There's no real point to this, i just wanted to see if anyone had seen this done somewhere on the internet.
The Volkswagen "W12" motor was literally just two VR6s siamesed together.
Are there other examples of this within OEMs?
And now for the logic jump: Have individuals ever accomplished this? The closest i can come to is the home-brew 4-rotor motors, but that's not really the same thing.
I'm not talking about doing it in their garage entirely... but paying/finding a business that might be able to do this would be worth reading about as well, especially since at the least, we're talking about a custom block and crank.
There is a company that turns the hayabusa motor into a v8 for marine applications I believe.
The BMW 5L V12's are another example of OEM's siamese-ing engines.
fidelity101 wrote:
There is a company that turns the hayabusa motor into a v8 for marine applications I believe.
DPcars has done the same....for a track car
This:
Lives in this:
WV did a W8, W12 and a W16 IIRC.
The Aston Martin V12 is effectively a pair of Duratecs.
Depending on how you read the history, the V-8 in the Triumph Stag was either two SAAB 99 engines put together, or the SAAB 99 enginer was the Stag motor cut in half...
fidelity101 wrote:
There is a company that turns the hayabusa motor into a v8 for marine applications I believe.
Beaten...dunno about marine applications though, this is what they use in the Radical SR8 if I'm not mistaken. Edit: beaten again...same setup, different company.
And it costs all the money.
The V12 in the Toyota Century is basically two separate 2JZs joined with a common crank. The two "halves" of the motor even have separate fuel injector controllers, throttles, etc.
Sky_Render wrote:
The V12 in the Toyota Century is basically two separate 2JZs joined with a common crank. The two "halves" of the motor even have separate fuel injector controllers, throttles, etc.
Those are 1JZs, and it even has two ECUs. If you search for that ecu on Ebay, it'll show as literally two ECUs in one bracket. 
Technically, the production engines are not "siamese" as much as they have been re-designed to be what they are- just based on the original design.
Like the AML V12 being a pair of duratecs- theoretically, yes, but realistically, it's a unique casting for the V12, unique heads, crank, cams, etc.
Same for the W12.
Some engines, you can carry over more of the parts- like on a V12 BMW, it can actually use the heads of the I6, and the W12 can use the heads off the V6's. Or an I4 can use the heads off the v8 base (or something like that).
While making one or two engines out of a welded block is realistic, once you get past a few engines, it's a LOT easier to make a single casting.
I do know of one v12 that is two blocks welded together. But it still needed a new crank and cams to be made....
Swank Force One wrote:
Sky_Render wrote:
The V12 in the Toyota Century is basically two separate 2JZs joined with a common crank. The two "halves" of the motor even have separate fuel injector controllers, throttles, etc.
Those are 1JZs, and it even has two ECUs. If you search for that ecu on Ebay, it'll show as literally two ECUs in one bracket.
Oh, and on this- the twin ECU's is not because of the origin of the engine, it's because for a LONG time, it was impossible to find an ECU that had more than 10 drivers on it. Not due to space, but due to computing power- the V10's didn't spin fast, so they could be run on a single module. V12s wanted the higher speeds, which required two modules so they could keep up.
theoretically, that's not a problem anymore.
The bike-based V8s are from Hartley (the one found in the DP cars) or RST (as used in the V8 Caterham and the V8 Atom, other than the one built by DP). They're really a custom bottom end wearing Busa heads by the time the engines are done. And they're not cheap.
I thought this was going to be about things like the square four used on the Suzuki Gamma and the Ariel motorbikes. Two crankshafts!
I have heard tell that the v8 in the Porsche 928 is two 944 engines
Thing about the BMW v12s.. for a long time they still ran the Straight 6 injection system.. with one system per bank of the engine. Think about that... TWICE the complexity
Wasn't the V12 in the early Lamborghini Miuras a siamesed engine?
J
mad_machine wrote:
I have heard tell that the v8 in the Porsche 928 is two 944 engines
Thing about the BMW v12s.. for a long time they still ran the Straight 6 injection system.. with one system per bank of the engine. Think about that... TWICE the complexity
I wouldn't call it twice the complexity. It just uses two parts doing the exact same thing.
Well, not exactly since there has to be some communication between the modules. So it's more complex, but not double.
It's interesting to do the tuning on the older set ups, since you need two complete sets of developent tools to do the work. More twice the space vs. twice the complexity.
alfadriver wrote:
mad_machine wrote:
I have heard tell that the v8 in the Porsche 928 is two 944 engines
Thing about the BMW v12s.. for a long time they still ran the Straight 6 injection system.. with one system per bank of the engine. Think about that... TWICE the complexity
I wouldn't call it twice the complexity. It just uses two parts doing the exact same thing.
Well, not *exactly* since there has to be some communication between the modules. So it's more complex, but not double.
Was there? My understanding is that they are completely separate systems, at least on the early V12 BMWs
Karacticus wrote:
Depending on how you read the history, the V-8 in the Triumph Stag was either two SAAB 99 engines put together, or the SAAB 99 enginer was the Stag motor cut in half...
It was the latter. However, I'm sure they gave a lot of thought to cutting the motor in half for the Dolomite (its real intended destination. The SAAB was a happy accident later) from the get-go. The "valley" water pump (wait a minute. I'm having a horrible flashback. Must. Get. Water. Pump. Horror. Out. Of. Head....... ARRGH. Okay, I'm better now.) is a dead giveaway. Getting two completely wretched motors for the price of one was the BL mindset at that moment in history. I rebuilt the SAAB version in 1988. I'm told the nightmares will cease soon.
mad_machine wrote:
I have heard tell that the v8 in the Porsche 928 is two 944 engines
Technically the 944 is half the 928 V8, but yes. They had a lot of common parts.
m4ff3w wrote:
alfadriver wrote:
mad_machine wrote:
I have heard tell that the v8 in the Porsche 928 is two 944 engines
Thing about the BMW v12s.. for a long time they still ran the Straight 6 injection system.. with one system per bank of the engine. Think about that... TWICE the complexity
I wouldn't call it twice the complexity. It just uses two parts doing the exact same thing.
Well, not *exactly* since there has to be some communication between the modules. So it's more complex, but not double.
Was there? My understanding is that they are completely separate systems, at least on the early V12 BMWs
Having gone through it, you can't really run them without a little info being passed between the two banks. The basic of the basic is that one module needs to decide some high level "modes" that the engine operates in. Say, idle, decel, or just throttle on. That way, if the mechanical throttles get slightly out of sync (which will happen- there's no way to avoid that), one side won't constantly be trying to idle or decel when the other is trying to move the car.
If you don't have any communication, then it's pretty easy for one side to force the engine to stall. Say it's throttle is closed, and thinks it's supposed to be at idle- it will ratchet the idle valve and the spark to the min level they can get to, and closing the other side's throttle for real will kill the motor.
We found that out the hard way.
In reply to alfadriver:
Back when BMW did their original 12 there was no such thing as e-throttles man. Kinda hard to make the two banks "out of sync" with a throttle cable and a distributor. Dozens of airplane manufacturers figured out how to do it...
Grtechguy wrote:
fidelity101 wrote:
There is a company that turns the hayabusa motor into a v8 for marine applications I believe.
DPcars has done the same....for a track car
This:
Lives in this:
also this just could be speculation or rumor mill, what about the Audi 5 Cyl in comparison to a lambo v10 or R8?
Javelin wrote:
In reply to alfadriver:
Back when BMW did their original 12 there was no such thing as e-throttles man. Kinda hard to make the two banks "out of sync" with a throttle cable and a distributor. Dozens of airplane manufacturers figured out how to do it...
Back when I did the Aston Matin V12, there was not e-throttles, man. And it is VERY easy to get the throttles out of sync enough to be a problem. With a throttle cable and a distributor of some type. Heat does amazing things. Especially when the engine uses very little power to move 10-20mph.
Airplanes rarely use EFI. Nor do they really worry about idle. Or driveability. In this case, it's about the engine under light load coming back to idle and making sure one side doesn't force the whole engine to stall.
