How high can you rev

[Evil Result]

Well how fast does the combusting fuel expand in comparison to piston speeds...and what kind of effect does this have on horsepower/torque?

[bjdm151]

Yes in theory the ultimate limiting factor will be the rate of combuistion (speed of the flame front)(?laminar flame speed?). But, we can change the fuel chemically are change the fuel alltogethor. We also will probably never develop , have a reason to or possibly be able to, an engine that will reach the that point. Thats why the engines ability to breath at the given rpm will affect it the most.

[grovesmuk]

my 1997 civic 1.8VTi revs to 8400rpm, dial goes to 9500rpm

[Kurtdg19]

I don't believe flame speed is as important as the overal design of the engine since it only takes roughly around 3/1000th of a second for normal combutions to occur. Of coarse it is important, but your still designing the engine with and around this.

If you figure even at 6000rpm, one revolution would happen every 1/100th second. Divide that by the one (power stroke) in a 4 stroke and you have 1/400th. Unless you get over the 10k rpm mark you should be fine. Even then, you also have the ability to control the spark to fine tune the timming. This what first came into my attention as I was reading an auto tech book about normal combustion time elapse. Then shortly after; reading this thread. Valvetrain IMO would have to be close the most important, as well as maintaining constant piston acceleration in comparision with the valvetrain. Air intake and exhaust exit IMO are still equally important in the real world, but those are the easiest parts to put on so.....ha!

So what do you guys think? Does this make sense for anybody out there who has a lot more knowledge about the physics of an engine than I do?

[Evil Result]

Rod to stroke ratio... that whole effect.

large ratio, low top and bottom piston acceleration but faster mid stroke piston speeds. helps decrease peak piston speeds, reduces side wall loading and engine friction, there for increasing the life span of the engine.

small ratio. high top and bottom piston acc but slower mid stroke. increased peak piston speeds, increased side wall laoding and engine friction, decreased engine life.... anyways read this.

Rod angularity

[TheSilentChamber]

I'v had my strait 6 to 9500 before the valves started floating.