Reposting because I didn't get a clear answer

also turbo is always a compromise between low rpm spooling and high rpm power so you choose lag or starvation depending on your turbo size when you run a single turbo configuration

Which engine is more effiecient, beign efficient means moving air into the engine, compressing it and combusting it as cleanly as possible and exhausting as much of it as quick as possible. So if your 6000rpm engine can move air through it very quickly and efficiently and the 10k rpm engine has some issues doing the same, then the 6k engine will make more power because its moving the gasses out quicker, obviously your volume will increase with your efficiency. But your question was if both engines are exactey the same except for operating rpm .. . . . in this scenario they will be the same.

>the bigger the turbo, the more airflow it will take to spool up
>Identical turbo
So all we're trying to determine here is exhaust flow.

>lots of airflow i.e. large displacement or high rpm
Think of the 10K engine as low displacement, high RPM, and the 6K engine as high displacement, low RPM. Which is going to create more airflow: displacement or RPM?

What about added ring drag in the 10K engine? Would that add some inefficiency at the same output power level, therefore adding exhaust volume?

Does this mean that inefficient engines are more suited to turbocharging?

You can remedy a lot of this by utilising a modern twinscroll VGT.

If you want to get really technical I think this is the wrong place. I was just trying to answer the question based on the info given in the OP . - this is user getting a closer answer to the new questions

then they aren't the same engine and won't have an identical power curve now will they?

but just to humor you
the 6k engine, like i said, would spool faster.
because a larger displacement engine would move more air at idle and low throttle than your proposed alternative 10k engine with equivalent airflow

What if they had a completely linear powerband? Engine A goes straight from 0 to 110 in 6K RPM, Engine B does the same from 0 to 10K RPM.

>A larger engine would create more airflow if they had equivalent airflow
What? Also, are you talking relative to their powerband?

YES relative to the powerband. hell the idle of the 6000k engine will displace much more air than the idle of the 1000k if they both have the same power curve and peak power and just have different displacements

That's not how identical transmissions work.

pic related, green is the turbo curve

i should note that blue is the 6k engine, red is the 10k engine, green is the turbo curve and the turbo rpm axis is vertical

They have a different final drive ratio though, as mentioned in the OP.
>Final drive as such that both cars drive at the same speed when they're at redline

Relative to it's powerband, doesn't the 10K RPM engine build boost earlier, if green is the boost curve?

Oops, must have missed that. That's not engines or turbos function either way.

no im a bad graph maker
see where the blue crosses teh green line higher up
that means theres more airflow at any given rpm
therefore the turbo should spool earlier if properly fitted to your application

also if you're this worried about linear boost performance, why not just use a jet engine?

I'm not completely looking for linear performance, I'm looking for quick spooling and better throttle response.

But there's no reason in that graph to suggest a 6K RPM 300hp engine would produce more exhaust flow than a 300hp 10K RPm engine. Boost curve of the turbo and engine power (when still naturally aspirated) is completely unrelated.

you're right. we can only compare two engines that have identical air needs @ 6000 and 10000 rpm respectively.
I believe your question was which would spool faster, in which case the 6000rpm most definitely would due to the higher air displacement @ idle

>Consider two identical engines.
>They make the exact same peak power.
>They have an identical volumetric efficiency.
>They have an identical air:fuel ratio.
You don't know how engines work, do you? What you stated is impossible. Read a book, nigger but after you watch this youtube primer on the subject.

youtube.com/watch?v=4BOryrhs9iA

For one, you can't have them make the same power at their respective redlines.

HP = Torque x RPM ÷ 5252

Meaning if you held HP constant and made RPM increase, total engine torque would need to go down.

But, let's just ignore that and say you have the same engine and you simply change where it redlines and nothing else.

The answer to that question is: It's going to build boost exactly the same way.

Now, if you had a very very large turbo, you may find that the amount of exhaust that you're producing at 6k RPM isn't enough to get it to spool easily. This would result in the cylinder pressures needing to be very high to use the turbo effectively. (The turbo would spool itself more)

You may find that at 10k RPM that the engine produces enough exhaust to spool the turbo by itself and so you may find that the turbo doesn't need to charge itself as much.

Again this is all theoretical and your original question assumes a lot of stuff that is impossible.

>How does tarbo work if physics don't apply
the thread

However my feeling tells me that the 10k engine will work the tarbo more efficiently due to straightening out airflow fluctuations.
Now go and write a scientific paper, you lazy shits.

>you can't have them make the same power at their respective redlines

You literally can't if they are identical.

See the formula I posted. Try the math yourself

You probably lost interest after shitposting but I made you a diagram explaining

The vw because only an idiot would make a motorcycle with a turbo

IP builds a device to make their torques identical without changing anything else.

What then?

Simple, you get different peak horsepowers

Which just makes the curves colinear