Engine tunning

is it possible to tune, or make an engine where peak torque, power, and efficincy all are at the same rpm

a really big turbo

its "tuning" btw

It would have to occur at 5250 rpm for HP and torque. Torque is always higher below 5250, and HP is always higher above 5250. Its a mathematical thing that has nothing to do with engine parameters. Define which efficiency you mean: thermal efficiency, volumetric efficiency, frictional efficiency, mileage?

It would have to occur at 5250 rpm for HP and torque. Torque is always higher below 5250, and HP is always higher above 5250. Its a mathematical thing that has nothing to do with engine parameters. Define which efficiency you mean: thermal efficiency, volumetric efficiency, frictional efficiency, mileage?
if the torque drops rapidly after peaking at any RPM, the HP peak would be there also

Its not very desirable IMO, to seak out such a situation. Easiest way would be to limit the RPM so that the torque curve doesn't peak until it hits the rev limiter. On a NA engine, this would require a really big cam(s), or a really big turbo, neutering the lower RPM as much as possible

But he didn't ask if it was an intelligent thing to seak, only how to accomplish it.

Sure.
On a diesel peak efficiency is usually very close to peak torque. So that ones easy.
As for peak power and torque. Simply governing the engine to the max torque revs will cause it's power to drop rapidly to nothing beyond that.

Bingo, all three in one.
However it's not that practical as a solution to anything. The typical diesel solution of peak power and efficiency in roughly the same spot works very well, peak power is accessed by going down a gear when you need to.

^^^ maybe i just dont understand what you said, but hp has nothing to do with gearing. you go down a gear to increase the torque to the wheels. hp stays the same.

No... he's saying that to access higher rpm hp, you can downshift. He wasn't saying that gearing affects hp.

Gearing has everything to do with H.P.! There is always a means to an end. Why would you want torque and H.P. to peak at the same time? Unless your pulling your doublewide with a half ton pick-up, your effiency would go out the window....Road

^^^ maybe i just dont understand what you said, but hp has nothing to do with gearing. you go down a gear to increase the torque to the wheels. hp stays the same.
Like Curtis said, downshifting gives you higher engine revs and access to more power at the same road speed.

ok sorry i must be tired or something. ill come back when i have my head on straight.