What is limiting crank HP mechanically?
 

I've been told that a Renesis engine can give 370~380 crank HP without modifications.

What is limiting this?

I'm by that not talking about limiting factors as injection system, intake pressure, exhaust or any other, but the engine block itself.

And; Is there any well documented projects that has made modifications to increase this limit?

Hymee did an engine dyno (JUST THE ENGINE) with a supercharger, and only got to I believe 340 crank HP..

Who told you 370-380?

I believe the ultimate limit is shaft deflection, due to the lack of a center journal.......

I could be wrong.

Yes but he runs a bolt on system, no change of fuel pump, ignition coils and so on.

And he got 360Hp running on E85.

This is more what I'm asking about. Bolts holding the block together is also a limiting factor, bearings might also be a problem? Apex seals I guess.

Thing is that I'm wondering how much that needs to be done if I want to go to 5-600Hp. If compression ratio is decreased(by machining) it is possible to increase boost, but what and when do I need to change?

Theimiting factor is the side exhaust ports before anything else

OK, so if I peripheral port my engine, how much is it possible to extract before I need to do further modification, and what is next limitation?

The biggest limit is probably how much money you have.

That too :lol:

OK, spoke to a guy on the phone and he said this as well, the problem is that seals will break if boost is too high. Peripheral porting is a problem, as I need to get it through emission control.

Have anyone done something about this exhaust port limitation? Beside streetporting/bridgeporting?

Unless you are racing then why does your ego need more than 400hp?

Good - phone guys always know their stuff :smoker:

Hp is only limited mechanically by how fast you can spin the engine whilst getting an efficient burn.

Torque is another matter.

+1.

The old saying "there's no replacement for displacement". How much hp? Depends a lot on where in your powerband you want it. If having no boost in stock hp until 8K rpm, the Renny is definitely a candidate for narrow, high horsepower powerbands. The Renesis is only 1.3 liters with 6 combustion chambers on a 2 stroke (360 degree) power cycle. That's a small engine working hard to produce high numbers. At some point volumentric efficiencies drop with higher rpm because you can't run enough advance to get an efficient burn. Heat is a huge power killer, and if I had to pick a practical limiting factor in the Renesis, I would say it has to be heat. If practicality isn't an issue, you can find all manner of YouTube vids with highly boosted Rennies, but they're grenades with loose pins.

OK, OK, TORQUE then:) I guess it is best to keep below 10 k rpm, if its meant to be reliable.

He, he, see what you mean. But I'm not a big fan of writing my fingers to the bone if I can have a good chat instead. Saves everybody a lot of time.

And yeah, he knows his stuff, he is delivering up to race- spec engines.

do we have to put premium 92 93 in the rx8 or can we use 87?

Put premium, it says so on the gas cap. Also post in threads that are relevant to your question.

If horsepower is limited by RPMs, wouldn’t torque be mechanically limited primarily by the number of force-producers… aka, rotors?

there’s no replacement for common sense and a basic understanding of context.
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