Reposting because I didn't get a clear answer. Consider

>>16207073
after 50%

>>16207082
Why?

>>16207073
how are these engines identical if they have differences?
stop being retarded please

>>16207086
goes higher so its going to take more time to get up their

>>16207090
Because all I'm trying to figure out is whether, theoretically speaking, more RPM = quicker boost, and thus better suited to turbocharging since there'll be less lag.

If you want a real world example, which would spool a turbo quicker: a 110hp 600cc motorcycle engine, or a 110hp 1.6L VW inline four?

>>16207094
But their gearing and power should be identical, so they'll take exactly as much time to get up to a similar RPM point (relative to their RPM range).

>>16207073
You answered your own question. If their efficiency is exactly the same as well then they'll both spool up at 50% (relative to their rpm). If your egnines are identical then their peformance will be identical irrespective of rpm, if you say the one boosts at 50% then naturally the other will boost at 50%.

Volumetric efficiency is the answer, if its the same it means they exhaust the same relative to rpm ergo they boost the same relative to rpm ergo they make the same power relative to rpm%

>>16207133
So, it's more of a matter of which engine is least efficient? Because less efficiency means more gas flow per unit of power produced, and therefore more exhaust volume, and therefore quicker turbo spool.

Which engine would typically have a lower efficiency then? High RPM peak or low RPM peak?

>>16207118
>>16207116
>>16207073
ok you idiot
theres a curve for how much power your turbo can add to your engine
so depending on the curve of the turbo's boost, either engine could boost first.
if you aren't a retard you can figure this shit out with calculus
the bigger the turbo, the more airflow it will take to spool up
you have to have a big turbo for lots of airflow i.e. large displacement or high rpm
if you mismatch your turbo to your engine either could be slower to reach boost
properly configured, the 6k redline will spool quicker but may make less power than the 10k rpm configuration

>>16207073
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

>>16207139
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.

>>16207144
>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?

>>16207149
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?

>>16207146
You can remedy a lot of this by utilising a modern twinscroll VGT.

>>16207156
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 .>>16207152 - this is anon getting a closer answer to the new questions

>>16207152
then they aren't the same engine and won't have an identical power curve now will they?

>>16207162
>>16207152
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

>>16207162
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.

>>16207167
>A larger engine would create more airflow if they had equivalent airflow
What? Also, are you talking relative to their powerband?

>>16207172
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

>>16207172
That's not how identical transmissions work.

File: TURBO.png (21KB, 1068x1000px) Image search: [Google]

21KB, 1068x1000px

>>16207162
>>16207167
pic related, green is the turbo curve

>>16207201
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

>>16207191
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

>>16207201
>>16207212
Relative to it's powerband, doesn't the 10K RPM engine build boost earlier, if green is the boost curve?

>>16207243
Oops, must have missed that. That's not engines or turbos function either way.

>>16207243
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

File: MTT%20Y2K%20Turbine%20SuperBike%20%20%203[1].jpg (32KB, 600x365px) Image search: [Google]

32KB, 600x365px

>>16207243
also if you're this worried about linear boost performance, why not just use a jet engine?

>>16207259
I'm not completely looking for linear performance, I'm looking for quick spooling and better throttle response.

>>16207252
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.

>>16207268
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

>>16207073
>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.

https://www.youtube.com/watch?v=4BOryrhs9iA

>>16207073

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.

File: rly.jpg (45KB, 740x721px) Image search: [Google]

45KB, 740x721px

>>16208787
>you can't have them make the same power at their respective redlines

>>16208920
You literally can't if they are identical.

See the formula I posted. Try the math yourself

File: diagram.png (52KB, 1478x599px) Image search: [Google]

52KB, 1478x599px

>>16208920

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

>>16207116
The vw because only an idiot would make a motorcycle with a turbo

>>16209025
IP builds a device to make their torques identical without changing anything else.

What then?

File: diagram2.jpg (93KB, 1478x599px) Image search: [Google]

93KB, 1478x599px

>>16209058
Simple, you get different peak horsepowers

Which just makes the curves colinear