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yeah, i was thinking this could be a negative side effect of one

ddgonzal and l18 I can see what you are saying and I to agree 3 cylinders is going to be better than 2 cylinders that's plain to see.
I also agree the initial burst as the valve opens is going to be its maximum force.

One thing I think is your term of "pulses" is actually the same as my term of "gas flow" and like I said I agree the initial valve openning is its peak power. I can see how you get the term "pulse" because of its highs and lows, like its starting then stopping but when at only 1000RPM this comes down to 100th's of a second can you say it would have such a negative effect that it's no good? And think about it as the revs increase this 100th of a second pulseing becomes even smaller.

I still dont belive to say 3 cylinders is the minimum to use, for the only reason that you dont see car manufacturers or such as being a good enough reason for not to bother doing it with only 2 cylinders.As when you look at it, its coming down to 100th's of a second.

I still belive pulsing is the wrong term to use when talking about a turbine.
I understand using the term pulsing when describing how extracters work but to use it to describe a turbine operation( a fan which requires a volume to pass it to operate) is misleading.

To me "pulse" means a beat
"gas flow" means a volume.

One other thing L18

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4cyl
revs per minute 2500
fires/exhausts per rev 2
pulse to each turbo per rev 1
pulses to each turbo per minute 2500
pulses per second 41.67
cyl displacement (2ltr)* 0.5
exhaust flow (l/s) 20.83

6cyl
revs per minute 2500
fires/exhausts per rev 3
pulse to each turbo per rev 1.5
pulses to each turbo per minute 3750
pulses per second 62.5
cyl displacement (2ltr)* 0.33
exhaust flow (l/s) 20.83

*Assuming that each motor is 2ltr, for argument sake, trying to assume equal turbo size

from that table u can see the diffrence from 4cyl to 6cyl in exhaust pulses to each turbo is the diffrence of 41.67 to 62.5 per SECOND, and if all was equal (like same size displacement motor (2ltr in this case)), the size of each pulse from the 4cyl to 6cyl is 0.5 to .33 of a litre

so i think it would come bloody close to evening out really, as event though the 4cyl only has 66% of the peaks, the 6cyl peaks are only 66% of the size of the 4cyl, in other words it averages out

and surely you would agree that at such low revs as 2500, the pulse coming 41 times per second, the turbine wheel would only slow by the minutest most negligible amount concievable between each pulse? yes or no???

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I give up. Yes, I did say

L18 is rite in his logic E M C X2.How fast can you spin a bike wheel with two hands,now hit the wheel with the tip of your finger at the rite angle sharply.That is = to pulse,wheel spins faster now.
Ever thought about the turbos mounted inline.One will work at low speed till you get to a certain RPM then the next one will cut in and you should get X2 the pressure.
Thats what my TURBO book says,can post a pic from it.

yeah post that pic mate, i want to see how the plumbing works, maybe with an external wastegate or something???

L18 I too am starting to give up.
If thats your explination so be it.

Like I said I can understand using the term pulsing when describing HOWextracter work. Just like the way you explained in your last post.

Now like I said I belive it is the wrong term to use when describing a turbines operation.
Heres why;
Firstly lets make it clear, yes any volume no matter how big or small can pass through a turbine with out operating it. Yes the turbine is a restriction in its path but at a slow enough speed any volume can pass it.
Now if we take the exhaust gas volume from one cylinder it will pass through the turbine unnoticed, but if within a 100th of a second we add another and so on, the exhaust gas volume will have increased and the turbine will be a good restriction now. And then this volume of exhaust gas will try to go to the lowest pressure it can find and this is on the other side of the turbine. ( In the un restrictive exhaust) As this exhaust gas volume moves to the lower pressure it is this gas flow that causes the turbine to move and begin to rotate.
Isnt this why on a turbo motor you put a non restrictive exhaust to aid in flow?
Now lets look at turbo sizing;
Take a small turbo, its going to spool up at a lower rpm. It wont take a great exhaust gas volume to create a flow to start the turbine spinning
Take a bigger turbo, its going to spool up at a higher rpm. At a low rpm the exhaust gas volume easily passes through the turbine unrestricted. At a higher rpm the exhaust gas volume is being created to quick for the turbine, so much that the turbine becomes a restriction and the flow of this exhaust gas volume starts the turbine spinning.
Now lets look at a short turbo manifold compared to a J pipe turbo manifold;
Short manifold is a smaller area before the turbine. If we add exhaust gas volume to this it too passes through the turbine unnoticed but if we increase the volume of gas the turbine becomes a retsriction and the flow begins the turbine spinning at a certain engine rpm.
Now take a J pipe setup, there is a larger area before the turbine,same thing gases pass through the turbine unnoticed, but but increase the speed of which these gases are created and the turbine will begin to spin from this exhaust gas flow. But with a j pipe setup since there is a larger area before the turbine the exhaust gas volume will have to be increased(ie; higher engine rpm ) before the turbine will become a restriction for this flow of exhaust gases.

Short manifold and a J pipe setup still create same boost level, just the short manifold causes the turbo to spool up earlier in the engines rpm range.

Now if these exhaust pulsesare what mainly drive the turbine theoreticly yes the short manifold would be sent the strongest pulses to the turbine making it spool up quicker than a J pipe setup. This being as by the time these pulses get to the turbine on a J pipe setup, these pulses are weaker. Thus the J pipe setup will not spool up as quick.
BUT WHY do both setups still create the same overall boost level?

This is why I think pulsing has little to do with it. And this is why I say it comes down to gas flow.

Cheers Steve

HOW DO YOU PUT IT ON HERE X2 turbos inline

like this mate