Two engines controlled by one ECU POSSIBLE???

[Diablo_niterider]

there was this 1 car with 2 kawasaki zx12r engines (1 for front and 1 for rear), it was featured on a show with tiff needell (5th gear host), i dnt rmmbr the name but i guess it had a single ecu and it looked like the caterham. and it looked fun to drive and tiff pushed it so hard, he ended up blowing up 1 of the engines, do check it

[Eryk Sokolowski]

tiger z100 and it was rear wheel drive, they made only one with 4 wheel drive for acceleration record...

they are no longer in production...

already spoke to the company making them...

the engines are completely independent, it has two gear boxes and they are coupled by a Y diff...

[ZAMR]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RenM:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ZAMR:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RenM:
if they are not connected together mechanically and you can not assure a constant ignition spacing your engines will hardly work at all if you are using one intake. (which you have to do because you have to use one restrictor)

There will be a huge difference in the amount of air every engine gets dependent on your ignition spacing! If they both suck air at the same time they will get far less air then with a 360° difference. It will be impossible to tune the engine mapping because you will either run extremly lean or extremly rich, to the point where your mixture wont be able to combust. </div></BLOCKQUOTE>

2 stage intake </div></BLOCKQUOTE>
you will need 1 restrictor and thats the problem </div></BLOCKQUOTE>

Have the restrictor go to one plenum. Then, have 2 runners go to 2 separate plenums. Have the two separate engines draw from the two separate plenums. That dampens the pressure effects and intake event problems.

[Wesley]

Though your flow losses will mount significantly.

[Sisyphus]

I like the way you think but you are thinking too small.
Back in the 70's there was a CanAm car with 4 two cylinder, 2 stroke McCullock engines in it--one for each wheel. No ECU's in them days--all mechanical linkages, etc
I think it might have made one lap...

[RenM]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ZAMR:

Have the restrictor go to one plenum. Then, have 2 runners go to 2 separate plenums. Have the two separate engines draw from the two separate plenums. That dampens the pressure effects and intake event problems. </div></BLOCKQUOTE>
If you are working with multiple plenums and a lot of volume you will have a catastrophic throttle response and still not be able to completly compensate the effects.

[Adambomb]

We've sort of "bench raced" the idea of using two engines (never seriously), more so that you could get rid of the diff and even get "torque vectoring" as Hector mentioned. Obviously, as Drew mentioned, both engines would necessarily need to be able to run at different speeds.

And even then, taking into consideration what has been mentioned here, it sounds like exponentially more pain than what it is worth (mostly due to the fact that you are forced to run a single restrictor). I have a hard time believing you could get it to run right.

If torque vectoring is what you want, IMO you'd be much better off with one larger engine and an active diff!

On the other hand, one other thing we came up with when discussing multiple engines: Baja rules don't specify that you can only run one engine...

[Adambomb]

Also, forgot to mention: ISU has a mini-tractor pull team (Power Pullers). Their rules state that they can use as many engines as they want, as long as they are un-modified spec. Briggs and Stratton v-twins (I'm thinking they are like 16 or 20hp) and total vehicle weight is under 900 lbs. This year I think they're running 5. One of their old cars has 4 of them, and they are timed for even-fire, it sounds vaguely reminiscent of an old flat-head Ford V8.

[ZAMR]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RenM:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ZAMR:

Have the restrictor go to one plenum. Then, have 2 runners go to 2 separate plenums. Have the two separate engines draw from the two separate plenums. That dampens the pressure effects and intake event problems. </div></BLOCKQUOTE>
If you are working with multiple plenums and a lot of volume you will have a catastrophic throttle response and still not be able to completly compensate the effects. </div></BLOCKQUOTE>

Heisler page 263. 2-Stage intakes exist. They are deisnged for multiple cylinder engines that have overlapping intake events.

You need 1 restrictor. yes. You need 1 intake. Yes. You CANNOT tune an intake if you CANNOT predict the intake event timing. You need 2 plenums, with a damping plenum beforehand. If not, you may have intake events that send pressure waves that interfere with drawing air through the restrictor. If you want to use Helmholtz business, you need to separate the intake events.

Perhaps you will have flow losses, yes. But I see this as the only way to maintain consistent airflow and wave properties, ergo a consistent fuel map and consistent air/fuel mix and VE for a given RPM/throttle. Otherwise you can't drive your car.

If you can make sure the ECU lines the cranks up (impossible or very hard) then you can make a normal intake.

I don't agree that the idle will be harder to control. Your total plenum volume for the 3 plenums for the two engines should only be slightly larger than if you ran 1 engine with equivalent volume. Airflow will be smooth because of the damping chambers, but you should be able to control the plenum pressure just as effectively as a single engine.

[L B0MB]

Airflow meters would be the only way to run 2 engines off one restrictor as MAP would be constant across the x many plenums whereas engine speed would vary depending on available grip at the driven wheel

Edit: 2 engines in fsae is a silly idea