets say- "power" on each individual axle will prohibit the vmax.As having the same "power" on each axle , simply will not have the required 'grunt' to continue accelerating past a given point...
No?
As for the other example surely two engines placed side-by-side, - or similar- will not double the power, unless they share the same crankshaft...
I chatted about a year ago to a guy that had built a twin engined Renault 5 Turbo... He said he did just for the challenge as he had the engine, and it certainly made the car faster as the extra power in the rear overcame any weight gain of the additional engine/tramission and frame to accomodate it all..
he reckoned it wasn't to hard to set-up the two engines to sync at exactly the same revs, but I think he was being modest, as I've seen another twin turbo Mustang engined Sierra he's built..
he reckoned it wasn't to hard to set-up the two engines to sync at exactly the same revs, but I think he was being modest, as I've seen another twin turbo Mustang engined Sierra he's built..
Edited by chevy-stu on Wednesday 1st December 01:48
MX7 said:
Everything already been done, and someone has got the link to prove it on ph haha.I've started sifting though it now, although i've found very little explainations so far.
Ty anyway, ph never ceases to amaze!
Or888t said:
intrepid44 said:
Of course it doubles the power. It works in the same manner as any other 4wd system, in terms of power at least. What matters is AWHP, the amount of power that is transmitted to the tarmac by the driven wheels. Everything being equal a 4wd car with the same amount of power (and power/torque curve not that this is possible) as a rwd car, will reach the same VMAX, and accelerate exactly the same providing there are no traction issues.
Really? Is this a fact? Still a little confused surely the max -lets say- "power" on each individual axle will prohibit the vmax.As having the same "power" on each axle , simply will not have the required 'grunt' to continue accelerating past a given point...
No?
As for the other example surely two engines placed side-by-side, - or similar- will not double the power, unless they share the same crankshaft...
C
Hugo a Gogo said:
why do they make engines with more than one cylinder?
surely each cylinder is just making the same power?
Haha i'm geting it now, after reading though the linked thread; seams like the engines don't have to be matched rpm etc, if they're conected to the same driveshaft they'll double the power. Simple as that...surely each cylinder is just making the same power?
I think
Or888t said:
Hugo a Gogo said:
why do they make engines with more than one cylinder?
surely each cylinder is just making the same power?
Haha i'm geting it now, after reading though the linked thread; seams like the engines don't have to be matched rpm etc, if they're conected to the same driveshaft they'll double the power. Simple as that...surely each cylinder is just making the same power?
I think
Or888t said:
Hugo a Gogo said:
why do they make engines with more than one cylinder?
surely each cylinder is just making the same power?
Haha i'm geting it now, after reading though the linked thread; seams like the engines don't have to be matched rpm etc, if they're conected to the same driveshaft they'll double the power. Simple as that...surely each cylinder is just making the same power?
I think
MX7 said:
Or888t said:
Hugo a Gogo said:
why do they make engines with more than one cylinder?
surely each cylinder is just making the same power?
Haha i'm geting it now, after reading though the linked thread; seams like the engines don't have to be matched rpm etc, if they're conected to the same driveshaft they'll double the power. Simple as that...surely each cylinder is just making the same power?
I think
PhillipM said:
AS said before, you don't need to match the engines, all this crap about syncronising power and revs between them just came from a few bulls
t max power articles where the installers tried to make it look like they did more work than just bung a front subframe in the back.
The clutch and gearlinkage is the worst bit.
The engine is always, always, slowed down by the load - i.e. Accelerating the mass of the car - ergo, no matching is necessary as both axles on the car are connected by the road, and hence already synchronised.
Magic eh?
Anyhow, it seems a good idea down the pub until you realise that you've just added the weight of another crankcase, water pump, oil pump, crank, bearings, flywheel, clutch, transmission, shafts, hoses, radiator, etc, etc.
It's like that tandem bike someone mentioned earlier - great, you've now got twice the power for when you hit a hill!
But, you've also got two fat bds aboard to drag up there rather than one - the only thing it's helped with is it's made the bicycle feel a bit lighter..
Then you realise that a pair of 100bhp engines in a car are probably not going to be any faster than a nice little turbo bolted on your original 100bhp engine to give it 150-160bhp for about 20kg more weight....
Especially if it's the normal cut-and-shut and front subframe in the rear and hope-to-fk-it-doesn't-kill-you-in-the-wet approach to suspension geometery most of these heaps have...;)
Thanks to everyone whos contributed to me overcoming my confustion t max power articles where the installers tried to make it look like they did more work than just bung a front subframe in the back.The clutch and gearlinkage is the worst bit.
The engine is always, always, slowed down by the load - i.e. Accelerating the mass of the car - ergo, no matching is necessary as both axles on the car are connected by the road, and hence already synchronised.
Magic eh?
Anyhow, it seems a good idea down the pub until you realise that you've just added the weight of another crankcase, water pump, oil pump, crank, bearings, flywheel, clutch, transmission, shafts, hoses, radiator, etc, etc.
It's like that tandem bike someone mentioned earlier - great, you've now got twice the power for when you hit a hill!
But, you've also got two fat b
ds aboard to drag up there rather than one - the only thing it's helped with is it's made the bicycle feel a bit lighter..Then you realise that a pair of 100bhp engines in a car are probably not going to be any faster than a nice little turbo bolted on your original 100bhp engine to give it 150-160bhp for about 20kg more weight....
Especially if it's the normal cut-and-shut and front subframe in the rear and hope-to-f
k-it-doesn't-kill-you-in-the-wet approach to suspension geometery most of these heaps have...;)Edited by PhillipM on Saturday 3rd July 00:33
Edited by PhillipM on Saturday 3rd July 00:34
Or888t said:
Hugo a Gogo said:
why do they make engines with more than one cylinder?
surely each cylinder is just making the same power?
Haha i'm geting it now, after reading though the linked thread; seams like the engines don't have to be matched rpm etc, if they're conected to the same driveshaft they'll double the power. Simple as that...surely each cylinder is just making the same power?
I think
Each engine is sharing the load.
The twin engined tiger ZZ1 kit car got it's fastest 0-60 time (2.8 seconds or something silly) with the engine driving the back wheels in 1st gear and the engine driving the front wheels in 2nd. Get you're head around that!
"Matching" engines isn't an issue either. Assuming there is enough traction, if engine 1 goes faster than engine 2, it takes all of the load. But as engine 2 now has no load it spins faster until it takes up it's share of the load again. In reality, this happens almost instantaneously so there is never an issue.
ETA seems PhillipM has unknowingly beaten me to it!
"Matching" engines isn't an issue either. Assuming there is enough traction, if engine 1 goes faster than engine 2, it takes all of the load. But as engine 2 now has no load it spins faster until it takes up it's share of the load again. In reality, this happens almost instantaneously so there is never an issue.
ETA seems PhillipM has unknowingly beaten me to it!
Edited by busta on Wednesday 1st December 17:26
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